ysr 50 to yscr 250r motor swap first test ride

Finally have the bike all mocked together for testing to see what needs changed only to find out someone had drilled main jet in carb waaaaaay too big and it ran like total crap.

Category:

Autos & Vehicles

Tags:

• ysr
• cr250
• derbi
• pocket
• bike

[82mnbvcxz]

im just saying...why put all that effort into a motor swap if youre going to do it wrong?

[sporkbiking]

@82mnbvcxz I understand your point, but the purpose of this was for testing. At the time it didn't have the room for an expansion chamber. It now has one and is better, but still not right and I haven't had time to do more with it. This is one of about six billion projects I have going on so It has been sitting collecting dust till I feel like messing with it again.

[82mnbvcxz]

You dumbass! The reason it runs like shit is because you cut the expansion chamber off the muffler and welded a straight tube on it. 2strokes need that expansion chamber to run properly. Without the expansion chamber, the motor will run horribly and have no power like it does on your bike. And it also looks like youre running way too rich oil mixture judging by the huge white cloud of smoke...

[sporkbiking]

@82mnbvcxz You're so smart! I envy you, and i'm sure I speak for everyone that your brilliance just casts a huge shadow over the rest of us feeble minded commoners!

[honeybunchickens]

I believe its a 250 but damm! that engine needs some serious adjustments. Nice build by the way.

[sporkbiking]

@honeybunchickens I still haven't had the time to mess with it much since then. Did some sprocket tweeks and pipe tweaks which made a huge difference, yet it still runs like dog shit. Does hit near 90mph currently.

It's somewhere around 290cc due to 74mm eddie sanders racing stroker crank, and big bore ported/polish kit.

[Diaz1015]

Its the dam crank seals jeez bro change em out & rip it....

[82mnbvcxz]

@sporkbiking ok fair enough. good luck with it

[marcusrusek]

cool !! post more