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Timing vs Cam Location

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Alright, I'm aware you see 2 TDC marks for a 'full' revolution of the cams. I had to replace my valves and I put it back together and just timed it off of 1 of the TDC marks but it will not start at all. How do I determine if I am 180 degrees out of phase or not? What is the proper way to time this bike? I am aware of how the timing marks should look based on this pictures here... Cam Timing

What is suggestions to go from here? I'm afraid to rotate the cams over the 180 degrees on the other TDC mark as I might screw things up again? I have a feeling your going to tell me to possibly switch it though, but I would like some logic behind that instead of just plain to changing it to see if it works yaknow. Maybe I can somehow relate this to the compression stroke? I'm confused in case you can't tell.

Thanks in advance.

Confused in MI.

Matt~

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The piston reaches TDC twice per power stroke. That is 360 apart not 180. There is only 1 TDC mark. The piston is at TDC at the start of the intake stroke and again at the start of the power stoke. That is determined by the valves. So - no, it is not possible for the valves to be out of phase (360 out) with the piston. On a DRZ and most motorcycles ignition occurs at every TDC so it is not possible for the power stroke to be out of phase with the ignition. Your problem is elsewhere.

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As Nobel said , there is only one mark.

Procedure is so simple,many get confused.

Place the crank on the TDC mark (thats the line.. Not the T. The T just tells you the line is the TDC mark)

Place the cams at the 10 and 2 O'clock position.

Push in on the cam chain guide,making sure to take up the chain slack.

Check cam timing, check the TDC mark.

Install the MCCT, rotate the motor over by hand twice, line up TDC mark

Check cam timing, check the TDC mark.

Install valve cover, tank and seat. go ride :thumbsup:

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As Nobel said , there is only one mark.

Procedure is so simple, many get confused.

Place the crank on the TDC mark (thats the line.. Not the T. The T just tells you the line is the TDC mark)

Place the cams at the 10 and 2 O'clock position.

Push in on the cam chain guide,making sure to take up the chain slack.

Check cam timing, check the TDC mark.

Install the MCCT, rotate the motor over by hand twice, line up TDC mark

Check cam timing, check the TDC mark.

Install valve cover, tank and seat. go ride :thumbsup:

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Okay, I'll have to look at it tomorrow. I am 100% sure the cam timing is right. I think my valves might not be opening enough / too far. We'll see. Hopefully it gets fixed soon.

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"I think my valves might not be opening enough / too far" Can you explain your meaning? The valves move as controlled by the cam. How can they open not enough or too far? I assume you have adjusted the valve clearance?

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"I think my valves might not be opening enough / too far" Can you explain your meaning? The valves move as controlled by the cam. How can they open not enough or too far? I assume you have adjusted the valve clearance?

I had my exhaust cam jump time and the exhaust valves smack the piston. blah blah. I had some guy put it back together for me and he said he shimmed the valves to be the correct gap or whatever... I have not checked this myself and I intend to tonight. Hopefully I get this figured out.

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OK. Yes you need some clearance for it to start and run. If you can spin the buckets by hand it has enough clearance to start but it is so easy to check for correct clearance, you might as well do it right. IN .004 to .008, EX .008 to .012. Valves are new? Valves were fitted for good seating? Excess clearance will not prevent it from starting but obviously correct clearance is best.

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