clutch and mainshaft

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JohnnyBeckett
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clutch and mainshaft

Postby JohnnyBeckett » Thu Jul 11, 2019 8:44 pm

can you tell me the thickness of the thrust washers on needle roller cage and how do you hold or lock shockabsorber and mainshaft sprocket to du up the the two nuts on 1954 nh 350 thank you

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alan.moore
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Re: clutch and mainshaft

Postby alan.moore » Thu Jul 11, 2019 10:55 pm

Have a look at this post re the thrust washers viewtopic.php?f=4&t=5572&hilit=clutch+thrust+washers

To lock the engine in order to tighten the two shock absorber nuts I made a tool out of two old plain clutch plates with a friction plate between them all bolted together with a long arm with a couple of spacers attached to two of the bolts . If you mount the clutch baskets and fit the primary chain (I use an old one for this) this allows you to wedge the arm of the tool against the bench / floor and tighten those two nuts. Make sure you have the correct lock washer between the nuts with the 'legs' bent over the back and front nut.

The tool can also be used to lock the clutch to tighten its centre nut after the outer primary case has been fitted and the clutch installed

SDC11682.JPG


SDC11684.JPG
Lock nuts with lock washer between them


Cheers
Alan
1939 VH Redhunter;1942 RN WNG;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
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nevhunter
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Re: clutch and mainshaft

Postby nevhunter » Fri Jul 12, 2019 1:26 am

Nothing beats making /having the right stuff to get the job done. Having the bolt in below the inner chaincase is very "clued" too. .Nev

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Re: clutch and mainshaft

Postby Mick D » Fri Jul 12, 2019 7:17 am

Hi

My method is not as elegant as Alan's but requires less fabrication and it works for torqueing the gearbox sprocket too.
I have an old secondary chain which I pass around the gearbox sprocket and a length of bar which I pass through the rear wheel spindle location, with a couple of long 5/16" bolts I secure the chain together fore and aft of the bar and thus lock the sprocket.

Sprocket Locked.png
Sprocket Locked.png (308.7 KiB) Viewed 627 times


Regards Mick

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Re: clutch and mainshaft

Postby JohnnyBeckett » Sat Jul 13, 2019 7:55 pm

thank you Alan and Mick i am going to make both how tight do you do the nuts up on shock absorrber and gearbox sprocket and clutch bolts and nut nice bikes

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paul.jameson
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Re: clutch and mainshaft

Postby paul.jameson » Sat Jul 13, 2019 8:04 pm

Shock absorber nuts, gearbox sprocket nuts and clutch centre nuts should be tightened to " ***king tight" or even "really ***king tight". The six bolts which hold the clutch basket on are prone to coming loose however much you tighten them but if you drill and wire the heads they will stay put for years.
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Now Archivist once more - but not Machine Registrar.

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alan.moore
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Re: clutch and mainshaft

Postby alan.moore » Sat Jul 13, 2019 9:59 pm

As Paul says, very tight. Use a good fitting socket and a decent breaker bar (other than the six bolts use a smaller lever here or you will strip/snap them). All those nuts and the six clutch bolts can benefit from an application of threadlock. Make sure the threads of the shaft threads and nuts are really clean (use thinners to make sure) so you get a good bond.

There are also locking tabs for all these :

3381-41 for the six bolts (there is also a three separate lock tabs version available which I think are better(see photo)
3091-33 for the gearbox sprocket
3070-50 for clutch centre nut (note there are two sizes of centre nut 3068-50 is the bigger one and goes with this tab washer. The smaller one 3068-31 originally had a split washer behind it, Drags list a plain washer 3067-40 and there is also a smaller tab washer available (see photo's)
1299-28 for the crankshaft shockabsorber nuts

SDC12893.JPG
3381-41 (3 separate tabs version)


SDC12895.JPG
3091-33 gearbox sprocket


SDC11693.JPG
3070-50 large nut and tab washer


SDC12894.JPG
smaller nut and tab washer


Cheers
Alan
1939 VH Redhunter;1942 RN WNG;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
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Re: clutch and mainshaft

Postby david.anderson » Sun Jul 14, 2019 8:53 am

The easiest way to tighten the engine sprocket (and half time pinion nut) is a bar (in this case a socket extension piece) through the conrod resting on a couple of bits of timber
David
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Re: clutch and mainshaft

Postby Mick D » Sun Jul 14, 2019 1:41 pm

Hi

It's interesting to hear reports of the six clutch to chain wheel bolts becoming loose, when I dismantled my FH I thought the bolts had been 'bodged' with the screwdriver slots cut by a PO and I decided to replace them with standard hex head bolts which would be more secure in use, (less prone to deformation under torque). It now looks like the slots were cut by design, (which is a little strange as it would imply quite a low design torque), but I think I'll still go for replacing the bolts with standard ones.

As for torque figures and because I have a good range of torque wrenches I have torqued the gearbox sprocket to 60 LBFT and will torque the shock absorber and clutch centre to 50 LBFT

Regards Mick

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Re: clutch and mainshaft

Postby chris.shearwood » Sun Jul 14, 2019 2:07 pm

Mick D wrote:As for torque figures and because I have a good range of torque wrenches I have torqued the gearbox sprocket to 60 LBFT and will torque the shock absorber and clutch centre to 50 LBFT


Both of those torque values seem low to me. I have never used a torque wrench to put on those nuts but have just tightened them as much as I could with a "cheater" pipe on the end of a breaker bar. I am guessing that would give a result much greater than the figures you have mentioned.
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