Picked up a project bike, 2 stroke 70 viper. Unfortunately has a chinese carb and a cone filter on it. Bike would barely start and would only idle with choke on and would not move at all. Went through the carb, pulled the jets and cleaned them with compressed air and carb cleaner. All looked good to me. Nothing really changed. Picked up the back wheels and atleast the bike would rev up but die out when given anything past half throttle. Opened up the clutch and the belt was way high on the variator, ill follow up with a pic after this post. I took front clutch apart and the sleeve (not sure whats its called) that goes through variator was pushed way in somehow so the belt couldnt even sit on it. after I reassembled it appears the belt is sitting properly however ive been in a clutch on an lt80 and when I disassembled that, the belt was sitting on a washer. In here there is no washer between the variator faces, should there be? What issue could be caused without using that washer? After I did that the bike now moves but still anything over half throttle and it wants to completely stall out. Any thoughts, dig back into the carb? The spark arrestor is removed as well.

 

Heres how it was when I opened it.

Here is how far in that sleeve was, i cant even recreate it, wondering if its just going to happen again.

Here is where a washer may go? if so, what harm will be done without it?

 

NO washer. It looks like the variator isn't sitting back far enough.
It may have got a roller flipped during installation. Do yo lean the machine on it's right side? It helps.

 

Thanks so atleast Im not missing a washer then. i got it put back together and it appears the clutch is performing as it should I was able to drive it around a bit but couldn't get over about 10mph without it wanting to stall out. Certainly not out of the woods yet. Still having trouble getting it to just idle with the choke completely off but it won't. While messing with the air and idle screws it shut off then couldn't get it started again. Wore the battery down too much from trying unfortunately and heard a kinda strange bang noise. Going to charge it up and get back in the carb even though it looked good inside.

One more concern, while messing with the carb screws, I could feel air coming from the cylinder area right by the spark plug. Noticed this shortly before the engine just died out on me. I assume thats no bueno?

 

Just charged up the battery and she fired right up again. Ran a compression test and getting just under 90psi. Can i just get a new piston/rings and gaskets? Anyone have a reputable source?

 

Never used them myself but Alpha sports are the people with regard to old E-Tons. However, 90psi isn't that bad, particularly as you loose half the compression stroke (until the piston gets past the exhaust port) on a two stroke. I would guess that the engine is running very weak, particularly as choke is needed all the time. If you can adjust the main jet needle in the throttle slide, do so and see how you go. Could be worth checking if you can get the genuine carb and airbox assembly at a reasonable price. I do sometimes just fit rings, if the bore is within tolerances (usually about 0.003") and the piston skirt not badly worn/scored.

 

Thanks, Ive been on that site, just wasn't sure it it was legit but they seam to have just about everything. I did score a used OEM card for $25, waiting on that to be shipped then rebuilt. Hunting down a stock air box as well. Also, I realized this morning, I didn't let the engine warm up before testing the compression, so I need to do that again.

 

Compression is the same, maybe barely better when warmed up @ 90psi. If the bike acts the same way whether im riding it or have the back wheels off the ground does that rule out the clutch? It wants to stall out pretty quickly even with the wheels off the ground. Could it be CDI related? the CDI does not appear to be stock either.

 

Back to the clutch which is now where I think my problem lies. With the case off I can see that the belt is as high as it can go on the variator face at 1/4 throttle. Is this typically a secondary clutch issue, maybe the spring is worn?

 

I think you need to take the clutchs off and see what's wrong.