I finally split the case on my c15 today and have been justified by what I found to do so. The crank case had been sealed with silicon like ever other joint and there was a small amount inside the crank case.
AFter removing the bearings (with heat on a lidded BBQ) I could see that both bearngs had turned in place with the gearbox bearing being the worst. It fell out when I had only got the case to about 150C.
You can see the shiny surface on the gearbox bearing. I can also feel and see the inner race wobble when I apply sidewards force with my fingers.
Crank bearing not quite so bad, but like the gearbox bearing sounds rough when spun.
Will be replacing both bearings.
The bush on the sleeved gear in the gearbox is shot, the primary drive oil sleal has nearly rubbed right through it.
I can feel wear on the crank sleeve so according to Rupert Ratio it needs replacing
My biggest concern though is the timing side plan bush. It has some minor scoring, but bigger worry is with just finger pressure I can move the steel sleeve in and out by about 1mm. Hard to see in this photo but there is about a 1mm gap between case and inner edge of the sleeve in this photo.
As the bronze bush has some scoring and its steel sleeve is loose it obviously needs replacing and since I am now up for some cost I am thinking of replacing it with the needle roller conversion kit.
My question is, is this something I should take to an engineering firm to do, or is it simple a matter of heating up the case and pushing out the steel sleeve?
This last photo shows the spacer that goes on the crank on the primary drive side before sprocket. Is this showing heavy wear on the spacer and it needs to be replaced, or is it meant to be like this?
Finally can anyone recommend an online supplier that is known to sell quality bearings so I don't end up with some duff Indian made bearings that fail after a few hundred kilometers?
Also who am I best buying the needle roller conversion kit from to ensure I get a quality part.
I only know of one maker of the needle roller conversion and that is Alpha Bearings but its stocked and sold by a few retail outlets, I have fitted 2 and I did it myself with heat etc. While you have the crankcases apart also renew the ball and spring under the grub screw below the main bush on the inside, remove the excess aluminium that is staked over it and heat the crank case before trying to undo using a impact screwdriver, you do not want to risk ruining the screwdriver slot.
For the bearings make sure they are FAG or another good brand and you can use a good local bearing factor that supplies the local factories. Both bearings need to be C3 fit or you will be wondering what all the funny noises are (don't ask me how I know )
Can't be certain but the spacer may be machined that way, the crank nut holds it all tight anyway.
I am concerned about the bearing fit, I rebuilt a B40 with fits like those and used loctite, when I took it apart some 8 or 9000 miles later all the loctite had gone and the fit was worse. I have scrapped the cases and have a new set, if I found another set going the same way I would be looking to copper plate the OD of the bearings to restore the fit. Again you should be able to find a plater to do this, its a common fix in factories on old machinery.
Thanks Kommando. I have seen the Alpha bearing needle conversion kit, just sure if there was more than one maker of these kits and just wanted to make sure if there was I bought the good one. I've got a small but growing pile of parts I have ordered over the internet in the last year that now sit in the corner of my workshop that are just too poorly made to want to fit to my bike and if possible I want to avoid adding to it. :-)
I'll look into if I can find a plater that can copper plate the OD of the bearings as I'm hoping once I have finished this I won't ever need to open the case again based on the amount of riding I plan to do on it.
Already have a new spring a BB on its way to me and a NOS sludge trap screw.
Guess I will find out about the spacer when I refit the final drive and check alignment as the crank sprocket looked to be polished on one side by the chain and not the other, so I suspect the alignment is out
My project has been stalled for the last few months due to work and repairs around the house and the car, but I'm hopefully about to get it back on track. My local bearing supplier sells NSK bearings. I must admit I don't know much about bearings, but do know there are some bad ones out there. A quick look on the web and I think NSK bearings are of good quality, but can someone confirm this before I go buy them as the amount I plan to ride this bike I don't plan on opening the bottom end again on this engine.
the crank sleeve doesnt look too bad it might be ok with a clean up with fine wet o dry and from what i can see of the bush it looks genuine if its only fault is being loose in the case then i would loctite it in place,i would also loctite the other bearings.a worn genuine bush will be far better than a new patern one, as for the roller conversion i find it iffy to say the least in the way it feeds the big end,i know a roller doesnt need much oil pressure but my personal experience of bushes in c15s is that they work well.
Personally having tried to use a set of B40 cases like this and then having them fail again shortly after I would go for a second set of good cases, C15 cases are cheap and there are unused ones about.
I think that thread is just some peoples opions and shouldnt be taken too seriously,loctite do a masive range and its important to select the right grade,most loctite dosnt give up until 250c and they retain all there strength up to 180c, if you have a crank case getting that hot you do have problems ! in my experience most british engines iv stripped look like the bearings have spun, iv used loctite hundreds of times and never had a problem.dont get me wrong i know plating the bearings is a nice way to go but is it practical for most people and the aplications?
Its not the temperature the loctite cannot handle but the different expansion rates of the metals, a steel bearing in a steel housing is perfect for loctite, but the alloy housing expands faster than the steel bearing and over a number of heat cycles the grip of the loctite reduces until the bearing is free to move again.
Thanks everyone. I got myself the NSK bearings. Over the last couple of months of waiting for cash to become available I've come to the decsion I will pay someone to assemble the bottom end for me. I'm going to call a place that specialising in restoring vintage bikes and get them to refit the bearings and crank. It will cost me more obviously, but atleast I will know its been done by someone who knows what they are doing. This is my first bike restoration and doing something wrong on the bottom end that ends up doing serious damage worries me.
AT my local club there are some C15 cases, but none for the distributor engines, they may be common in the UK, but not that common in Perth Western Australia, so for now I will need to use what I've got, although I've always got an eye out for spares.
Alex, C&D is selling the Alpha bearing conversion set up for distributor motors. One and the same. If anyone needs them in the USA I am now selling them for less than what you pay to get them from the UK.