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Dyna-S ignition system (now cam end float thread)

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K2-K6:
Same here with molyslip,  view it as accumilative for clutch friction and should be avoided.

It'll be interesting to see what you can find regarding cam movement Roy when you have a look inside.

K2-K6:
Just a thought Roy, categorized as "GS cam end float" are you certain of that and have you tried loading transmission with is held on rear brake to observe if if changes at all when pulling slightly?   

What I'm getting at is that it's assumed to be that stated reason,  but is there certainty in that diagnosis that's floating about?

royhall:
You may be correct there. I shall try loading the engine and see if it stops.

The cam end float I have measured previously. It was 6 thou on the intake and 5 thou on the exhaust, roughly the same as the guy in the "fix" had measured. I measured this with the head removed and the camshafts just sitting in the head. I set up a DTI and whilst pushing the cam one way I zeroed the dial then took the reading pushing the other way. So the clearance is 2.5 to 3 thou per side. There are visible marks on the head surface where the cam has been running for 55,000 miles but you cannot feel any of them with a finger nail. I think that clearance is what Suzuki intended as when it heats up the steel cam will expand by more than the aluminium head. I would love to know what the clearance is meant to be but cannot find that information anywhere and nobody appears to know.

I think I may be looking for something else as I have just rebuilt the top end and it has been perfectly quite for 300 miles. The knock came on suddenly after a long hot run rather than a gradual increase. I used Graphogen compound on the cam bearing faces during the rebuild but I doubt any of that would still be in after 300 miles of hot running. The oil in it at present is Fuchs Titan 15W40. The clutch basket was rebuilt by Grumpy1260 with welded rivets (the usual Suzuki mod) so will check that is still tight, there was a new starter sprag clutch fitted so I will also check all that is still tight. I will take the cam cover off and re-check the shims as the valves were re-ground and the seats re-cut so they could have closed up. Also as mentioned earlier in the thread (although the GS1000 does not have tensioner wheels) I will have another look at all the cam chain parts (cam chain itself is new), plus the auto tensioner appears to be working okay.

Then after that I'm stuck. If I can get it quite enough I will part exchange it for a new 1200 Triumph Bonneville. Happy days.

K2-K6:
"I used Graphogen compound on the cam bearing faces during the rebuild but I doubt any of that would still be in after 300 miles of hot running. "

Had a bit of a think while wandering around today  :)

That's really interesting. OK a speculative theory, the camshaft rotation of valve buckets I doubt they have used in that geometry as it requires thrust faces to resist. And so it must be running a non biased lobe to bucket geometry from original design with no attempt to turn the buckets for evening of wear characteristics.

But, and it's a big but, if through mileage it's created a wear pattern on one or more of the load faces such that it now tries to rotate that bucket,  then the contact point initially of the cam as it comes onto the static face will now attempt to prescribe an arc in spinning the bucket (still with me?) Which will shunt crossways load onto the camshaft to give longitudinal travel "knock" just as it flicks the camshaft left or right. 

This the graphogen may have prevented as that's what it's supposed to do. Now fully removed into the oil, including remnants in the surface texture,  it has seen a rise in stiction just sufficient to flick the cam.

Testing;- put some more graphogen on each cam load site and run it again to see if it improves.  Further action,  inspect all the buckets for flatness to see if you can observe any discrepancy.

royhall:
I think I'm with that? The problem with the wear theory is that this is a shim over bucket design and all the shims are new giving a fresh flat face. I can easily check what wear is on the old shims that I took out. My first target when the top comes off is to check the new shims as there could be a faulty one not heat treated correctly or something. It will be a few weeks before I can open the engine up as I have house renovations to do now (on threat of castration if it doesn't happen). >:( >:(

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