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Discussion Starter #1
Two months ago my 95 Sprint become to start difficult. I check the valves. Exhaust valves are O.K. Again intake valves with no (zero) tolerance - 4 of all 6. I replace the shims. The bike run well, but I'm not happy. One of the shims is 2.20mm after this second adjustment (2.70mm when was new). Dropping 0.50mm just in two adjustments. First adjustment was before two years an 37000km. And minimum shim size are 2.00mm!
So I believe I must change the valves and do the valve seats after year or two. Any other suggestions ?
 

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tight valves

check compression, if all 3 cylinders are close (and in spec) I would guess you just have a bike that likes it's valves adjusted. check it again every couple of thousand miles, to make sure you are not loosing lash beware of running lean, if you are running too hot the intake valves could be growing enough to eat up the available lash then leaking. the exhaust valves have a larger lash for this reason

Do you loose power when the bike is hot? and did you adjust the valves to the loose or tight end of the tolerance range each time you did the job?
 

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Discussion Starter #4
No loose of power. The bike runs fine in all range of temperature, load and rpm.
I did the valves to the loose end of the tolerance range (0.20mm) now. I have done adjustment twice (at 77000km and 114000km). And first time I also did the valves to 0.20mm.
I believe I have bad valve seats.
 

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your valves could be hosed, but I really think you would be seeing power loss / compression issues. To be sure I'd see about looking into it with a bore scope, through the spark plug hole or in through the ports. should give you a pretty good idea whats going on, before you pull the head (maybe you can see the valves through the intake with the carbs off?)
 

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I did the valves to the loose end of the tolerance range (0.20mm) now. I have done adjustment twice (at 77000km and 114000km). And first time I also did the valves to 0.20mm.
I believe I have bad valve seats.
Your rate of wear seems a little high but you are using extended valve adjustment intervals. You might try reducing them to 16,000km to keep a closer eye on everything. If your bike has good power then I'd just keep adjusting them until you can no longer get shims that will fit. That might get you to 145,000km. Do you give the bike a lot of revs? High rpm will pound the seats and faces accelerating wear.
 

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Discussion Starter #7
Maybe because the extended valve adjustment intervals my bike is in this conditions. You are right sailfish, I keep adjusting them until I can no longer get shims that will fit. The bike has good power and I don't give the bike a lot of revs (4000 to 6000 rpm).
 
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