Compression check = valve clearance?????

At 30,000 km I checked my valve clearance, 6 exhaust valves and 2 intakes were right at the limit of specs. I'm now at 60,000 km and thought I should check the valves again, I do most of my own maintenance including valve clearance checks, but I think this time some might need to be re-shimmed and I am not comfortable pulling the camshafts so I went to the local Honda dealer where a friend of mine is the mechanic. He said just do a compression check, if the compression is good your valves will be good. Have any of you heard of this? I would think the only way a compression check would be valid is if they were so far out of spec that a valve was being held off the seat. I think I need to find another mechanic.

Since an overly tight valve will be on its seat a shorter time than others, you *may* find a cylinder's compression lower than others, but this sounds like a pretty dicey way to check clearances to me!

No need to feel apprehensive about pulling the cams though. Just be sure to dab a permanent marker on the sides of the meshed cam gears, so that you are certain they go back in exactly as they come out, eg. the correct tooth of the cam goes into the correct root of the driven gear. The cams are under some tension because some cam lobes will be pushing against valve springs and the cam can pop up away from the holders and rotate as you loosen the bolts.

Have an accurate torque wrench too, as the cam holder bolts are very small and only require 9 ft/lb on them.


Just noticed you have the 1300, so I'm not sure if my 1100 experience on this will apply to you.

Compression will NOT tell you your clearances, UNLESS they are so tight the valve is being held open. If that were the case, you have more problems than correcting the clearance. Many on this forum will gladly help you out with written instructions to remove and replace the cams if a shim needs to be done. I had Scooter (on this forum) check mine a couple of years ago. None needed to be changed and this was at 100,000 miles.

Good luck.

Yes, find another mechanic. By the time compression suffers you are well on the way to a burned valve if it didn't already happen.

+1 ... find another mechanic. There are good mechanics on this forum.

Bush, the ST13 is chain driven (your technique works on the ST11, but not the ST13).

BakerBoy said:

Bush, the ST13 is chain driven (your technique works on the ST11, but not the ST13).

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Thanks for clarifying that.

I have an 06ST also and similar to yours, I have 5 exhaust valves and 2 intake right at their limits. Been that way for the past 45K miles with no changes. I now have 86K miles on the bike and I check the clearances every 16K. If mine ever need reshimming, I'll do it myself with the help of guys on this site as I don't trust the honda shop here.

Maybe there's someone on the site that lives nearby and has done an adjustment. You already know how to do a check so you know what's involved there. Pulling the cams can be a bit apprehensive the 1st time and the right side is tougher than the left side. For me, you do need to mark them where they were when you took them off and not move the camshaft at all until they're back on and you're doing checks again, that and dropping something into a cylinder are the biggest mistakes you can make. But, marking them before taking them off and putting rags in the openings so nothing falls in will help reduce any issues. Odds are, they won't even need to be adjusted.

Thanks for all your replies guys, maybe I'll check them and then decide from there. Bush, where in B.C. are you located?

notagix said:

Thanks for all your replies guys, maybe I'll check them and then decide from there. Bush, where in B.C. are you located?

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The best place to be - the Lower Mainland, not far from the Peace Arch border crossing.

Check your valves first before you plan for more than you may need.
My bike was measuring 4 valves towards the limit at the last check 15,000 miles ago. Last month I checked them during my winter maintenance and expected to be adjusting a few. It turns out that all valves are within .01mm of nominal without any adjustment.
Goes to show, you may not need to pull any cams.

Mellow said:

For me, you do need to mark them where they were when you took them off and not move the camshaft at all until they're back on and you're doing checks again, that and dropping something into a cylinder are the biggest mistakes you can make.

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What do you mark the cam shaft gear/sprocket? If these are chain driven do you mark the chain and the sprocket tooth? Did you mean drop something down an oil drain hole? - I'd assume there is no way to get anything into a cylinder unless a nut or bolt goes in the spark plug hole.

SMSW said:

What do you mark the cam shaft gear/sprocket? If these are chain driven do you mark the chain and the sprocket tooth? Did you mean drop something down an oil drain hole? - I'd assume there is no way to get anything into a cylinder unless a nut or bolt goes in the spark plug hole.

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Poor choice of words. I would actually put everything back to TDC and then NOTE the cam markings so when it was re-installed, it would be at that specific spot, then I'd rotate the cams to re-check the one I adjusted. I'm sure there are better techniques.

Right on the 2nd point as well, not about dropping anything in the cylinder but the engine.

Mellow said:

Poor choice of words. I would actually put everything back to TDC and then NOTE the cam markings so when it was re-installed, it would be at that specific spot, then I'd rotate the cams to re-check the one I adjusted. I'm sure there are better techniques.

Right on the 2nd point as well, not about dropping anything in the cylinder but the engine.

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I liked your idea of stuffing rags in all the oil drain holes (or anywhere something might fall). If as said elsewhere, one or more of the cams is compressing a valve, does everything just go back together easily when you start tightening the bearing bolts? I seem to remember someone had problems at this point. He did not want to force things and stopped the tightening process.

I've indexed the timing chain to the cam gears two ways. First is to wipe the oil off a chain link and adjacent timing gear with a rag wetted with acetone or brake cleaner. Use a magic marker or sharpie to mark a line across the link and gear. If you do this Do Not wipe or rub the marked area with another rag after disassembly and remove the marks. I did this and removed my marks. That led me to the second method on the other cylinder bank.

The second way was to use a small zip tie to tie the chain onto the gear thru one of the holes in the gear. When you lift the camshaft off of the head the chain cannot move off the correct teeth and there are no marks to line up.

dduelin said:

I've indexed the timing chain to the cam gears two ways. First is to wipe the oil off a chain link and adjacent timing gear with a rag wetted with acetone or brake cleaner. Use a magic marker or sharpie to mark a line across the link and gear. If you do this Do Not wipe or rub the marked area with another rag after disassembly and remove the marks. I did this and removed my marks. That led me to the second method on the other cylinder bank.

The second way was to use a small zip tie to tie the chain onto the gear thru one of the holes in the gear. When you lift the camshaft off of the head the chain cannot move off the correct teeth and there are no marks to line up.

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Second way is a great idea. I've wiped my register marks off stuff in the past. Going to have to remember that one.