Cam Fitting Trouble -- Which Position

[Guest]

I am fitting the camshafts to my 650 top end conversion and am not absolutely sure which is the correct position for the exhaust cam. I cannot get the #1 arrow to line up exactly with the upper cylinder head surface.

Study the following pictures and tell me which position you think is the correct one. Thanx.



Pic. Number 1 -- motor at TDC on 1-4, correct position for timing the camshafts.



In this position the #1 arrow is above the head surface, I was lead to believe it should line up with the head surface exactly. I have marked two indexing marks on the sprocket and chain to make things easier when moving the chain position on the sprocket. In this pic the two white dots are lined up.



Picture Number 3. Also in this position the notch in the end of the camshaft and the other indexing line are lined up with the head surface exactly.



Picture 4: in this picture I have rotated the sprocket forward on the chain. It can be seen the white index marks now are off by one link. And the #1 arrow now is below the head surface and cannot be seen.



Picture 5: It can be seen that with the cam in this position the notch and index mark on the end of the cam are not lined up with the head surface.


My feelings are that the first position where my two white indexing dots line up is the correct position. If I had a rocker cover gasket on the head then the arrow would be almost in the correct position.

What do you guys think. Any opinions?

Thanks for any contributions.

Hope I have explained it OK.

[waterman]

Did you see this post Don?

http://www.thegsresources.com/_forum/showthread.php?t=156312

I am guessing you will want it at the pic 4 and 5 position. It is kinda hard to figure since this a 550/650 hybrid and I am definitely not a mechanical engineer. It does seem to be a little farther below the gasket surface than normal.

I have one of my 650s apart, I will check it at lunch time and report back. I do know it will run with one tooth off, at least mine did until I corrected it. Did you ever figure a way to measure the cams timing (degreeing them)? That would confirm your suspicions and verify where they should be. Are these the 550 cam gears on the 650 cams or are these the 650E cams?

[Nessism]

I agree with you Don, looks like the first position is correct, or more correct as it were. Did you check the cam chain for wear?

[Don-lo]

I agree with Don and Ed, the first position looks more correct IF the cam chain is completely tight across the front of the motor.

[Agemax]

the cam chain is too slack, have you got the tensioner installed?
you need to line up the timing marks and then install the tensioner and get the correct tension on the chain, you will find that the proper chain tension will pull the cams round a bit and line up the marks.
its a case of trial and error, slipping the chain on the sprocket by a link maybe but they will line up

[Suzuki_Don]

I agree with you Don, looks like the first position is correct, or more correct as it were. Did you check the cam chain for wear?

ED I have fitted a new HD TSUBAKI cam chain, when I had the cases split. So should not be a problem there.

[Suzuki_Don]

Did you see this post Don?

http://www.thegsresources.com/_forum/showthread.php?t=156312

I am guessing you will want it at the pic 4 and 5 position. It is kinda hard to figure since this a 550/650 hybrid and I am definitely not a mechanical engineer. It does seem to be a little farther below the gasket surface than normal.

I have one of my 650s apart, I will check it at lunch time and report back. I do know it will run with one tooth off, at least mine did until I corrected it. Did you ever figure a way to measure the cams timing (degreeing them)? That would confirm your suspicions and verify where they should be. Are these the 550 cam gears on the 650 cams or are these the 650E cams?

I am using 650E cams and sprockets. I might double check the 650 sprockets against the 550 ones to see if the bolts holes, timing marks are in the same positions relative to each other.

[Suzuki_Don]

the cam chain is too slack, have you got the tensioner installed?
you need to line up the timing marks and then install the tensioner and get the correct tension on the chain, you will find that the proper chain tension will pull the cams round a bit and line up the marks.
its a case of trial and error, slipping the chain on the sprocket by a link maybe but they will line up

At this stage I do not have the intake cam installed. I have just made sure there is no slack between the crankshaft sprocket and the exhaust cam sprocket. I might install the intake cam at 19 pins and fit the tensioner and rotate the motor a few revolutions and see where the marks line up then.

Other option (don't know if it will work) would be to install a couple of thin shims on the #4 exhaust and intake buckets and fit a degree wheel zeroed in at TDC then rotate the motor and using a .002" feeler gauge take two readings when the cam lobe comes onto the feeler gauge and when it comes off the feeler gauge and from this work out the lobe centre figure and if it is in the 102 to 108 degrees range then that should be the correct position for the cam.

[chef1366]

Use the timing in the first two pics, count your pins to the #3 mark and go.
Have you figured out how to degree in the cams?

[Suzuki_Don]

Use the timing in the first two pics, count your pins to the #3 mark and go.
Have you figured out how to degree in the cams?

Not really Bill. What do you think of my previous post to check timing.

[Steve]

Not sure if it would apply in this case, but it's something to check, just to be sure, ...

do the sprockets on the 550 and 650 cams have the same number of teeth?

Just one or two rotations of the crank could lead to expensive disaster if they don't match.

.

[chef1366]

Not really Bill. What do you think of my previous post to check timing.

That would work if you have the proper TDC found.
Are you saying you are checking the clearance coming in and coming out of the shim?

[Suzuki_Don]

Not sure if it would apply in this case, but it's something to check, just to be sure, ...

do the sprockets on the 550 and 650 cams have the same number of teeth?

Just one or two rotations of the crank could lead to expensive disaster if they don't match.

.

That's a good question Steve. As the "E" and "G" models on the 650 do have different numbers of teeth on the cam sprockets. The "E" crank has 15 teeth so the cam sprocket has 30 teeth. The "G" crank has 17 teeth so the "G" model cam has 34 teeth.

To answer your question, YES I do have the 30 tooth sprockets on the 650E cams.

BTW I have just fitted the intake cams (Good Friday morning here) and the tensioner and rotated the motor a couple ot revolutions and the marks came up the same as before on the exhaust cam. Picture to follow.

In this position the notch in the end of the cam is level and square to the upper head surface. And in all the pictures I have seen of other examples of timing this is the position of the cams when at TDC.

[tkent02]

BTW I have just fitted the intake came (Good Friday morning here) and the tensioner and rotated the motor a couple ot revolutions and the marks came up the same as before on the exhaust cam.

Hopefully with no soft clunking or crunching sounds?

[Suzuki_Don]

Hopefully with no soft clunking or crunching sounds?

That's right. Thankfully no unfamiliar sounds.