So today was a beautiful day up here in AK. And like any other rider would want to do, i decided to go riding. Well when i first fired up my bike. One of my friends pointed out that every time i would wop it, exhaust would come out of the black drain tube that comes from my power valve housing. Also while riding, my bike would rarley hit the power band. Whenever id gas it and try doing braaps and stuff like that. Or even just laying the gas on softly, it would half bog, half hit the powerband. It felt like it really wanted to hit the pb, but just barley couldnt. And sometimes if i started in first i could get it to hit, then shift up and keep it in it. But as soon as i let off on the throttle... Blop blop. It would bog again
125 Exhaust coming out of power valve drain tube
- Thread starter AkYz125Ripper
- Start date
It is a 2003 Yz 125. Everything is stock i think. Bought it used. Also, the jetting is at stock setting. 410 main. Air screw is at stock setting also. Might be the 2 week old premix. But i put some in my buddies bike (he uses the same stuff as me) and his ripped all day.
So just take the engine off the frame. Take off whole top end and replace it and do you think id need to replace the PVs also?
and, usually no need to take the motor out of the frame. The top end should come off in the frame.
It looks like chips are missing from the top edge of the walls but that is just burnt on oil or carbon
If what ive been reading about detonation is correct. Then my bike doesnt have or do it. There is no pinging sound when the bike is running. And the exhaust pipe doesnt get too hot. The only issue that ive had with the bike is the bog.
The photos of the head HAD tell-tale detonation. Absolutely no doubt in my mind it had pinging issues at some point. BUT, the piston that is currently installed has not had the same issues, AT ALL. Looks like it got fixed before you got a hold of her. No worries, one of my bike's has the same evidence, runs awesome today.
So, back to the topic at hand...
You cleaned out the power valve cavity and linkages, GOOOD. That was most likely the issue with your bog. I would spray a bunch of carb cleaner into that area to ensure the powervalve doesn't bind at all, and reassemble the engine.
Clean the carb while you're at it. No reason to ignore it while she's out.
Try riding it again. Report back! -BIG DAN
So, back to the topic at hand...
You cleaned out the power valve cavity and linkages, GOOOD. That was most likely the issue with your bog. I would spray a bunch of carb cleaner into that area to ensure the powervalve doesn't bind at all, and reassemble the engine.
Clean the carb while you're at it. No reason to ignore it while she's out.
Try riding it again. Report back! -BIG DAN
Im assuming carb cleaner is safe to spray into the power valve housing. Ill have to make a run to napa or somewhere and pick up a few cans of that. And i am currently cleaning the carb right now. Once everything is put back together i will tell yall if it fixed the problems or not. Thanks big dan and everyone else!
Yeah it is, it works well, I use Deep Creep by Sea Foam, it does a really good job of getting thru the carbon and gunky paraffin build up, it doesn't wash the stuff away like carb or brake clean, so you may want to go behind it with that if you want.