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Discussion Starter #1
Rebiult topend on foreman 450s road for about 2hrs never went pass half throttle it never smoked one bit cranked it up this morrning and its smokeing like a train any ideas the head was reabiult also

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If an engine blows smoke after sitting for a while then it could be valve guide seals ------------ don't get too alarmed yet , give some time to ensure all the oil is burned out of the muffler , and give some time as the rings might still seat ------ check your oil level and be sure that the carb float didn't stick and fill the crankcase full of gas
 

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If an engine blows smoke after sitting for a while then it could be valve guide seals ------------ don't get too alarmed yet , give some time to ensure all the oil is burned out of the muffler , and give some time as the rings might still seat ------ check your oil level and be sure that the carb float didn't stick and fill the crankcase full of gas
Thanks bro its abrand new carb but it never smoked when we first started it and ran it for like 2r3hrs then parked it woke up this morrning and cranked it up and started smokeing right away the muffler is full of oil now it had no oil in it from the beginging so probley valve giudes ...

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Did you do all the assembly work on the topend or was it done in a shop? Was it bored out or just honed? New piston? New ring set? Which brand are they?

Is it a genuine OEM carburetor you put on it?
 

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Yeap i did all the work my self the bike was board .25 over had the cylinder mic at shop they say it checked out good so i got a wisco piston and rings

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What was your final piston to cylinder wall clearance? Did your oil ring have an upside marking? Was your cylinder checked for taper and out of round?

Has this engine ever been sunk?

Rick
 

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.... and did you scrub the cylinder in hot, soapy water with a brush after the machining work was done? Really work at it scrubbing and scrubbing and wiping that cylinder perfectly clean?

Did you assemble the oil ring properly?

Was the cylinder bored and honed BEFORE you got the new Wiseco piston for it?
 

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Never been sunk and it was board already all they did was hone it out to smoth down a couple rough spots but the shop had mic'ed the cylinder out and they said it was good and not out of round i just tore it all down again and its 5000th gap between the cylinder and piston on one side you can see day light on one side of the piston and it gets worse the futher the piston goes down

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But just dont understand why it didnt smoke from the get go i mean i road it for 2r3hrs yesterday and never smoked on bit then start it up this morrning and its smokeing like a train and oil all in the muffler

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The piston is largest at the skirt (90 degrees from the wrist pin bore) so that is where you must slide your feeler gauges under (carefully) to measure the clearance. Do so with piston at the top of the stroke, in the middle and at the bottom of its stroke. The crown is much smaller diameter than the skirt is, that is normal and necessary, so don't measure there. A proper boring procedure means the person doing the boring and honing should have the new piston in hand while final honing the cylinder in order to get the proper clearance. Is the clearance within Wiseco's specifications now?

As far as oil suddenly flooding the exhaust... you'll have to figure that out cause we can't see or touch it from here.

The reason I asked you about scrubbing the cylinder is because after machining, the bore is loaded with grit. It can appear to be clean... but if you put the motor together without a thorough scrubbing of the bore the new topend runs in that grit continuously and can very quickly wear everything out.

At this point it may be a good idea to have someone inspect (a qualified professional machinist, very few really are) all of your motor parts and advise you.
 

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Thanks bud but at the skirt i had almost 9 thousands not good think that shop screwed me over but i should have double checked it befor i put it all together just trusted the machineist

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Give G&H a call and ask them what they can do for you. If your cylinder can be bored to the next oversize, those folks are ones you can trust. Everyone praises their work... Good luck, hope you get it going soon.
 

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Ok got the problem fixed it was the cylinder got everything new put it back together now i have a noise on the front end when i shift to 2nd it sound like a stuck lifter in a car its not topend noise it from the front but after you ride it a while the noise quiets down it will not doit while its at idle only when you get out of 2nd gear and give it gas to shift tho 3rd 4thand 5th

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If it goes away after awhile that tells me that a warm engine expands and stops the rattle.

If it wasn't there before you tore it back down I'd check the exhaust for a loose clamp before I tore back into it.
 

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Is it pinging (pre-ignition) on poor quality and low octane fuel under load? Try emptying the gas out of the tank and put some fresh premium gas (non-ethanol, non-MTBE) in it and if the noise disappears for good by the time the fresh gas reaches the carb (a few minutes idling)....
 
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