Vibration and mechanical knocking from shaft

[legaleli]

1982 GS850 I thought it was the spline... took it apart and it's fine. The splines are perfect with no real sign of wear - further the entire back end seems "solid" - a very fluid and smooth movement with no slop from wear - it feels "new".

But I definitely have a terrible vibration when at 80kms that gets worse as I increase speed - it definitely feels related the the shaft as the vibration is NOT related to RPMs - but is to speed. Further, when I am on the throttle the vibration goes away, and when I am off throttle is goes away - but it is very noticeable when I am cruising with just a little bit of throttle. I want to take out the shaft and see how it looks at the front end - not the spline end... how do I do this? here are some pics from today.

** NOTE** I want to remove and inspect the propeller shaft - I think the issue may be in the saddle joint or "U" joint. It feels like the way it gets in a rear wheel drive car when those start to go. The shop manual doesn't really say how to get the thing out!

 

[TheCafeKid]

Look in your wheel... the mating splines inside the hub on the 82 shafties were known for stripping out. If you have a bum tooth or two, it could cause that. You also need to double check that the spline retainer bolts inside the wheel hub are in there good, and havent backed out. This happened to my 1100G at the Red River Rally a couple years back, AFTER the hub spline had blown on the way down there (fortunately BWringer brough me one when he came down) but because we didnt have lock tight the bolts backed out and were rubbing the inside of the pumpkin.

 

[legaleli]

The splines on both sides look really good... and when I move away the grease there is nothing in it gritty, and when I rotate the mechanism by hand it is perfectly smooth and free with almost no slop in the movement.

I think I need to look further forward at the propeller shaft - but I can't figure out how to take it out.

I will recheck everything in the "pumpkin" again that is viewable without tearing it down.

Here are better pics of the splines:

 

[TheCafeKid]

Did you pull the hub spline out? What you can see of it with it in doesn't even contact the splines on the drive. They'll always look great. You need to pull it out and inspect it, and I'd suggest getting some Molly paste to pack it.

 

[waterman]

I agree with what TCK is suggesting. You need to remove the spline hub from the rear wheel by removing the six short bolts that hold it in place. Then inspect the middle spline area for wear. The outside spline edge, as shown in your picture, almost always appear okay since they don't come in contact with the opposing spline drive.

To inspect propeller shaft, you will need to remove swingarm and unbolt shaft from engine in front of universal. Swingarm is fairly involved since rear brakes and shocks need dealt with, then simply remove swingarm bearings. Prop shaft is held in position with four bolts under the rubber boot. Note these bolts are held in with lock tight.

Typically speaking, the shaft isn't a source of trouble. Usually it is the weak splines on the wheel that fail or if really unlucky, it will be a secondary bevel gear trouble. Hopefully, it will only be the splines.

 

[legaleli]

I agree with what TCK is suggesting. You need to remove the spline hub from the rear wheel by removing the six short bolts that hold it in place. Then inspect the middle spline area for wear. The outside spline edge, as shown in your picture, almost always appear okay since they don't come in contact with the opposing spline drive.

To inspect propeller shaft, you will need to remove swingarm and unbolt shaft from engine in front of universal. Swingarm is fairly involved since rear brakes and shocks need dealt with, then simply remove swingarm bearings. Prop shaft is held in position with four bolts under the rubber boot. Note these bolts are held in with lock tight.

Typically speaking, the shaft isn't a source of trouble. Usually it is the weak splines on the wheel that fail or if really unlucky, it will be a secondary bevel gear trouble. Hopefully, it will only be the splines.

Hi Waterman (and CafeKid),

I now see what I'm doing wrong - I am not going in far enough. Thank you very much for the description of what to do! I can now "see" the procedure that I have to perform. The shop manual on Basscliff's site makes WAY more sense after you wrote me that. I tried to understand what do to from the manuals but they don't really go through how do do things... they just say "remove this and remove that" without saying HOW. Then for reassembly they mostly just say to do in reverse what they did to get it out.

I will get to this today and take pics and put them up tonight! Thanks again everyone!

 

[zehrmacht]

Had the same issue

Had the same issue

Waterman has a point when he said to check the prop shaft.

