Bikers Workshop Series

300,000 mile GL1500 Cylinder Head Overhaul.

By GLGREZMONKI(Jim) on our forum.

This page came about from a discussion on our forum when Jim started working on a 1994 GL1500 Goldwing with 300,000 miles on the clock. To read the full discussion thread, CLICK HERE.

This 1994 Goldwing GL1500 has 300,000 miles showing on the clock. A friend of mine got it for a song. The body is in pretty good shape for an almost 16 year old Goldwing. The history is unknown but it doesn't look like the previous owner(s) of this GL1500 had maintenance high on their list of priorities. It was smoking like a plugged up woodstove  and #1 cylinder had about 40 lbs of compression. Today I removed one cylinder head from the Goldwing and  here is what I found so far. Lots of crud, carbon and a burnt exhaust valve in the #1 cylinder. I haven't gone any further as I don't know what the owner wants to do yet. Just wanted to say that these Goldwing engines are amazing. I drove the GL1500 home the other day and despite these problems, and aside from smoking bad on startup and when backing off the throttle, it drove ok. If a poorly maintained Goldwing engine with these problems is still running at 300,000, how far will a properly maintained engine go?


You can see the cruddy oil from lack of maintenance.

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The GL1500 cylinders look ok even though  there may have been some coolant or other liquid sitting in #5 for a while, I can see some light stains. There is no significant movement in the pistons. The exhaust valve for #1 cylinder has a big chunk out the side and is crudded up pretty bad. The remainder of the valves in this head look ok and will probably clean up. The valve guides are good. The valve seals are as hard as nails. I guess the smoke was due to oil getting past those seals. The GL1500s owner doesn't want to spend a whole lot on this project right now so I think it will just be one new valve and do the rest over. I have not removed the other head from the Goldwing yet.......

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The drive home... it did drive ok, and there were no knocks or rattles. The other five cylinders pulled the weak one along with them I guess. I plan on replacing the one valve along with new valve seals, head gaskets etc. I removed the left head today. These valves had lots of carbon on them but cleaned up ok. There are some marks in the #5 cylinder that look worse in the picture than they actually are. The Goldwings owner wants to be very frugal with this repair and would be happy with no or at least, reduced smoke.......

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Update; I was able to save, restore and reuse 11 of the GL1500s existing valves. I have one exhaust valve on order to replace the broken one from the #1 cylinder. The heads have been cleaned up and the valves have been lapped in and so far I haven't run into any major problems. Parts on order cost $440 and that's head gaskets, valve seals, valve etc. One picture shows a hint of how to keep head bolts, cam bolts etc. in order. Hopefully the smoking problem will be eliminated or at least reduced. Will update further as the job progresses.....Gm

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Today's pictures show the valves, valve seals, spring seats, springs, retainers and keepers being installed in the GL1500 heads along with pictures of the heads ready to re-install. As I mentioned in the original posts the owner wants this done as cheap as possible but so far the parts have cost $450. I will update the progress of the  project as I proceed.

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I suppose that this might seem repetitive and boring to those members who do a lot of this type of work but perhaps it will assist someone who does not. The following pictures show what I completed this afternoon and I will briefly explain that.
Cylinder heads were installed after cleaning both mating surfaces (head and block), new head gaskets and I made sure to replace the coolant tube o-ring. Cleaned and greased the threads and under the head of the cylinder head bolts. Torqued  the head bolts in a crisscross manner in several stages (33' lbs). Dont forget the small 6mm bolt under the head. I tightened that to 10.5 nm. Coated  the cam lobes, journals, bearing surfaces with assembly lube. Honda suggests using Moly60 paste. It is expensive but a small tube will go a long way. Installed the cam, new cam seal, and cam holder and torqued bolts in the same crisscross manner to 20nm. Installed the timing belt pulleys and timing belts. Made certain timing marks were correct. Turned  the engine over  by hand with the crank bolt several times to make sure there is no binding. Rechecked  the timing marks several times. Then I hit the kill switch and turned the engine over with the starter. All okay.
When I get back at it I will finish hooking up the intake and exhaust. Then a new oil filter, oil and coolant. Then start it. I expect it to smoke with the first start up form the residue fluids. They always do after this type of repair. Subsequent starts will tell if there was any improvement.

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Yesterday I finished putting the GL1500 back together enough to start it. It fired right up, had a lot of tappet noise for about a minute or so and then it stopped after they pumped up. Initially there was no smoke at all. After a few minutes I observed smoke coming evenly from each exhaust. I expected that to happen so I wasn't worried. I let it idle for a long time until the fans came on while I was purging air form the rad. I snapped the throttle several times while it was heating and the smoke began to subside until there was almost none. The engine sounds good except for an exhaust leak between the left header pipe and the muffler. At that point I quit.
This morning I went out at 7am and started it again (temp was  0 Celsius (32 Fahrenheit). It was parked on the center stand, no smoke at all. Previously it would fill the garage and yard with clouds. I let it run for about five minutes. Tonight I will park it on the side stand and see if it smokes tomorrow. I don't care about a little smoke on startup since most Goldwings do that anyway. Now what it needs is a good long drive and then another oil change before it is put away for the winter. The weather will determine whether it gets driven or not.
At this point I am satisfied with the outcome but I will have to see how the Goldwing works on the road and with subsequent starts. Our riding season is pretty much over now so I don't know if or how much this GL1500 will be driven. I think there is some life left in it yet. I will post again when it is all back together and tested further. Thanks to all for your interest in this project and I hope that the info may help someone else in the future........... GM

Update; Since the news says we have a "nor'easter" blowing through tonight and tomorrow with the possibility of heavy snow and high winds I figured that this would be my last chance to get this GL1500 Goldwing out for a ride this season. I didn't plan on going too far because it is only  about 4 Celsius (40 Farenheit) which is too cold for me. Once again it fired right up with no smoke. I let it warm up a bit and left. My wife told me later that when I pulled out of our driveway she saw a little puff of smoke but that was it. I went into the sub-division behind us and drove around for probably 3 miles. I had the mirrors tipped down some so I could see if it was smoking any and it was not. It felt like it wanted to stall when I slowed down and stopped but I think that is fuel related or perhaps I bumped off a vacuum line or something like that. As quiet as 1500's are they are a lot louder when the plastic is off. There is also an exhaust leak to be fixed. So far so good. Sometime later on I will address that possible stalling problem . Even though it was cold it felt good to get out for a ride on a Goldwing. So now I have to divert my attention to fixing a flat tire on my snowblower...

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