engine smoking after rebuild

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mikesatvgraveyard

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Hey guys, been a while since Ive done a top end on a 350, ive done about 4, and i dont remember any of them smoking after top end. I used the same shop-bored and honed the jug to 1mm over, used the weisco 10 to 1. rebuilt head, new valve seals and valve job. I have not been able to put any load on this quad, its sitting on a work table while i finish other things. Smokes bad after sitting overnite, gradually clears. havent run engine more than 5-6 minutes total. Is this normal? Any thoughts thanks
 
could just be old oil burning in your pipe from before rebuild or the.rings havent seated yet. run the quad before tearing into it again.
 
MackMingles said:
could just be old oil burning in your pipe from before rebuild or the.rings havent seated yet. run the quad before tearing into it again.
Click to expand...

what are you talkin bout? there should be no oil in the pipe if it was off the quad. and even so its better off to check everything before he ruins it by running it this way!
 
It's not going to get ruined!
The exhaust pipe can have accumulated oil in it from running it prior to the rebuild. If this is the case it should pass with dome running.
I don't think that is the case though.
If it smokes at startup and clears after a couple if seconds then the valve seals are suspect.
How many hours or minutes are on the rebuild?
 
Make sure the valve stem seals did not get damaged when the springs was installed. Seen many people compress the springs too far and smash the seals
 
smoking after rebuild

Yea thats what I thought too, in the head. There is no oil in the pipe, as the entire system came from another motor. I have another good head, so I am going to take yalls advice and tear back into it. I was going to just run it, but I went out & started it this am and same situation. Something is not right. Dont want to have it not right after all this $$ invested. Ill let yall know what I find. Thanks for all the input
 
sparkymichigan said:
It's not going to get ruined!
The exhaust pipe can have accumulated oil in it from running it prior to the rebuild. If this is the case it should pass with dome running.
I don't think that is the case though.
If it smokes at startup and clears after a couple if seconds then the valve seals are suspect.
How many hours or minutes are on the rebuild?
Click to expand...

he said 6 minutes on the rebuild, and ya never know dude it could be effed up somewhere we dont expect. always good to double check on a problem like this.
 
Mine needs valve stem seals. I just let it warm til the smoke clears and go riding. Too lazy to change em out. Course I check the oil frequently.
 
motor smokin after rebuild

I cant justify spending all this money and time and accept a smokin motor. The guy who does the machine work Ive used several times and had no prob. Hes lookin @ the head now. Along with the weisco and machine work, I installed a Hot Cams stg 1 cam and new valve springs also. I will resell this quad in the spring, just bought to keep busy in the winter. My other Yamahas are doin fine, even my Ol Polaris Magnum 325 4x4. (I know I hear yall groanin, but this Polaris is tank). Its oil cooler is larger than my Griz 600. Ive heard the fan come on once in 3 years.

Im still lookin for a good factory front rim, have an excellent crank/rod assy and cases for sale. Let me know if anyone out there needs these things or has a wheel.
 
polaris' are tanks, way overbuilt; BUT are super hard to work on! the only quads i have real problems with are chinese ones. i saw one last time at the mounds: the front shock mounts gave out on a jump. :p
 
Engine sorted out

I promised to let yall know when I got this 350 (360) sorted out, and what I did was this: pulled the top end back off, sent the cylinder and head to my machinist, who checked all the work he did. Everything checked out. On his suggestion, I bought another replacement set of valve seals. He installed them. I contacted Weisco-who apparently can do no wrong btw, replaced the rings for 15.00. The only way they would warranty my new rings were to send them bak, study them,ect ect... and with a new ring set, new valve seals. and finding out I )(*^&*O(&^%$%*))) forgot to install the oring on the bottom of the jug. OMG!!!! Would this cause it to smoke??? Anyways we are good to go.
 
sounds to me like it's just moisture in exhaust or old oil in exhaust like Josh said
 
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