Bikers Workshop Series

Honda Goldwing GL1500, 4th Gear Repair.

By Bobby Newhouse.


Many Honda GL1500 Goldwing owners have experienced what has been referred to as a bent shifting fork. You know when you have it. It can be manifest through a few different symptoms or all of the following. At times while riding along and you shift into 4th (either from 5th down or 3rd up) you let your clutch out and give it the gas only to have the bike pop right back out of gear. Some have stated that they cannot even get it to go into 4th. Or... You are slowing down and downshifting as you prepare to stop. While decelerating in 3rd, 2nd and 1st you hear the unmistakable sound of gravel in a Pepsi can coming from your gearbox. Its a sad sound indeed because you got it and there is no way around it.

There are 3 ways to handle this problem. The first is to sell your bike immediately and get a new GL1800 Goldwing. That solution is not that practical for some so you have to look at numbers 2 and 3. The second solution is to start shopping and find a good used GL1500 engine from a Goldwing that has been salvaged. You can either do the work yourself or hire it done by a local shop. I have seen engines on the internet for anywhere from $500 for older engines to $2500 for the later model engines. Now once you make that purchase remember, unless you are going to install it yourself you will probably be paying between $300 to $500 for someone to install it for you. The third option is to take the engine out of your Goldwing and tear it down and do the work yourself. That means splitting the case and saying hi to your pistons and transmission personally. I cannot stress this part enough... Unless you are a mechanic or an EXTREMELY competent shade tree mechanic I would advise that you go the used engine route or pay someone to do the engine work for you.

Cost: I spent about $600 on parts. Those who have decided to keep their engine and have the work done spent between $2500 and $3500 for parts and labor.


Getting right into the nuts and bolts of the problem... In the picture below, the left arrow points to 5th gear, the right arrow points to 4th. The center white arrow is pointing at the shift fork and the red arrow points to the problem. That gap between the shift fork and the sidewall of that groove that the fork rides in allows that shifter to bounce back and forth between 4th and 5th gears and those big cogs (sometimes called "dogs") bump the inner dogs of the 4th and 5th gears. This only occurs while in the first 3 gears because if you are in 4th or 5th that shifter will be fully engaged inside the 4th or 5th gear.


This is the new GL1500 shift fork and shift collar installed. Notice how the shift fork fills the collar gap fully allowing no play of the collar while the transmission is in this configuration. Also notice that the dogs are larger on the shift collar on the 4th gear side then they were on the old collar. That means when you order your parts you will be replacing your 4th gear for sure and 5th gear if it looks worn on the dogs as well as your shift collar and shift fork. I replaced my 5th gear too. More on that later.


It's time to pull the engine. My Craftsman bike jack worked great for this job. It provided a nice large solid base to support the GL1500 engine while it was being lowered and moved around and eventually reinstalled.

The Honda GL1500 Service Manual suggests pulling the right intake manifold and right cam pulley cover to provide more room to manuever the GL1500 engine out of the frame but I have heard that some have removed it with both manifolds in place. Get a digital camera and take lots of pictures of the job in progress. Start before you pull your engine with pics of how your wires are routed and hooked up, cables attached, hoses hooked up, vacuum lines attached etc. The pictures on these pages are resized in the interest of saving space but when you load all your pics on the computer they will be quite large and you can zoom in and see great detail which will be valuable while reinstalling and hooking the engine back up. Also in the service manual in the "Fuel" section there are some really good diagrams of the routing of all the vacuum lines, and breather lines.

I went to Walmart and got a cheap bath rug to put the engine on the floor. As you get to the point where you are ready to split the case you will be rocking the Goldwing engine over and resting the right valve cover on the carpet. The carpet will protect the cover from scratches.


This is another good example of why you should take many many good pictures with different angles and detail. This is the back of the GL1500 engine with the rear cover removed. Most of the gears in this shot are to support the reverse system on your bike so if you have the "Interstate" model you won't have all of this.


Not shown here but I highly recommend that after you pull your timing belts off and you do have to pull both at first, reinstall your right timing belt to protect your valves and pistons as you rotate your engine through with a socket and breaker bar during different steps of the job. Note that in this picture you are looking at the front of the engine so the left side of the picture is the right side of the engine.

The rebuild for me was the fun part. In fact it was so fun that I took the time to do it twice. More on that later but suffice it to say that when you begin your rebuild you need to really follow the service manual even when it seems something is so simple and obvious. I'll try to point out a few things that you need to watch out for so they don't sneak up and bite you later. 


