Author Topic: GTR Clutch Basket Rubbing On Engine Side Cover  (Read 385 times)

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Offline hgzumanity

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GTR Clutch Basket Rubbing On Engine Side Cover
« on: July 22, 2018, 12:06:27 AM »
Hello everyone,
I recently got my GTR running and I can hear the clutch basket rubbing on the engine cover underneath it. I did some digging about this in the forum search and found out that an engine cover that gave more clearance to the clutch was made after my GTR was made ( I have #1908). My question is: Can I shim the clutch basket to move it away from the engine side cover so it doesn't rub anymore? Or, do I have to find a newer engine side cover to put on my engine to stop the clutch basket from making contact?

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #1 on: July 22, 2018, 06:40:12 AM »
            I believe, the modification to the right crankcase cover and clutch outer cover was more aimed at providing further side clearance between the clutch housing and the side of the basket. BS were convinced the basket fingers were spreading under load and rubbing the case. A steel band round the basket fingers was also added at some time.
         As far as I can tell the later clutch outer cover does not provide increased clearance to the outside of the clutch. Take the outer cover off and see where it is rubbing.
        Scoring on the inside of cover is quite common and is more likely to be due to the clutch hub nut or the 40mm ring nut on the clutch basket (behind plates) having come loose. Check these first. It is also possible your clutch has the wrong combination/ No. of plates, pressure plate running skewed, or push rod arrangement is not correct, or wrongly adjusted.
       The clutch basket cannot be shimmed to move it inward.                                                    Brian
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Offline hgzumanity

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #2 on: July 22, 2018, 11:23:31 AM »
Thanks, Brian. I looked to see where the rubbing is happening. The outside edge of the back of the clutch basket is rubbing on the crankcase cover. The clutch was working nicely before I took it apart this morning, and I double and triple checked the arrangement of the clutch parts and push rod parts when I put the engine together about a month ago. I'll have to check when I reassemble if the pressure plate is running skewed. I assume this is done by pulling the clutch lever and checking the clearance between the pressure plate and clutch disk. Harry

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #3 on: July 22, 2018, 12:06:23 PM »
       I'm not quite clear on where rubbing is occuring. Is the outer side of the clutch basket hitting the side of its housing. If so, can you feel any wobble on the clutch basket. Are any of the fingers bent outward?
     If there are no marks showing on the clutch/carb outer cover, its sounds like your clutch plate pack, pushrod, etc are OK.
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Offline hgzumanity

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #4 on: July 22, 2018, 01:08:10 PM »
This is where it’s rubbing.

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #5 on: July 22, 2018, 01:09:34 PM »
And here.

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #6 on: July 22, 2018, 01:45:12 PM »
I wonder if I am missing #5 in this parts diagram. It’s 09048-112 “22 thrust washer” Where does that thrust washer go?

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #7 on: July 22, 2018, 06:34:48 PM »
           Thanks for photos.   Item 5 sits behind oil seal 3 inside the splined mount for the clutch basket.   It wouldn't affect the position of the clutch basket if missing (which is unlikley).
          More likely is item 23,   ''22 thrust washer''   behind kickstart gear A.  Unfortunately you have the strip the crankcase cover to check if missing.  Can't think of anything else it could be, anyone got any alternative  suggestions?
         
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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #8 on: July 22, 2018, 06:58:44 PM »
Thank you, Brian. Well I went ahead and took the crankcase cover off. The thrust washer that is number 23 in the parts diagram is right where it's supposed to be, so I didn't leave it out when I put the engine together. I carefully made sure I put everything together right while I had it apart that far, and I am now sure that I have all of the parts in the right place and nothing is missing. I am half tempted to use a Dremel and remove a small amount of material from the crank case cover where the clutch basket rubs.

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #9 on: July 22, 2018, 11:09:21 PM »
Since you have the correct washers, etc., I can't figure it out either.  You could add a spacer at the spot indicated in the image, but there must be something else wrong. Is the bearing locator 1/2 ring that locates the ball bearing (#20 in transmission asm) in the crankcase there? There's a photo on P.11 of the service manual that shows the approximate location of the bearing relative to the crankcase behind the clutch drive gear.
« Last Edit: July 22, 2018, 11:20:47 PM by OldSwartout »
Karl Swartout
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BS175 Roadracer
BS350 GTR

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #10 on: July 22, 2018, 11:31:01 PM »
Any chance the clutch basket itself has become deformed?
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Offline hgzumanity

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #11 on: July 23, 2018, 02:13:48 AM »
That just might work, moonpup. I'll try to make a shim tomorrow and tell how it turns out. I know for sure that bearing locator clip is where it's supposed to be and the rub mark on the clutch basket is the same width all the way around which tells me its running true. I don't even want to think of taking this engine apart when it runs and shifts as nicely as it does.

