YAMAHA YL1 100cc TWINJET - Original and still in use today!

[arndtwc]

I was suprised there is no smoke. These were always heavy smokers that I remember.

[rosscoYL1]

@arndtwc

You are right ..there's not much smoke nowadays! Back in the 70's we had lead in the fuel as well as pretty basic detergent type 2 stroke oil. It was a greeny blue that certainly did leave a smokey blue trail from the exhausts! Todays 2 stroke motor oil is a far superior product and with no lead in the fuel results in a much cleaner burn, you can still smell the familair 2 stroke smell but the smokey blue exhaust has gone! This certainly keeps the spark plugs running better as well!

[twostrokeornill1]

@arndtwc  What fine things modern day synthetic oils can do.

[rosscoYL1]

Yes this bike has been a survivor! So much so I have restored a YL1 of my own back to brand new condition, see my other videos!

[gilbertsonscott]

Beautiful look and sound.

[oldmanmille]

I had a red one as my first bike in 1971 and paid £40 for it - wish I still had it!

[vinnothelizard]

good bike , had one but always giving trouble!!! the bikes today are a different class!!! wish they had them when i was young!!!

[bigkitten]

OMG! I had a 1967 model back in 1977...fantastic little bike!

[DocDazzler]

Wow, awesome childhood memories are coming back. My dad had one of these. As a small child, I thought it was a huge bike... LOL. I remember it haveing a center stand. I would sit on it for hours. My love of motorcycles was born (especially Yamaha).

Thanks for posting this. I hope to get an FZ1 soon, but I'll always remember this bike :)

[natequmi]

Nice speciman from the golden age of Japanese bikes. I owned a '67 identical to this one with the exception of a black/white seat similar to the 305.I loved that little rascal,and it would scat.Thanks for the memory.

[rutkowsky1000]

you have any pics of your bikethanks for your help i am pretty sure on what the reading should be i confirmed it with my buddy thanks for your help

[rosscoYL1]

You can see a few pics of my YL1 at yamaparts

[rutkowsky1000]

hi what i meant was i want to check compression on heads now what should the reading be on compression tester is what i meant thanks

[rosscoYL1]

OK, you may be better to check with your local Yamaha dealer as regards to the compression reading you should get on a 2 stroke engine. I fitted new cylinders, pistons and rings to my YL1 so I haven't ever used a compression tester.

You can feel the compression ofcourse if you slowly kick start the bike. Sorry can't be of any further help.

[rutkowsky1000]

hi just woundering if you no what the proper compression reading is on those 100cc bikes thanks john rutkowsky

[rosscoYL1]

Hi John, compression ratio is listed at 7.1:1 in the workshop manual for the YL1 .

[rosscoYL1]

This YL1 was one of the last of the models produced, it would be round 1971 but it wasn't registered here for the road until 1973. This bike was lent to me to take out for a ride, I own an earlier 1968 YL1 twin in Peacock Blue and Silver. The LS2 100cc twin replaced this model in 1972.

[rutkowsky1000]

hi what year is the bike i am buying one all original only difference between your and mine is the colour yours is blue mine is red mine is a 1971 model what year is yours bye

[tpvalley]

Yamaha did a race kit for these bikes that made 18bhp, it was expansion chambers, cylinders/pistons and carbs and maybe ignition and crank cant recall.

[haddles2000]

Yes they did. I have a set. There were single ring pistons, ported barrels, heads, bigger carbs with no oil injection and exhausts. Shame I don't have the bike to go with it. I have the later 100 LS2 which it won't fit.

[tpvalley]

I'd love to see the port arrangement.

do they have a bridged exhaust?

how many transfer ports?

[haddles2000]

check your mail. I've tried to take some photos but hard to focus down a small barrel.

[pugscustom]

I am restoring a LS1. Is there any chance you would part with your race kit.

Thanks for your consideration