Some people use baggies with labels, some use huge paper cups. I chose these Styrofoam bowls. I used a marker and wrote on the inside bottom of the bowl the nomenclature of the part and bolts. Believe me after a few days of the engine being apart.. all the bolts you take out and put back in all start to look a bit alike. Notice on the left picture above the white paper with all the bolts lined up...That is the case bolts. They are different sizes and lengths so I laid them in order top to bottom on the case so they would be easier to reinstall in the right locations. The bottom line here is organization. Try to keep everything organized and clean.



While you have everything torn down and probably at some point waiting for parts its a good time to have other routine maintenance planned and performed. I pulled my final drive and drive shaft and inspected and lubed both ends of the shaft. I also had a crack in my exhaust collector so I removed it and had it welded. It would be a great time to replace that torn U joint boot as well, get a new tire installed, install new performance shocks etc.


It is time to talk about tools. There are a few tools you will need that probably aren't in your garage tool box. In the picture below it's already removed but the left arrow is pointing to the transmission mainshaft. The clutch basket resides right there and it requires a 46 mm 12 point deep socket to remove the nut. I shopped all over town and on the internet and couldn't turn one up. I finally bought one from a Honda shop. Your local Honda dealer probably has one in their service department and I know of one guy that put his engine in the back of his truck and took it to the shop and had them bust it loose for him. The same picture, right arrow points to the output shaft. Again you can't see it here because when I took this shot I hadn't pulled that little cover yet but under that cover you will discover that you need a 36 mm 12 point deep socket. You can get by with a 12 point box end wrench but a socket would be ideal since there is a specified torque on that nut when you go back on. If you can't get your hands on a 36 mm socket or box end wrench I happen to know that a 1 7/16" 12 point box end wrench will do the job.


The picture below shows the transmission mainshaft just how it will look when you separate the case halves. Its kind of ironic that you do so much work to get to that point then suddenly there is the shaft - and how do you get it out of the case to work on it? You just grab it and take it out of its cutout.

The arrow in that picture is pointing to the nut on the end of the mainshaft that you will need to remove to take the gears and shift collar off. Note: That nut is a left hand thread.

There is a special tool also for holding that shaft but you can be creative and bust the nut loose. Again use your service manual for proper torque specs when you re-tighten the nut.


After you get the left hand nut off, 5th gear will just slide off, then the shifter, the shift collar and then 4th gear.


When you are ready to go back together with it watch out for this. The Honda service manual tells you to line up the lubrication holes in the shaft with the shifter. I don't know for sure but I am pretty sure that is a misprint because there are no holes in the shifter but there is in the collar below the shifter and a hole in the shaft. Oil flows down the inside of that mainshaft and comes up through a little port in the splines of the shaft and through that hole in the shift collar and lubes the inside of the bearing surface of 5th gear. Remember when I said I got to build my engine up twice?  Just make sure that you have those little holes lined up before you put your gears all back on.


This picture is for reference only. See the case surface around the edges... It takes quite a bit of tedious time but you will need to scrape all that old gasket off of this surface and about 4 other case parts that you remove. Its a painstaking job but you need to do a good job because... Its a Honda. No leaks, right? Also be very careful as those edges on the case are sharp as knives. Ask me how I know (and know and know).

Parts. I used an online microfiche and looked up everything I needed. I then ordered all my parts from Service Honda online as they are a whole lot cheaper then a local shop. I thought it a good idea to also change the thermostat while the engine was out and it was so accessible. Make sure you change the gasket too which is a big O ring. I changed one a few years ago on my old 1500 with the engine installed and it wasn't pleasant. I also ordered the upper and lower engine gasket kits so I would have everything I needed when going back together. The gasket kits ran about $240 together. I only used about half of the gaskets because I'm sure you can see that you don't take everything apart but it would be impossible to try and guess in advance all the gaskets and O rings you need. My big gripe is that the O rings are not in separate baggies and labeled with part numbers so you just have to take the old ones off and find a match. Most of the time that was pretty easy but when it came to the O rings for the water pipes and thermostat housing I couldn't determine for sure which O rings were the right ones so I just ordered new ones separately and they came in little baggies with part numbers. I did not want to have to mess with a water leak on those water pipes once I had it all together and you will notice those pipes are pretty buried under the manifolds and vacuum lines once they are installed.

