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Quick question. is it possible for a TC88 to be 180 out. I was replacing my chain tensioners and inner cam bearings. i had just removed the outer cam, chain and mainshaft timing gears when my buddy decided to roll my bike foward. Now I am wondering if I go to line up the cam dots and the timing gear dots is it possible to be out 180. I know the gears have a key so they cannot be advanced howver. Advice would be appreciated the bike is a 2000 stock CV carb
The pistons will be at TDC twice for each cam revolution, but you can't be on the wrong stroke (or the 180 degrees out that you are questioning) because until the cams and timing gears are installed the piston doesn't know if it's an intake/compression stroke or exhaust stroke. Only once the cams, gears and chains are installed does there become an intake/compression stroke or exhaust stroke.
Line up the marks and you are assured that the cam timing is correct (within tolerance).
Last edited by 2black1s; Jul 18, 2012 at 01:58 PM.
What about spark? Doesnt it only fire on the compression stroke?
Originally Posted by 2black1s
No! Line up the marks and you're good to go.
The pistons will be at TDC twice for each cam revolution, but you can't be on the wrong stroke (or the 180 degrees out that you are questioning) because until the cams and timing gears are installed the piston doesn't know if it's an intake/compression stroke or exhaust stroke. Only once the cams, gears and chains are installed does there become an intake/compression stroke or exhaust stroke.
Line up the marks and you are assured that the cam timing is correct (within tolerance).
What about spark? Doesn’t it only fire on the compression stroke?
You asked a question in a 14 year old thread and 2black1s hasn't posted since 2023....
So I'll answer your question..... Yes, and that is what the front gear timing marks are for.
When the front gear marks are lined up, it puts the rear cylinder at TDC, and syncs the crankshaft (pistons) with the cams (valves), so everything works as it should....
NOTE: On a Twin Cam engine, the cams also need to be aligned properly when set into the rear of the cam plate with their chain.
Last edited by hattitude; May 7, 2026 at 09:02 AM.
Thank you for the response. But what tells the engine to fire on compression stroke and thats its compression not exhaust? If the crank sprocket is 180 out wouldnt it fire on the exhaust stroke?
Originally Posted by hattitude
You asked a question in a 14 year old thread and 2black1s hasn't posted since 2023....
So I'll answer your question..... Yes, and that is what the front gear timing marks are for.
When the front gear marks are lined up, it puts the rear cylinder at TDC, and syncs the crankshaft (pistons) with the cams (valves), so everything works as it should....
NOTE: On a Twin Cam engine, the cams also need to be aligned properly when set into the rear of the cam plate with their chain.
Thank you for the response. But what tells the engine to fire on compression stroke and thats its compression not exhaust? If the crank sprocket is 180 out wouldnt it fire on the exhaust stroke?
Newer models use camshaft position sensor. Older models use crankshaft positing sensor. Even older models use points.
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Can a tc88 be 180 degrees out of timing?
