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92 GS500EN lower end

Started by arnermd, October 31, 2022, 02:42:30 PM

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- rebuilt carbs with stock jets.  We shall see...
- Rebuild kit did not contain the float o-rings, that's pretty annoying.  I think they are 6mm x 8mm x 1mm , a little hard to find, got some on order.
    - Edit:  Not sure 6x8x1 mm is the right size, seems a little small.  I was able to install 2 in each groove and just went with it.....
- Left cylinder running very rich, fuel coming out the exhaust port while running!  Scary!
- Found a leaky petcock diaphragm....  Fuel in the vacuum line.  Searching this forum it seems to be a pretty common problem.

After hours of searching (this forum and others) I am unable to find a replacement diaphragm, would need to purchase a whole new valve.  Would rather not spend $60-70 on a new valve when a $20 diaphragm would fix the issue.

Anybody know of a source of supply for a 92 GS500 frame petcock diaphragm?

Gonna pinch off the vacuum line and run on prime setting for now.
1992 GS500N


Rebuilt carbs installed, blocked off the vac line to the petcock. much much better....  Definitely have a leaky diaphragm.

Was able to do an initial mixture adjustment and balance.  Ended up with mixture ~3 turns out.  Idles real nice and good throttle response off the idle.

Checked compression after 20 minutes of running and it was 145/137 cold, a little oil in cylinders brought it to 155/151.   A bit better than where I started so hopefully the rings seat nice and it climbs a bit more.

Next up is a test ride to put it under some load.
1992 GS500N


Ordered a petcock rebuild kit off Amazon from All Balls (60-1309).  Nice kit but the diaphragm does not fit correctly, it is just a bit too small in diameter so the OD does not sit in the groove.  Working with All Balls now to see if they will replace it under warranty.

Rigged up some fuel line and and rode the bike for a short ride.  No significant issues.  Needs some more carb tuning.

Had a hard time getting from first gear back to neutral, kept finding second....  not sure if there is an issue there or just operator error.

Checked compression, 150/150 with engine warm.
1992 GS500N


It can be hard to find neutral sometimes. Seems like how warm the engine is, what oil you are using, how old the oil is, and having a perfect 3 point clutch adjustment all effect it. If your oil has some miles on it, sometimes an oil change makes the transmission work much nicer.


Running 10W-30, has 0.8 miles on the oil....hahaha.   
Fresh rebuild so new oil.  Probably should run some break in oil?

Clutch seems fine, but I will double check the adjustments.

Wondering if that spring (#21) on the gear cam might be a little soft?  As I recall that detent on the cam sets in the pocket there to help locate neutral....

Thanks for the suggestions.

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1992 GS500N


Quote from: arnermd on April 03, 2023, 05:29:13 AMOrdered a petcock rebuild kit off Amazon from All Balls (60-1309).  Nice kit but the diaphragm does not fit correctly, it is just a bit too small in diameter so the OD does not sit in the groove.  Working with All Balls now to see if they will replace it under warranty.

Please update on how this turns out! I was looking to replace my petcock diaphragm before it gave out. The lack of options aside from a $100 total replacement turned me off from doing that.

If the All Balls kit actually fits, I might give it a shot.
2006 GS500 Naked Touring Bike


Quote from: arnermd on April 03, 2023, 04:23:32 PMRunning 10W-30, has 0.8 miles on the oil....hahaha. 
Fresh rebuild so new oil.  Probably should run some break in oil?

Conventional or synthetic? From what I've heard, you should stick with conventional oil after a rebuild. It allows everything to wear in together properly.

I definitely notice a difference in my transmission with used vs. new oil. It shifts a lot better with new oil. On mine, I have a hard time getting into first when the oil is dirty.

If you're off a fresh rebuild, you might just have to deal with a bit of wonky shifting until all the metal shavings come free and and oil is changed.
2006 GS500 Naked Touring Bike


Oil is conventional, I also read that synthetic is "too good" for break-ins....

