Dynamo mount - Rapide
- Thread starter Phil Baker
- Start date
All seems to be in usual spec. I'm just going to continue making up spacers and grinding them down until the sprocket sits in the centre of the chain run. Thankyou all for your input.
Phil
Phil
Managed to sort out the dynamo problem. For some reason the dynamo was sitting at a slight angle to the face of the rear primary case. It had about 50 thou clearance at the top whilst hard up at the bottom. There is no logic to the following. Placing a washer from 1/4 bsf bolt under the primary side of the dynamo collar lifted the face of the dynamo so that it mated fully with the rear of the inner primary case. I then clamped it into position and the sprocket, with a shim, sits with acceptable clearance in the middle of the primary chain centre links. Whilst writing this I have seen the light - lifting the rear of the dynamo changes the angle of the sprocket by pushing the top out and the bottom, therefore, draws in. The nut is on far enough too. All's well that ends w .... lots still to do!! Exhaust system looks fabulous!!
Placing a washer in the cradle for the dynamo cannot be a good solution, I have no idea what would be, but that aint it.
Decades ago I fitted a Fiat dynamo conversion ( made I believe by Ian Savage or his brother) and its flat base plate had to be sat flat on a larger area of the top of the gearbox casing than the original dynamo cradle occupied. This entailed reducing a raised part of the crankcase casting at the central seam.
Could Phil's problem be that the cradle isn't sitting down properly? Shimming flat under the cradle edge may be a better solution than shimming between cradle and dynamo body.
Could Phil's problem be that the cradle isn't sitting down properly? Shimming flat under the cradle edge may be a better solution than shimming between cradle and dynamo body.
Last edited by a moderator:
Ian
Thankyou for a well-mannered and constructive comment. The dynamo cradle on the B is cast into the crankcase so shimming underneath the cradle is not possible. To others I'd like to say that I was pointing out that a solution in terms of dynamo orientation and angling had been found and that my next step would be to create a shim to do the job in a neater fashion.
Thankyou for a well-mannered and constructive comment. The dynamo cradle on the B is cast into the crankcase so shimming underneath the cradle is not possible. To others I'd like to say that I was pointing out that a solution in terms of dynamo orientation and angling had been found and that my next step would be to create a shim to do the job in a neater fashion.
I hate to ask an obvious question, so forgive me if I am, but are you using the ET202 eccentric collar for the 3 inch instrument into the 3 1/2 B cradle? I am fitting an Alton to my B and the thickness of the spacer in correct rotated position is just about the thickness of a 1/4 nut.
Ron
Hi Phil,
I had checked back to your first post where you stated original 3" so I assumed (incorrectly but my assumptions normally go that way) that you had the removable 3" cradle. With the cast in 3 1/2"cradle I expect you'll to need to make a special ET202 (ET202/PB ?) with its bore on a carefully angled centreline to obviate the need for shims.
Beyond me Ian - I have a Unimat 4 lathe and milling head. I could make a model one and put it in the microwave!
Ron - interesting point but I found that I had VERY limited movement on the cradle/collar/dynamo union before the (I can't find the number off-hand) inner locating/rotating two-holed collar thing started to foul on the steel collar mounted in the rear primary.
Ron - interesting point but I found that I had VERY limited movement on the cradle/collar/dynamo union before the (I can't find the number off-hand) inner locating/rotating two-holed collar thing started to foul on the steel collar mounted in the rear primary.