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1977 GS750 Valve Issue ?
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XGS750X
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XGS750X
Ok. Measured with a Toonie. You Americans need these as they are almost the exact size as the shims.
The Toonie is 1.80 mm thick and I could just barely fit a .80 mm feeler gauge in each valve. So I'm thinking I need 2.55 shims. Here's the math - 1.80 mm + .80 mm = 2.60 mm - .05 mm for clearance = 2.55 mm. I think I got this correct?
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Read the manual again...or type the right measurements..but its .08 MM as the MAX gap and .03MM as the minimum. A .80 MM gauge is wrong to use.Last edited by chuck hahn; 09-14-2015, 08:45 PM.MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550
NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.
I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.
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XGS750X
I used my larger set of feeler gauges as the toonie was only 1.80 mm thick and created a pretty significant gap. I went up in feeler gauge sizes until the gauge just barely fit which was .80mm. Adding those two thickness together would create a 2.60mm "shim" which would have no clearance. I then subtracted .05 mm which in theory would then be my clearance (right in the middle of spec). So as mentioned I think 2.55 mm shims should be a safe starting point.
Maybe my previous post made no sense but to me these numbers make sense or am I from Mars - which is totally possible!
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.05 clearance would be OK to shoot for, but I tend to shoot for the MAX clearance. Primarily, because the clearance wears tight with time, and even a slightly over clearance (.09-.1mm) clearance won't do any damage. It will give you more time between lash adjustments, and according to the guys who used to build the Vance and Hines FZR motors actually provided a very small, but measurable gain on the dyno. This was information I got from a tech at V&H many years ago when I was club racing FZR400s.
You might want to get a few 260's in case the gap is too largeLast edited by 8ball; 09-14-2015, 10:09 PM.1979 GS550, 2003 R6, 1998 XR400 Dual Sport, 2004 V-Star.........
Decisions, decisions, what to ride, today.
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My GS550 Build
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Originally posted by chuck hahn View PostRead the manual again...or type the right measurements..but its .08 MM as the MAX gap and .03MM as the minimum. A .80 MM gauge is wrong to use.1979 GS550, 2003 R6, 1998 XR400 Dual Sport, 2004 V-Star.........
Decisions, decisions, what to ride, today.
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My GS550 Build
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Originally posted by XGS750X View PostI used my larger set of feeler gauges as the toonie was only 1.80 mm thick and created a pretty significant gap. I went up in feeler gauge sizes until the gauge just barely fit which was .80mm. Adding those two thickness together would create a 2.60mm "shim" which would have no clearance. I then subtracted .05 mm which in theory would then be my clearance (right in the middle of spec). So as mentioned I think 2.55 mm shims should be a safe starting point.
Maybe my previous post made no sense but to me these numbers make sense or am I from Mars - which is totally possible!
Your math made sense. I think Chuck missed the fact that you had a coin in the buckets. Most of us Yanks don't know a Toonie from a three fer. LOL I just have happened to work for Canadians much of my career, so I am familiar with your Monopoly money and crazy coins. I have returned from the Great North more than a few times with my pockets too heavy with Loonies and To
onies1979 GS550, 2003 R6, 1998 XR400 Dual Sport, 2004 V-Star.........
Decisions, decisions, what to ride, today.
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My GS550 Build
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XGS750X
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XGS750X
Originally posted by 8ball View PostYour math made sense. I think Chuck missed the fact that you had a coin in the buckets. Most of us Yanks don't know a Toonie from a three fer. LOL I just have happened to work for Canadians much of my career, so I am familiar with your Monopoly money and crazy coins. I have returned from the Great North more than a few times with my pockets too heavy with Loonies and To
onies
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Dont get TOO high 8ball. S hims have been known to jump out of the bucket a little on way loose valves and get snapped...and then its a torn up bucket and cam lobe.MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550
NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.
I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.
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Originally posted by chuck hahn View PostDont get TOO high 8ball. S hims have been known to jump out of the bucket a little on way loose valves and get snapped...and then its a torn up bucket and cam lobe.
Noted. .1 mm is less than .004", and I wouldn't ever suggest going more than that. My suggestion is, merely go for the high end of the spec. but don't sweat it if it was just out. But you are correct. Most of the motors I have dealt with are shim under bucket, so there is no risk of a dislodged shim. But the lash spec on these engines is the tightest spec I have ever dealt with.....STUPID tight! My R6 valve lash spec is 5 to 6 times bigger than my GS!1979 GS550, 2003 R6, 1998 XR400 Dual Sport, 2004 V-Star.........
Decisions, decisions, what to ride, today.
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My GS550 Build
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XGS750X
New shims in! I started the bike, it warmed up much quicker than before, great throttle response and no smoke either but it did have a bit more or a valve rattle / noise? it was never perfectly quite and it did have louder spots at certain RPMs but it seems more consistent now? Either way, I haven't had a chance to ride it yet, I'm planning to do that tomorrow but here's a quick rundown of the shims originally found in the bike, the new shims I put in and the clearances i'm now getting. Thanks again for the help. Will report back after a good rip.
Cyl #1 EX
Original shim: 2.70
New shim: 2.50
Clearance: .07mm
Cyl #1 IN:
Original shim: 2.70
New shim: 2.50
Clearance: .07mm
Cyl #2 EX:
Original shim: 2.75
New shim: 2.55
Clearance: .09mm
Cyl #2 IN:
Original shim: 2.75
New Shim: 2.55
Clearance: .08mm
Cyl #3 EX:
Original shim: 2.75
New shim: 2.55
Clearance: .07mm
Cyl #3 IN:
Original shim: 2.75
New shim: 2.55
Clearance: .09mm
Cyl #4 EX:
Original shim: 2.70
New shim: 2.50
Clearance: .05mm
Cyl #4 IN:
Original shim: 2.80
New shim: 2.55
Clearance: .08mm
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Forum LongTimerGSResource Superstar
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Those numbers suggest damage occurred. You best recheck them in 500 miles or so.Ed
To measure is to know.
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XGS750X
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