Posts
266
Joined
11/5/2018
Location
Uhrichsville, OH
US
bierbower105
11/6/2019 9:57am
11/6/2019 9:57am
Edited Date/Time
11/7/2019 11:17am
So I bought a used 2009 YZ125 off a guy here in Ohio - said the engine was just rebuilt (I know the guy that rebuilt the motor - good wrench and he has built me engines before - I trust his work - he confirmed recent rebuild)
Picked up the bike - started it in the shop - everything sounded good - jetting crisp - adjusted the air screw just a bit to get a flat spot out right off idle - other than that carb is 100% stock jetting
Vforce reed cage - bills pipe
Drained renegade race fuel previous owner had in it - unknown pre mix ratio - I put in pump 93 with 927 32:1
First day I rode it - 3rd session out - bogs and no compression - won't start.
Plug was brand new - it had some oil on it when I pulled it at the track - doesn't look to have been running extremely lean?
Only thing I can think that would have caused this is an air leak - I'm not totally thrilled with the seal between the carb and the reed cage - I ordered a new carb boot to see if it might seal better on the reed cage.
I just ordered a new head, cylinder etc - I don't want to put all this money into the bike and have it blow up first ride again.
Any help will be appreciated.
Picked up the bike - started it in the shop - everything sounded good - jetting crisp - adjusted the air screw just a bit to get a flat spot out right off idle - other than that carb is 100% stock jetting
Vforce reed cage - bills pipe
Drained renegade race fuel previous owner had in it - unknown pre mix ratio - I put in pump 93 with 927 32:1
First day I rode it - 3rd session out - bogs and no compression - won't start.
Plug was brand new - it had some oil on it when I pulled it at the track - doesn't look to have been running extremely lean?
Only thing I can think that would have caused this is an air leak - I'm not totally thrilled with the seal between the carb and the reed cage - I ordered a new carb boot to see if it might seal better on the reed cage.
I just ordered a new head, cylinder etc - I don't want to put all this money into the bike and have it blow up first ride again.
Any help will be appreciated.
Air filter clean? Detonating has a pretty distinct sound while you're riding, normally.
Air Filter and Air Box brand new - I didn't see any dirt or anything in the boot or carb when I pulled everything apart.
Airboot when I pulled it off. Super clean bike. - Unless the previous owner sucked dirt and then cleaned it really really good and sold it to me. I know the guy from seeing him around the track - but still.
The Shop
And the head does not appear to be cut.
New cylinder, head, and piston should all be here tonight.
Used bikes seem to turn into projects even if you don't want them too.
richer needle from stock with 100LL AV-GAS in my 125 YZ .
Although my motor is not stock Yamah's like good high quality fuel.
Post a reply to: Detonation? - Like a lot....2009 yz125