ET: Engine (Twin) Chopped Cases
- Thread starter D.Harvey
- Start date
That does not look good to me. The weak part on the stock drive side case is the outside drive bearing and it has been made substantially worse by removing so much of the journal and the retaining clip. Normally, the crank is centered by tightening the nut on the drive side and pulling the crank toward the ESA. The outside circlip has been removed, so there is only the inner circlip to pul up against.
Also, it looks like they were planning on running a shortened main shaft by removing the journal and webbing. This is possible with the transmission removed, but it is difficult to tell how well the drive-side bearing will be supported because it takes a beating. I don't think I would expect this mod to stand up to Lightning power for very long.
I think there are some ways to repair the journal, but the work will have to be good and that usually means expensive. You will have to design a new drive side first and there are not many primary drives that will survive Lightning power that are not expensive.
David
Also, it looks like they were planning on running a shortened main shaft by removing the journal and webbing. This is possible with the transmission removed, but it is difficult to tell how well the drive-side bearing will be supported because it takes a beating. I don't think I would expect this mod to stand up to Lightning power for very long.
I think there are some ways to repair the journal, but the work will have to be good and that usually means expensive. You will have to design a new drive side first and there are not many primary drives that will survive Lightning power that are not expensive.
David
I have one here that was bad like that....... I think it had been repaired quite badly and it was full of cracks (from previous welding mostly).......We machined the whole area out and made up a complete new bearing insert, fully welded in........just needs the final line boring to align the drive side to the timing side acurately.......this is done in a CNC mill.......A lot of chopped cases I've seen here are in a terrible state.......most all have been raced and blown up somehow........they are precious now, but back then no one gave a damn really. To find good chopped cases is unrealistic now I feel.......There is an opening for someone to make up newly manufactured ones and add some extra lugs at the rear to attach the engine/ gearbox plates to....... Of the 3 sets of chopped cases i have here, 2 of them are in a bad way, the third one was the lucky one.
It went well , Back in the day !.
Maybe it was to line up primary chain on whatever Gearbox he used, I can't remember,
Any chance you have the gearbox to go with it ?.
Good Luck, Bill.
Maybe it was to line up primary chain on whatever Gearbox he used, I can't remember,
Any chance you have the gearbox to go with it ?.
Good Luck, Bill.
Don't give up too soon,
I see there is nothing to screw a primary case on,
Trying to find some photos.
I have something like yours, But not as bad,
I am trying to build a Comet that was raced in the 1970 T.T. as a 654 cc Outfit !.
There is always a way !.
I see there is nothing to screw a primary case on,
Trying to find some photos.
I have something like yours, But not as bad,
I am trying to build a Comet that was raced in the 1970 T.T. as a 654 cc Outfit !.
There is always a way !.
If you go into our Search thingy top right hand corner,
Type Stuart Howe, Nothing else and enter !, You will see a bit from " I think " ??/, His younger brother ,
With an email address, Maybe he can help with history or photos.
Bill.
Type Stuart Howe, Nothing else and enter !, You will see a bit from " I think " ??/, His younger brother ,
With an email address, Maybe he can help with history or photos.
Bill.
Photo of Stuart Howe at Mallory Park which could be the engine in question. On the back of the photo it says Mallory Clubmans May 1972:
This is an article in Motor Cycle News 31st May 1972 which says Stuart Howe at Cadwell. It shows the primary side.
Just a guess, I think it's a Chain for the primary, A bit early for belt drive ??,
But might be better to go Belt drive ?
There are a few on here that have done it, Bill Cannon etc,
I can't see how to stop the oil, Coming out the main shaft ?,
There does not seem enough meat on the case for an oil seal ?, Like some have fitted to even standard cases ?,
But you could use a Sealed Bearing ?.
There are no signs of the bearing wanting to work itself out ?,
They normaly walk the inner bearing in ! ?.
Lots to think about.
But might be better to go Belt drive ?
There are a few on here that have done it, Bill Cannon etc,
I can't see how to stop the oil, Coming out the main shaft ?,
There does not seem enough meat on the case for an oil seal ?, Like some have fitted to even standard cases ?,
But you could use a Sealed Bearing ?.
There are no signs of the bearing wanting to work itself out ?,
They normaly walk the inner bearing in ! ?.
Lots to think about.