Valve stem seals, valve spring plus a question or 2

[Def]

Okay, so I tried to replace my valve stem seals on my 79 GS1000 with the head still on and the engine in the bike. Yup...it can be done! It took me forever but it worked.

Anyway...after installing the last valve stem seal I realized that the valve springs have a certain way they should be installed. I did not realize that so there is a real good chance some of them are installed the opposite way. What are the repercussions if I just leave it?

Also, can changing the valve stem seals affect valve adjustment in any way? I measured up the valve clearances before I removed the cams so if not then I can replace shims very easily before installing the cams.

Gurus...please impart me with your knowledge.

 

[Nessism]

Whether to take it back apart is a tough call. I'm not an expert but I doubt the spring orientation is critical.

 

[fastbysuzuki]

Also, can changing the valve stem seals affect valve adjustment in any way? I measured up the valve clearances before I removed the cams so if not then I can replace shims very easily before installing the cams. .

The shims should be the same however it's not a big job to recheck them (peace of mind)
As for the springs ime with nessism.

 

[Steve]

The clearances should not have changed. However, ... there is that slight little chance that the retainers are not yet fully-seated on the keepers, which might throw any measurements taken NOW off a little. I would wait a few hundred miles to make sure everything is settled properly, then check clearances.

I also doubt that spring orientation matters (much) on a street engine.

.

 

[Def]

Thanks for the input. I decided to remove the collettes and check the spring orientation. 5 were correct and 3 were not. Glad I checked cuz it would have irritated me to no end. As for the shims...I measured them before I removed the cams so I will go ahead and change the ones outside of the tolerance level when I reinstall the buckets. Cheers.

 

[Def]

I should mention that after changing the valve stem seals my oil consumption did not change at all. Still using 1 qt of oil per 800 kms. The other noticeable diff is that my compression is now about 25 lbs less per cylinder than it was before. 100, 85, 90, 105.(Checked while engine was hot, plugs out, full throttle) It has affected my ability to set the carbs properly. I think the lower compression is due to a few chunks of carbon breaking off the valve lips allowing an even poorer seal. (These are just theories based on my limited experience). So.... I'm going to tear down the topend to see what's really going on. Should be fun and pricy all at the same time!!

Anyway....while I'm in there...what should I check for? Just thought I'd put it out there for you engine rebuilders out there. I'll check things out as per the shop manual but a little (or a lot) of advice would be greatly appreciated. I'm trying to accomplish 2 things, primarily. Stop the oil consumption and bring up the compression to a respectible, even reading across all four cylinders.

 

[hillsy]

Depending on how you secured the valves, you may have slightly bent them.

 

[hillsy]

There's only really 2 ways oil can get burnt - seeping through the valve stem seals or up past the rings.

A leak down test will tell you a lot more than just a compression test, however, if a teaspoon of oil in each cylinder boosts the readings than you can suspect the rings are not sealing properly.

 

[Def]

Could oil leak past the valve guides? Or is that what the valve stem seals are for? I used the rope-stuffed-in-the-cylinder-thru-the-spark-plug-hole method...then fashioned a plastic tool to hold down the valve springs while I removed the collettes and springs...then removed old valve stem seals, installed new ones and re-assembled in reverse order.

 

[gs11ezrydr]

Oil can leak past the guides but It's highly unlikely in your case. Unless totally worn out and out of round. Doubt if any is passing past the guides and the guide bores The springs need to be installed with the tighter coil windings facing the head. I have had them float in other engines when installed backwards when revved to red line.. I agree with the other post on doing a leak down test first and see what the results are. Could have slightly tweaked a valve. If starting and running probably not. I would turn the springs over to the correct position and run it a while and re check compression and leak down. Sure you did not damage a few seals by pressing down too far on the springs causing the retainers to distort or damage the seals. Just a thought. Also posted was to squirt a little oil in the cylinders. to check the rings. Good idea also.

 

[Sandy]

What's the history on the bike. Has it sat for a long time? Maybe a stuck ring. Mileage, etc? I had excessive oil consumption on mine, about the same as yours, at around 70,000 kms but was sure it was just dried up 35 year old valve seals. I however did the full top end anyway because I needed to change the head because of a spark plug thread repair that eventually failed again. So I did a hone, new rings on stock pistons and the valve seals. Oil consumption now is negligible, maybe a liter in 3,000km.

 

[Def]

Yeah...I could live with a litre of oil comsumed every 3000 kms. The bike has 53000kms on it and I've ridden it 6500 kms this summer. It sat for 3 years prior. I'm thinking that with the riding I've done this year it is unlikely stuck rings....however, I'm no expert. It starts and runs very reliably. Since the compression drop after the valve stem change it idles a bit erratically but idled perfectly prior to that. I rebuilt the carbs just after I bought it...lights all work...clutch is in great shape...had to put the ape nut on it. The only oddity was when I first did the valve adjustment a couple of the exhaust valves had no clearance whatsoever. I don't think the po adjusted the valves during his ownership and he was the original owner.

Would a leakdown test show me more than taking the head off and inspecting it and the pistons and rings?

 

[Guest]

Have you rechecked your valve clearances since putting the cams back in? and you're sure you have the cam timing spot on?

 

[Def]

Beenn mulling that over also...pretty sure valve adjustment and cam timing was bang on, however, I'll check the valves before fully tearing down the top end. Good suggestion azr.

 

[gs45082]

I wonder if one or more of those exhaust valves are burnt. Leakdown test could determine if this is the case.

Yeah...I could live with a litre of oil comsumed every 3000 kms. The bike has 53000kms on it and I've ridden it 6500 kms this summer. It sat for 3 years prior. I'm thinking that with the riding I've done this year it is unlikely stuck rings....however, I'm no expert. It starts and runs very reliably. Since the compression drop after the valve stem change it idles a bit erratically but idled perfectly prior to that. I rebuilt the carbs just after I bought it...lights all work...clutch is in great shape...had to put the ape nut on it. The only oddity was when I first did the valve adjustment a couple of the exhaust valves had no clearance whatsoever. I don't think the po adjusted the valves during his ownership and he was the original owner.

Would a leakdown test show me more than taking the head off and inspecting it and the pistons and rings?

 

[londonboards]

It think this again proves the unreliability of compression testing. Nothing you have done so far would explain the differences in compression testing results satisfactorily.

Most likely cause of oil burn in this case would be that the rings need replacing and the cylinder needs honing. Or a leak somewhere. Have you checked around the sump?

 

[DohcBikes]

Yes you definitely need to put your springs in right. Its hard to believe anyone would even ask, for the simple fact that essentially you are asking us to tell you whether or not knowingly doing it the wrong way is ok. The answer is no. It actually makes a big difference in how fast the valve changes directions and most certainly will cause valve float.