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #12 on: July 23, 2018, 06:59:24 AM »
              Just checked 4 crankcase covers for scoring as yours. Only one has no scoring, two have minor tell tale marks and the fourth is worse than yours. So this is not uncommon, the rear of the clutch basket runs with minimum clearance.  Any minor variation in the parts and it will score the case.
         A couple of thoughts, how thick is your washer 23, just measured one at 1.8mm. Possible previous owner has put wrong washer in.
        While you have the side cover off, assemble the clutch basket to its carrier and try it on the shaft, can you feel any wobble, does it spin true. In my experience they do wobble slightly which is part of the problem. Looks like you have the later basket with the band, maybe these were slightly different to earlier ones.
        A word of caution, shimming the clutch basket outward may mean the 'o' ring seal on the clutch carrier (driven gear) is not compressed enough to stop oil leaking but is your best option at this time. A spare 40mm lock washer with the outside cut off would be suitable, just fits to the outside of the oring. 
        Increasing the thickness of washer 23 also has issues, the clutch carrier must not be moved beyond the shaft shoulder which the clutch hub sits against.

      It's only when you look at an issue like this, you realise how closely these motors were engineered.
       
« Last Edit: July 23, 2018, 08:15:33 AM by BRT-GTR »
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Offline hgzumanity

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #13 on: July 23, 2018, 01:07:51 PM »
It's interesting that this type of rubbing is not uncommon. I have to say, these BS 350's have more little issues and complications than any other Japanese motorcycle I've ever worked on. But I like a challenge! My washer 23 measures the same as yours at 1.8mm. I assembled the basket on the shaft and tightened down the big lock ring. There is no play in the shaft/bearings and the basket spins true by eye but I didn't have a dial indicator to put on it. I'm sure it has a few thousandths run out. Like I said earlier, the scoring on the clutch basket is the same width all the way around so i think that says it spins true.

With all that said... I cut a shim out of steel .006 shim stock. I cut out the shape of the carrier splines on the inside hole so the shim would stay centered on the shaft after I pushed it on past the splines where the o ring is. I put the o ring on after the shim, so the o ring sits on top of the shim. The OD of shim was, of course, the same size as the hub of the clutch basket. then I put everything back together, started the bike, and the noise was gone. I had to adjust my clutch cable slightly. I went for a 15 mile ride and the noise did not come back. I took the clutch/carburetor cover off to see if any oil had leaked and it was dry as a bone in there.

I believe the problem is fixed, but I will check now and then to make sure no oil is leaking into the clutch chamber.

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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #14 on: July 23, 2018, 01:18:35 PM »
Glad to hear all's quiet on the clutch front, but I'm still looking for possible causes.

Maybe a thicker aftermarket inner cover gasket could be the culprit by pushing the cover out just enough to make contact with the clutch basket?
« Last Edit: July 23, 2018, 01:58:42 PM by moonpup »
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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #15 on: July 23, 2018, 02:54:36 PM »
            The 350 Bridgestones were put on the market very soon after the 175s and didn't benefit from years of development so they do have a few niggles.
       Great job on cutting the shim to fit round the splines, I'm sure the oring seal will now be fine. Was surprised that 6 thou did the trick although the drum had already worn itself some clearance. My money would be on the later drum being the culprit, will see if I can find an earlier drum and compare the profiles.
       Hope you can now look forward to many years of trouble free riding, you've earned it.  ;)                                                         Brian.
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Re: GTR Clutch Basket Rubbing On Engine Side Cover
« Reply #16 on: July 23, 2018, 04:48:39 PM »
Thanks again OldSwartout for the shimming idea. Maybe the aftermarket gasket is slightly thicker, but it squishes down very thin when its compressed between the crankcase cover and engine case. I really appreciate everyone's help on this. This GTR is a blast to ride.

 


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