Chain tensioners

[bfarthing83]

Hi, I got the bike in the workshop on Friday night to clean out the carbs and do the tensioners. Started with the rear first and for love nor money could I get ri to be in line with the head re was when rt was in line with the notch. Am I being a tool? Is there a locking tool or some way of stopping the cam shafts moving?
Cheers ben


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[Cadbury64]

Am I reading correctly that when you line up the crank mark, the cam marks don't align with the head. I'm going to say that they're probably all like that, Sir, and I think it is due to chain stretch with age. Certainly found that with my bike, with the crank mark lined, up, the sprockets were rotated around 1/2 a tooth off being correctly aligned. I guess if I was sufficiently anal, I could slot the cam sprockets and rotate them to compensate, but doubt it would make a big difference.

[tony.mon]

Am I reading correctly that when you line up the crank mark, the cam marks don't align with the head. I'm going to say that they're probably all like that, Sir, and I think it is due to chain stretch with age. Certainly found that with my bike, with the crank mark lined, up, the sprockets were rotated around 1/2 a tooth off being correctly aligned. I guess if I was sufficiently anal, I could slot the cam sprockets and rotate them to compensate, but doubt it would make a big difference.

Just to avoid expensive mistakes, this is a picture of the front head, and shows the Ri and Re marks at an angle above the top surface of the head because each cam sprocket has both rear marks and front marks on it.
The two dashed lines level with the head surface are the inboard marks opposite the front head marks (Fi and Fe) on each sprocket, just out of shot.

[Cadbury64]

Quite correct Tony; the frame spars get in the way of a good picture of the back head.

[bfarthing83]

I shall check it out when I get the chance on Friday night. I've done hundreds of cam belts in my time but chains, not so many and always on cars so it's a learning curve for me. I tried to slip the chain off and correct it with only the cam cover off. What a pain that is lol


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[bfarthing83]

The rear chain I managed to set perfectly in the end. When doing the front chain initially the inlet cam sat slightly lower (inside the head) but all other marks on this side were perfect. So we adjusted the inlet sprocket 1 tooth. It runs but quieter and is a bit flat under load. So it's back out with the spanners and put it back by one tooth. Have you guys ever seen it where the bike was running good but the marks don't fully line up?


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[VTRDark]

It all depends on whether you want to ever so slightly advance or retard things in relation to the other cam...move the power band up or down and then there is the valve clearances to take into consideration and the fuelling. It's all related.

[Pete.L]

The rear chain I managed to set perfectly in the end. When doing the front chain initially the inlet cam sat slightly lower (inside the head) but all other marks on this side were perfect. So we adjusted the inlet sprocket 1 tooth. It runs but quieter and is a bit flat under load. So it's back out with the spanners and put it back by one tooth. Have you guys ever seen it where the bike was running good but the marks don't fully line up?


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Yep!
Cam chain stretch. The markers seldom align up perfectly on old bikes.
If it's running okay when you turn it back I wouldn't worry about it unless the bike is really down on power

Pete.l