Layshaft bearing upgrade, gearbox on bike

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singring

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Jul 27, 2009
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Just starting the upgrade, but ran into my first hurdle....I cannot get the gearbox outer cover off. It appears that a previous owner has had the gearbox open at one time, as there is some sort of gasket sealant that was used with the appropriate gasket....which has made removal near impossible. I have been referencing Mick Hemming's gearbox video, and the shop manual, but no amount of tapping with a dead-blow hammer, or pulling on the mounted gear shifter for leverage has helped. I did throw some heat on the gasket area with a heat gun, still no joy. I may have to just give up and hope that the layshaft bearing issue was addressed before.
Any ideas??
 
Find the PO and flogg him!! Seriously, I would remove the inspection cover and use a wooden broom handle as a pry device.
 
Take a short block of 2x4, place it on top of the outer cover with the 2x4 grain in line with your blow and give it a whack with a hammer. You may have to try several times around in different places, but at some point it should break free. Don't need much sealant on the inner or outer cover gasket, if any at all. There is also a neoprene one available. I wouldn't pry on things too much or put a screw driver in the gasket. You could try a single edge razor blade to break the seal, but it would be a lot of work.

Dave
69S
 
I used to use sealer on those gaskets; boy was opening the cover a bitch - and inevitably the gasket would tear.

But it didn't leak a drop!

Now, I install them dry - as recommended by, among others, Sir Mick Hemmings.

Still doesn't leak a drop!

Live and learn.
 
I'd try an 1" wide metal paint scraper.
The one I have has a very thin blade.
Tap it through the gap.
Since the gasket or sealer is there it should push through it without damaging the metal.

Bob
 
tie a piece of rope to it, then round a door handle. then slam the door! works for teeth and they are glued in well. hope that helps :)
 
flibity said:
tie a piece of rope to it, then round a door handle. then slam the door! works for teeth and they are glued in well. hope that helps :)
Click to expand...

Or find someone with a bulldozer, line up the corner of the scraper right at the joint, roll it straight back(you will only need a few yards) then straight through. This should release the seal to where you can pull it off while pulling from the inspection cover. If you want to save $2.00 to $3.00, you must try to save the gasket.

Or, there is usually a slight lip at 10 to 11 oclock position , or there abouts, along the joint. I have in the past taken a screw driver and gave it a little pop from the drive side through to release the initial seal and then pull it off. What ever notch you may or may not make make in the cover is easy to file clean and is unseen later.

And make sure all your screws are out or you may have to make a second pass with the bulldozer. :p
 
Yes, make sure all the screws are out!

I have had some luck with taking the blade out of the utility knife and grabbing it with the vice grips parallel to the cutting edge so that the back of the blade is exposed. You can then sort of carve a start at the gasket face and (while wearing safety glasses of course) whack the back of the blade with a brass hammer or similar object. I won't promise that it does no damage but minimal damage at some point becomes acceptable. If the description makes no sense, basically you are driving a hard steel wedge in between the faces. They do break with some enthusiasm when you are whaking them with hammers.

I would also get out the heat gun and heat the whole thing til it is hot to the touch before attempting this.

Russ
 
I got the outer cover off....I applied more heat, then used a straight edge razor blade, tapped it gently into the top of the mating seams, then was able to move it around a bit. A thin blade paint scraper was next to go all the way around, and some jiggy action got it removed. Now to scrape off the old gasket material with some plastic paint scrapers, and continue on with the inner cover. Thanks to all who replied, I will ask for your generous and expert advice as I progress.
 
Singring, you know about the detailed "how it works" and dissassembly/reassembly instructions on Old Britts' web site, yes?

www.oldbritts.com - look in the technical articles section. Great, very detailed info, with photos, and a reassembly checklist that I highly recommend using.

Best of luck.
 
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