I got given an SRM dynamo belt drive for Christmas by my Mum (well, she gave me some money and I bought it). And today, with the help of my 8 year old son, I got round to fitting it.
What should have been a very simple job has pretty much driven me up the wall. For starters I experienced all the difficulties with removing the chain sprockets which have been well documented in other threads. Eventually I got them both off and was finally ready to fit the new kit. First the pinion pully. Went on ok, but it seems that the thread on the idler pinion shaft is damaged. The SRM supplied nut will not go on at all and the original nut must also have a damaged thread as it will not lock up. (the original set up used a tab washer and didn't appear to slip).
I left this and moved onto the dynamo end. The pulley slotted on fine, but obviously as soon as I tried to tighten up the supplied sleeve nut the dynamo just rotated and I could not see any way at all of preventing it and allowing me to get the nut tight. Needless to say there is nothing in the supplied instructions about how to do this. By this point my son had wandered back into the house to play Fortnite. So, this leaves me with two clear questions:
- Does anyone know what the original thread of the idler pinion shaft is so that I can run a chaser down it and hopefully resurrect it?
- How have other people managed to prevent the dynamo from rotating while they tighten up the nut on the pulley/sprocket?
But right now it is 2 degrees C in my garage, damp and rapidly going dark (no heating or electricity), so I think I will give up for today. Not my best ever day of BSA ownership.