I really think you're enjoying the YZ far that much and you really should let the VR move on to sit next to its old mate the VB360
The standard gearing according to my parts manual is 12/50. I didn't check the chain guide contact with the chain problem due to the 56 rear sprocket until you mentioned it
. Not good, I changed the rear sprocket for a genuine Monty 48 rear sprocket I had (standard for a 360 I think). I now want to get an 11 tooth for the front. Do XR250 sprockets fit straight on? I think you told me that I need to make a spacer from the old sprocket is that correct?
Mine has the Amal and it is not worn excessively. The bike happily idles away for as long as you want. Poor idle or no idle is the first sign of a worn Amal slide/needle etc.
The only problem with mine now before rego is to get a 6V 18/5W bayonet cap globe with offset pins. Not easy these days. Blowing the rev dependant horn brings back memories, is sounds like a distant dying but angry bumble bee.
I agree the brakes are great for a Monty. The front brake is very similiar in appearance to the front brake from an early '80s Honda, does not work as well as one of them though. This is one of the little Honda influences that started appearing about that time. If you look at the exhaust design and method of construction you can also see it there. The same type of thing was appearing on the Trials bikes of the same period.
The thing handles well and the rear suspension layout is almost identical to one of those German thingys (MaiKo or something).
Looks like you have one of the gear levers from SoloMontesa as well. Whoever designed them had size two feet
They are for too short for my liking.