Model 31 faults

specific · Post by **specific** » Wed Sep 12, 2012 10:22 am

Hi Folks,
I have a friend whom wants to get into classic bikes,he currently owns a BMW 650 PD and a BMW 1100 Roadster.
He has his eyes on a 1962 AJS Model 31 and wanted to know if there were any major faults he would have to look out for with this year/model.
He is mechanically minded but just wants something he and his partner can jump on without having to repair/rebuild each time they want to go for a ride.
All comments gratefully received.

Cheers,
Spec.

ghost123uk · Post by **ghost123uk** » Wed Sep 12, 2012 10:42 am

A quick read through the posts here in the G12 / M31 section will reveal the most common problems. Obviously a lot depends on the state of the bike in question. If it has been fully and professionally built with some modern additions like electronic ignition and solid state voltage rectifier and regulation the later versions such as the 62 you mention should be very reliable (magnetos, 6 volt dynamos and non nodular crankshafts on the earlier ones being more prone to problems). However so much depends on the skills used and the quality of the parts used in the engine and electrics etc

One thing they all seem to do is "wet sumping" where, if left unused for a week or two, oil leaks from the tank into the crankcase via the oil pump. This can cause damage to the engine if it is fired up whilst the case is full of oil. Imagine the crank and con rods splashing around in a pond of oil even at tick over

A bike of this age and type, in my opinion, is not just a "ride" like his BMW's are, they are a hobby in them selves and should be looked at in that light.

The above is just my opinion, others mileage my vary as they say Edited by - ghost123uk on 12 Sep 2012 09:45:37 AM

Malleon · Post by **Malleon** » Wed Sep 12, 2012 1:14 pm

I agree that my bikes are the main features of my hobby, but I do use and ride them all year round, even in winter when we seem to have better weather than in our summer.

Crafty · Post by **Crafty** » Fri Sep 14, 2012 5:51 pm

The Ghost talks sense, but please don't be put off. Sensible maintenance will give its own rewards. In the 1950's I used an AJS 500 twin for every day travel, and I must admit it was not a cherished machine. However it never had any problems or let me down.
I would sugges an anti sumping valve to overcome oil in the sump.

Enjoy.