13 missed valve adjustments

TwistedKestrel

TwistedKestrel

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Went to look at a GS500 today. Owner has put ~ 52,000km on it, and never once did a valve adjustment on it (factory service interval is every 4,000km). Appears to have performed oil changes at least annually, bike does not smoke. Otherwise it's a nice bike. Would you or would you not roll the dice on the bike yourself?
 
TwistedKestrel said:
Went to look at a GS500 today. Owner has put ~ 52,000km on it, and never once did a valve adjustment on it (factory service interval is every 4,000km). Appears to have performed oil changes at least annually, bike does not smoke. Otherwise it's a nice bike. Would you or would you not roll the dice on the bike yourself?
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Im guessing you meant 24k intervals in service manual. I dont think ive ever had to change shims at the first 24k check, 48k check is a different story, though it shouldnt be at a point its catastrophic to the engine.
 
DownUnder said:
Im guessing you meant 24k intervals in service manual. I dont think ive ever had to change shims at the first 24k check, 48k check is a different story, though it shouldnt be at a point its catastrophic to the engine.
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Whoops, sorta - I meant 6,000km (it's specificed as 4,000 miles, so only 8 missed checks instead of 13) but it is definitely that low, more or less what I expect for an air cooled bike. Are you speaking from general experience, or from dealing with a GS500?
 
From the online parts diagram, that engine uses shim-under-bucket adjustment. I've never seen one of those that required checking every 4,000 km - they are normally pretty good for staying within spec nowadays. Rocker arms with screw adjustments have more finicky and fiddly bits between the cam and the valve, and they can go out of spec a bit faster, but it doesn't apply in this case.

If you want to buy that bike, use the missed service as an excuse to drive the price down ... and check them the moment you take delivery. But if it starts easily and runs OK, it's probably not much of an issue.

ZX10R with shim under bucket - never had to change any shims at 24,000 or 48,000 but I knew I would have to do some at 72,000 km - but I opted to do a rebuild with some different bits inside, which changed everything.

FZR400 with shim under bucket, and this is my race bike. I just had the engine apart because of broken transmission parts. All valves were still within spec after about 5 years of beating on it. (And today's chore was finishing up putting that engine back in the bike ... and it started on the first try.) This cylinder head has had a valve job in the distant past, though.
 
Again, the bike should be ok as long as its starting and running without some strange ticking etc, drop $500 or so from his price based on this and tell him its for an inspection of the clearances then do it yourself when you get the bike home. Even on a bike with a valve cover thats easy to get to I wouldnt be checking the clearances that regularly.
 
biggest issue with those gs's are that they burn oil like crazy. Ive never worked on as many GS's until this year...they all burn oil after a decent amount of kms.

If you really want a 500, go with the ex500 - way more reliable, way less headachs. The GS's get too hot or too cold.

For those gs....used motors are expensive, used parts are expensive, used forks are expensive. All in all...just an expensive bike for parts. Heck Id never pay as much for used part as gs ppl pay vs. my 636's.
 
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They are 'checks' and not necessarily adjustment.
And you are checking, most importantly, for valves that are too tight!
These obviously will not tick, but are more seriously detrimental than loose, ticking valves...

In the event that this GS500 has one or more tight valves, especially exhaust valves, they can become kinda scorched.
A leakdown test - or just a common compression test I believe - can quickly ID a tight valve situation... or obviously just a valve inspection.

My mechanics tell me that long operation with a tight valve is a messy business.
Over time that valve, valve guide and exhaust port can become quite burned up and carbonized...
And if the valve seat is cruddy with carbon, you'll never regain good compression by simply loosening the valve to proper spec. :shrug:

Anyway, the combination of 52,000 km and tight valves is not confidence-inspiring.
The owner will probably tell you "they're fine - there's no ticking, right?" :tongue:
 
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Thanks Brian and frekeyguy - will take that into consideration. Two bikes I was looking at had forks that were toast - I looked into what replacements would cost and it didn't seem too bad. Motors, I dunno, hoping not to cross that bridge.
 
Gryphon said:
They are 'checks' and not necessarily adjustment.
And you are checking, most importantly, for valves that are too tight!
These obviously will not tick, but are more seriously detrimental than loose, ticking valves...

In the event that this GS500 has one or more tight valves, especially exhaust valves, they can become kinda scorched.
A leakdown test - or just a common compression test I believe - can quickly ID a tight valve situation... or obviously just a valve inspection.

