Topic: How much can a valve guide take?

[547]

Here is the history of this engine-
Bought the bike in a package deal and has been in my basement for a few years.
I got bored and started tearing into the engine.
Cam sprocket and cam chain were both broken so I took apart the top end and then split the cases. I cleaned out all the
broken bits of metal and a stray Allen wrench that the PO must have lost in there. Everything but the cam sprocket and chain was fine.

This is what I did-
I wanted to lap the valves so I used the hammer method to remove the springs. What happened was that on one of the exhaust valves only one of its holders came off. I think the uneven tension and having to hammer it again to get the last holder off may have been what bent the valve stem. Then to get it out of the guide I had to use a long bolt and tap the valve through.

My question is-
Is what I described too hard on a valve guide? I can't see any apparent damage to it. How do you know when you need new valve guides?

[camelman]

Ummmm, I don't know if this is a joke, but here's your answer:

You done broke it.  Either your valve guide or the valve stem... or both, are bad.  I don't think you can bend the valve stem back, but you might be able to get that valve guide bored.  The only issue is that there might be an eccentric hole left in the valve guide afterwards.  It is probably best to take it to a machine shop and ask them.  I'd expect a new valve and guide if I were you.  It actually shouldn't cost much money to fix.

Camelman

[faux fiddy]

I have seen valves bent back in to shape, and if you are precise and the valve is not too far out of shape it can be made to work fine.

I posted a comment about that here:
http://forums.sohc4.net/index.php?topic=69170.msg769049#msg769049

Most people say just find one, and yours  is probably bent on the opposite end as they usually are which may create other considerations. It can be done sucessfully though, and it requires precise measurement.  The comments folowing mine raise cnsideations of the MC vs Car application, and probably your style of riding might dictate whether you want to get new stuff.

As far  as what it might have done to the guide, just for sh8's and giggles, I would check the guide with one of your good valves and see what kind of slop you  can feel or measure.

[754]

Like the last post said, if a known good valve does not spin freely replace it. They can break up.

 I drill & break them to remove them if I have the time..

[547]

The valve is trash so that's not an issue. I plan to replace it. I don't trust that bending it back would be something I could do accurately. As poorboi suggested I used another to test the guide for slop.
There wasn't any. That is good enough for me.

[754]

You are not looking for slop, you are looking for binding.. ie if it dont slide thru on its own, guide may be tweaked..

Guides have relief, at the mounting surface & that is where they can break or crack..

 ...................................................................................

 Where did you get that username...

.. it looks familiar..somehow..

[547]

754, they spin ok in that guide so I am thinking the guide is fine.

My user name- it was the Unit # of the warehouse I used to work in.


I can see where it might be familiar