82 xj550 Maxim, Consequences of New Valve Seats

I inherited this bike in terrible condition and had to do a lot of work to get it running well again. I rode it for about 3k miles and had to stop due to lack of compression. I ended up pulling the head and redoing the valve seats due to pitting. Unfortunately I forgot that my valve shims would be completely out of spec due to new seats being cut. I am at the point where I just need to measure the lash but my measurements are coming out very inconsistent. Some valves had .06" of clearance where as others maxed out my feeler gauge. Any recommendations on what to do?

 

Get the smallest shim and use it as base to measure the clearance on each.
Lotta work moving them around.
Handy to have a small size spare in your case.

 

I did end up getting a 2mm shim to measure it, do I need to have the cams fully timed in order to measure accurately? Like should I be rotating the cams around to get accurate measurements? Ive just been taking the cam on and off every time I measure.

 

Yes you will have to keep the timing in check otherwise you run the risk of the valves hitting the top of the piston if they are open when the piston comes up.
Painful stuff.

I don't know how effective putting all the pistons at a low point and moving the cams manually without the chain on the sprockets would be... probably a way if you have a spanner than works on the hex on the cams.

 

Oh and I reckon a head guy... can actually take a smidge off the top of the valve stems if they are way out of spec. I wouldn't attempt this myself and you'd be taking your head down to the head guy at this point.

 

STOP, dont rotate the cams independently, apart from the danger of the piston hitting the valve , theres also a danger of the valves hitting each other, i managed to bend 4 valves even with the head on the bench by rotating the cams with a spanner on the flats
i'll see if i can find the link to my build, explaning it

 

this is it , if it works.
bensalf's 4 year caferacer build | XJBikes - Yamaha XJ Motorcycle Forum
the valve bit is about 2 thirds way down on page one

 

Back up.
When you replaced the valve seats did you also replace the valve guides, or at least make sure that they weren't worn?

 

How did this end up?
I ask because I just ran into the same issue on a head I purchased from a wrecker.
And after seriously taking @bensalf s advice and finding some 220 shims managed to do a measurement.

How did you go?

 

If you still have the head off of the bike, you can check clearances by rotating the cans independently. You are ONLY checking the clearance between the BACK of the lobe and the shim. If the head is still off of the bike, you won’t hit any pistons.
But once you’ve set the clearances, don’t remove the cams, or you’re gonna run the risk of something changing slightly. Shouldn’t change, but it’s a risk.
Make sure cams are properly positioned before the chain goes back on, and the head goes back on the bike though.
If your head is back on the bike, then DONT do them independently…… now, the timing DOES matter.