1st or all i have a kx 85 i was wondering if you have to remove all of the parts u did like the gas tank , etc. 2 nd how would u go about the kips valve it looks diferent than the power valve on this bike 3rd if u said a mechanic could do this in an hour or so and they charge by the hour why do they charge you for like 3 hours or more
make sure to clean the power valve and reeds.....oil cakes on the powervalve and is not good......use brake clean.....but keep it away from any gaskets
i do my rebuild on my kx 250 and my 85 125 with out removing the head. leave it on and remove the four cyclinder nuts and take it out as one part. save cash on the over priced head gasget. try it it works on most 2-stroke bikes!
Video's are very well made by this Man. Really helps me to understand how all of the top end is done. Thanks. & I rebuilt my top end the same way you done it & All works fine. Never Looked Back :)
today when i was driving my ktm 125 it started to bogg down, i turned it off and it wouldnt start,i put a new spark plug in, it started on the push start but when i tried to hit the powervalve it still wouldnt take of.. when i drived it again it would still be bogging out any ideas?
what would you say "low compression" is on a 250 2 stroke i hear of them being up at 190 and stuff on newer top ends but ive heard of that being a hi compression piston and 160 is average. i know 130 was bottom line on my 2000 yz 125. if they have a same or close compression ratio the psi readings would be the same right?
@crimson22s - on some bikes you can. Some bikes have to have the head off to get the cylinder out (it will hit the frame otherwise). I would pull the head either way though. It is usually a good idea to hone the cylinder.
It doesn't matter. The point is to allow to piston to get broken in. Do whatever you want just warm the bike up and keep the RPM's low. Do three fifteen minute cycles
i got a 79rm 400 it has 70psi. im assuming piston and rings. Do i need a special piston or will they all be the same for the bike. because i herd something about a sleve before and the original piston might not be big or something like that. What do you think? is it true that the original new piston might not work?
@RockyMountainATVMC Would I be able to follow this video for my Honda? Or does this only cover Yamaha? Also, my kickstarter won't go down, does that mean I need an new piston?
@tattddeb - The honda is very similar. This video and a little common sense should do the trick. having a service manual makes life easier too. Regarding your kickstarter, it could be several things. you need to take it apart to see what is going on.
@honda1296 - if you installed the correct piston and ring, it would have been real hard to getthe cylinder on the piston if the rings weren't lined up right.
hello, this may sound retarded but i bought my bike taken apart and i was in the process of repairing it. can you tell me how to install rod thingy thats part of the powervalve assembly?
i freeking love you. im a uni studend and dont have the money to pay a mechanic to fix my bike so its been sittin in m back yard for months and now thanks to you i have fixed it your awesome
hi i have a 2006 rm85...when i give it gas there is no power...no matter what gear im in...do i need a new top end?or what? also... it smokes quite a bit...
@hulkbond1 - try starting it first! Just kidding. It is hard to say what is going on with the lack of info, but make sure your carb is clean and that you have no blockage in your exhaust or intake.
@RockyMountainATVMC i was told by your online chat that it might be the reeds...welli have orded from you guys in the past and hope to order more...also the video is going to help when i have to rebuild my top end :(
i have a 2001 cr125r and it runs like shit, mine is always fuckin boggin when i twist the throttle real quick when im puttin around, is it supposed to do that, what could cause all this bogging??? and when i rev it out it dont sound smooth like this one does in the video, what do i need to do to make it run perfect, and smooth, and NO BOGGIN??
what kind of piston do u recomend i bougtht a namura piston for my 2000 yz125 and dont know how good they r and i bought it its a 54mm but a motorcycle shop said i need a 54.05mm oversize idk if the one i got well work it fits in good not as much play????
@mattycmx3 if you cant tourque it down, go with snug or just past depent on how muscular you are and if you strip bolts often or if you have a problem with not tightening them enough, haha
@aLexuNitFmX - A mechanism that opens and closes to keep the exhaust ports smaller at low RPMs and bigger at higher RPMs to make the most usable power throughout the RPM range.
@Yamahayz2502t - refer to the inspection guide line in the manual. If there are obvious scratches or wear then you need to. if it looks good you may need to measure the bore and the piston (refer to manual). The rings should be changed every so many hours regardless (refer to manual).
hey i need help i got a little coolant down in my crank and i tiped my bike over for a long time and let it run out i also got a bit of premix in there is my crank gonna break should i sell my bike or will it not be that big of a deal i cant affored to pull it apart for sure just looking for help thank you
hey i have a little bit of play with my piston will that casue my bike not to run like it runs when i bump start but when i kick it over nothing any suggestions could it be my seals in my botttom end?
@honda1296 - I am not certain what thing you are talking about, but I think you are refering to the holder. we just used an allen wrench. Yamaha puts this there so you don't put stress on the powervalve when you remove or tighten the bolt.
