Heads Up On Installing A New Cam

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In addition to my cam chain tensioner issue presented in my other post, we are running into cam and valve problems.

My stock 850 cam was pitted and worn out, so we ordered in a Megacycle 5600 cam, along with new Black Diamond valves.
You cannot buy a stock lift and duration new cam, we called the major cam makers. Ok, now someone will tell me where we could have!
The 5600 is offered to increase breathing with some 40 thou higher lift and longer duration, not considered radical.
My stock valves were found to be just ticking the tops of the pistons, so we set the new valves seats into the head deeper.
We still found the new cam was making the valves contact each other, so I have taken them to a machine shop today to have 10thou taken off the sides all around, this should solve that problem.
We called Megacycle as there was no warning language regarding the valve and seat modifications necessary.
We also found that the cam timing was 10 degrees retarded with that new cam, and this was using the stock cam timing marks. Not a big deal, but again one would assume cam timing would be on the marks. No answer from Megacycle on this question, considering the possible damage that could be done if one installed it per the standard settings.
We also had to cut notches into the pistons for the valves.

Yes, one always knows the unexpected is a matter of course, but dealing with a very knowledgable expert mechanic is a must. There is no way I could have dealt with all the engine geometry myself!
 
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We also found that the cam timing was 10 degrees retarded with that new cam, and this was using the stock cam timing marks.

This isn't the first I've heard about Megacycle cams being off. The Web cam I installed is spot on.
 
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I have also heard of some people having issues with Megacycle cams lately . Leo Goff is putting a custom Webcam grind in my 880 . While the cam is spot on , he had to line bore the cam bore in my case and then fit a bushing to take up the extra space in the drive side case . That and my crank journals were off by 2 degrees so he replaced it with a good Mk 3 crank from his supply . Why is it that everything I buy always seems to be crap ? :evil:
 
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OK, I'll step in on your first question!

My original cam was badly worn, and following a pretty huge consensus on this forum as to what the best profile is, I got it re-done back to standard by RGM.
It took around 6 weeks and cost around £60.
 

grandpaul

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I've done 2 Megacycle 560s with zero issues and excellent results.

One in a stock 850 with stock valves, the other 850 with Black Diamond valves.

I have another one on the shelf for my 880 build, it will get the adjustable cam sprocket and the Baisley head has nifty 7mm stem valves. Should be plug-n-play with the JE dished top pistons, according to Kenny Dreer's instruction sheet sent with the block, head & jugs.
 
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The Cam dilemma;

Had my stock 850 MK III soft cam stellite welded and re ground. It looked like they ground it by hand; file marks and the lobes out of phase, inconsistent lift, in general not usable. I've reluctantly decided to go with a 1s that I picked up at a jumble just to keep the project moving, however so slowly. Not looking for a world beater just a nice running dependable ride but I suppose I should bite the bullet and spring for a PW 3 and be done with it. Any other suggestions?

Scooter
 
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highdesert said:
My stock valves were found to be just ticking the tops of the pistons, so we set the new valves seats into the head deeper.


You say new valve seats, were they machined to the correct height, because if they are set to high it can cause all of your above problem, bar the incorrect timing, it does sound like they are still to high.
 
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