Low Compression Readings. I Think the Rings Are Shot

[Nessism]

FYI, you don't need any fancy metric feeler gauges to check the valves, you just need a set that goes down to .0015". If that feeler doesn't go, you need a thinner shim. You also can use the tie wrap method to remove the old shims (check Basscliff's website for info). Also, get Steve's spread sheet and get ready to take an inventory of your existing shims and clearance. First thing to do is take inventory, then put in an order with Z1 for new shims. Oh, and never turn over the engine with any shims removed. You will have to pull the shims one by one after measuring the clearance, then record the shim thickness, then replace that shim back into the engine before moving to the next shim.

I wouldn't bother trying another compression gauge until the valves are verified. It could very well be that the valves were never adjusted and now they are all tight.

[MadCapsule]

You did have the throttle physically open when checking ???

Yep. I was holding the throttle open while doing the test. Also, just out of curiosity, I did a couple tests with the throttle closed and didn't notice too much of a difference. Could that be an indication of anything?

If the valve clearances are Ok? I would check the cam timing ? maybe it has jumped a tooth

I'll check the cam timing while I've got the cover off.

FYI, you don't need any fancy metric feeler gauges to check the valves, you just need a set that goes down to .0015". If that feeler doesn't go, you need a thinner shim. You also can use the tie wrap method to remove the old shims (check Basscliff's website for info). Also, get Steve's spread sheet and get ready to take an inventory of your existing shims and clearance. First thing to do is take inventory, then put in an order with Z1 for new shims. Oh, and never turn over the engine with any shims removed. You will have to pull the shims one by one after measuring the clearance, then record the shim thickness, then replace that shim back into the engine before moving to the next shim.

I wouldn't bother trying another compression gauge until the valves are verified. It could very well be that the valves were never adjusted and now they are all tight.

Well, I already have a 25 pc. metric feeler gauge set on the way from Z1. Probably overkill.

"Oh, and never turn over the engine with any shims removed." I'll commit that to memory! Thanks for the tip.

[bellucci]

Are you in the city or 'burbs? Who did the head? Just wondering right now...
Curt

[MadCapsule]

Are you in the city or 'burbs? Who did the head? Just wondering right now...
Curt

I'm in the city.

Motorcycle Mania installed the head. They've got a really good reputation and are one of the only places around here that will work on vintage Japanese bikes.

I'm not ready to fault them just yet. Not until I get the valve cover off and see what's what with the valve clearances.

The feeler gauges came in today, but it started raining after I got off work and I don't have a garage. I'll have to wait till it clears up.

[Nessism]

It's critical to always torque the cylinder head and check the valve clearances after a brief break in period, 600 miles or less, after performing engine work.

[MadCapsule]

It's critical to always torque the cylinder head and check the valve clearances after a brief break in period, 600 miles or less, after performing engine work.

Ah. Wasn't aware of that.

Well, here's hoping I haven't burned up any of the valves. Is there a way of spotting a burnt valve without removing the head?

[tkent02]

Is there a way of spotting a burnt valve without removing the head?

You probably haven't hurt it yet. The fact that your compression numbers are more or less even hopefully means nothing is burnt. A burnt valve would give very low compression if any. Just check the compression after the valves are adjusted correctly.

[MadCapsule]

You probably haven't hurt it yet. The fact that your compression numbers are more or less even hopefully means nothing is burnt. A burnt valve would give very low compression if any. Just check the compression after the valves are adjusted correctly.

Good to know.

I'll report back after I've gotten the clearance numbers.

[bellucci]

Keep us in the loop. If you need another set of eyes, let me know. The gang is going to Union Grove to race on Thursday. If by Sunday you are no closer, give me a call. My house visits are very reasonable...(fuel).
IF its a big problem, I will call Mr. Wizard(Trippivot)
Curt

[MadCapsule]

Just got home from work and I'm about out of usable sunlight (I really want a garage). This may have to be a Saturday morning project.

I don't want to start and then leave the bike sitting outside with the valve cover off, even if I do have a bike cover.

Thanks for the offer, bellucci. I'll give you a shout if I need more help.

[5150/gs]

After valve seals and a lap i adjusted my valves 3 times before they settled in.And retorqued 2 times.

[MisterCinders]

Wait a minute. You took the bike to a shop to do the cylinder head!?!

Dude, you should have called me. We could have done that here in an afternoon.

If you end up needing parts for the top end, I have fresh rings and some valves for the 750.

Shoot me a text.

[MadCapsule]

Text sent. Looks like I'll be taking the bike over to Mr. C's place soon.

My new 530 chain and sprockets arrived today as well. I have some questions about the installation, so I'll start a new thread in the appropriate section.