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After going through the carbs three times I finally figured out why I can't get it running right!! I Know your going to say should have checked compression first, I just made the adapter for my SAE compression gauge. Anyhow i'm getting 120, 120, 120 and60 . If I add oil it jumps to 180 and 90. Since this bike sat is it possible the rings just need to loosen up and reseat?? Just wishfull hopeing. Can anyone recomend a good source for rings headgasket ECT, or do I need to go to Honda. Thank You Tom
 

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Of hand, I'd say it looks more like a valve that is leaking since oil didn't fix it.... and that may even be just a sticking valve stem or even soot/dirt under the seat... but it may be a bent or burned valve too..

I'd start with check of timing belt and valve timing, valve clearances and if that doesn't help,then maybe the head needs to come off....... don't be to hasty to takethe engine apart yet...

SDB/Jim
 

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Thanks timeing belts are new just put them on for maintainence purposes. I'm sure the one 60 is a valve but the three 120s need help Tom
 

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Before taking the engine apart, I would want to try everything else first.

How about soaking it overnight a couple of times with penetrating oil in the cylinders? I would like to think that just maybe the rings are stuck and that time and patience will eventually turn them loose.

I would also want to verify the valves are okay as SDB has suggested. That is important, you don't want to burn a valve seat. Pulling the heads will also allow you to put on new head gaskets removing yet one more doubt from your mind.
 

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I wouldn't worry about the 120psi readings yet. If the bike has been sitting a long time stuck rings could cause that but the low reading on one cylinder has to be investigated. First off check the valve clearance to make sure all the valves on that cylinder are closing fully. I've seen rust on the stems of engines that have been ignored for long periods, that can stick the valve in the guide. A shot of penetrating oil on the stems through the exhaust or intake ports can sometimes free that up.

Once you have that solved retry the compression using a large capacity car battery, make sure you have the throttle full open, choke likewise. Low readings on compression is as much a test of your electrical system and starter as it is of the engine so it can be low if the engine cranks slowly due to low voltage at the starter or a starter in poor condition. If it were mine I'd take care of the low cylinder, might have to pull the head and take a look if it doesn't loosen up with penetrating oil and some cranking over. Once that's done don't worry about the compression until you've got the engine running a bit, that often will free things up nicely and the following compression test will show a major increase.
 

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Thanks for the encouragement . Bike has new battery new starter and all plugs out, it's cranking as good as it gets. I did check the valve clearence they were all within spec. The heads are very clean inside the valve cover no rust to be seen although I will examine this cylinder a little closer. I'm a little hesitant to run it this way fear of posible damage. Thanks Tom
 

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timeing belts are new just put them on for maintainence purposes.
This is the part that concerns me.

Are you sure the belts went on proper without a valve getting damaged?
It's easy to damage a valve on the right head if the spring action of the cam is allowed to snap back or the valve timing is off.

I agree with not being too concerned with the 120 psi.
If the engine sat awhile, I bet that compression will come up, if there's no valve damage or leaking by.
 

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I am certain I didn't damage the valve doing the belts. I am pretty carefull. It's the #1 cylinder thats weak front left Thanks Tom
 

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thessler wrote:
I am certain I didn't damage the valve doing the belts. I am pretty carefull. It's the #1 cylinder thats weak front left  Thanks  Tom
Make sure the carbs are either off, or you test compression with the throttle wide open. I think the 120 is way too low, considering factory stock is around 170 on a GL1100.

Raymond
 

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If the compression comes up when you put oil in the cylinder that tells me that the rings in that cylinder are leaking. If it was the valves, oil wouldn't make any differance. Just run it and maybe the rings will free up and reseat. ;)
 

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As Silicon Sam and several others have mentioned the throttle has to be wide open. That can easily make 30-40 psi difference. I would run your test again. If she has sat and you have 120 I would exercise it and odds are it will respond.

