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Josh185
03-29-2013, 08:39 PM
I was riding my 125m today and I took a break and when I. Tried to start It it wouldent start. It has spark and gets gas any ideas

Badbmwbrad
03-29-2013, 08:48 PM
Gas, spark and compression is needed for the engine to start. If there's low compression then it could be the result of insufficient valve tappet clearance.

Watch for each of the valve tappets to rise fully then verify 0.003" clearance between valve tappets and rockers.

Josh185
03-29-2013, 08:59 PM
It did smoke petty bad

kb0nly
03-29-2013, 09:05 PM
Might have lost compression as it heated up, bet it starts again after it cools off.

barnett468
03-29-2013, 10:09 PM
Hello


Good info a few answers would help everyone greatly to help you determine the exact cause of your problem.

I strongly suggest not riding it until you find the cause of your smoking problem, you could do more damage to motor!


Did it suddenly start smoking just PRIOR to the no start event, like started smoking 1 hour before or had it been smoking for days?

This is important. What color was the smoke, dark black or light gray to white?

Did the smoke linger in the air or did it disappear quickly?

After it has sat at least an hour or more then without trying to start it look at your spark plug, what color is it, almost white, medium tan or black, black, black?

If it it is black is it DRY and POWDERY like dust or does it look even slightly wet and possibly slightly gooey?

Can you post a photo of your plug?

Did it suddenly start making any loud ticking noise just prior to the no start event?

Did it make unusual noise in general?

Check valve adjustment and for valves opening as badmwbrad suggested. He wants to see if your cam is going flat but probably not. Aflat cam does not cause engine smoke but the material from a worn cam can get in your oil and rings and damage them, your piston and your cylinder bore.

Do a compression test if you can, post the reading, around 115 is minimum you want. Gauges are not exact unfortunately but if your compression is like 70 then this info will help.

PLUG COLOR - ANY wetness on plug is oil irregardless of plug color is oil [not good], any dry, dry, black is excessive fuel, white is too lean.

SMOKE COLOR – Quickly dissipating dark gray/black is excessive fuel, lingering light gray/white is oil.


Hope this info helps.

barnett468
03-29-2013, 10:10 PM
Hello

Please try to answer one question at a time in line order fashion not all in one paragraph, it is easier to understand answers that way.

Thanks

Josh185
03-30-2013, 10:52 PM
The timing chain must of jumped some teeth. I took it apart fixed it and got it running

barnett468
03-30-2013, 11:18 PM
Hello

great news however this will not cause it to smoke. Did it quit smoking? The fact it jumped a tooth clearly shows that either the chain is excessively worn, the chain adjustment was incorrect and/or the chain guides are worn.

Hope this info helps