How to shim valves?

Recently had my valves redone at a machine shop (had the head off the bike to get at the pistons for a ring job) and now they've got a bit of a rattle to them as the bike idles down that my local mechanic says is a valve rattle and they should be shimmed. It's not anything savage, but is annoying since I've put so much effort into this old beast that I want it to run perfectly.

Anyone care to give me the basics on how to do this? What tools and weapons I'll need, parts, etc. I'm pretty handy -- redid the rings and reset the timing myself when I had it apart, so I'm confident that I can do it myself, just not sure what to do.

Thanks,
Mike

 

Where in Ontario are you?

You need to check the valve clearances to confirm your mechanic buddy's suspicions. You need an allen wrench to pull the cam cover off and some feeler gauges. Think about a gasket as well for the cam cover.

Once you know what your valve clearances are, you can determine what size shim you need and where you need it. Check the clearances means that you are checking the space between the top of the valve cap and the bottom of the cam lobe when the valve is shut (read, cam not contacting the cap).

 

Here are a couple of great photos of what needs to be done from a previous post. The pics are at the end of the thread.

http://www.xjbikes.com/Forums/viewtopic/t=5078.html

 

You'll need this also.

Source:
"Xj600 92-on Haynes repair manual"

 

I'm in Welland, why? Are you nearby and do you work for beer?

 

Awesome! That's dead easy to do. I've already taken this whole neighbourhood of the engine apart a couple of times. Do the shims just sit on top of the valve caps? Where does one get such shims? Are they a standard thingy or a special order from my local bike shop?

 

That's handy, thanks.

 

LOL! It's in the fridge, man, what are you waitng for? Bring your wrenches!


Well - Kitchener isn't all that close to Welland but I do work for beer![/quote]

 

It's in the fridge man, what are you waiting for? Bring your wrenches. LOL

 

Ok, here's a question. If the valves have a significant gap between the cap and the cam lobes, will that rob power at top end? I'm thinking that if there's a big gap (she rattles like a frickin' sewing machine) that the valves aren't opening fully, and thus the cylinders aren't getting a full air/fuel charge each time. What do you wiser minds think of my theory? Best top-end speed I can get out of this bike (wide open in 5th gear) is 110 km/h (65 mph). Ack!

 

No.

Some noises are good noises ... as irritating as they might be!

Measure them.
If they are "Tight" out of Specs ... you need to do something about that because you risk having them become too tight and burning.

If they are "Loose" out of Specs ... you need to do something about that; too.
If you are running too loose you risk "Throwing a Shim!" Very bad news!

If they are NOT tight ... AND ~~> Within Specs ... You leave it alone!
Shimming to reduce the "Noise" will only place you AT Risk of running that Valve Tight ... in the future ... and placing the Cam Lobe at risk for being worn down prematurely.

But, if you have the money for having a Cam Lobe resurfaced ... go ahead.

 

Hrm. Ok. Thanks Rick. I'll tear the top off it and measure the gaps when I get a minute. I know it needs shimming. When I had the valves redone last summer, I just took the head, valves and valve caps to the machine shop to do it...stupidly left the cams at home so the machinist said (obviously) that they weren't shimmed. Needs to be done, I'm sure.

Any theories as to why I seem to hit a wall at the top end? This thing should go like spit. Last Maxim I had (mind you it was a 650, but still) I never did get to the top end of it -- was too scared to keep pushing when it kept climbing at 160 km/h and no end in sight. Why might this one be topping out at 110-120 km/h?

Cheers,
Mike

 

I don't understand: "They weren't shimmed"

They WERE shimmed and Not Adjusted.
-or-
They didn't replace the shims???

 

Sorry...they have the original shims in place that were there prior to the valve work.

 

Measure them up.

Run across them with the two feelers that ARE the limit.
You know which ones are IN and OUT.

Go back and do the hard numbers on the ones that are OUT.