@jjlew06 - I don't suggest hitting it with a hammer. you are putting stress on the rod and you could bend it. use a piston pin puller instead. We sell the Motion Pro.
looks fairly simple to do. im just a little worried about the ring end gap size. why would it be to small in the first place if the piston manufature made it for that bike?
@crimson22s its just to double check before you get it all the way together. its the same concept of spark plug gaps some people just throw em in and 99 percent of the time there correct but you usally check the gap. and when its something as important as a top end i would check takes 30 seconds save you in the long run but yes they should be correct
NIce video, i have a 2000 yz250 and it leaks burnt up premix oil out of the seal that is on the power valve pivot rod...just behind the nut you took off on the pv linkage...? is can i do this seal from the out side or do i have to pull the power valve apart or take top end off??? Thanks i also used your fork seal video everything went well just like your video!
@04CHEV - Unfortunatly you have to take the powervalve apart in order to get to that seal. That means pulling the cylinder out of the frame. I always put a new seal in whether it needs it or not when I have the top end apart. The Tusk top-end gasket kit comes with the seal.
awesome vid its good help. when you do a top end. on the piston there is 2 rings do you have to measure both rings and adjust them in needed. and dose the rings have to go in order like theres a one for bottom and top or can you use any?? also to youtubers and rocky mountain what is better a long or short pipe for a 2 stroke 125 like whatsthe performance diffrents cheeeers :)
i have a question about my quad. i have a 2002 grizzly 660 and when im driving it, when its in a high rpm and I let go of the throttle to slow down it pops or back fires. is due to bad exhaust gaskets?
I have never done anything like this before, but I am replacing the cylinder and piston on my Motorhispania Furia... What should I be aware of and pay special attention to my first time?
awsome ordered my parts on monday arrived Thursday to newzealand , mega fast shipping , really cheap prices , everythings here so satisfied with the order DEFINITELY buying from you guys again , cant wait to start on my top end now
hey i wanna rebuild my top end on my 98 cr 125, do you have to do that power valve thing, also how do you tell or how long for the bike to brake in.... and do you have to go slow with low revs until it breakes in?? thanks
@aazz0099z - what powervalve thing? It needs to be unhooked from the bottem end or you wont get the cylinder off. I would just ride it slowly the first few times in 10-15 minute steps.
hi i have an 06 yz85 does that have a power valve because i have never seen anything like that in the bike... also i was wondering if there are any ways you can tell if the piston and rings need to be replaced without taking the cylinder off
Hi! I've got a yz 125 and i must change the piston,cylinder is a B and I brought it in a center Specialized workshop for measure it. Technicals have seen fit to polishing the cylinder.They then measured 54.03mm-2.1272in. I must put B or C prox piston? How accurate is the measurement? The polishing did take away some material? Many many thanks and sorry for the many words
on the rubber seal for the power valve housing cover, is it okay that its kinda squishy and loose in there, the seal is pretty damn new and installed correct but i notice its kind of loose in there?
Do you put grease on the o-rings to get them to stay in the top-end grooves? I always have a heck of a time keeping them in place when putting the top end back together.
@MrQuadracerkid1 - You don't want to strip anything, and you don't want to lose bolts either. your manual will have specific torque settings for each bolt. It never hurts to check.
@RockyMountainATVMC alright man thanks a lot, im kinda new to all this stuff and i want to do the top end on my lt250r so i wanna get all the info i can
hey i wanna know if you can lose compression of your engine when your expansion chamber is loose (the spring broke) my bike has virtually no compression its a yz100 it feels like a kickstarting scooter almost
is it bad that i drained my oil for a rebuild like 2-3 months ago, and i havent gotten to it? i put rags in every hole i could find, and i kinked the case vent tube. i jus wanna know if its gonna rust er somethin like that
very good video, was doubting that i could rebuild my yz 125 but now that i watch this video i think i can do it but before i tear into it i want to get your input i think it is a seized piston i was riding for 10 mins at high rev and the back wheel locked and before that it felt like it was losing power like power band was cuttin in an out then it locked up i tried to kick start it and couldnt get it to budge then i broke the kick start due to it not kickin down sound like seized piston to u?
