Comet Gearbox Removal Procedure

youngjohn

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Non-VOC Member
Just planning ahead a little here, can anyone tell me the best/correct way to remove the gearbox form a Comet. Does the inner primary case have to come off, or will it 'wiggle' out once the clutch and mounting bolts are removed?
Thanks.
 

Martyn Goodwin

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Non-VOC Member
Just planning ahead a little here, can anyone tell me the best/correct way to remove the gearbox form a Comet. Does the inner primary case have to come off, or will it 'wiggle' out once the clutch and mounting bolts are removed?
Thanks.

Inner case can remain in place
 

davidd

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VOC Member
Young John,

I found it quicker to pull it out the timing side even for a CS sprocket change. Of course, the racer has lots of mods, but you can see that I have left quite a bit in place.
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David
 

nkt267

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VOC Member
I will wiggle out,gives you a chance to practice all your ancient Anglo Saxon.
I found that I had move/remove the oil feed pipe to make things easier. Once the clutch is off and the bolts removed and the gearbox link is dropped it's a matter of rotating and pulling to get it out..
Good luck with the swearbox.....Sorry gearbox..John
 

chankly bore

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Non-VOC Member
Please do everything possible to ensure absolute tightness of the clutch drum nut and the countershaft sprocket nut. Use both the locking tabs and Loctite "Notluck" (excuse the prep. humour). No need to buy a great tool to do the sprocket nut, it can be held in a vice and the sprocket hammered around with a brass drift.
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Please do everything possible to ensure absolute tightness of the clutch drum nut and the countershaft sprocket nut. Use both the locking tabs and Loctite "Notluck" (excuse the prep. humour). No need to buy a great tool to do the sprocket nut, it can be held in a vice and the sprocket hammered around with a brass drift.

There is no excuse for butchery on bikes like ours. You can purchase the correct spanner for the sprocket nut for very little and remember, you will need it around every 10,000 miles when you replace the chain and sprockets (as a set) as part of your regular maintenance.

Here is where I obtained my spanner

http://www.ebay.com.au/itm/181301604855?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 for just A$22.

Use a length of old drive chain wrapped around the sprocket to hold it while you tighten the nut - this method places zero strain on the gearbox internals. Use a lock washer and Loctite on the drive pinion nut.

As to the clutch drum nut, I recommend that you use a lockwasher AND safety wire as well - you will need to drill through the flats on the nut to accommodate the wire.

The image shows a Honda clutch basket installed in my Comet.

I did have a Burman Clutch but cannot supply photo's as I loaned it (the Burman clutch ) to another section member and it was never returned. Sigh - that's bye bye to $400 or so and when I return my gearbox to original I will be forced to seek out a Burman unit for sale, if I can find one. Bit pissed about the whole thing but then again, by his own admission, he does have Welsh Alzheimer's.

IMG_0034.JPG
 

nkt267

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VOC Member
While you have your clutch off,assuming it is a Burman clutch, check at the base of the plate slots on the basket as they have a tendency to crack here. If they all crack then the the top of the basket can spread and jam the top plate.Mine jammed at the international in 2007,made life interesting till it got sorted.
It may be adviseable whilst it is apart to add a strengthening band around the basket as was done to the Matchless clutches..John
 

youngjohn

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Non-VOC Member
Thanks for the replies. The plan is that I have a spare BAP which I'm going to make a start on rebuilding and just use the bike as is for now. I hate bikes being in bits and this way, if it needs an overhaul it should only be apart for a weekend. The little 'crunch' when changing in and out of third is pretty light and the bike would probably go on as it is forever, so it should be ok for this year.

I'm using a Honda clutch which has had a few 'dragging' problems before so I need to strip and clean that, and also maybe water down the Penrite Semi-Fluid Grease in the box with some oil before I face up to the need for more expensive solutions!
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Thanks for the replies. The plan is that I have a spare BAP which I'm going to make a start on rebuilding and just use the bike as is for now. I hate bikes being in bits and this way, if it needs an overhaul it should only be apart for a weekend. The little 'crunch' when changing in and out of third is pretty light and the bike would probably go on as it is forever, so it should be ok for this year.

I'm using a Honda clutch which has had a few 'dragging' problems before so I need to strip and clean that, and also maybe water down the Penrite Semi-Fluid Grease in the box with some oil before I face up to the need for more expensive solutions!
Stay with the semi fluid in the box, lest you end up with leaks.

In the primary case, use Auto transmission fluid with the Honda clutch
 
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