I got one that was seized from 2wingsjohn and when it broke free it was at 80 psi. Now after many soaks and some exercise it is back to 140-150, and ready to install. I thoroughly expect it to get better once it is running.
 

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Doubleeyes wrote:
If the compression comes up when you put oil in the cylinder that tells me that the rings in that cylinder are leaking. If it was the valves, oil wouldn't make any differance. Just run it and maybe the rings will free up and reseat. ;)
Just a comment here.... What you say is partially true, but what is more important here is not so much the absolute value,but the variation between cylinders... whether it is 120,120,120,60 or 180,180,180,90 doesn't matter at this point except to point out that one cylinder is abnormally low..that was the essence of my first post... there is one cylinder with a valve problem....

As to whether it needs rings, as you point out, the rings may take care of them selves with time, but in my experience, I have never seen a leaking valve "heal" itselfunless it was just soot,debri or sticking...a "burned" valvealways gets worse and running it under those conditions can do serious damage by erroding/burning the valve seat beyond repair... so I would not just run it until I investigated (and repaired) the valve issue........
 

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I'm in agreement with brass - oil only makes a small difference as you've experienced. It sounds like a leaking valve in that cylinder. Somebody might have snapped a belt before you got hold of it? Maybe changed the belt and hoped for the best - realized damage done and sold it off?

Since you're going through the steps a leak-down test will reveal a lot more than compression check but you will need to plumb some fittings and have a tank of compressed air to do a proper cylinder leak test.

An easy method to check for leaking exhaust valve is to run the bike and hang a rag over the tailpipe. If it's leaking exhaust valve it will suck the rag (or a dollar bill, piece of paper, etc.) into the pipe every few revolutions.

Oh yeah, throttle must be held wide open to get an accurate compression reading. Choke should make no difference on a GL1100 enrichment circuit. I don't remember a choke plate inside my carbs but it's been a long time since they've been apart - maybe I'm confusing it with another bike but I'm pretty sure I remember it being an enrichment circuit which would make no compression test difference...

best of luck
 

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Thanks for all the input. I guess I'll run it for a while and see if compression returns. But first I must deal with the valve, i'm guessing the only way to truly deal with it is yank the head and have a look. If the head is off I might as well put new valves in it unless there is a better way. I'm all ears!! This engine does pop a little through the carbs but I think they aren't dialed in yet, the pilot screws are three and a half turns out or it won't idle and I say idle very loosly the RPMs go up and down by a few hundred. Thank You Tom
 

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thessler wrote:
....I must deal with the valve, i'm guessing the only way to truly deal with it is yank the head and have a look. If the head is off I might as well put new valves in it unless there is a better way. I'm all ears!! ......
Like you say, I'd pull the one head.. but probably only needs one valve.... second alternative is to just replace the whole right side head assembly... they are plentiful and cheap.. from free to $100 and $100 would be expensive.. most go around $50
 

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If the head is off I might as well put new valves in it unless there is a better way. I'm all ears!!
No need to replace them all, just the bad one.
The others can be lapped if you want to go that route.

This engine does pop a little through the carbs but I think they aren't dialed in yet, the pilot screws are three and a half turns out or it won't idle and I say idle very loosly the RPMs go up and down by a few hundred.
That sounds like carb problems, cleaning and sync needed.

I wouldnt attempt any troubleshooting of these symptoms while the carbs are on the bike until the one low cylinder compression is fixed.

As for buying used heads from the net, IMO your better off repairing your old heads because you dont know what your getting with a used head which may have the same problems. Then again, if you do want to go that route, there are many members here who can recommend reputable suppliers so you wont get screwed. Some members may send you a spare for just shipping cost.
 

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I think it is probably not a bent valve, if one were bent the clearance would be way loose. Maybe a burned one but since the compression went up 50% with oil I'm betting on rings stuck. I would get the piston to the top with the valves closed and fill it with PB blaster or Marvel mystery oil and let it sit a while.
David
 
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