[doral]

I finally got my new to me GL650i ready to ride. I switched around the throttle cables because the PO had hooked them up backwards. I overhauled the front brake calipers. I replaced the leaky fuel valve with a new one without the vacuum and sealed of the original vacuum hose that went to the petcock. Changed and/or added to all the fluids and pumped some grease into the zerk fitting on the final drive. I've done a few short drives and now I find an annoying amount of free play in the drive. On the center stand, in gear I can move the back wheel about 2 1/2 inches measured on the tire tread. There is no detectable noise from the drive when I'm riding. I'm guessing that I have worn out splines. Since there aren't many good riding days left this year, in the frozen north, I'd like to hold off on the repairs till it gets too cold to ride. Would that be unsafe? Is there any other place that could be worn to make that much shaft lash? Thanks for the past help. I don't know what I'd do without this forum.

 

[Hobbit on a Honda]

That is about the same as mine. I hope it's just normal free play / gear lash.



At slow speed it is awkward to have that slop between throttle off / throttle on.

 

[Blindstitch]

It's probably fine to drive. The only thing that would cause a problem is if the flange on the wheel has worn teeth but 2 inches isn't really much.

 

[doral]

Thanks Hobbit and Stitch. You're right Hobbit. The only time it really bothers me is at slow speeds. I can get pretty herky-jerky between throttle on and throttle off. Guess I'll just have to get used to it.

 

[Reg in Bristol]

I wouldnt worry about it too much

Most CX's have this backlash and both my K series beemers

have or had similar.



When my first CX was 'new to me' I had similar concerns

over real wheel play but since then and quite a few CX's

later, Its never manifested into a real problem



Slow speed = low gears and they can all jerk a bit

in that situation

 

[Shep]

When I had this a won a cheap drive box replacement off Ebay.Neither of my CX have any lash from the drive system,drive shaft,engine drive shaft, or gearbox.





My 10 penn'th

 

[Will]

Yeah, I used to notice that a lot too, then I did a simple carb clean. The jerkiness is still present a little in low gears, but throttle response is a lot smoother now, which really smoothed out the low gear jerks. I just disconnected the fuel line and sprayed straight carb cleaner in with the engine running, then let it sit for a few hours. This made a big difference.

 

[richnct]

Shep, maybe the terminology is vague. If you put the bike on the centerstand, rear wheel off the ground, tranny in gear, there is no/none/zero play in the rear wheel when turned one way, then the other? That would seem to me to be very very unusual. A noticeable amount (not a great deal) of play has been evident in every CX/GL I have had.

 

[Shep]

Shep, maybe the terminology is vague. If you put the bike on the centerstand, rear wheel off the ground, tranny in gear, there is no/none/zero play in the rear wheel when turned one way, then the other? That would seem to me to be very very unusual. A noticeable amount (not a great deal) of play has been evident in every CX/GL I have had.

Noted.I was talking about slow speed riding etc when there's a load on the engine.

 

[Allan]

I just checked my 78, it is sitting just outside on the center stand. In 1st gear, there is about 1 1/4 in. or less, measured where the tire meets the rim (the outermost part of the rim.)

 

[gopher]

Same test as above on the 9000 mile 81 GL500I showed a lash of exactly 1"

 

[doral]

Now I'm confused. Maybe terminology or maybe I'm just not a bike mechanic. Shep, what part of the drive is the "drive box"? And when one is driving and there is a load on the engine I don't see how it would ever be possible to speak of "play" because it would all be taken up under load. Seems to me that "play" or "lash" can only be measured when the back wheel is off the ground, the engine is shut off, and the bike is in gear. On my bike play can certainly be detected while driving when changing throttle back and forth from powering to coasting and most notably at slow speed and lower gears.



Thanks for all responses. My bike has about 36,000 miles on it, mostly city driving to work and back. I think I'll just keep riding and see if the play gets any greater in the next 36,000. From now on the miles will almost all be open road miles.

 

[Shep]

The drive box,



http://www.cmsnl.com/honda-cx500a-1980england_model16465/partslist/F14.html



Worn parts in this and as per above can cause play/lash when putting the engine under load when changing gears.This normally shows as a delay and clunkiness when setting off or changing gears upwards.

 

[doral]

Thanks for the terminology clarification Shep, about the "gear box", which Honda calls a gear case, and old farm boy mechanics like me just call a "rear end". For me, gear box is another name for a transmission, like scramble box.



I just tried using a stethoscope to listen to the final drive, on the center stand of course engine off & in gear. It sounds like the slack is near the front end of the swing arm. U-joint maybe? There seems to be a very tiny bit of sound in the gear case with very slight movement of the wheel, which I assume is just the normal ring gear and pinion backlash.



Another newbie question: is it possible to inspect the u-joint by moving the boot forward?

 

[Shep]

Thanks for the terminology clarification Shep, about the "gear box", which Honda calls a gear case, and old farm boy mechanics like me just call a "rear end". For me, gear box is another name for a transmission, like scramble box.



I just tried using a stethoscope to listen to the final drive, on the center stand of course engine off & in gear. It sounds like the slack is near the front end of the swing arm. U-joint maybe? There seems to be a very tiny bit of sound in the gear case with very slight movement of the wheel, which I assume is just the normal ring gear and pinion backlash.



Another newbie question: is it possible to inspect the u-joint by moving the boot forward?

Yes but getting the boot back on can be a PITA

 

[doral]

Thanks again Shep.

 

[risingphoenix]

I couldn't resist checking mine. I got 1.50'' at the tread at 58,000 miles. I'd suspect the U joint 1st.

 

[doral]

risingphoenix, I'm inclined to agree with you about the u joint. I've had to replace dozens of u joints on cars, trucks and various farm machines over the years but I can't recall ever having to replace a spline. BTW, I've got about 40,000 miles on my bike.