Adjust valves to middle tolerance allowed?

Should you shoot for the middle of the allowed tolerance or the minimum or maximum. It is better if they are looser in the long run right? Thanks!

Aaron

middle to maximum gap, never the minimum.

bountyhunter wrote: middle to maximum gap, never the minimum.

+1

Thanks guys!

Middle to max.
Smaller gaps reduces the impact of valves on seats so I shoot for middle, but if that's not possible, then I err on larger side.

I try and aim for tigher end of scale for intakes since they dont expand nearly as much as exhuast valves,exhuast valves I run just a tad looser than the middle range to allow for expansion of valves

Always the maximum tolerance. These valves always loose clearance as they run. If you set them to the middle or the minimum they will be out of spec sooner.

893cv wrote: Always the maximum tolerance. These valves always loose clearance as they run. If you set them to the middle or the minimum they will be out of spec sooner.

This is true for for many but not all KZ's. I've seen this written many times, so I understand that it must often be the case, but that has not been the case on my KZ650 engine. I've tracked the valve clearances on my engine since it was new (April, 1977), and over the past 52,000 miles the clearances have changed slightly but they have never moved out of spec. I have only adjusted 1 valve in all that time (at 500 miles) and that was because from the factory the #1 intake valve was set right at the extreme lose limit. Overall my valve clearances are now 1 to 2 1000's of an inch loser than when the bike was delivered. They started life at .004" (including #1 intake after I adjusted it) and now they are at .005 - .006" Strange but true. Ed

An average of 1500 miles pro annum. Man, at this rate it will pass 100k in about 32 years already and you may have to consider the first overhaul

Valve clearance change due to wear and/or carbon build-up. Where wear appear (the most) dictate whether clearance increase or decrease. If the cam lobe and/or shim retainer wear more than the valve seats - valve head and/or cylinder head - clearance will grow. And in extreme cases carbon can build up so heavily on the upper side of the valve heads that they are prevented from closing fully, again increasing valve clearance. Not likely on Ed's bike. Instead, chances are that his valve seats are perfect and that the cam lobes have worn minutely. Just how sturdy these engines are is shown by the fact that no adjustment has been required in 52k miles from wear. It also indicates a man taking well care of his engine, both when it comes to oil changes, how it's used when cold and that it's not abused under any circumstance.

Sensible people usually have the best engines

faffi wrote: An average of 1500 miles pro annum. Man, at this rate it will pass 100k in about 32 years already and you may have to consider the first overhaul

Valve clearance change due to wear and/or carbon build-up. Where wear appear (the most) dictate whether clearance increase or decrease. If the cam lobe and/or shim retainer wear more than the valve seats - valve head and/or cylinder head - clearance will grow. And in extreme cases carbon can build up so heavily on the upper side of the valve heads that they are prevented from closing fully, again increasing valve clearance. Not likely on Ed's bike. Instead, chances are that his valve seats are perfect and that the cam lobes have worn minutely. Just how sturdy these engines are is shown by the fact that no adjustment has been required in 52k miles from wear. It also indicates a man taking well care of his engine, both when it comes to oil changes, how it's used when cold and that it's not abused under any circumstance.

Sensible people usually have the best engines

Sensable people drive volvos,this is a kaw forum we're nuts in general! :woohoo:

I have to admit, I've been called a lot of things (unfortunately, most of them richly deserved) but never sensible. :laugh:

wireman wrote: Sensible people usually have the best engines

Sensable people drive volvos,this is a kaw forum we're nuts in general! :woohoo:[/quote]

I drive a Volvo :blush: