Hi All,
I'm pretty new to the forum and own a 2008 GS500F K7 in the UK, with around 35K miles on the clock.
When performing a recent valve clearance check I noticed the exhaust camshaft mark "1" is 1 tooth away (anticlockwise) from being parallel to the cylinder head, when RT generator mark is aligned. Also there are only 17 cam chain pins between the "2" mark of the exhaust cam and the "3" mark of the inlet cam. My Haynes manual and Suzuki dealer say this should be 18.
I'm the 2nd owner from 3000 miles 3 months old. The bike runs like clockwork so I'm unsure if this is a real issue that I should be concerned with? I have replaced the tensioner for safety but I found it too difficult to move the exhaust cam to the alignment marks (not enough slack even with tensioner removed and slackening the chain by moving the crank). I didn't want to remove the camshaft end bearing caps so I have left the exhaust cam in the misaligned position and re-assembled the bike.
Is it possible the chain has jumped a tooth or is it possible its been assembled incorrectly in the factory?
Or is the offset is intentional?
Will this cause any damage to engine/valves etc?
I have searched through the posts but have not found anything that exactly matches, so apologies if this has been discussed previously.
Any advice gratefully received.
Cheers,
Steve
Pictures? We LOVE pictures.
It could be how you're looking at it. I know it can be confusing because the head is at an angle and the pictures show the head perfectly horizontal. It plays games on your eyes and brain.
I would tend to say if the bike is running perfectly, don't touch it. If it is off a link, one link is maybe 5 degrees which isn't that much for our engines. That may amount to the same as a shim a little too loose or tight.
Thanks for the quick reply, hopefully attached some piccies.
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That black stuff on the rotor in your pic kind of blurs the marks a bit so I can't see it clearly but it looks to me like the rotor needs to be turned clockwise a bit more to get it aligned on the marks like shown in my diagram. Turning that a bit more clockwise would have the finished top of the head line splitting a link more like shown in my diagram. I can't count the links looking at the marks in your 2 different pictures but it should be 18 pins from arrow 2 to arrow 3 as shown in diagram. Count pins not links. 18 pins would have 17 links between them I think. I made that diagram putting together a couple different pics and directions from the Suzuki shop manual.
(http://www.gs500.net/gallery/data/500/gs500signalgenerators.jpg)
Note the notches on the cam ends are pointing directly towards each other and in alignment with the head top finish when engine is in proper timing position.
I have tried to zoom in to show the correct generator alignment. Also I have included the only photo I have that shows the end of the inlet camshaft. The notch is perfectly aligned and parallel with the cylinder head facing forward. Unfortunately its a little out of focus.
Also please note only 17 pin chain spacing, rather than the 18 specified.
[attachment deleted by admin]
The proper notch alignment of the intake cam and the misalignment of the exhaust cam notch does confirm it's the exhaust cam that's a tooth late in timing as clarified by your last 2 pics. Can't really see the arrows and numbers on the cam gears but you can see them clearly.
I guess if that was mine I would fix it right by taking the camshaft loose to move the chain a tooth. My guess would be it came from the factory that way but you never know for sure on a previously owned bike. My 02 came from the factory with a bucket fit too tight and an exhaust valve stuck wide open one freezing cold morning and was broken off by the resulting internal clash and I had to pull the cams and head to repair. I put the cams back with great care, we've had too many broken cam caps and stripped bolt threads to do it unless necessary.
But it could be Addy's suggestion above was best, "if the bike is running perfectly, don't touch it." Don't see where that one cam being off one tooth could cause any internal conflict if it doesn't bother you.
Thanks for the replies. I think I will leave it this year as i am more scared of damaging the cam bearing caps. Perhaps I will try to rectify when I winterise the bike in November.