A Puzzler for you Gearheads

[nosebag]

I got a 1980 yamaha yt125 that I cant get to run. It did run, however, when i first tried after it had sat for 15 years. I cleaned everything thoroughly, put fresh gas and spark plug in it and it has good compression and spark. I think the problem is in the ignition system(not sure). The list of mods is bigger aftermarket carb, twist throttle, aftermarket head, DG air filter, and DG pipe. It ran for a minute, then died. Now it wont run at all, even with an intoxicating amount of starting fluid. Iv'e been fighting the thing for months so this is my last try before its headed to the shop. Any help would save me a great deal of money and time. Thanks

[Tri-ZNate]

have you replaced the plug or cleaned the carb?

[nosebag]

Iv'e tried 2 different fresh plugs and have gone through the carb many times.

[atcsteve]

Fuel, air or spark!Check those and you'll find the problem.Sounds like you have fuel(starting fluid),now check your spark.If thats good check for restrictions in the air intake system.Try taking the silencer off it to start.Is it the right plug?Is the boot making good contact? Is your kill switch working right? That should keep ya busy for awhile!! Good luck!

[nosebag]

Its got a hot blue spark but you cant always tell what its like inside the cylinder. Is there a cheap way to test it? I shot the starting fluid straight into the airbox with the filter and cover removed.

[atcsteve]

Are you sure your not flooding it? It happens very easy.Try it dry then a small shot in the cyl.

[tecate kid]

I've always had better luck with premixed gas directly into the cylinder. Its not as harsh as staring fluid and it will still start good.
tecate kid

[RedRider_AK]

I agree w/ the above.