Some Sport Troubles

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Gum
750 Sport [BEVEL]
Posts: 219
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Location: Australia

Some Sport Troubles

Post by Gum » Fri Nov 05, 2010 3:38 am

Gday, I have just got my Sport 73 on the road after an engine rebuild. The clutch is slipping badly. I have adjusted correctly, any ideas ???

Also and the one that concerns me, I have oil leaks coming from the Bevels at the top, it looks like where the towers meet the upper housings, please tell me this is an easy fix, cause it doesnt to me.

Thanks Gum

bobnorton
860 GT / GTS
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Location: bromley kent

Post by bobnorton » Fri Nov 05, 2010 8:19 am

Hi Gum, A rebuilt clutch with old parts swopped around can take a while to bed in, too high oil level? too slippery oil? the funny shape plate in the wrong place? enough slack on the center adjustment? cable slack means nothing,clutch center notched by the plates and does not like the new plates? Drive it gently for 10 miles and see if it improves.

wdietz186
888
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Joined: Sun Sep 10, 2006 4:40 pm

Post by wdietz186 » Fri Nov 05, 2010 1:28 pm

Gum, If the leak is at the tube to housing joint try to rotate the tube back and forth a bit.Sometimes the oring gets rolled and distorted when the tube is installed and oil sneaks past.If you get a good grip you can also go up and down gently,that will help unroll things too.A pair of small soft jawed pliers that plumbers use on chrome fittings work if you can narrow the jaws some to gain clearance.Or hard rubber/plastic and reg. pliers if you are careful. If that fails you'll either live with it or lift the heads to replace the rings.But spinning the tubes usually works.
Bill

Gum
750 Sport [BEVEL]
Posts: 219
Joined: Sun Nov 23, 2008 3:15 pm
Location: Australia

Great

Post by Gum » Fri Nov 05, 2010 1:51 pm

Great, lift the heads, that will fun, I dont think its tubes, but I could be wrong, I will give it a go.

Clutch, correct oil, correct adjustment. Fitted by an expert, so it still slips, this cant be happening, but it is.

Thanks for the replies, I expect issues with a rebuilt bike, so one by one I will fix them.

It rides great, runs well super smooth, just the oil leaks are not good from an expert engine re builder, I can fix that clutch in an hour for a few hundred bucks im sure, but those oil leaks. MMMMMM

Thanks Gum

Gum
750 Sport [BEVEL]
Posts: 219
Joined: Sun Nov 23, 2008 3:15 pm
Location: Australia

All Sorted

Post by Gum » Fri Nov 05, 2010 11:16 pm

Ok, the clutch is just rubbish. So im getting a surflex, that will fix it.

Then this week I will get both heads off and redo the bevels, that will fix that.

Gum

bobnorton
860 GT / GTS
Posts: 280
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Location: bromley kent

Post by bobnorton » Sun Nov 07, 2010 12:37 am

There were some obscure alterations to clutches over the years, wrong parts?.

machten
MHR / S2
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Post by machten » Mon Nov 08, 2010 3:14 am

Gum,
I have oil leaks coming from the Bevels at the top, it looks like where the towers meet the upper housings
If it is leaking through the upper bevel housing gasket, then it is an upper bevel shimming problem. It is not an easy fix if you haven't done it before. Above the upper bevel bearing, you need to get the bevel gear clearances right or you'll stuff the bevel gears, below the bearing - you need to ensure (given the variable gasket sizes available), that you have shimmed enough tension on the bearing race to stop it from spinning in the alloy mount, while at the same time providing enough compression onto the gasket to make it seal. Unless you have a good selection of the shims, and know what to do, it is not simple. You need to expect to take several shim changes to get it right - that's why you need a good shim selection to work with. (and you'll need the head off to do it). Every shim change you make above the bearing affects the shims you need below the bearing - and vice versa - in order to make the gasket compress and seal.

The process is way too hard for me to explain via email, and the worst consequences of doing it wrong are significant - stuffing up your bevel gears, or leaving your bearing race to spin. Fixing the oil leak on it's own is easy! The trick is shimming to cover all three.

The best way to learn this is to have someone who knows how to do it to show you.

Kev

bobnorton
860 GT / GTS
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Post by bobnorton » Mon Nov 08, 2010 8:18 am

I had a similar problem on my single bevel, it took three head off sessions to fix the leak!!,I can imagine the problems with a roundcase which has both cylinder bevels interacting, glad I've got an 860 which at least seperates the bevels.Getting a nip on the gasket at the same time as trapping the steel bushing is the issue. You will have to use a sealer ,carefully!!

machten
MHR / S2
Posts: 481
Joined: Sun Oct 29, 2006 8:37 am
Location: Perth, Western Australia

Post by machten » Mon Nov 08, 2010 11:17 pm

I had a similar problem on my single bevel, it took three head off sessions to fix the leak!!,I can imagine the problems with a roundcase which has both cylinder bevels interacting, glad I've got an 860 which at least seperates the bevels.Getting a nip on the gasket at the same time as trapping the steel bushing is the issue. You will have to use a sealer ,carefully!!
In this case Bob, if the problem is as I mentioned, you don't have to mess with the lower bevel chest shims (thankfully). That shimming is independent of the upper bevel shimming.

Kev

bobnorton
860 GT / GTS
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Post by bobnorton » Tue Nov 09, 2010 12:53 am

As the "expert" made a hash of oil sealing and clutch i would definately check the bevel meshes while its in bits, a short run after a rebuild can also throw up a few unexpected changes.

ducadini
750 Sport [BEVEL]
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Location: Antwerpen

Post by ducadini » Thu Nov 11, 2010 4:31 am

You have to fit the heads on the engine while checking the mesh (and take them of to change the shims) otherwise the bevels may not line up as they are while 'working'.
As machten already said : a bit strange to write down, but fairly clear when You see it.
Check play between shafts on the oldham-coupling (just above the lower-bevel-housing) to be sure these don't interfere.
Be carefull, the "result" can cost You a LOT.
cu
ducadini
Nego i ricordi peggiori
Richiamo i migliori pensieri

Bern
Parallel Twin
Posts: 100
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Post by Bern » Thu Nov 11, 2010 11:24 am

I was looking at the exploded parts diagram to get an idea of what the shims are doing. This is probably a stupid question but what I don't get is the lower shim, and seeger clip (part 95 and 1747). What are these resting against? Is there another bearing in the yoke housing? What is the lower shim spinning against or does it rest against the outer bearing race?

bobnorton
860 GT / GTS
Posts: 280
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Post by bobnorton » Fri Nov 12, 2010 11:18 pm

Hi bern, on the single motors there is a shim that that sits in the bottom bevel housing , if its too thin the whole bearing assembly (and bevel) can move up and down, if its too thick theres no gasket nip and it leaks. I think the twin is the same?.

bobnorton
860 GT / GTS
Posts: 280
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Post by bobnorton » Fri Nov 12, 2010 11:34 pm

Had a look at the parts book, the circlip and shim allows you to adjust the bevel meshing and play, shims are moved above or below to change the settings although the total shim pack measurement stays the same(providing it was set up right in the first place and has not been fooked with!!) The total pack thickness should just allow the circlip to be fitted with no play.Also the whole assembly ,bearings and steel bushing must be clamped down ,as per my earlier post.Its not usual to adjust these shims,its normally done with the crank bevel .A test to check that the assembly is clamped is to tap under the center of the horizontal bevel and see if it moves up and changes the clearances.Mine moved about 6 thou!!.Not good.My experiences are all with singles, GTS next.---thought about it some more!!, I think the shim abutts the inner bearing race so it should all be going round together.

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