I have a new mistress in my life. A 1950 BSA B31 Saw this on gumtree late November last year and knew I had to have it. So after waiting for it to be trucked over to Adelaide and arriving 2 days after I left on a 6week overseas trip ( i swear I thought about this bike everyday we were away) I finally saw it for the first time late January. It was a big risk buying an unseen bike but was more than happy with it and had been given a very realistic discription by the seller. Long story short I did the following. Gearbox oil Clean out oil tank, new oil (3 changes) Primary drive case gasket and oil Clean the chain and oil Cleaned the carby. New seals and gaskets New battery Checked brakes New fork boots New spark plug Fresh fuel After about 5 kicks she came to life. So much relief. Got rego for it the other day and took it out for its first (legal) ride yesterday with a massive smile on my face. Can't wait to take it out again I realise this is not the typical bike on here but I'll think I'll hang around as there is such a wealth of friendly knowledge around here.
Oh My that brings back some memory's nice bike use to love mine but had to sell her back in the early 90's As I could only bring one bike when I moved to S.A
So started to pull the engine apart for a general checkover and to remove the Magneto as it needs a referb. The more I pulled apart the more I discovered. Drilled out timing gears, ground rockers and then discovered it has been bored out to fit a Triumph T140 piston to make it a (roughly) 400cc. This would also explained the larger than stock carb its running. Someone has done some work to this engine in the past
Nice, cant complain about that. Look's like the head has had some port work done as well, or at least the intake has, i reckon the short return's would have been cleaned up too
There used to be quite a few iron BSA singles active in Classic racing here. The recipe as you have it was quite common. They go quite well too. The big question is - what numbers are on the cams ?
Yep that's the next thing to look at. Hoping the bloke who did this didn't do all of this without replacing the cams with goldie ones or the like
So long story short I put in new rings and she is running sweet (for now, let's hope it continues) also a new set of tyres. Took it out this arvo for a bit of a shake down. Did the obligatory Jetty road then espy cruised it back to Brighton (the Adelaide guys will know) all went well till i felt the battery holder hit my leg. Pulled over put a cable tie in did a U turn and fount the bolt in the middle of the road. Not bad at all considering. Had a massive smile on my face the whole way
An awesome old classic, these bikes can be modified very successfully for the modern classic racing scene. One advantage with the older cast iron cylinder heads is there is almost no restriction on how open you can enlarge the intake & exhaust ports. with modern camshaft theories its not that difficult to design your own what call scatter profile patterns, and machining up cams is not that expensive these days. Come on guys, whats your thoughts?