@RockyMountainATVMC actually im thinkin it is a tranny problem now. i took the top end off and the piston still wont move. im thinking maybe something with the gears. oh well. with your imformative videos im pretty sure i can get her fixed up!!!
because i have a cr125 and i keep getting black oil on my plug and it only starts for 5 or 6 secongs and then boggs out and turns off . then when i take my plug out i has no spark and the i clean it off and it starts and does the same thing
i dont no if it has bad ring or what
but it has an fmf rev pipe if that has anything to do with it
@46000rpm hey with 2 strokes when you do not rev them hard enough the plugs foul im not machanic ( yet) but yeah its could be the oil i got a cr 125 and got told by a motorcyle place that the oil ration is 40:1 which means 40 leters of petrol to 1 leter of oil.. but buy a new plugg change the oil ratio to 40:1 and take your biek out somewre liek a moto track or somewere big and give her some high revs. and ride it hard. also let it warm up ( idle ) for about 5 minutes. am i right rockymoutain??
i had my cr125 going yesterday and today because i got a new spark plug. but now i fouled the plug again. what am i doing wrongi only had it for 2 days . i dont ride it super hard because there is alot of ice so i cant go fast i can bearly heat the engine to hot. i fun 32:1 gas mixture.
i had my bike going yesterday and today because i got a new spark plug. but now i fouled the plug again. what am i doing wrong. i dont ride it super hard because there is alot of ice so i cant go fast i can bearly heat the engine to hot. i fun 32:1 gas mixture.
@MyHamburgerhelper - you are most likely running too rich on your carb jetting. This especially happens at lower rpms. You most likely need a leaner pilot jet and possibly need to drop the needle.
I did this on my cr 250 and everything was fine I went just cruising around for 3-4 hours with out getting into it at all but then I went our to a local track to go riding and after an hour I really started getting into it and it did fine for half the day but after that I would come out of the corners it is like the choke is on and it keeps cutting out. It hits the powerband nice but then again in to top end it seems like it is just cutting out and wont stay wide open any ideas?
hi, i have a 1989 kx80 and i want to do the piston and rings! but when im ridin, an i start to go fast, an hit the power band, it raises the rpms rlly high, an it rips in a wheelie! is there something wrong, or is that normal?
i don't get why you remove subframe ?
d4nnyboy1986 1 day ago
I don't even own a 2 stroke but I watched the whole video anyway...
BlanchProductions 1 week ago
This is a great video thank you so much ... Y'all are great
Anthonybentel1 1 week ago
to many screws and bolts
lgwillie 2 weeks ago
awesome videos guys
glxdinamii24 2 weeks ago
I forgot to order a needle bearing for the crank. Is it important to replace that during every rebuild? This one has 35 hours on it.
MxRider721 2 weeks ago
if you are running premix instead of using the oil pump is it better to leave the oil pump throttle cable attached or to disconnect it?
outdoorsman310 2 weeks ago
1st or all i have a kx 85 i was wondering if you have to remove all of the parts u did like the gas tank , etc. 2 nd how would u go about the kips valve it looks diferent than the power valve on this bike 3rd if u said a mechanic could do this in an hour or so and they charge by the hour why do they charge you for like 3 hours or more
20mm1 4 weeks ago
@20mm1 If you were getting paid for labor by the hour, you would be foolish to go as fast as possible.
W1NDOWS7myIDEA 1 week ago
how long does it actually take to do this?
tyhudson989 1 month ago
@tyhudson989 - it depends on the bike and person doing it. This bike can be done in an hour or so.
RockyMountainATVMC 1 month ago
@tyhudson989
surferman29 3 weeks ago
make sure to clean the power valve and reeds.....oil cakes on the powervalve and is not good......use brake clean.....but keep it away from any gaskets
gnarlyanimal 1 month ago
i do my rebuild on my kx 250 and my 85 125 with out removing the head. leave it on and remove the four cyclinder nuts and take it out as one part. save cash on the over priced head gasget. try it it works on most 2-stroke bikes!
GUNBUNNY2BG4U 1 month ago in playlist motorcycle repair
Nice work! Where's the Clymer manual? 4 1/2 stars in our website's reviews!
ClymerManuals 1 month ago
@ClymerManuals - We stock your manuals
RockyMountainATVMC 1 month ago
Video's are very well made by this Man. Really helps me to understand how all of the top end is done. Thanks. & I rebuilt my top end the same way you done it & All works fine. Never Looked Back :)
400exjason 1 month ago
@400exjason - Thanks! Good job on the rebuild.
RockyMountainATVMC 1 month ago
I really liked your video I watched like 10 to 15 videos and yours was the best so far thanks
carlito199322 1 month ago
Very nice video. You explain everything very well and not too fast!
NITROLLATOR 2 months ago
today when i was driving my ktm 125 it started to bogg down, i turned it off and it wouldnt start,i put a new spark plug in, it started on the push start but when i tried to hit the powervalve it still wouldnt take of.. when i drived it again it would still be bogging out any ideas?
themadbuzzer 2 months ago
what would you say "low compression" is on a 250 2 stroke i hear of them being up at 190 and stuff on newer top ends but ive heard of that being a hi compression piston and 160 is average. i know 130 was bottom line on my 2000 yz 125. if they have a same or close compression ratio the psi readings would be the same right?
jlcyamaha 2 months ago
@jlcyamaha - there are several factors to condider - bike, altitude, etc. I would recomend checking the service manual.
