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Model 7 dynamo clamp

Submitted by philip_ham on Sun, 14/06/2020
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Heavy Twins

I've started work on my 1953 Model 7 and want to remove the dynamo clamp at the front of the engine.  Can anyone explain how to remove the lower pin that the clamp pivots on? 

There isn't a hole on the clutch side to drive the pin out and on the timing side I can only see the plain end of a pin that is about 5/16" diameter, shown in the photo.

Attachments
Model 7 dynamo strap.JPG

Submitted by george_farenden on Sun, 14/06/2020

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act as an alignment dowel for the crankcases and the strap comes off when you split the cases? 

This suggestion is a pure guess as mine is an alternator model.

Regards,

George.

Submitted by ian_richtsteig on Mon, 15/06/2020

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Yes you are correct George. The strap is on a dowel which is fitted to the drive side crankcase so the crankcases need to be split to remove the strap and dowel. The strap and dowel should be refitted to the drive side crankcase before mating the crankcases during assembly as the model 7's I've worked on have had a tight fitting dowel on the strap. 

 

 

Submitted by andrew_westmore on Mon, 15/06/2020

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Philip I have a 1950 model 7 which I am restoring. I realized some time ago that I wouldn't be able to remove the strap without striping the engine. My strap has surface rust. I intend to treat the rust and paint it in situ.

Submitted by philip_ham on Mon, 15/06/2020

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Thanks for explaining this, I'll have to do the same as Andrew and restore in-situ as I'm not planning to dismantle the engine.

Is the dynamo held to the timing side with three 2BA studs and rounded top nuts?

Thanks, Philip

Submitted by ian_richtsteig on Mon, 15/06/2020

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Hi Phillip, 

Yes the dynamo is held to the timing side crankcase as you describe. I bought new studs and rounded  nuts from Norvil for my model 7 and rigid model 77 late last year. 

 

....but  two solutions come to mind.   1. Drill the dowel, tap it, then ease it out with a matching bolt built up as a puller.

2. Drill a small hole in the casing directly behind the dowel the size of an appropriate pin punch and after a little soaking in release oil pop it out.  You could always close the hole with a closing screw or even an aluminium dowel.

Cheers

Jon

 

Submitted by philip_ham on Wed, 17/06/2020

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Thanks for the note about Norvil supplying the 3 studs and nuts.

I had considered drilling a hole for a pin punch as suggested above, but the strap is good enough to repair / paint until eventually the engine comes to pieces for a rebuild.

 


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