DG Rider
Member: Triple Clutch Club
Lifetime Member
RE: Finding TDC compression...
Slowly rotate the engine watching the intake valves. They will open and close, and once they start to close you are starting the compression stage of the cycle.
At this point, you can simply start looking for the "T" mark very carefully, or you can actually peer down the spark plug hole with a light and watch the piston rise.
[ Alternately, you can stick a CLEAN screwdriver down the plug hole and "feel" the piston rise, BUT BE VERY CAREFUL IF YOU USE THIS METHOD, YOU DON'T WANT TO BIND/BREAK THE SCREWDRIVER (even though this would take much mojo on the socket turning the crank shaft ). JUST MAKE SURE YOU LET THE SCREW DRIVER RISE NATURALLY OUT OF THE PLUG HOLE and you should be fine. Yes, you could use a wooden dowel, but that would be too easy to break if you screw something up, and you'd never get it out. DO NOT USE THIS METHOD IF YOU ARE A KLUTZ!]
Whatever method you use, once you see the piston nearing the top of the cylinder, you can now start looking for the "T" mark. This is where the screwdriver method is handy because you can look for the mark while "feeling" where the piston is. If the piston starts back down, or you see exhaust valves open, you've gone too far, and need to start over.
Note: Don't confuse the "F" mark with the "T". Once you see the "F", you are getting close.
Also, do not deviate from the factory method for adjusting valves. You may notice that once you adjust the valves at the "T" mark, rotating the engine very slightly may cause them to loosen up because the intake valves may not be fully at base circle on the cam ( this engine may not even do this, but some do ). If this is the case, the factory specs take this into account. If you simply roll the cam to 180 degrees from max lift and adjust, your valves may be too tight, and loose valves are preferable to tight ones. Honda has been doing this for a long time, and doing it very well. Don't second guess their instructions.
Slowly rotate the engine watching the intake valves. They will open and close, and once they start to close you are starting the compression stage of the cycle.
At this point, you can simply start looking for the "T" mark very carefully, or you can actually peer down the spark plug hole with a light and watch the piston rise.
[ Alternately, you can stick a CLEAN screwdriver down the plug hole and "feel" the piston rise, BUT BE VERY CAREFUL IF YOU USE THIS METHOD, YOU DON'T WANT TO BIND/BREAK THE SCREWDRIVER (even though this would take much mojo on the socket turning the crank shaft ). JUST MAKE SURE YOU LET THE SCREW DRIVER RISE NATURALLY OUT OF THE PLUG HOLE and you should be fine. Yes, you could use a wooden dowel, but that would be too easy to break if you screw something up, and you'd never get it out. DO NOT USE THIS METHOD IF YOU ARE A KLUTZ!]
Whatever method you use, once you see the piston nearing the top of the cylinder, you can now start looking for the "T" mark. This is where the screwdriver method is handy because you can look for the mark while "feeling" where the piston is. If the piston starts back down, or you see exhaust valves open, you've gone too far, and need to start over.
Note: Don't confuse the "F" mark with the "T". Once you see the "F", you are getting close.
Also, do not deviate from the factory method for adjusting valves. You may notice that once you adjust the valves at the "T" mark, rotating the engine very slightly may cause them to loosen up because the intake valves may not be fully at base circle on the cam ( this engine may not even do this, but some do ). If this is the case, the factory specs take this into account. If you simply roll the cam to 180 degrees from max lift and adjust, your valves may be too tight, and loose valves are preferable to tight ones. Honda has been doing this for a long time, and doing it very well. Don't second guess their instructions.
Hondasxs
Club Founder
Staff member
Ya. I got all that. It just always seem it will get almost to the T then fly by. But then again I was using one with a pull start as the method to turn the shaft.
Thinking about it... I guess you can control the shaft better as there is no pull start.
If you need all those disclaimers you do not need to be working on it. Lol
Thinking about it... I guess you can control the shaft better as there is no pull start.
If you need all those disclaimers you do not need to be working on it. Lol
DG Rider
Member: Triple Clutch Club
Lifetime Member
Was really just meant as a general post for everyone, but yeah..i use the pull stater as well, and its easy to go too far. Should be easier with a socket.Hondasxs said:
