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Uh Oh, Sticky Cam Follower Bucket?? Help!

6K views 51 replies 13 participants last post by  SCB 
#1 ·
I picked up an '08 Navi Comfort with 37k a couple weeks ago. Started it and let it idle while I unloaded it from my truck and let it idle in my driveway while I put the tie downs and ramp away. After about 25 min I noticed it had started shooting coolant out of the overflow hose. I quickly shut it off and heard the coolant bubbling in the engine. Temp gauge was in the red but the fans were not running. Let it cool down, refilled the radiator and overflow bottle.

While doing a couple warm up/cool down cycles to get any air out I began looking for the problem. I jumped the high voltage side of the fan relay and both fans work perfectly. Also, relay is good. Problem is no 12+v on the hot wire of the relay trigger circuit. Turns out it had only been driven 60 miles in the last 15 months, had been stored in a barn, and had become home to a family of hard working mice. Most of their debris was in the airbox (pic coming if I can figure out how) which I found and cleaned out when I replaced the air filter. I can also see some debris above the left side cylinders, under what I assume are the intake throats. Haven't had the front fairing off to verify yet. I assume they chewed the 12+v wire that comes up from C11. In any case, over the next couple weeks I put about 500 trouble-free miles on and all seemed good.

I mention all this as some history for my current problem. Last week I did a valve check, found all valves on the tight end of the acceptable range with the #6 intake just a bit too tight. I pulled the left side cam, swapped a few shims, replaced a couple to bring all valves back to the middle of the range. While doing so I had trouble pulling the bucket off the #6 intake. It felt like there was a bit of a lip or tight spot that kept the bucket from sliding out of the bore. Wasn't glad to see that but in the end I figured it had gone 37k that way so it must be OK. I buttoned it back up and put another hundred or so trouble-free miles on it.

This morning I decided to do a compression test. Pulled the plugs and got started. The first couple readings went fine. Then, while spinning the engine for the next reading, I thought I heard a 'rap' sound. Wasn't sure I really heard something so I continued on. A bit later I heard it again, but decided it must have been something falling on the floor so I continued. Finally, while rechecking a reading on the left side I heard it again and it sounded like it came from the area of that #6 cylinder so I stopped. The only thing I can think it might be is that valve bucket sticking open a bit and then releasing and slapping up against the cam.

Any thoughts? Should I take the cam back out and take a look? Maybe switch a different bucket in there and see if it also seems tight? All thoughts welcomed!
 
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#3 ·
My guess would be not to swap lifters aroud. They wear to their bores and could/would damage other lifter bores. Check the suspect lifter with a micrometer to see if it is mushroomed or if it has a high spot. You may need to replace it. If you think a valve is sticking, it wouldn't hurt to use a fuel system cleaner that also cleans the valves and combustion chamber. I use Amsoil PI at 5k intervals in the bike and cars. HTH
 
#5 ·
Seems unlikely to have a problem with the bucket or the bore. The effort required to remove the buckets varies from bucket to bucket. I think that's a function of how tight the oil film is in that bore. On my '08, sometimes it took just one magnet to pull some buckets out, other times two. Having said that, I don't know what would cause your noise. I doubt you'll find a lip but if the bucket was really hard to remove, requiring more than a magnet, I would check it. Check for scoring, measure for roundness. The service manual says to be sure to reinstall the buckets into the same bore from which they came, so if you want to try to fit another in #6 to see how it slides, you can but I wouldn't run it. Other thoughts: does the cam lobe look good and like the others, is the bore smooth with no signs of scoring, is your cam timing correct?
 
#7 ·
It did require more than a magnet, and I had a pretty strong magnet. I ended up having to cover it with a cloth and grab it with pliers to get it out.

I didn't see any dark discoloration on either the lifter or bore but there was some wear which I assumed was normal. I did not measure the bucket for roundness.

Cam lobe looked fine, all smooth and shiny. I'm pretty sure I got the timing right as I checked it a couple times and the bike ran great.

I really can't think of anything else it could be. At this point I guess I'm going to take the cover off and take a look. I'll double check the timing and then probably pull the cam and try another bucket in there just to see if it moves more freely. Maybe try the sticky bucket in another bore to see if it slides freely. New bucket are fairly cheap if I decide I need one.
 
#10 ·
I don't know whether your noise is a sticking cam follower but I do know that swapping used followers is a no-no. It's not so much the follower bore that is an issue but the cam lobe wears a slightly grooved pattern onto the surface of the follower. Swapping two followers will create a mismatch on those two cam lobes with consequent extremely high loads where only the high spots on both the lobe and the follower rub together.

The followers should spin in their bores, it's caused by the wiping action of the cam lobe, the lobes are deliberately offset over the follower to encourage the rotation of the follower. This is done to prevent rubbing so the cam lobe effectively rolls over the follower surface. Now, carefully look at the surface of the follower on the errant cylinder, if the follower is sticking you will see a definite rub patch on the follower surface.

This isn't in any way a guarantee of the follower sticking down but it will be a clue that there may be a problem since a tight follower will not spin.

If the follower proves to be faulty, freeing it is not a complete solution because is will now have a slight indentation where is was being rubbed by the cam lobe and it is likely to rotate to that position and stay there. In this case you've got two options, a new follower or reface the old one. Followers are normally made from chilled cast iron and so the surface hardening is deep enough to allow refacing unless it's seriously worn. You can easily reface the follower by rubbing it in a circular motion on a sheet of wet-or-dry abrasive paper. The paper must be supported on a perfectly flat surface and you should adjust your grip accasionally to prevent uneven wear. A piece of class is a good flat surface. I'd use 320 grit paper until the surface marks are all but removed then follow with 600 grit paper for finishing. Lubricate the paper with oil. Work it until all surface marks are removed then no more.

Now you've got issue number two whether the follower is new or refaced. The follower is flat but the cam is worn to a pattern so the lobe will be subjected to high pressure. The best you can do is lubricate it really well before closing up the engine and drive fairly softly to allow the cam to break in the follower just as you would with a new bike. The first rubbing is critical and you can buy special cam lubricant for this very purpose but using gear oil on the lobe is likely just as good since gear oil is a high pressure lubricant designed for use on rubbing surfaces.

Hopefully you won't have to do any of this but there you have it if it's necessary.

I doubt whether you're hearing the follower jump up to clatter the cam but if it's sticking down the risk is that you will get piston to valve contact.
 
#11 ·
Holy Cow!! Did not know there was this much to cams and valves! Thanks for all the info....

Regarding swapping the followers, I was only thinking of swapping them in to see if they bound up, maybe point me in the direction of what the problem is, not actually running it that way.

Now that you mention it, it makes sense about the spinning of the followers in their bores. I'll check it for unusual wear. If it does have unusual wear I don't think Ill refinish it, for $30 I'd put in a new one and follow normal break in procedure.

I agree that it's hard to believe the rapping noise is a follower hitting the cam, but I can't imagine what else it could be. FWIW, I never heard this noise while the engine was running before the compression test. Also, the compression test involved a lot more runs than normal as I had some odd readings from a poorly sealing compression test insert so I reran the test with a second insert. All readings were then within 5 psi of new.
 
#12 ·
Thanks to all who responded and sorry for the slow replies. I had responded to both Techdude2000 and JW but just now found my posts listed as deleted. Does anybody know if they are actually deleted or if that's a holding area because I'm a FNG?
 
#17 · (Edited)
I dunno about the GL1800, but most motors, in addition to the cam lobes being offset, they are tapered about 3 minutes (60 minutes=1 degree). Also, the buckets' mating surfaces are spherical. The taper and conical specs are so slight, it is difficult to measure them without access to professional equipment. So it is NOT a good idea to attempt to resurface the buckets by hand. But you can usually check the ends of two buckets by putting the ends together, there my be an ever so slight rocking motion, but sometimes difficult to discern.

It sounds like the bucket may be hanging up in the bore, for whatever reason. I'd begin by gently cleaning the bucket and bore real good, with a green Scotch pat and something like acetone. Then light coat of oil on both, and re-check for fit. Before cleaning, inspect the surfaces very carefully with strong light and a magnifying glass, if possible, to try to pinpoint surface scuffs or other imperfections. If in doubt, I'd install a new bucket. As for swapping with other buckets to test fit, fine, but don't get them mixed up, and put them all back in their original positions before reassembly. I'd also look closely at the related valve spring and keepers.

CORRECTION: The cam follower's face is spherical, not conical. I knew what I meant, but crewed up the terminology. Corrections have been made in all instances where I used the incorrect term. Sry bout that!
 
#20 · (Edited)
I dunno about the GL1800, but most motors, in addition to the cam lobes being offset, they are tapered about 3 minutes (60 minutes=1 degree). Also, the buckets' mating surfaces are conical. The taper and conical specs are so slight, it is difficult to measure them without access to professional equipment.
I'm aware of the taper on cam lobes and the cam lobes on the wing are certainly tapered, I've measured them. I've refaced many followers without issue but never seen conical ones though I don't doubt they exist. I guess though that the cam will soon have them angled during break in.

SCB, if you're at the dealers getting followers, see if you can get two face to face to check for flatness, it would be interesting to know. :thumbup:
 
#25 · (Edited)
This morning I decided to do a compression test. Pulled the plugs and got started. The first couple readings went fine. Then, while spinning the engine for the next reading, I thought I heard a 'rap' sound. Wasn't sure I really heard something so I continued on. A bit later I heard it again, but decided it must have been something falling on the floor so I continued. Finally, while rechecking a reading on the left side I heard it again and it sounded like it came from the area of that #6 cylinder so I stopped. The only thing I can think it might be is that valve bucket sticking open a bit and then releasing and slapping up against the cam.

Any thoughts? Should I take the cam back out and take a look? Maybe switch a different bucket in there and see if it also seems tight? All thoughts welcomed!
Are you referring to a intake or exhaust valve ???

Yes ... remove the cam. Inspect it's high point (toe) for any noticeable wear. Use another lobe as a reference. If worn, it should be noticeable. Wipe the bucket and inspect it too. Again, the wear should be noticeable. With the bucket still in place, reach in and see if you can spin it with your fingers. Compare its free movement to another.

Next, with your thumb, push in the bucket and then allow the valve to seat. Compare the "seating" noise to others. While you are doing this, be aware that some of the pistons may be in a higher position in relation the valve. When you compare the snapping close noise, compare it to another intake or exhaust. The important part is that it snaps closed.

Now, remove the bucket. Sometimes 1 or 2 can be more challenging to remove. I usually use a strong magnet; however, sometimes I'll have to remove one with a pair of needle nose pliers, and a rag to protect the lobe.

With the bucket out, inspect that both keepers are in place. Inspect the bucket and the area of the head that the bucket goes up/down in.

Once all that is checked, report back with your findings.
 
#27 ·
Lots of great advice/ideas. Looks like the consensus is to open it back up, inspect things, clean everything and report back with findings, so that's what I'll do. This is our busy time at work so not sure if I'll be able to get it done before the weekend but I'll try.

Anybody else who has any ideas about what that noise may have been, feel free to throw your 2 cents into the mix. Thanks again for everybody's help!
 
#30 · (Edited)
Then, while spinning the engine for the next reading, I thought I heard a 'rap' sound. Wasn't sure I really heard something so I continued on. A bit later I heard it again, but decided it must have been something falling on the floor so I continued. Finally, while rechecking a reading on the left side I heard it again and it sounded like it came from the area of that #6 cylinder so I stopped. The only thing I can think it might be is that valve bucket sticking open a bit and then releasing and slapping up against the cam.
Ok ... the "rap" you are describing is probably a slow closing valve. Under different spinning conditions, such as turning it over a "hand speed", or for some at starter speed, or for others while running, an intake valve is closing slowly due to old, sticky, fuel that can built up on an intake valve's stem. GL1800's are very unique in this one fact. It's the only engine that I know of that has horizontal valves with an injector that sits directly above the valve stem.

5th gens that sit for a while that have this condition occur can result is sever valve damage. Basically the piston comes up and smacks the intake forcing it to close. Sometimes the noise can be described as a snap, tap, rap, or light knock. A bent valve can occur.

For now don't start it. The next few things you do can be critical in trying to determine if indeed that is what is happening. Even with doing everything, often the only thing left to do is to start it and hope. However, it is best to do this in "smart" way.

Do the same checks to the other valves ... checking that all the keepers are there, the buckets spin, and when you push in on the valves, that you can hear them snap closed. Then do the same to the other head. Once all that is done, put cams and chains back on, and verify that the valve timing is correct with the chains under tension. From there, with the plugs out, crank the engine over by hand feeling for any resistance while turning the engine over using a ratchet and 14mm socket. To turn the engine over, while sitting in front of it, turn it over in a CCW direction.

Next, re-due the compression test. This time pay extra attention to needle movement, and the sound of each bump as the needle moves. Continuous needle movement with each bump is critical. There should be no "momentary hiccups" in any of the bumps as the needs moves upward. Any hiccups can be heard too.

I'm assuming that you had this running. Did it make any noise while running ??? Has the old gas been removed from the tank ??? When the gas cap is removed, any rust in the filler neck ??? Did you or the prior owner indicate that there is/was an additive put in the tank ???
 
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#42 ·
Ok ... the "rap" you are describing is probably a slow closing valve....

Do the same checks to the other valves ... checking that all the keepers are there, the buckets spin, and when you push in on the valves, that you can hear them snap closed. Then do the same to the other head. Once all that is done, put cams and chains back on, and verify that the valve timing is correct with the chains under tension. From there, with the plugs out, crank the engine over by hand feeling for any resistance while turning the engine over using a ratchet and 14mm socket. To turn the engine over, while sitting in front of it, turn it over in a CCW direction.

Next, re-due the compression test. This time pay extra attention to needle movement, and the sound of each bump as the needle moves. Continuous needle movement with each bump is critical. There should be no "momentary hiccups" in any of the bumps as the needs moves upward. Any hiccups can be heard too.

I'm assuming that you had this running. Did it make any noise while running ??? Has the old gas been removed from the tank ??? When the gas cap is removed, any rust in the filler neck ??? Did you or the prior owner indicate that there is/was an additive put in the tank ???
So it sounds like what you're saying is that you think a valve may be sticking in its valve guide. If that's true then replacing that bucket with a new one won't help. Sounds reasonable.

OK, got all the other valves on the left side checked, all were fine. Put the cam back in and timed. Spun the engine by hand a few times to be sure nothing hit. Checked the valve clearances again just to be sure I got everything back together correctly. All good. I got the valve cover off the right side and will try to get that cam out tomorrow.

Yes, I did have it running and generally it ran fine. The only thing I had noticed was a very minor miss or slight vibration when it was cold and I first started it up and it was idling. I thought it was just normal or maybe from old gas/not having been run for a while but it really didn't change over the course of several tanks of fresh gas. Once it warmed up it smoothed right out. Never heard it make any unusual noise.

There is no rust or discoloration in the filler neck. The inside of the tank looks clean as a whistle. When the PO said that it had barely been run in the last 15 months I asked him if he had put Sta-bil in the gas. He said he hadn't, which kind of bummed me out at first but then I thought at least he was honest.

Working on releasing that right side cam chain tensioner, what a BITCH!
 
#31 ·
Why has no one asked about cylinder leakage. If a piston tapped valve is suspect, cylinder leakage would be an indicator. To my thinking the engine is good except (Rodent nest) can cause excessive fuel deposits on intake valves. In my profession I get to see a lot of low mileage city driven cars (10 years old with 5k miles) that just needed a Top engine clean to get rid of the valve deposits and get rid of weird noises and better gas mileage. And do not get me started on the new direct injection engines. The pictures here are from an engine with severely carboned intake valves. And yes those cylinders are so burned that the block can not be repaired had to replace the block.
 

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#35 ·
Not sure if you're asking about a leakdown test? I don't have the stuff to do one of those. Compression-wise it was perfect (to the accuracy of my compression test equipment). Would be nice to have a look with a borescope and see if there's a mark on the top of the piston from it tapping the valve.

Regarding a top end clean, that sounds like a great idea. How do you do it?
 
#34 · (Edited)
Here's a pic of the valves with the buckets off. The offending intake valve is on the right (on the top now, not sure why my pic was rotated 90 degrees when I uploaded it?). I notice it does have some discoloration on the spring. Some of the other springs have a bit of discoloration but this one seems to have the most. Not sure if that means anything.
 

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#43 ·
Alright, used a small vicegrip and a cut down screwdriver to finally get that cam chain tensioner loose and got the cam out. No abnormal wear on the cam lobes, buckets or bores. All valves snapped shut cleanly.

All of the valves on this (right) side were on the tight side, intakes all 5's, exhausts all 8's, so while I've got the cam out I might as well go down a size on each of the shims. I'll be able to swap 3 shims but will need to pick up 3 new ones. Once I get that done I'll button it all back up and redo the compression test, see if there's anything funny in how the pressure builds.
 
#44 · (Edited)
Actually, it is probably best that there was no fuel additive in the tank. For whatever reason, the ones I've dealt with have been stored with an additive in the tank. I'm not a chemist, so I have no idea what additives really do in fuel, however, the probably make them more stable and prolong their ability to fire. But that does not necessarily mean that the fuel is less sticky. You are correct, the inspections are for a slow closing valve. As you've already can tell by pushing in on the valves, they have little spring pressure to close them. In the mean time, do not start it.

Let me know when you redo the compression check watching for any "miss needle movement" as it cranks over and bumps the needle while listening for any irregularities also.
 
#46 ·
Went out to the garage to do the compression test again this morning and I gotta tell you, I was nervous. Hit the starter button for just an instant a couple times just to double check, no problem. Then I turned the engine over a few times with the starter and no compression tester attached, no problem. So I started the test. All reading were about 15 psi too low...until I remembered to hold the throttle open. Jezzuz, first rodeo??

Once I got that right the test went fine. No odd noises, no unusual jumps or pauses in the pressure build up, all readings 200-205 psi.

Time to put the plugs in and see what happens?
 
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