I have a 1977 atc 90 that ran great now its smoking really bad and backfiring from the carb and exhaust.
First Time Rider
Arm chair racerNew to the board
I have a 1977 atc 90 that ran great now its smoking really bad and backfiring from the carb and exhaust.
1983 ATC 185s 200 jug bored .20 9.5:1 Naumura piston. Fast as ass when its not stretching the drive chain or stripping hubs.
1986 ATC 250ES. *Total garbage trying to sell it*
1983 YTM 200E. Runs good, forks are super bent but aside from that its mint.
1984 YTM 200L. Barn find, everything is mint except the bottom end is bad... *waiting on a new engine*
FACT ! I have no edit button
Arm chair racerThe day begins with 3WW
Is it lite blue smoke or black?
Is it constant and a fairly big amount?
If its lite blue, your top end is probably wasted.
If it's black, you might only have a carb problem.
Check the valve clearance.
Post a photo of the end of the spark plug.
Do a compression test with the gas off and throttle wide open and kick it 5 times.
.
At The Back Of The Pack
Arm chair racerFirst time rider
ATC; odds are that your piston rings are worn out, time to tear it down & take a look.
John Tice
503-593-2908 Alternate 541-508-3944
www.smallenginemachineworks.com & www.nwsleeve.com
Turning Custom Cylinder Sleeves Since 1971
Power User
The day begins with 3WW
It could also be related to timing, such as a timing chain jumping a tooth. I'd throw checking the crank and cam timing on the list of things to check. Seems kind of odd it is all of a sudden, might want to check your air box as well, maybe some mice made a home there.
At The Back Of The Pack
Arm chair racerFirst time rider
Check timing, valves, and spark plug. Could be your points plate that moved or that the timing chain jumped a tooth or so.
1979 Atc 110 helm and son
1977 Atc 90
1980 Atc 110
1984 Atc 110
1985 Atc 110
1988 XR 200 bored 40 over,
Atc 200x bottom end.
First Time Rider
Arm chair racerNew to the board
timing was off but its good now. I think the rings stuck again, because when you pull it over with the plug in and then take it out it will be wet with oil.
1983 ATC 185s 200 jug bored .20 9.5:1 Naumura piston. Fast as ass when its not stretching the drive chain or stripping hubs.
1986 ATC 250ES. *Total garbage trying to sell it*
1983 YTM 200E. Runs good, forks are super bent but aside from that its mint.
1984 YTM 200L. Barn find, everything is mint except the bottom end is bad... *waiting on a new engine*
At The Back Of The Pack
Arm chair racerFirst time rider
Ok probably be a good thing to take top end off and put in new rings. Or could possibly be your valve seals. But probably not if you say it's only when you pull it over then has oil on plug, be a good thing to replace valve seals when putting in New rings. Good luck
1979 Atc 110 helm and son
1977 Atc 90
1980 Atc 110
1984 Atc 110
1985 Atc 110
1988 XR 200 bored 40 over,
Atc 200x bottom end.
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