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1980 CX500 Custom
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Discussion Starter · #1 ·
Hi I'm in the process of fixing a 1980 CX500 Custom. The transmission will not stay in 5th gear. I am working towards disassembly of the motor now and have run into specialty fasteners and tool requirements per the honda service manual. Where are some good suppliers for these tools?
 

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'84 CX650E that is evolving into a GL500
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The only special tools you should need to remove the transmission from the engine is the clutch nut wrench. They are available through the aftermarket but a lot of us have just modified regular sockets to fit (about 10 minutes work with an angle grinder).

I would also recommend having 3 sizes of torque wrench, 1/4" drive for all of the M6 fasteners, 1/2" drive for the clutch nut (+ the flywheel bolt if you ever need to take that off and a few other parts of the bike) and 3/8 drive for everything in between (Harbor Freight usually has a coupon on their site to buy them for $10 each).

You will have to take the rear cover off to release the transmission from the shift linkage so I would open that and have a good look at the linkage before I removed the transmission (front) cover.

Welcome to the forum. Please add your location and your bike's model and model year to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature).

And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and the Previous Owners may or may not have done the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).
 

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1980 CX500 Custom
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Discussion Starter · #3 ·
I appreciate the advice. This bike has certainly seen better days. It appears to have been rear ended and I'll be sending the frame off to have it professionally repaired. I've found a vast number of hand tight nuts and bolts on the bike among other disturbing things like the stem nut being hand tight. Needless to say I've got a pretty big project ahead of me to turn it into a cafe racer as I had planned. I'll brag a little and say I've only had the bike a little over a week and it's completely stripped down and frame is ready to send off. I'll have the transmission swapped out by end of next week and then it's a waiting game for the frame and probably the tank to be painted. I've also got to rebuild the front forks replace all hoses, brake lines, brake pads, spark plugs. It's a list for sure but I think it will be so much fun once I'm finished.
 

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The are a few good suppliers on Ebay for those peripherals (like the clutch-nut) if you chose not to make your own.
If interested:

One shop is listed here. (PM if you want a bigger list)
 

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Appreciate that.....being halfway through a project you dont necessarily want to wait weeks for a package from the UK.
(Or pay $60-80 for superfast delivery).........
 

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1980 CX500 Custom
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Discussion Starter · #7 ·
Well I got the transmission out today and I see no visible signs of wear. It appears to shift and all of the gears look pristine. So now I'm on the hunt for what would cause it to not stay in 5th gear. I'm thinking possibly clutch, maybe a shift fork though I see no visible damage on the forks.
 

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'84 CX650E that is evolving into a GL500
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You will have to take the rear cover off to release the transmission from the shift linkage so I would open that and have a good look at the linkage before I removed the transmission (front) cover.
 

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1980 CX500 Custom
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Discussion Starter · #9 ·
It appeared to be fine, maybe I missed something? I'm going to put it back together tomorrow and see if I can shift through all the gears with it sitting inside the assembly via the shift linkage. Any tips on what I should be looking for?
 

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'84 CX650E that is evolving into a GL500
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Bent or otherwise damaged parts. I wish I could help more but I never did figure out why one I have kicked back into 4th before I replaced the engine for other reasons.
 

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81 Gl500i 83 CX650E
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Common for the transmission to drop back to fourth or neutral between 4to5th, most of the time when i'm to lazy to pull in the clutch. What I suppect happens is the end clearance of the transission is getting loose. Was a little better after replacing the bearings in the 500. Never figured out how to mearure it or find shims to tighten it back up again. Do believe the engine/trans case maybe spreading a bit from age and mileage.
 

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I replaced a shim in a CX transmission with a stainless washer, surface sanded to thickness. I don't know how long the stainless washer will last but as I was missing the shim I went with this. There is the scope here to adjust the endfloat as I needed to keep sanding the washer until it had about 4 thou of float. I'm not sure which bike this was, but they all work OK.
 
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