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JM 159 clutch case depth ?


Phillip1
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29 minutes ago, bullylover said:

That inner basket is the wrong one for a 159. A 159 should have nuts to hold the clutch springs in not pins. I think most of the later Sherpas all use the same clutch but I`m not sure when they changed from the pins to the nuts. But any clutch inner basket that used nuts should work.

 

159 is a pin type hub, I've not seen one with the threaded type. 

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Lots of different opinions as to type of correct clutch and shaft spacers !

Due to the horrendous amount of damage to the inside of my old clutch case caused by rubbing in a rotary motion and no damage to the ends of the clutch spring mounting studs, or the small 2mm.retaining pins and washers,it appears the clutch centre hub has previously been replaced.

As the clutch retaining centre nut and the crankshaft flywheel nut were both only finger tight,when I received the bike,it is possible both crankshaft and gearbox mainshaft spacer collars have been changed. 

I assume due to age of the bike,no Micro Fiche or part number lists exist ?

 

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Hi Phillip,

Well... disregard what I mentioned about the distance between the clutch spacer and seal surface.  My memory of working on the 159 was too foggy to accurately recall.

I cracked open the clutch cover last night to take a few measurements and photos (attached).  All seem to be in line with the measurements Woody provided as well as confirming his description of the 159 clutch hub (original to mine, anyway) incorporating studs with pin retainers NOT threaded.

On the off-chance you simply have a weird clutch cover, I did measure mine internally using a straight edge and came up with 72mm taken from the ledge of the threaded access port for external clutch adjustment (see photo). Hope this helps a bit. Good luck!

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Hi Mr.Vintagenut and thank you for supplying the measurements.

Can you confirm your 72.02mm. was from the case gasket face to the inner clutch cover to next to the threaded access hole ?

My replacement clutch cover measures only 67.1mm and the old damage original clutch cover measures very similar,allowing for the damage caused by the rotation clutch pins.

So it appears both my covers are 5mm. too shallow.

My clutch shaft top hat spacer looks to be the same height as yours.

Problem is what to do now,as I cannot keep buying old clutch covers on the off chance of finding a deeper one ?

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Confirmed - measures from the gasket surface to the point mentioned.  For comparison sake, I also measured the cover from my 199a. As you can see, the factory removed the step that can be seen on the 159 cover, gaining an additional 3mm clearance - 75mm depth total (attached).

Does seem your cover is from another model or lost 5mms worth of material on a sanding table.

Cheers-

Christian

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5 hours ago, Phillip1 said:

Problem is what to do now,as I cannot keep buying old clutch covers on the off chance of finding a deeper one ?

You could get the seller to measure.

If you can say which design cover you want I can measure some up for reference

Edited by feetupfun
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Confirmed - fits perfectly.  No visible gaps - all screws seat correctly.  I've included a pic taken through the access cover to illustrate clutch hub clearance.  No contact there.  When shopping for a replacement, definitely follow Feetup's advice in getting a measurement from the seller.  Shouldn't be too much to ask of the seller if reputable.

Cheers!

C.

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Thank you for your help Christain.

Looks to be 5 or 6 mm clearance there over the clutch studs,so I need to find a 199a case,preferably without the inside boss.

Your caseing looks to be a more accurate casting then the earlier 159 case,do they not counter bore the mounting cap heads ?

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