RockyMountainATVMC 2 months ago
if i blew my top end would i have to bore it out? because i could do this but i just need to know if theres any way the cylinder could be damaged
evilchez666 2 months ago
@evilchez666 - There is no way of knowing until you take it apart and inspect the cylinder.
RockyMountainATVMC 2 months ago
if i want to install a 70cc cylinder in my 50cc moped, is this the way to do it ?
MrChrislur 3 months ago
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@MrChrislur Yes, inbox me if you need help.
MrGiftedRyu 2 months ago
do you even have to take the head off?? cant you just check the ring gap on the bottom of the cylinder
crimson22s 4 months ago
@crimson22s - on some bikes you can. Some bikes have to have the head off to get the cylinder out (it will hit the frame otherwise). I would pull the head either way though. It is usually a good idea to hone the cylinder.
RockyMountainATVMC 4 months ago
do you warm it up during break in by riding it easily or just letting it idle with low revs?
madinolfi04 5 months ago
@madinolfi04
It doesn't matter. The point is to allow to piston to get broken in. Do whatever you want just warm the bike up and keep the RPM's low. Do three fifteen minute cycles
MxRider721 5 months ago
@MxRider721 - good advice!
RockyMountainATVMC 5 months ago
i got a 79rm 400 it has 70psi. im assuming piston and rings. Do i need a special piston or will they all be the same for the bike. because i herd something about a sleve before and the original piston might not be big or something like that. What do you think? is it true that the original new piston might not work?
bradleylariviere 5 months ago
What is the best way to break in the top end after a fresh rebuild?
OffroadBeaver 5 months ago
@OffroadBeaver - a few 15 minute cycles of warming it up and cooling it off.
RockyMountainATVMC 5 months ago
@RockyMountainATVMC to the 15 minute cycles to break it in thing, is that for the rings if i were to replace them only?
landonu12 3 months ago
@landonu12 - It doesn't hurt. One cycle should be fine.
RockyMountainATVMC 3 months ago
Im doing a rebuild on a 96 rm 125 , do i really have to remove or dissasemble the power valve ?
jruba 5 months ago
@jruba - you don't have to, but if it looks like it could use a cleaning, then I would do it.
RockyMountainATVMC 5 months ago
can i just use wd-40 and not raw premix for my tri-z 250?
Pavone30 5 months ago
Comment removed
Pavone30 5 months ago
take the rad hose off before you take out the spark plug. just a little advice
swss12 5 months ago
I once forgot to refill the radiator. Got a good 5 minutes out of the new top end.
StevoDisaster 5 months ago 2
@StevoDisaster Oh man that sucks
johndeere445 5 months ago
How do the coolant run through the engine? does it go directly into the piston barrel or does it go in little chambers around the barrel?
UnitFmX11 6 months ago
@UnitFmX11 - chambers around the barrel. If it went into where the piston is, it would go out the exhaust pipe.
RockyMountainATVMC 6 months ago
@RockyMountainATVMC Would I be able to follow this video for my Honda? Or does this only cover Yamaha? Also, my kickstarter won't go down, does that mean I need an new piston?
tattddeb 5 months ago
@tattddeb - The honda is very similar. This video and a little common sense should do the trick. having a service manual makes life easier too. Regarding your kickstarter, it could be several things. you need to take it apart to see what is going on.
RockyMountainATVMC 5 months ago
@RockyMountainATVMC Ok thanks (:
tattddeb 5 months ago
is this the same for an 04 yz 125?
RImotocross07 6 months ago
What specific oil would you use to lube everything up the "raw premix" Cause if im gonna do this im doing it right
gavinabcdefghi 6 months ago
how many hours were on the piston before you put the piston in
Hungovercheese 6 months ago
@Hungovercheese - Not sure on that bike. It was a friends bike.
RockyMountainATVMC 6 months ago
no piston ring compressor ??
LORDDis0FFICIAL 6 months ago
Jeeze finally someone with simple videos that get to the point! Thanks RMATVMC!
Rhino179 6 months ago
great vid i jus dont quite get the steps with the rings
acdc2197 6 months ago
the subframe doesnt need to be taken off.
justyoustupid 6 months ago
@justyoustupid - you are right! but It makes things easier (and easier to see on a video!)
RockyMountainATVMC 6 months ago
@RockyMountainATVMC just thought i might throw that out there so people save some time
justyoustupid 6 months ago
@honda1296 - if you installed the correct piston and ring, it would have been real hard to getthe cylinder on the piston if the rings weren't lined up right.
