Jump to content
Sign in to follow this  

What is causing the valve tightening???

Recommended Posts

Good question - I would like to understand what "normal" or typical valve tightening is and what to expect as my valves haven't changed for 500+ miles (checked often) and I recently had to adjust the intakes by 0.002" as they were approx 0.004" - 0.005" and the spec is 0.006".

MSTex

Share this post


Link to post
Share on other sites

Its when the valve starts to cup where it meets the valve seat on the head. Take a piece of metal and hit it with a hammer and it will dent. Same thing with the valve. Just takes alot more hammering before the dent forms.

Share this post


Link to post
Share on other sites

If the problem is the valve it's self, then higher quality valves could effect the problem... Is there an aftermarket valve that does this. If that is all it takes, the problem is a pain in the .... but solvable. Is that correct???

Merlinn

Share this post


Link to post
Share on other sites

If the spring pressure is too low the valves bounce off of the seat. That is what causes the hammering. The valve then sits further in the seat the clearance goes away. From what I understand the valve stems are too small and won't handle increased spring pressure. I guess that is why 05's have bigger valve stems.

Share this post


Link to post
Share on other sites

From what I have heard Kibblewhite is test (or will be testing) a SS valve and spring. That may be an option in a few months.

brown

Share this post


Link to post
Share on other sites

Its when the valve starts to cup where it meets the valve seat on the head. Take a piece of metal and hit it with a hammer and it will dent. Same thing with the valve. Just takes alot more hammering before the dent forms.

known as "Valve Beat In"

It does happen as part of normal wear, during initial breakin.

It can occur due to soft valve face. Soft valve seat. Springs too stiff. Soft valve springs will cause valve float, not usually beat in. Showing as poor high speed responce(difficulty breathing) and piston contact! :cry:

It can be rectified a number of ways. e.g.Harder valve face, but if you go to far you simply shift the wear point to the seat!

If you have seen some other threads on the topic,you may see them talk of seat angle. Increasing the contact area (smaller angles)between the valve and seat decreases the wear, spreeding the load.

AN engine such as the 4 stroke performance bike engines are revving at what was just a few years ago the reality of only F1 type machines. We are riding in a WONDERFUL ERA of performance for the money. Everyone has some teething problems with new product. And when you change even something as simple as the manufactering materials, you change the whole dynamics of the component. Changing to SS valves may be the answer, but something WILL change! Probably the ease of attianing 13 - 14,000 rpm!

Still a fantastic product :cry:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×