shimming valves...

.... sucks really bad. i hope i never have to do it again.

 

I'm about to tear into mine soon. I'm waiting on the new cover gasket and bolt rubbers then I'll start taking things apart. It doesn't look too complicated to me. I have a Clymer manual with all the photos and directions, so I ain't sceered.

 

It would be no big deal if you had an inventory of shims handy. Problem is you end up doing it twice - once to figure out what you need and a second time after the shim order comes.

 

I guess I didn't think pulling the discs out was a big deal. I guess I figured making the tool was harder than using it? I'll find out I guess.

 

I've read the procedure. Why can't I make up 8 wooden shims so I can pull the steel ones out? I have a spare motor to swap shims from. The wood won't hurt the cam. Having all the shims out at the same time would help?

 

Hey, that gives me an idea!! I have a 650 Maxim motor just sitting here too! I may have to tear into that one and see what size the pucks are! Thanks for the idea TimetoRide!

 

I bit the bullet and had the dealer adjust mine. They put in two shims and charged me $102.30. They said they adjusted the cam chain too. They must have adjusted it looser because it rattled worse than I've ever heard it. I took 5 minutes and adjusted it myself and it is perfect now.

 

I did mine a few weeks ago, its a tedious job, but not a hard job. It helps if you make a plan so you know which valves require new shims and which you can switch from other valves, them map out the moves so you always have the proper shim out when your going to need it.

 

It might be a royal pain to the regular person (something I'm far from it seems) but if I need to pull all the shims, I have simply removed the cams. Bit more work and not without its risks but a real quick job of swapping out shims if you've done your homework.

 

Exactly what I ended up doing as I had to replace all but 2, so it was easier to pull the cams and relocate/replace the shims and put it back together. I was fortunate that the Yamaha dealer close by just let me swap them out for what I needed as they said they have no call to use what they had in inventory... Now they shut the place down and I'm outta luck for the turbo if and when I have to do them on it.

 

bleh... that probably would have been better for me to pull off the cams... i had to physically open the valve with a standard screwdriver and then grab the disc with a magnet then grind it to spec and check with a micrometer and reinsert... i ended up doing 4 discs but it still wasn't fun to push open all the valves... if i had a proper tool rather than just a screwdriver i'm sure it would have been much easier. but the good thing is its over!

 

true enough, the tool (bought from chacal) is an indispensable tool ffor this job!

 

You ground your own 8O . I just bought new ones.

I hope you ground the side with the writing on it. Otherwise the next guy will get royally screwed when he reads those old values.

 

I found a local shop that will do it for a lot cheaper than the dealer. He said it was an easy task and charged a minimum fee to do so. I had some other work done but I believe the shimming itself cost me about 50 bucks. I didn't mind paying that to save me the trouble.

 

My local Yamaha dealer has an exchange program for shims. You just bring in ones you don't need then trade for the ones you do. Free! Of course, you do have to endure the kidding about the "giant" shims and the "let me see if we still have any of those *old* ones" remarks.

 

ya i was lucky enough that the only ones that needed adjusting were ultra tight so they could be fixed by grinding rather than getting a bigger shim. it was tedious task because i didn't want to take much off. i just touched it to the flat side of a bench grinder with a fine wheel. after I got it to the desired fit i measured it with a micrometer and marked it with an etcher (on the down side of course) and so i'll remember next time! hopefully there won't be a next time for a long time though!

 

You realize that grinding corrupts the "hardness" of the shim, as the rockwell treatment that "hardens" the metal only extends a few microns past the surface.......!!!

 

My Haynes manual says valve clearances should be checked and fixed every 6 months. I haven't had my bike that long so don't know how quickly they change. How frequently to others check / fix clearances?

 

Most people never do it, which is a problem. They don't do it because it's a big pain in the hard-tail.

Yamaha recommends checking them every 5000 miles/8000 kms or yearly. I think on the 900 models, the clearance check interval is a little longer, like every 7500 miles.

BTW, if you don't check and adjust the valve clearances, you're "basically" wasting your time synching the carbs and/or colortuning them............

 

when the mileage is low, or after the bike sat for a long time, the clearances will change more dramatically as the valves wear in to the seats. usually the clearances will get tighter, and would require a thinner shim. alternately, as the cam lobes wear, the clearances might increase, requiring a thicker shim.


if you don't know the state of the shims, I'd recommend at least checking them.

too tight = really not good - could burn a valve, since they're not closing all the way.
too loose = not as bad, but still not good...

I found that the most annoying part is to get the damn valve cover gasket to seal up afterwards. Checking the clearances is easy.... A cheap feeler gauge does just fine.

there's a thread somewhere that describes the use of a folded zip tie instead of the valve retention tool (which can crack the head if you're not careful). I've used this method on both of my bikes, without any problems. also, the shim buckets can be rotated so it's easier to get to that little notch where you can pry the shim out.