RockyMountainATVMC 7 months ago
Great video! What bike is that? 05 yz 250?
seadoolover360 7 months ago
@seadoolover360 - close! It is an 04. The 05 was the first year with the aluminum frame.
RockyMountainATVMC 7 months ago
@honda1296 - points at the exhaust.
RockyMountainATVMC 7 months ago
hello, this may sound retarded but i bought my bike taken apart and i was in the process of repairing it. can you tell me how to install rod thingy thats part of the powervalve assembly?
gehennamaggot666 7 months ago
@gehennamaggot666 - i would suggest getting a service manual specific for your machine.
RockyMountainATVMC 7 months ago
simple
1991tommygun 7 months ago
i freeking love you. im a uni studend and dont have the money to pay a mechanic to fix my bike so its been sittin in m back yard for months and now thanks to you i have fixed it your awesome
mrrefereeman 7 months ago
wish i had a torque wrench built into my arm ;-P
BowHunt1229 7 months ago
hi i have a 2006 rm85...when i give it gas there is no power...no matter what gear im in...do i need a new top end?or what? also... it smokes quite a bit...
hulkbond1 7 months ago
@hulkbond1 - try starting it first! Just kidding. It is hard to say what is going on with the lack of info, but make sure your carb is clean and that you have no blockage in your exhaust or intake.
RockyMountainATVMC 7 months ago
@RockyMountainATVMC i was told by your online chat that it might be the reeds...welli have orded from you guys in the past and hope to order more...also the video is going to help when i have to rebuild my top end :(
hulkbond1 7 months ago
@hulkbond1 Clutch need new its not disengaging
HitmarkerPro 7 months ago
hi i have a 2006 rm85...when i give it gas there is no power...no matter what gear im in...do i need a new top end?or what?
hulkbond1 7 months ago
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i have a 2001 cr125r and it runs like shit, mine is always fuckin boggin when i twist the throttle real quick when im puttin around, is it supposed to do that, what could cause all this bogging??? and when i rev it out it dont sound smooth like this one does in the video, what do i need to do to make it run perfect, and smooth, and NO BOGGIN??
jeremybrown1942 7 months ago
what kind of piston do u recomend i bougtht a namura piston for my 2000 yz125 and dont know how good they r and i bought it its a 54mm but a motorcycle shop said i need a 54.05mm oversize idk if the one i got well work it fits in good not as much play????
yzer125derrick 7 months ago
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why do u need antifreeze?
konRAD4395 7 months ago
why antifreeze?
konRAD4395 7 months ago
hey how do you know if your power valve is broke
XxAnthonyxX4 7 months ago
@XxAnthonyxX4 - I guess if you see broken parts you know it is broke. If it isn't working you can conclude something is wrong.
RockyMountainATVMC 7 months ago
@RockyMountainATVMC okay do you mean like wont start or wont Run normal? and i have an 06 rm85.
drjays223 7 months ago
@drjays223 - It depends i suppose. If it is stuck, it will still run - just not as good as it should.
RockyMountainATVMC 7 months ago
@RockyMountainATVMC okay thanks really helped
drjays223 7 months ago
how tight does the spark plug need to be,would it damage the head if you over tighten ?
mattycmx3 8 months ago
@mattycmx3 - refer to the torque settings in your manual. Yes you could strip the threads.
RockyMountainATVMC 8 months ago
@mattycmx3 get it as tight as you can with your fingers, then just snug it
oSHOLLIVERo 7 months ago
@mattycmx3 if you cant tourque it down, go with snug or just past depent on how muscular you are and if you strip bolts often or if you have a problem with not tightening them enough, haha
jdirtbiker1 7 months ago
Whats a power-valve ?
aLexuNitFmX 8 months ago
@aLexuNitFmX - A mechanism that opens and closes to keep the exhaust ports smaller at low RPMs and bigger at higher RPMs to make the most usable power throughout the RPM range.
RockyMountainATVMC 8 months ago
one of THE BEST videos on the internet. Thanks!
MeetTheMattsons 8 months ago
K thanks alot
Yamahayz2502t 8 months ago
Oh and how do i know if it needs a new piston and rings
Yamahayz2502t 8 months ago
@Yamahayz2502t - refer to the inspection guide line in the manual. If there are obvious scratches or wear then you need to. if it looks good you may need to measure the bore and the piston (refer to manual). The rings should be changed every so many hours regardless (refer to manual).
