I am installing a set of race cams on my ds. I cant seem to find any info on the timing. The magneto has 2 seperate marks on it. Which was is used for top dead center? It seems that top dead center is somewhere between these marks, and not on any of them. If anyone could shed some light on this, I would be greatly appreciative.

Thanks,

Gary

 

There is a bolt you remove on the bottom left side of engine. It takes a 6mm allen head to remove. At TDC there will be a groove in the crank - shine a light into hole to see groove. You can buy a crankshaft locking bolt to use once you find TDC, but it's not necessary to have.

NOTE: There are two grooves in the crank, make sure you near TDC before finding the groove!

On the magneto side of the motor, removing the plastic plug in the center will allow you to insert an allen head & rachet and rotate the crank by hand (CLOCKWISE ONLY) in small increments.

Of course, remove the spark plug to release compression.

 

I appreciate you help, Im looking for the groove right now,

 

I found it, jeeze, what a relief. Now, if you dont mind one more question. With groove lined up, we are at tdc right? Then this is where the cams should be installed with indicator lines lined up? If you can answer these last questions, dinner and beer is on me if we meet on the trails someday.

Gary

 

yes the lines in both the cams should be lined up horizontally with the arrows on the plastic cam chain guide bolted to the cam carrier. when checking for alignment you need to push in on the cam chain tensioner to get rid of the chain slack.

 

Gotcha, Im going to get the cams in now, Im so glad someone was on today that had this info.

Thanks,

 

Im back, only one more stupid question!!!!!. If the cams are aligned, sprockets aligned and at tdc. I do not see how you can adjust valve/cam clearances. I must be missing something?? Thanks again for the help.

Gary

 

Hey D stroyer, Are your cam lobes facing away from each other at top dead center? You need to make sure that they are or you are 180 degree's off. Also I find the best way and the fastest way to check lash is to bolt the cam carrier in with the cams and sprockets on, make sure you torque it down to spec. Don't connect the chain. Start with either cam it doesn't matter. Now line up the cam marks even with the tensioner mark. Also the cam peg that hold the gear in check on the cam should be pointing straight up. Now just hold the cam there with your hand and take your gauges and measure the clearance. For race cams you should be at .008 thousandths on both the intake and exahust. You can be off a taste in either direction. As long as they are at .006 minimum and .009 maximum.

 

I thank you for the input punisher, but I was wondering how you go about adjusting that clearance? Its not like a normal valve adjuster. I dont see any means of adjusting the clearance at all. Please help

 

You adjust the clearance by replacing the shims with thicker/ thinner shims, there is no other way. There are creative ways to modify the shims IF you have the correct equiptment. Otherwise just calculate the size you need based off the existing clearance and go buy them.