Steveg Posted March 11, 2021 Share Posted March 11, 2021 (edited) Hi, Just thought I would share this with the forum regarding the cam timing on certain GS1000 models with the cam wheel part number 451. A number of years ago, the top end was serviced and as per the manual, 20 rivets between the cam arrows had been set. Although it was not noticed that the end notches did not face each other as the factory manual was followed. However, the performance was always on the pow side for a 1000cc machine and not much was thought about it until I read recently that cam wheelsd with part numbers 451 should have 19 chain rivets between the arrows. This also lines up the cam end notches so they face each other. I took the cam cover off and found that I had the 451 number on the inlet cam and 490 on the exhaustr cam so today I have adjusted this to 19 rivets. see picture. Thinking about this, the cams have 30 teeth so one tooth measures as 12 camshaft degrees (24 crankshaft degrees!) so I am hoping that this fixes the performance issue. There was never any contact between the valves and pistons so I guess I was lucky, but the factory manual did not have this information documented in their manual and I have only just found this out recently. Edited March 11, 2021 by Steveg Too many pictures 2 Quote Link to comment
bomberone Posted March 11, 2021 Share Posted March 11, 2021 Yep definitely sounds like you’ve been lucky if you really have got away with it! Quote Link to comment
AmericanDefender Posted April 26 Share Posted April 26 I think I may have this issue as well. Where do I find the part # for the cam gear? Quote Link to comment
gorbys Posted April 26 Share Posted April 26 5 hours ago, AmericanDefender said: I think I may have this issue as well. Where do I find the part # for the cam gear? It's stamped right there on the cam wheel. 451. Quote Link to comment
Reinhoud Posted April 27 Share Posted April 27 How many rivets isn't interesting, the gaps at the end need to line up with face of the head where the valve cover mates. How is that? Quote Link to comment
AmericanDefender Posted April 29 Share Posted April 29 On 4/26/2024 at 8:26 PM, Reinhoud said: How many rivets isn't interesting, the gaps at the end need to line up with face of the head where the valve cover mates. How is that? Mine are just slightly retarded. Maybe say half a cam chain link. Quote Link to comment
AmericanDefender Posted April 29 Share Posted April 29 3 minutes ago, AmericanDefender said: Mine are just slightly retarded. Maybe say half a cam chain link. This is with the crank at TDC. I've tried everything to figure it out and haven tried to counter it by putting the cams in advanced with the crank slightly retarded. No matter what I do, this is the result. Quote Link to comment
gorbys Posted April 29 Share Posted April 29 Chain stretch perhaps? Mine wasnt 100% flush either. Somewhere in between yours and completely straight. Compression is good and the bike runs like it should so not to fussed about it Quote Link to comment
Reinhoud Posted April 29 Share Posted April 29 (edited) It's never perfect from factory. When you have sprockets with slots in it you can get it like it should. But I don't think you'll notice a difference when you adjust it like it should. Edited April 29 by Reinhoud Quote Link to comment
andyroach Posted Friday at 08:18 AM Share Posted Friday at 08:18 AM I had the same issue on my first GS1000. Someone had fitted a set of high lift cams and not dialed them in. The bike was reluctant to start and slow for what it was. I stripped the top end and 3 valve seats were burnt. I recut all the valves, skimmed the head, slotted the cam chain sprocket holes and dialed the cams in. After that it went like it should. I know this is an extreme case and my engine had been put together by a chimp (there was no clearance at all on 4 valves), but it does highlight that we should always check a bike when we buy it. Quote Link to comment
Reinhoud Posted Friday at 09:36 AM Share Posted Friday at 09:36 AM 1 hour ago, andyroach said: I had the same issue on my first GS1000. Someone had fitted a set of high lift cams and not dialed them in. The bike was reluctant to start and slow for what it was. I stripped the top end and 3 valve seats were burnt. I recut all the valves, skimmed the head, slotted the cam chain sprocket holes and dialed the cams in. After that it went like it should. I know this is an extreme case and my engine had been put together by a chimp (there was no clearance at all on 4 valves), but it does highlight that we should always check a bike when we buy it. Your valve seats will not burn because of cam timing! That's not enough/no valve clearence. How were the gaps in the cams aligned with the head? Becaase it needs to be WAY of before it causes to not wanting to fire up. I'm pretty sure you had different problems then the cam timing. Quote Link to comment
andyroach Posted Friday at 10:02 AM Share Posted Friday at 10:02 AM 23 minutes ago, Reinhoud said: Your valve seats will not burn because of cam timing! That's not enough/no valve clearence. How were the gaps in the cams aligned with the head? Becaase it needs to be WAY of before it causes to not wanting to fire up. I'm pretty sure you had different problems then the cam timing. Like I said, my motor had been put together by a chimp. There was no clearance on 4 valves and 3 had burnt out. The timing was pretty far out (I can't remember the degrees. it was 30 years ago). It was a problem of bad cam timing and the valves not having enough clearance to seat, hence burnt seats 1 Quote Link to comment
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