RockyMountainATVMC 8 months ago
@Yamahayz2502t also if you notice a loss of compression it may be time to rebuild it(i am doing mine right now lol)
rider412719 8 months ago
I have a 1999 yamaha yz 250 could i get a manual from you
Yamahayz2502t 8 months ago
hey i need help i got a little coolant down in my crank and i tiped my bike over for a long time and let it run out i also got a bit of premix in there is my crank gonna break should i sell my bike or will it not be that big of a deal i cant affored to pull it apart for sure just looking for help thank you
Slyder1212 8 months ago
Hey Great Video, i have a 2000 KX 125 thats due for a top end, it has the KIPS system does this make it harder to do the top end?
cummins92bankspower 8 months ago
could i replace just rings and not the head?
vincent12225 8 months ago
hey i have a little bit of play with my piston will that casue my bike not to run like it runs when i bump start but when i kick it over nothing any suggestions could it be my seals in my botttom end?
gujada9776 8 months ago
@honda1296 - If you have a YZ250, yes.
RockyMountainATVMC 8 months ago
@honda1296 - I am not certain what thing you are talking about, but I think you are refering to the holder. we just used an allen wrench. Yamaha puts this there so you don't put stress on the powervalve when you remove or tighten the bolt.
RockyMountainATVMC 8 months ago
how much does this cost
YZ125ups 9 months ago
can you reuse gaskets and o rings?
littleseanx 9 months ago
Dont you need to put premix oil on the piston skirt and cylinder
markr977 9 months ago
@markr977 - i do. it can't hurt.
RockyMountainATVMC 9 months ago
Hey my wristpin wont "go in" when im ready to put the piston on the rod it wont go through the uncirclipped side of the piston? HELLpppp!
Rm125MX14 9 months ago
@Rm125MX14 - make sure there are no burs in the piston where the circlip groove is cut. Make sure you have the correct wrist pin.
RockyMountainATVMC 9 months ago
what if the rist pin wont come out i tried everything it wont come out i took the 2 clips off idk i even tried silicon
sniperpr0100 9 months ago
@sniperpr0100 i couldent get mine out, so i put a socket in just like the vid but i hit it with a hammer to get it out.
jjlew06 9 months ago
@jjlew06 - I don't suggest hitting it with a hammer. you are putting stress on the rod and you could bend it. use a piston pin puller instead. We sell the Motion Pro.
RockyMountainATVMC 9 months ago
If I do a complete motor rebuild (top-end and bottom-end), will my bike be faster? What company makes the highest-performance motor kits?
125CRYZ 9 months ago
good ol craftsman socket wrench. i got the same 1,no need 4 an expensive snap on brand thats gonna last just as long as a craftsman
jlinn91 9 months ago
looks fairly simple to do. im just a little worried about the ring end gap size. why would it be to small in the first place if the piston manufature made it for that bike?
crimson22s 9 months ago
@crimson22s its just to double check before you get it all the way together. its the same concept of spark plug gaps some people just throw em in and 99 percent of the time there correct but you usally check the gap. and when its something as important as a top end i would check takes 30 seconds save you in the long run but yes they should be correct
Rm125m 9 months ago
so do you dont need to to put oil on the ring/ cylinder wall?
brettmjones 9 months ago
@brettmjones - We put oil on the cyclinder wall at 6:25
RockyMountainATVMC 9 months ago
@brettmjones - We put oil on the cylinder wall at 6:25
RockyMountainATVMC 9 months ago
how do i tell if my piston is standard or not?
yz100f 9 months ago
NIce video, i have a 2000 yz250 and it leaks burnt up premix oil out of the seal that is on the power valve pivot rod...just behind the nut you took off on the pv linkage...? is can i do this seal from the out side or do i have to pull the power valve apart or take top end off??? Thanks i also used your fork seal video everything went well just like your video!
04CHEV 10 months ago
@04CHEV - Unfortunatly you have to take the powervalve apart in order to get to that seal. That means pulling the cylinder out of the frame. I always put a new seal in whether it needs it or not when I have the top end apart. The Tusk top-end gasket kit comes with the seal.
RockyMountainATVMC 10 months ago
awesome vid its good help. when you do a top end. on the piston there is 2 rings do you have to measure both rings and adjust them in needed. and dose the rings have to go in order like theres a one for bottom and top or can you use any?? also to youtubers and rocky mountain what is better a long or short pipe for a 2 stroke 125 like whatsthe performance diffrents cheeeers :)
bigboxingmike 10 months ago
i have a question about my quad. i have a 2002 grizzly 660 and when im driving it, when its in a high rpm and I let go of the throttle to slow down it pops or back fires. is due to bad exhaust gaskets?
raptorandblaster 10 months ago
@raptorandblaster - it could be a lean air/fuel mixture. Are you running an aftermarket pipe?
RockyMountainATVMC 10 months ago
@RockyMountainATVMC no the quad is all stock. i just changed the oilfilter,oil, airfilter. when i start it it smokes a lot.
raptorandblaster 10 months ago
How do I empty out the cooling system?
I have never done anything like this before, but I am replacing the cylinder and piston on my Motorhispania Furia... What should I be aware of and pay special attention to my first time?
