Valve adjustments on a thumper...

[bonneville54]

I recently purchased a used TW200 for my sons...took it in for the initial 600 mile service and the tech said all was well except the exhaust valve was a bit tight.

I went for a ride yesterday and now there is a very noticible "tick, tick, tick noise. Quite loud, in fact. Too loose now? Normal?

Thanks in advance...

[forgeta]

Hello, I was wandering if you find an answer to your "click" problem. I bought a month ago a 2005 TW200 with 1200Km (800M). I also have this "click" noise but I'm not sure if it is valve related because it is not regular. The dealer tell me the valves have been checked during the first maintenance.

I remember reading somewhere that sometime, on motor with self ajusting chain tensioner, the tensoner get in a position between 2 teeth and the chain is a little bit too slack. I'm wandering if the noise can come from there.

[bonneville54]

My clicking is/was quite regular and some folks over Advrider convinced me that this was a good thing....better to hear the valves than not. Looser valves better than tight, etc.

A few hundred miles later and the 'ol boy is running as good as ever.

Good luck

[CaddmannQ]

Air cooled engines typically run the valves a little loose. Valves need a little clearance because when the engine gets hot the valves get longer, cams get bigger, rockers get fatter, etc. This all conspires to reduce the valve clearance. Air cooled engines heat up more quickly than liquid cooled ones, and typically need extra clearance to protect the valves under hard running.

The valves MUST close completely if the engine is to develop full compression. If they stay open even a little bit, compression (and power) is reduced.

Furthermore, they need to be cooled so they don't burn up. This cooling mainly takes place from two things: the incomming air (charged with vaporized fuel) cools them; but also they cool by directly transfering heat into the head when they touch the valve seat. This cools the very edge of the valve, which is also the thinnest part of it, and the most likely to burn away.

So when a valve is too "tight" it doesn't touch the seat long enough (or at all) and the edge will burn away. Once it burns away enough to leak compression, the engine will run poorly due to reduced compression, and will then need a "valve job" to restore it.

[bonneville54]

Great info! Thanks....so a little "loose" is good, eh? One should be able to hear them?

[CaddmannQ]

Originally Posted by bonneville54

Great info! Thanks....so a little "loose" is good, eh? One should be able to hear them?

Yes, and you shouldn't have to listen too hard to hear them either.

Some engines are quieter than others, but when cold they will usually all have some valve noise. Bikes with pushrods or any rocker arms will have more noise than models with bucket lifters and overhead cams.

Also, and engine mods like unrestrictive exhaust systems and induction setups can make the noise more aparent. My bike has both of those, but even before those mods you could readily hear the valves/rockers/cam chains pretty clearly, even though my bike is liquid cooled and has hydraulic lifters.

However, the noise quiets a lot when the engine is fully warm, and yours should as well.

[bonneville54]

Again, many thanks!