Hitchcocks Forum

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An inside view.























tabellarius de verbis ostensor gaudium

It should be interesting with see-through covers.

Scalyback – very informative images, many thanks.
I hadn’t realised that the primary chain tensioner is supported by a loop spring in most twins but (I think) no singles. I wonder why that tensioning method was not adopted for all models? I suppose if the spring came loose it could make a right mess, but that was less likely in a lower-powered single - and there's essentially no power on the bottom run, just bounce.
Cheers, ChrisD

Great things to look at, and very difficult to make/look good

There's "power" on the bottom run when you shut off to slow down, then the top run is slack.

I got rid of the big adjuster and spring, springs are useless on all the ones I have seen, from memory I have fitted Bullet ones to at least 3 twins with no ill effects. Early ones had the chain running straight on the steel adjuster with no cushion on it, chain straight on the steel

The spring is a bit of a mystery. It was presumably fitted to stop the tensioner "clacking" off load (most British motorcycle chain tensioners have something similar,) but given the amount of deflection it puts in the bottom chain run there is unlikely to be any movement possible. The Factory obviously thought so too and deleted it on the Interceptors. The rubber mushroom adjuster fitted as a replacement does a better job of tensioning and reduces the noise transmitted from the chain to the primary case which can be a major source of engine noise on the Twins. A belt drive is even better! Most Twins I've worked on have lost the spring at some time anyway.
REgards, Mark