Strange and weird stuff. Here is a photo of one that does NOT have such "fitting."OK. What is this! On the Gearbox inner cover on the bottom, front edge is a fitting that looks like it is a modification. The fitting is also plugged. Does anyone have an idea of what this would have been for? I may have it welded up if it is not necessary. Thanks.View attachment 53260View attachment 53261View attachment 53262
Righty-O. That's a later model non-speedo-drive that uses a gearbox speedo drive on the rear axle opposite the drive/brake side of the wheel.Strange and weird stuff. Here is a photo of one that does NOT have such "fitting."
Those tolerances have never seemed to cause any problems in nearly 30 years and over 100 overhauls, restorations & custom builds. I always ordered by part number from one of the same 3 main supplies (JRC mainly) and have NEVER had a bearing or bearing-related failure. I think when you build a performance engine, spending bigger bucks and expecting higher performance (racing, typically), you start to delve into the finer details. Not me.Left and right crankshaft bearings - Question. I did not realize there were about 3 different bearings for the left and right side of the crankshaft, marked CN, C2 and C3. I didn't realize this when building my last engine, and will have to look through my receipts to see what I installed. Can anyone explain this issue and how one determines which bearing to use in a 1967 T120R engine. My parts book says the part number are E2879 for the main bearing left, and E1591 for the main bearing right. Thanks for any advice!
Thanks grandpaul. On another forum an inmate provided a chart from CBS on which bearings are supposed to go in what engines referring to CN, C2 and C3. I didn't notice the CN designation when I did my first and only engine last year - so it sort of threw me when I was looking for bearings for my current engine. I am not trying to build a race engine, just some thing that will be relatively reliable.Those tolerances have never seemed to cause any problems in nearly 30 years and over 100 overhauls, restorations & custom builds. I always ordered by part number from one of the same 3 main supplies (JRC mainly) and have NEVER had a bearing or bearing-related failure. I think when you build a performance engine, spending bigger bucks and expecting higher performance (racing, typically), you start to delve into the finer details. Not me.
Ah, yes, the ole "speedo-drive on the rear axle." I wonder (to myself), which one was/is the better?Righty-O. That's a later model non-speedo-drive that uses a gearbox speedo drive on the rear axle opposite the drive/brake side of the wheel.
If you re-instal the respective gears to that worn shaft, is there a lot of play, you know, real loose and clattering-about and such like? If not, I might suggest using synthetic gear oil upon reassmbly. I find that synthetic oils have reeeel good lubricating qualities and stanch further wear as much as can be expected. The only alternative is, uh, new, SUPER-EXPENSIVE parts! Aaauhg!Transmission main shaft a bit worn. So I disassembled my transmission and it all looks pretty good except for the transmission main shaft. I don't know if this kind of wear makes this unserviceable and would appreciate any comments in this regard. Thanks!View attachment 53275View attachment 53276
No, there is not much play, but it is obviously worn.If you re-instal the respective gears to that worn shaft, is there a lot of play, you know, real loose and clattering-about and such like? If not, I might suggest using synthetic gear oil upon reassmbly. I find that synthetic oils have reeeel good lubricating qualities and stanch further wear as much as can be expected. The only alternative is, uh, new, SUPER-EXPENSIVE parts! Aaauhg!
The C range (350 and 500 twins with unit engines) have a different gearbox, cannot accommodate a speedo drive, always had a rear wheel driven speedo (gearbox supplied by Smiths), used the same rear hub as the 650. So it did not make a lot of sense to have extra manufacturing processes and make extra parts (gearbox speedo drive, spacer for the rear wheel in place of the Smiths gearbox) for the 650 when the 350/500 parts would fit."speedo-drive on the rear axle." I wonder (to myself), which one was/is the better?
I have found a used main shaft that looks to be in very good shape and is not too expensive, so I think I'll be using that on this re-build.If you re-instal the respective gears to that worn shaft, is there a lot of play, you know, real loose and clattering-about and such like? If not, I might suggest using synthetic gear oil upon reassmbly. I find that synthetic oils have reeeel good lubricating qualities and stanch further wear as much as can be expected. The only alternative is, uh, new, SUPER-EXPENSIVE parts! Aaauhg!
First, get access to a good set of v-blocks block and dial guage. If it checks out, get it dye or magnaflux tested. The cheaper it is, the MORE it will cost if it's got a nearly invisible crack!I have found a used main shaft that looks to be in very good shape and is not too expensive, so I think I'll be using that on this re-build.
Grandpaul, ok some more learning for me. I've never used v-block before but I can see why I'd want to. Thanks.First, get access to a good set of v-blocks block and dial guage. If it checks out, get it dye or magnaflux tested. The cheaper it is, the MORE it will cost if it's got a nearly invisible crack!
Thanks grandpaul!More precise cylinder alignment with crankcase.