Removing the transmission case

[wayne]

Frustratingly, after a year of work and just about to try and fire this bike up, I now find I need to remove the transmission case.

I've had a gearbox oil leak which I've been trying to chase for weeks. It isn't seals or O rings, it's hairline cracks in the transmission case itself below the shaft that drives the gear indicator mechanism.

Is it possible to remove the transmission case without removing the whole engine ? Has anyone done this ?

It looks like I can do it but would need to rotate the engine up and forward pivoting around the front engine mount.

I'd appreciate any tips or tricks before attempting this.

Wayne

[FC Zach]

I also removed my tranny due to a leak. If I recall, I had no luck removing the gearbox by itself without dismantling the engine. I was very frustrated while doing this (trying to remove the transmission by itself) so I wasn't clearheaded and eventually abandoned the idea and just went ahead and removed the engine, so hopefully someone else will chime in. What was even more frustrating was the leak that I "repaired" wasn't even the source of the leak. It was the gear indicator mechanism ! I look back at that as a learning experience

[wayne]

Hmmm........that might be sage advice.....be clearheaded and just do the job properly (ie remove the lot). I've sort of been down that road myself where trying to cut corners ends up driving you insane.

I have also been fearful that I could be barking up the wrong tree. I'm going to seal what appear to be cracks in the first instance and if this stops the leaks, then I'll proceed further. However, in my case, I have an NOS digi gear indicator with new O ring and the leak is definitely not coming from the sprocket or clutch push rod area.

Wayne

[ziggystardust]

For what it's worth my A model clutch cover is full of surface hairline cracks to the inside, so much that I did post my concerns about it a few years ago but have had no leaks to date.

I would also consider cleaning the cracks thoroughly and covering with DB putty or alternative to see it that cures it.

I would have to be absolutely positive that an 'O' ring or oil seal was not the problem before stripping out the engine/gearbox.

Z

[wayne]

Thanks Ziggy. The leaks are most definitely from the hairline fractures, I've spent some time with a powerful light and the area in question at eyeheight. I filled it with oil, and you can see it oozing from the cracks themselves. The cracks are hard to see but show up well in the photograph below.

The cracks are all below the digi drive. The two distinct lines to the left of the photo that look like cracks are raised casting lines.

But I did get some Devcon epoxy steel putty and after grinding the whole area that has the cracks with a dremel tool and thoroughly cleaning it (I hope), I've applied the putty. After a few days I'll check for leaks again before doing anything too radical.

I absolutely want to be positive, I am not keen at all about pulling this project apart.

Thanks,
Wayne

[mike500]

i have used belzona to seal cracks in other bike cases and it worked perfect as it will withstand very high heat etc regards mike

[raychappo]

Belzona, now theres a product I remember from 30 years ago. We used it to repair pin holes that occured due to corrosion in our high pressure heating system. It was a fantastic product although at the time I remember it was horrendously expensive.

[mike500]

it still is very expensive ray but it does the job first time so well worth the cost and once its cured you can drill it, tap it, file it etc i use it on gt750 barrels to rebuild the holes for the exhaust bolts would never be with out it in my tool boxes

[wayne]

That's a product I've never heard of but sounds like I should get hold of some. The Devcon that I'm using has a max temperature rating of only 121 degrees C. But I'm pretty confident that part of the casing will not reach that temperature- having said that, a higher temp alternative would have been better.

Wayne

[pmcburney]

Hey Wayne,


I've heard of a product that will seal cracks as you describe.

It's apparently very thin and will penetrate deep into such cracks and set and seal them from within, so to speak.
You do it all from the outside, so you shouldn't have to remove the tranny at all.

I'll track down the name of the product if I can and let you know.


Cheers
Paul

[wayne]

Thanks Paul..............may be too late, I've already used the Devcon which is setting while we speak but please do let me know.

Wayne

[mike500]

belzona link www.belzona.com/prod1k.aspx

[wayne]

Right, first of all an apology to Ziggy in particular...........I was convinced that I could see the oil oozing out of the fractures. But I think that I was wrong. And Zac, I think that I may have your problem.

I ground the area, cleaned it, filled it with Devcon putty steel which, I think, is pretty much the same as Belzona. Kept it warm and well above the min cure temperature and 50% over maximum strength bond time.

Filled it up with oil and it still leaks. More importantly, the RATE of leakage is exactly the same.

I've done such a thorough job with the putty that I would have expected at the very least, a reduction in the flow. But it's had no impact.

The leak must be the digi gear indicator. But it's NOS with a new O ring so this brings me back to Zac..............what part of your digi gear indicator was at fault and how did you fix it in the end ?

Wayne

[FC Zach]

I'm not exactly sure which particular part was defect. What I had done was replace the o-ring which still didn't solve the problem. So this eventually led me to my last resort which was accomplished with a sealant called SealAll. I practically injected the unit with a healthy dose of this stuff, wait for it to dry and then returned to fill it up. I believe it may have stopped the leak! I'll look at it closely when I return to the shop this weekend. Tonight I'll get you more info on the sealant. What I do know about it is that it is fuel and oil resistant, flexable, and cheap!

I'll get back in touch with you this weekend, so I can see for myself if it did anything. I'm anxious myself

[wayne]

Thanks Zac. That was going to be my next step, useing a sealant around the digi O ring.

I do have a couple of products, one made by Loctite and the other by 3 Bond. The latter is supposedly used by the factories themselves these days. Both are oil resistant and made for sealing so I'll try that option. But let me know how things go this weekend.

I'm thinking of filling the gearbox with 1600 cc of ATF just to use the colouring to help me perhaps pinpoint this leak. I won't be starting or turning anything.

I don't imagine if I just used it in this way and then drained it fully it would do any harm to the (NOS) clutch plates ??

Wayne