Next... the gears. As I tried ordering the gears and shifter it got a little confusing because some of the parts have been discontinued. Not to worry, Honda just merged a couple parts into one part number. Just so we are on the same page about nomenclature, the collar is the sleeve that slides on to the shaft and the shifter is the silver gear that slides back and forth with the shift fork on it. I know that sounds dumb me saying that but I just want to be clear. I ordered a new 4th gear, 5th gear, shift fork, shifter collar and shifter. Honda has combined the collar and shifter into one part number. Its 23010-MAM-305. You will see when you get your new parts that the new collar and shifter have different splines than your old one so I guess thats why they bundled them. I'm pretty sure the part numbers for all the parts are the same for all the year models but you need to check the parts fiche for your year model to make sure. My gears, shifter, shift collar and shift fork ran another $250

Rejoining the case halves. Honda uses some very specialized tools to reunite the case halves but after talking to another 1500 owner / mechanic that did this same job, I used his idea and just used some hose clamps. The pistons are if I remember 2.8 inches across. I had a clamp on each set of rings and a helper holding the case and lowering it on each piston one at a time while I lined up the pistons from below and the hose clamp would slide down as the piston slipped up in the bore. At that point I would just loosen the clamp all the way and take it off. The pistons seemed to want to slip up in the bores pretty easy. I oiled up the pistons and the cylinder walls but it really didn't take much tension at all on the clamps to hold the rings compressed. The clamps slid down fairly easy. You kind of have to practice a couple times to learn some techniques like where you want the clamp screws and such. Also don't put any sealant on the case till you get the pistons all back in the cylinders. Before you even start this whole job make sure to take the time to clean the case mating surfaces of old sealant. Once the pistons were all happy back in their cylinders I used a small wooden block to keep the case halves apart while I wiped down the surfaces with lacquer thinner and applied the Hondabond 4 sealant. There are a couple hard to reach places but I used little acid brushes and was able to get in there pretty easy. Then pull the blocks, apply sealant to the remaining area and slam it home. Have all your case half bolts ready to go in right then and torque them appropriately using the crisscross pattern.

When putting the lower front case back on, the one with the oil filter and water pump, one would think that you just put it in place and put the bolts in and tighten it down. Not so fast... Read your manual. It will tell you to make sure that you have the transmission in neutral and then line the little shift indicator pin on the front cover (not shown) up to slip in the little notch on the front of the engine where I placed an arrow. That is where the neutral light gets its position and more importantly the engine control unit gets its information to adjust the timing for different gears and speeds.


Clutch. The following applies if you did not take your clutch plates all apart but instead just took the clutch out as one assembly. The clutch can be pretty fussy about going back on. All the splines have to be in the exact right location. So go ahead and slip your clutch basket on the splines but don't install that big 46mm nut just yet. Try and put your clutch assembly on. You may have to rotate the clutch assembly a few splines here and there till it lines all up and goes on. If you cant get it to go all the way back in pull your clutch assembly back off and pull your clutch basket off again and rotate it a spline or two and slide it back on then try putting your clutch on again. Do this till your clutch slips all the way on. At that point take a sharpie and mark a couple dots on your clutch assembly to clutch basket outer edge and then make another mark for your clutch basket to the mainshaft splines. Then slide your clutch assembly off and install your washer and 46mm nut for the clutch basket and torque it to specs and bend your safety tabs in. Now your clutch assembly should slide right back on using your alignment marks. Sorry no pics.

Starter installation. After your engine is installed and you are involved in the hook up and you are getting anxious to hear that puppy run again, take your time and use the book. When you go to install the starter it will slip about half way in and start binding. Now its so close that one would think you could put a couple bolts in it and tighten them down and draw the starter in place but DON'T! I didn't know that and I probably would have done that very thing except I saw on the message board that a couple guys had done that and broke their reverse gear. You know what that means... engine back out. What the manual says to do and what I did and it worked really well is to put the starter in as far as it will go. Then with the transmission in neutral put the bike in reverse. Then slowly work your back tire a little spinning it just a bit back and forth while pushing in on the starter and it will all of a sudden just slip right in.


This is a very labor intensive job and takes lots of time and patience and mechanical experience and this article was written with the intent of providing some insight to what the job entail's and hopefully avoid costly problems. I would be happy to try and answer questions for you about this job via email if you like.

I hope you realize that I cannot be responsible for any problems malfunctions or damage that may occur to you or your equipment just because you read this article. I offer this only as friendly advice.                   Good luck. Bobby Newhouse. 

If you would like to contact me with feedback or questions; [email protected]