"To inspect propeller... Prop shaft is held in position with four bolts under the rubber boot. Note these bolts are held in with lock tight."

Today I had an odd heavy clank when going over a hard bump I.E. RR tracks.... Clymers guide had a tip that worked. Loosen the clamp on the rubber boot and push it back. Mine had 2 bolts that fell off and the other 2 were loose! After getting new bolts I was able to get them in with a 12mm open end wrench, no removal of swingarm or rear wheel etc...not bad for $2.89!

 

[legaleli]

Found it!

Found it!

jhillier449 was kind enough to come over yesterday and help me look at the pumpkin and propeller shaft. He felt (as I did) that the pumpkin was fine. We then set removing the swingarm (read HE removed it and I watched ).

What we discovered, and what Bikecliff on his site on the link "Bevel Gear Shaft Repair" calls "all too common on these bikes" was a broken gear shaft, just next to the u-joint that I thought may be involved (missed it by | | that much).

I would prefer to replace, than repair, the bevel gear shaft, but would like to hear any comments from people with respect to my preference for replacement over repair (or any other comments of course).

Again - MANY thanks for jhillier449 who came over to my garage on an evening that he could have been riding and then spent some good riding time OFF his bike helping me to get mine on the road. It is truly appreciated - and... I hope I can steal some more of your time when I begin my repair!

Anybody have a bevel gear shaft for sale?

Here are the pics of the bevel gear shaft with the bolt broken off:

 

[Nessism]

Some seriously bad luck there but good job to find the problem.

Finding a gear set shouldn't be too hard but you might want to check the part numbers to figure out if Suzuki changed the parts at some point during 850 production just to be safe.

 

[jhillier449]

No worries Eli, I'll be around if you need a hand.


I found this on ebay, this looks like the one you need, unless they changed it for some reason.

http://cgi.ebay.com/ebaymotors/1981-Suzuki-GS850-Output-Drive-Gear-GS-850-Shaft-
Drive_W0QQcmdZViewItemQQhashZitem5191a490aeQQitemZ350335832238QQptZMotorcyclesQ5fPartsQ5fAccessories

I'm not sure how to check the gear backlash, so gotta figure it out.

There is an o-ring on the bevel gear housing you should replace, available from our local suzuki dealer.

 

[jhillier449]

Sorry, fubared the link, here it is.

http://cgi.ebay.com/ebaymotors/1981...5832238QQptZMotorcyclesQ5fPartsQ5fAccessories

 

[legaleli]

Some seriously bad luck there but good job to find the problem.

Finding a gear set shouldn't be too hard but you might want to check the part numbers to figure out if Suzuki changed the parts at some point during 850 production just to be safe.

Stupid question: How do I check the part numbers (and if I simply look for a number on the actual part - I am TRULY sorry for such a dumb question and will gladly offer the blank stare of a vacuous mind )?

 

[mike_of_bbg]

Legaleli,

Glad you found your problem, sorry it's been so hard to nail down.

You can go to some vendor, such as www.alpha-sports.com, which uses real Suzuki part #'s (bikebandit does not), then look up the part #'s you need on the fiche. Alpha is a good choice because they list all the part #'s, even if the part is no longer available.

Armed with the OEM part #, you can take that to www.babbittsonline.com and do an OEM part search to find all the models which also use that exact part #. One caveat: they have to have the model in their database! Unfortunately for me my model is not in there In other words, there might be some models which would work for donation but won't be listed.

 

[legaleli]

Legaleli,

Glad you found your problem, sorry it's been so hard to nail down.

You can go to some vendor, such as www.alpha-sports.com, which uses real Suzuki part #'s (bikebandit does not), then look up the part #'s you need on the fiche. Alpha is a good choice because they list all the part #'s, even if the part is no longer available.

Armed with the OEM part #, you can take that to www.babbittsonline.com and do an OEM part search to find all the models which also use that exact part #. One caveat: they have to have the model in their database! Unfortunately for me my model is not in there In other words, there might be some models which would work for donation but won't be listed.

OK - perfect - I just bought the Ebay part - price was good and I want it NOW!

Also, I noticed that the part number is the same for 1979, 1980, 1981, 1982, and 1983... hopefully it will fit.