My mechanics tell me that long operation with a tight valve is a messy business.
Over time that valve, valve guide and exhaust port can become quite burned up and carbonized...
And if the valve seat is cruddy with carbon, you'll never regain good compression by simply loosening the valve to proper spec. :shrug:

Anyway, the combination of 52,000 km and tight valves is not confidence-inspiring.
The owner will probably tell you "they're fine - there's no ticking, right?" :tongue:
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You can tell if there is anythign wrong with a compression test and looking at the spark plugs.
I bought a bike at 60K with one record of valve check (no adjustment needed)...after an "ohmygod..ohmygod...engine will blow up" moment from a friend, I checked the clearances, all still within spec.

Like everything else, depends how the bike was ridden.
 
Oh right, suppose I should update this with the outcome.

I looked at I think around 7 different GS500s ... the one I mentioned in the original post turned out to be the best prospect. Bought it, rode it home, etc. Valve adjustment had 3 out of 4 valves tight, one was tight enough that I could barely turn the bucket around to pop the shim out. Curiously, the one that was in spec was on the loose end of required clearance - it will probably never need adjustment ever (intake valve). All shims that I removed had factory markings, so this is definitely the first valve adjustment ever performed on the bike.

I want to point something out, though, since people seemed to be offering merely general advice here. The GS500 is an air-cooled bike, with a motor that has not changed much in design since 1989. Air-cooled bikes generally need more frequent valve adjustments since they experience more dramatic heat cycling and may experience higher engine temperatures. There is a reason that the inspection interval is 6,000km! There really isn't much excuse for skipping valve clearance checks on a GS500, because it's as about as easy as it gets - I'm a slow-*** mechanic and I had time to do it on a weekday evening. A professional could easily do it in under an hour.
 
The engine goes way back to the 1976 gs400, I think. It's always been a 2v/cylinder with 2 overhead cams, so not very hard to check, either. The platform has been tweaked for a while, too. It hasn't been strictly air cooled since 2002, going air/oil in 2004 until Suzuki canned it

The Red 89 with factory clipons and white wheels looks the best. Shame they're so overpriced, as they would make a good platform for chop/bob/cafe/rat.
 
Flywheel said:
The engine goes way back to the 1976 gs400, I think. It's always been a 2v/cylinder with 2 overhead cams, so not very hard to check, either. The platform has been tweaked for a while, too. It hasn't been strictly air cooled since 2002, going air/oil in 2004 until Suzuki canned it

The Red 89 with factory clipons and white wheels looks the best. Shame they're so overpriced, as they would make a good platform for chop/bob/cafe/rat.
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The overpriced thing doesn't seem to be consistent over time. I have definitely seen roadworthy GS500s for less than $1000 ... I didn't manage to snag one due to either the seller being nearly impossible to reach, or the bike being a bit too far out of my way. They do turn up locally. However, of course, the reverse was true - I looked at a lot of GS500s that hovered around $2000, no matter how old they were. I might have considered paying that, if any one of those sellers had any concept of maintenance!
 
TwistedKestrel said:
Oh right, suppose I should update this with the outcome.

I looked at I think around 7 different GS500s ... the one I mentioned in the original post turned out to be the best prospect. Bought it, rode it home, etc. Valve adjustment had 3 out of 4 valves tight, one was tight enough that I could barely turn the bucket around to pop the shim out. Curiously, the one that was in spec was on the loose end of required clearance - it will probably never need adjustment ever (intake valve). All shims that I removed had factory markings, so this is definitely the first valve adjustment ever performed on the bike.

I want to point something out, though, since people seemed to be offering merely general advice here. The GS500 is an air-cooled bike, with a motor that has not changed much in design since 1989. Air-cooled bikes generally need more frequent valve adjustments since they experience more dramatic heat cycling and may experience higher engine temperatures. There is a reason that the inspection interval is 6,000km! There really isn't much excuse for skipping valve clearance checks on a GS500, because it's as about as easy as it gets - I'm a slow-*** mechanic and I had time to do it on a weekday evening. A professional could easily do it in under an hour.
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Good thing you checked and didnt listen to the people on this thread that think they no better cause they checked a couple of bikes and the valve clearences were in spec......and then conclude it applies to all bikes. I checked one of my bikes at half the recommended interval and 25 percent of the valves were out of spec, I check alot more often now.
 
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