TheEastSniper 10 months ago
@TheEastSniper - there is usaually a drain plug on the water pump cover. i have never even heard of a Motorhispania Furia!
RockyMountainATVMC 10 months ago
What was the stuff you were putting on the rod bearing?
markr977 10 months ago
awsome ordered my parts on monday arrived Thursday to newzealand , mega fast shipping , really cheap prices , everythings here so satisfied with the order DEFINITELY buying from you guys again , cant wait to start on my top end now
meallmemx123 10 months ago
@meallmemx123 - Great! Thanks for the feedback!
RockyMountainATVMC 10 months ago
what happens if we scratch the top of the piston?
since there is already numbers stamped into it, (among other things) what does a scratch do?
and another great video, you guys make everything look so easy.
thanks.
laptopdragon 10 months ago
@laptopdragon - a scratch on top won't hurt anything.
RockyMountainATVMC 10 months ago
hey i wanna rebuild my top end on my 98 cr 125, do you have to do that power valve thing, also how do you tell or how long for the bike to brake in.... and do you have to go slow with low revs until it breakes in?? thanks
aazz0099z 10 months ago
@aazz0099z - what powervalve thing? It needs to be unhooked from the bottem end or you wont get the cylinder off. I would just ride it slowly the first few times in 10-15 minute steps.
RockyMountainATVMC 10 months ago
hi i have an 06 yz85 does that have a power valve because i have never seen anything like that in the bike... also i was wondering if there are any ways you can tell if the piston and rings need to be replaced without taking the cylinder off
thanks alot
drider365 10 months ago
@drider365 - sometimes you can't tell until it is too late. i would pull it apart and change it as often as the manual says.
RockyMountainATVMC 10 months ago
@drider365 - No it does not have a power valve, which makes it that much easier to rebuild!
RockyMountainATVMC 10 months ago
Hi! I've got a yz 125 and i must change the piston,cylinder is a B and I brought it in a center Specialized workshop for measure it. Technicals have seen fit to polishing the cylinder.They then measured 54.03mm-2.1272in. I must put B or C prox piston? How accurate is the measurement? The polishing did take away some material? Many many thanks and sorry for the many words
loop1612 11 months ago
@loop1612 - A,b,c,d piston on Yamahas are only a hair different. Most magazines in the industry will recomoned running the D in any used cylinder.
RockyMountainATVMC 10 months ago
very nice vid man
85bigred250 11 months ago
on the rubber seal for the power valve housing cover, is it okay that its kinda squishy and loose in there, the seal is pretty damn new and installed correct but i notice its kind of loose in there?
jarm250 11 months ago
@jarm250 - Just make sure it isn't leaking.
RockyMountainATVMC 11 months ago
Do you put grease on the o-rings to get them to stay in the top-end grooves? I always have a heck of a time keeping them in place when putting the top end back together.
jmicm13 11 months ago
@jmicm13 - sometimes I will. That can certainly help.
RockyMountainATVMC 11 months ago
Piece of cake
TeoZMuff313 11 months ago
when u said to return to your manual for tourchage ( cant spell) is that for the bolts? if so what does that effect if its not spot on?
MrQuadracerkid1 11 months ago
@MrQuadracerkid1 - You don't want to strip anything, and you don't want to lose bolts either. your manual will have specific torque settings for each bolt. It never hurts to check.
RockyMountainATVMC 11 months ago
@RockyMountainATVMC alright man thanks a lot, im kinda new to all this stuff and i want to do the top end on my lt250r so i wanna get all the info i can
MrQuadracerkid1 11 months ago
hey i wanna know if you can lose compression of your engine when your expansion chamber is loose (the spring broke) my bike has virtually no compression its a yz100 it feels like a kickstarting scooter almost
davison1021 11 months ago
@davison1021 - the pipe has nothing to do with compression. Coompression is all in the cylinder.
RockyMountainATVMC 11 months ago
is it bad that i drained my oil for a rebuild like 2-3 months ago, and i havent gotten to it? i put rags in every hole i could find, and i kinked the case vent tube. i jus wanna know if its gonna rust er somethin like that
paratrev 1 year ago
@paratrev - I would think you would be fine.
RockyMountainATVMC 1 year ago
@RockyMountainATVMC o thank jesus i did not wanna open up the bottom end lol.
paratrev 1 year ago
im going to rebuild my 1983 honda atc 250r. 250 air cooled two stroke, how much more power would i be getting
Acelaferriere 1 year ago
i actUALLY am going to take powersport mechanics and all and this actually gave me a heads up thanks mannnnnnnnn
124dirtbiker 1 year ago
what do you mean by raw premix??
