valve clearance too small. is that possible? gs450

[Anonymous]

i have just gotten around to checking the valve clearance on a very frustrating 1980 gs450 restoration project. I found that there was actually such a small clearance that it might actually be touching. Before i got into the mess of buying and replacing the shims i asked myself, is this possible? I mean why would an old beat up bike have a clearance that is too small concidering that wear usually increases the clearance. So this is why i ask anyone who can help me: is this likely to be true or am i simply checking the clearance wrong or is something more serious out of place? thanks

[Anonymous]

May be some one changed the shims without measuring the clearance in the past... I don't know your 450 history, but is the only thing that comes to my mind...

Regards!

[robinjo]

Yes it is possible, on my previous 1000S 6 out of 8 valves were too tight. 8O This can happen with normal wear.

[Anonymous]

valves

with the engine being over Head. Cam the wear on the valve seats at the point that they make contact wears, and this causes the valve to sit deeper in the seat area of the valve, in return this reduces the valve clearance at the cam and valve shim,

[saaz]

Yes they can tighten. Wear is not that much of an issue. The valve seats can recess a bit, tightening clearances. Untill the clearances bed in, it is worth checking them in case they tighten up too much, as burnt out valves can eventuate. A loose clearance is an obvious ticking noise.

[Anonymous]

A loose clearance is an obvious ticking noise.

Tappy Valves are Happy Valves!

[Anonymous]

That's very true!!!

It's better to have noisy valves and a little performance degradation than burnt valves...

If the valve clearance are difficult to get to specs, its better to have them loose than too tight...

[Anonymous]

earlfor and i have been dealing with my poor '79 GS750E--- the valve timing was off, the ignition timing was off, the compression is crap and now that i've checked the valve clearances, they're too tight as well-- i can't even get the spade of the feeler b/w the cam and valve--so...yeah. i know how you feel.

[crc1214]

Oh hell yes it can happen!!! 2 valves on my 550 were tight when I checked them last!

[Anonymous]

who cares whats it gunna hurt

[crc1214]

Nah, it won't hurt anything Mr. bboxer. Just keep riding with tight valve clearances. But make sure you have a lot of time and money......... oh and I almost forgot - a complete mastery of the skills it takes to do a valve job.

Please tell me that post wasn't serious.

[Wingnut]

Yes, as stated they get tighter with wear not looser. Should you ever run across an engine with low compression you should check the valve clearance first BEFORE condeming the engine. I have read here of people saying they have low compression on bikes with relatively low miles and can't help but suspect the valve clearance as the real cause.

[Anonymous]

Yeah i was being sarcastic....but anyways, how do they get tighter as it wears, and how tight is too tight, when i rebuilt my engine i didnt have the proper feeler gauge to do it...all i know is that even the smallest one wouldnt fit but the cam lobe doesnt touch the tapper its like a millimetre away from it maybe less is that too tight? Its a78gs400