Valve adjustment

[DaveMadsen]

1979 CBX with 40,000 miles.

The bike has not been ridden in years so I am at the point of assessing the engine. All but two valves were within spec (proper clearance). I pulled the head and scraped a fair amount of carbon from the pistons and bottom side of the head. I also replaced valve stem seals. I reassembled the head and torqued to spec and now I have ZERO gap on ALL valves. I managed to finish up with no left out parts so nothing seems to have been omitted upon reassembly. Totally perplexed, I pulled the head -again - and visually inspected the valves and seats to see if I could see something obviously amiss, and then reassembled the whole thing and - of course - nothing changed.

My immediate goal was to adjust the valves and perform a leak down test, but of course at this point I am sitting here with a valve train which will not "adjust".

Also, prior to replacing the valve stem seals, I sandblasted the heads to remove 40 years of grime and carbon. I mention this because during this process the valve seats would have been exposed to the blasting. I can't phantom that such would have materially changed the shape of ALL the valve seats, but in the effort of full disclosure, I wanted to memtion this.
Can you recommend a 'next step'?

[daves79x]

Never sandblast anything on the CBX engine. That said, valve clearances should not have changed that much unless you cut the seats and lapped the valves. That will tighten them up. I assume you put every bucket,shim and valve back where it came from? Also, you should give every installed valve stem head a good whack with a plastic mallet and small regular hammer to be sure every keeper is in place and nothing flies off. If the buckets will still spin, you can change all the shims, but if they're that tight, you may want to bench shim them, one cam at a time, before assembly. Still think something is not right though.

Dave

[DaveMadsen]

Thanks for your reply. I'm an idiot. Since the head is fairly symmetrical, I managed to swap the intake and exhaust valves. In my confusion (and frustration) which bucket and which shim going where became a fog. I'm in the process of straightening thing out with the hope of ending up with 24 valves in correct ports with correct shims. Sheesh!

[daves79x]

Dave - you have a bit of a mess there. You do know also that there are 'A' and 'B' shim buckets? They should go where they were, but that is out the window now, so just put 'A's in A-holes (no pun) and 'B's in B-holes. Then you really need to hand-lap the valves a bit since you don't know where they were and they will not match the seat you put them in. Then you will find the exhaust valves are pitted and will not give a good, smooth sealing surface. Do you let them go, or replace them? You need to now do a complete evaluation of the head and decide what you want to end up with. I'd personally put all-new exhaust valves in, Viton stem seals and, with 40K on the engine, pull the cylinder and evaluate that too. You are into it now, might as well do it right.

Dave