Author Topic: Clutch adjustment MkV  (Read 542 times)

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Offline Pallijen15

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Clutch adjustment MkV
« on: 16 Jul 2018 at 09:51 »
Hello to all, just bought a 1951MkV runs and changes gears great but there is no play on the clutch lever. The lever needs to be let almost all the way out before it bites. Should there be the usual 1/8 to 3/16 play at the lever as other British motorcycles? Don't want to  use it till I get this sorted. One other thing, previous owner left a note regarding the pushrod not being hardened on one side that he had changed, also being specially made 5mm longer. I can't understand why he didn't harden them before fitting. Any advice greatly appreciated. Thanks, Paul J

Offline eddie

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Re: Clutch adjustment MkV
« Reply #1 on: 16 Jul 2018 at 10:22 »
Hi Paul,
            Yes, there should be the usual free play on the clutch lever. If there is no slack, the thrust bearing will always be under load and will wear prematurely. Clutch thrusts are becoming hard to find - so take care of it!
  Regarding the push rod:- The ends should be hardened, but you need to know what material it has been made from. The most likely materials are either mild steel or silver steel. Silver steel is easily hardened by heating and quenching - so try heating just one end to a cherry red and quench it in oil - if that end is too hard to file, it is silver steel and will then need tempering. Polish the hardened end, then gently heat it until it turns a straw colour - then quench again in oil. Repeat the process on the other end.
  If the initial heating didn't result in any hardening, it is probably mild steel and will need to be case hardened. This involves heating the ends to a bright red and dipping in a carbon rich compound (Kasenit) and reheating before quenching in water. The depth of hardening can be increased by repeating the operation, but about 5 thou is the maximum you will achieve. With case hardening, there is no need to temper it.

  Hope this helps,
                         Regards,
                                       Eddie.

Offline Pallijen15

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Re: Clutch adjustment MkV
« Reply #2 on: 17 Jul 2018 at 14:01 »
Thanks Eddie,  so since there is no play on the lever and the clutch bites when lever nearly fully released then will I need new clutch plates or is there an internal adjustment method also? Paul J

Offline eddie

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Re: Clutch adjustment MkV
« Reply #3 on: 17 Jul 2018 at 14:59 »
Hi Paul,
            All you need to do is adjust the clutch cable. The adjuster is on the end where the cable goes into the clutch bellhousing. If there is no more adjustment available there, remove the small inspection plate just below the cable. Inside you will see the inner cable connected to the operating arm - this arm is held in place by a clamping bolt and nut, undo the nut about 1 turn and adjust the arm to give some free play on the cable - then retighten the clamp nut - aim for about 1/4" of free play in the cable. Now return to the cable adjuster and bring that free play down to about 3/32" - you will then have enough scope to adjust either way until you are comfortable with the 'feel' of the clutch.
   Providing your clutch is gripping OK, you shouldn't need to replace the plate (it's just a single plate, like a car clutch!).

Regards,
              Eddie.

Offline Pallijen15

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Re: Clutch adjustment MkV
« Reply #4 on: 18 Jul 2018 at 22:12 »
That's great, thanks Eddie, I'll give it a go on Sunday or Monday if I'm off

Offline Pallijen15

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Re: Clutch adjustment MkV
« Reply #5 on: 23 Jul 2018 at 10:30 »
Thanks Eddie, very impressed with  my newly acquired Douglas. The clutch was a doddle to adjust. Sorted my headlight which wasn't working. Now I'm all ready to go. Should leave the hardening of the pushrod for an initial time or do them straight away. Can't understand why the previous owner didn't harden them before putting them in. Is there a reason for this? My other concern is that I don't seem to have any reserve on my fuel taps. These are lever type which operate quarter turn from horizontal to vertical to open. Do you know if these are the correct ones for a 1951MkV? Fuel lines run direct to each carburettor. Thanks for help, appreciated. Paul J

Offline eddie

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Re: Clutch adjustment MkV
« Reply #6 on: 23 Jul 2018 at 12:18 »
Hi Paul,
            The original petrol taps were of the twin plunger type (see the attached page from the spares book) - each tap having a main supply and a reserve. The petrol pipes go from each tap to the carb - they are not joined together.
   Regarding the push rods - I would harden them before use. Hopefully, your new pushrod has been made correctly - they are 3/16" dia with a 1/4" dia head. Both ends should have a 1/8" radius dome - that gives a full dome on the top end, but only a part dome on the bottom end. Machined this way, they will sit correctly in the tappet and rocker arm.

  Eddie.

Offline Pallijen15

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Re: Clutch adjustment MkV
« Reply #7 on: 23 Jul 2018 at 21:16 »
Ok thanks Eddie, looks like I will have to get two new taps. The guy I boght the bike off said he had the pushrods specially made and that they were 5mm longer.

 

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