MattyTeare 1 year ago
@MattyTeare - oil for your gas - that isn't mixed in your gas yet.
RockyMountainATVMC 1 year ago
hey i bought piston frm u guys got it in bike runs for like 30 seconds then makes loud clickin and dies what is it theirs no damage
yz125rider194 1 year ago
@yz125rider194 - sounds bad. I would pull it apart to see what is going on.
RockyMountainATVMC 1 year ago
@yz125rider194 Can you ride away? if not then idk but if you can, turn up your idle it might just be stalling
QualityAirsoft 11 months ago
you knoow what sucks? when you do drop the circlip in the case. lol
dirtrider1526 1 year ago
@dirtrider1526 - that does suck. I stuff a rag around the piston before I pull them to keep it from happening.
RockyMountainATVMC 1 year ago
very good video, was doubting that i could rebuild my yz 125 but now that i watch this video i think i can do it but before i tear into it i want to get your input i think it is a seized piston i was riding for 10 mins at high rev and the back wheel locked and before that it felt like it was losing power like power band was cuttin in an out then it locked up i tried to kick start it and couldnt get it to budge then i broke the kick start due to it not kickin down sound like seized piston to u?
jpcwb360 1 year ago
@jpcwb360 - sounds like it seized alright.
RockyMountainATVMC 1 year ago
@RockyMountainATVMC actually im thinkin it is a tranny problem now. i took the top end off and the piston still wont move. im thinking maybe something with the gears. oh well. with your imformative videos im pretty sure i can get her fixed up!!!
jpcwb360 1 year ago
@jpcwb360
Your botton end bearing are prob bad to happened to my rm 125
Coolrockerdude 1 year ago
@Coolrockerdude your right thats exactly what happened
jpcwb360 1 year ago
@CRF80TOP55 your a bit low, not sure what the spec is for an 06, but my 1993 yz125 is at 120psi, so should be around there
yzkx711 1 year ago
@yzkx711 i was a bit low too, this # was before my rebuild
yzkx711 1 year ago
how much would you usually charge for this process?????
stacker97 1 year ago
hi need help
because i have a cr125 and i keep getting black oil on my plug and it only starts for 5 or 6 secongs and then boggs out and turns off . then when i take my plug out i has no spark and the i clean it off and it starts and does the same thing
i dont no if it has bad ring or what
but it has an fmf rev pipe if that has anything to do with it
46000rpm 1 year ago
@46000rpm - you either have way too much oil in your gas, or your jetting is way too rich.
RockyMountainATVMC 1 year ago
@46000rpm hey with 2 strokes when you do not rev them hard enough the plugs foul im not machanic ( yet) but yeah its could be the oil i got a cr 125 and got told by a motorcyle place that the oil ration is 40:1 which means 40 leters of petrol to 1 leter of oil.. but buy a new plugg change the oil ratio to 40:1 and take your biek out somewre liek a moto track or somewere big and give her some high revs. and ride it hard. also let it warm up ( idle ) for about 5 minutes. am i right rockymoutain??
FoUrCaRaT 1 year ago
@FoUrCaRaT - yes, but the bike should not be fouling plugs if not revved hard though if the jetting is right.
RockyMountainATVMC 1 year ago
how do you raise and lower the piston
ben1996ful 1 year ago
@ben1996ful move the kick start
CaseIH232 1 year ago
This has been flagged as spam show
i had my cr125 going yesterday and today because i got a new spark plug. but now i fouled the plug again. what am i doing wrongi only had it for 2 days . i dont ride it super hard because there is alot of ice so i cant go fast i can bearly heat the engine to hot. i fun 32:1 gas mixture.
MyHamburgerhelper 1 year ago
i had my bike going yesterday and today because i got a new spark plug. but now i fouled the plug again. what am i doing wrong. i dont ride it super hard because there is alot of ice so i cant go fast i can bearly heat the engine to hot. i fun 32:1 gas mixture.
MyHamburgerhelper 1 year ago
@MyHamburgerhelper - you are most likely running too rich on your carb jetting. This especially happens at lower rpms. You most likely need a leaner pilot jet and possibly need to drop the needle.
RockyMountainATVMC 1 year ago
I did this on my cr 250 and everything was fine I went just cruising around for 3-4 hours with out getting into it at all but then I went our to a local track to go riding and after an hour I really started getting into it and it did fine for half the day but after that I would come out of the corners it is like the choke is on and it keeps cutting out. It hits the powerband nice but then again in to top end it seems like it is just cutting out and wont stay wide open any ideas?
drtrider22 1 year ago
hi, i have a 1989 kx80 and i want to do the piston and rings! but when im ridin, an i start to go fast, an hit the power band, it raises the rpms rlly high, an it rips in a wheelie! is there something wrong, or is that normal?
89KxRider 1 year ago