I have contacted all balls and they are going to send me a new kit, but I have not received it yet.  Will let you know how it turns out.
You can buy entire valves for < $100 I have seen some for $65 on eBay.  Don't buy them all....  I might need one. :laugh:

***   I just noticed you have a 2006, I do not think that kit will fit your valve.  Fitment is listed as 1989 - 2000

1992 GS500N


I am happy to report All-Balls sent me a free replacement kit and the new diaphragm fits perfectly in my valve.

Not happy about getting a bad part initially but very happy with how they handled it.  I will buy from them again.
1992 GS500N


All-Balls is fine, but I will say their whole business model seems to be making it easy to find bearings that fit for people who don't know just how standard bearings sizes  and configurations are. Once you figure out the standard bearing size you need by reading your factory bearing, you can find a much higher quality made in Japan/USA bearing for the same price or less than All-balls made in China products. Just call your local bearing house or for a little more money find it on

For stuff like petcock diaphragms, carb parts, etc. I think they are great. Any company who is willing to continue making parts that fit older motorcycles after the OEMs stop making parts is a good company in my book.

Let us know how the diaphragm  replacement goes. The general consensus here had been to replace the entire petcock, especially for the '04+ new style. because people had had poor success with refurbishing them.


I installed an all balls front bearing kit and it seems fine, but too early to tell really.

Valve rebuild went fine once I had the right diaphragm.  As always, careful attention to detail is required, but it was not difficult.

Bench tested the rebuilt valve by applying vacuum (sucked on a hose and clamped it off with vice grips) and verified the ports were open while setting the valve to the various positions.  Vacuum held overnight....  so i think its leak tight....

Also verified ports were closed with no vacuum.

Ready to install and put fuel to it this weekend.
1992 GS500N


Well.....  One step forward two steps back.  Today I was trying to free up a frozen carb mounting screw, had the carbs on the bench, used some valve grinding compound to get a better grip on the Philips head. 

Managed to break the screw free but broke the damn nipple on the diaphragm cover in the process....  Arggggg. :hithead:

I didn't really even need to get that screw out, just did it because it was the "right thing" to do....No good deed goes unpunished.

Gonna try some epoxy, we shall see.  A new one is $45 with shipping.
1992 GS500N


Bought a good used diaphragm cover on Ebay, from Katana but same part as the GS500E.  All good now, $25 mistake....

Carbs are in, remounted airbox, new hoses and installed the gas tank and seat.  Looks like a real bike now.
The Wiki was incredibly helpful for hose routing, a big thanks to those who put it together.

What's left?  Body panels and exhaust.

Looks like I have a Vance & Hines slip on system with no mounting hardware.

Anybody have a picture or instructions on how to mount the Vance and Hines muffler? 
All I have is the slotted bracket welded to the can.

I assume there is another bracket and a dog bone that bolts to the muffler and the mounting hole in front of the passenger peg???
1992 GS500N


I got the exhaust hung   :woohoo:

Had to fabricate my own bracket from flat stock.  Pics below in case anybody ever wants to know....  it was a fun arts and crafts project.

Came up with a clever mounting scheme using cariage bolts and I made some dogs to sit in the square for anti rotation of the bolt.  Seems to work pretty well.
1992 GS500N


1992 GS500N


This is driving me batty ??? .....  Clutch Switch.

Am I correct in that the starter should only crank with the clutch lever pulled in?

The parts diagram seems to indicate otherwise. Notice in the pic below the board contacts are clearly shown on the  side towards the center of the bike.  This would mean the starter solenoid circuit is only closed when the clutch lever is out, which makes no sense to me.  Why would you want the bike to only start when the clutch is out? :cookoo:

Maybe I should bypass the darn thing and be done with it....
1992 GS500N


Well....  this project has just about come to an end.
- Spent the last month doing paint and clearcoat.  Polishing, sanding, polish again....
- Repacked the exhaust

Seems to run pretty good. Unlicensed, unregistered and uninsured...  I do not go too far. 
Anyone interested in taking it for a test ride let me know, I would appreciate any feedback.  I am in northeast CT.

Time to sell it and move on to my next project.
1992 GS500N

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