AJS Model 31 Seat Mounting questions:

Maybe I'm doing something wrong, but my seat mounting bolts near the shocks have loose nuts on the inside of the frame that are nearly impossible to get to. It looks like they should have welded nuts inside so the bolts can easily be removed without a second tool. Is there a trick?

Also: the seat appears to rest pretty heavily on the rear fender. This will mar the paint eventually. Is there supposed to be a foam or rubber cushion to protect the paint?
Jaydee

The seat mounting bolt nuts on my bike (1959 Model 31 deluxe) are also loose and a right pain to tighten. I see no evidence that the nuts were ever welded.

No foam under my seat. Not sure if there was any originally.

Isn't there an elliptical cut-out in the seat pan, in which the mudguard fits?

- Knut

Thanks Knut,
There is a shape there where a cutout could be, but it is flat flush by whoever upholstered the seat I guess. I put a piece of felt fabric there to minimize the damage.
I may decide to cut out the cutout later. Good to know.

Nice bike!

FYI. the seat cover and maybe the foam and seat base are from a 1960 or a bit later model. For 1959 the seat beading did not drop towards the front of the seat. For 1960 the beading drops 2/3 of the way towards the front, as your seat does, and the foam and I think the seat base is sculpted narrower at the front than the 1959 model to help accommodate those with shorter legs.

How many down tubes are there on the frame of your bike? If there is one, the bike is a 1959. If two, the bike is a 1960 or a bit later. I believe the number of cooling fins is also different between the '59 and later 650 engines, although I do not recall the specifics. The 1959 650 models were known for sometimes breaking crankshafts if pushed too hard. The 1960 and on 650's featured improved crankshaft metallurgy that resolved the problem. Most '59's will by now have been updated. If you do not know if yours has or has not, probably best not to get too enthusiastic with the throttle.