1969 TR 250W9 (BSA STARFIRE)

[J Greenhagh]

Hello forum ,could somebody point me to a company where I can buy an oil pressure release valve to fit a 1969 BSA Starfire .I have tried a couple of companies with no luck .Awaiting a reply JG.

[Ian C]

Is the engine definitely 1969 model year? Reason I ask is that BSA changed the type of OPRV on the 1970 models to the 'all in one' style. The earlier OPRV was made up of a separate cap, spring and ball.

[J Greenhagh]

Ian C,thanks thanks for your response.Yes,the bike has been dated 1969 .I was under the impression the release valve was now sold as one unit ,the problem is I cant seem to source it either way .With thanks JG.

[Ian C]

I don't believe the later style OPRV will retro fit to the earlier crankcase. I have looked for BSA Service Sheets to back this up but alas couldn't find any information.  I've also checked my Rupert Ratio unit single engine book and he does suggest that if your engine was fitted with the separate ball and spring type then this is the type you will have to use. From the 1969 parts book the ball is part no. 90-0241 (5/16" diameter), spring is 40-0387 (39/64" free length with 9 coils) and threaded cap 21-1972 plus a suitable washer would be required. I imagine that the correct parts for your application would be essential due to the plain bearing big end.. You wouldn't want to starve it of oil!! Sorry I can't be any more helpful..

[J Greenhagh]

Ian C,i am very grateful for your research into the oprv.Yeh Im going to struggle ,the one I did receive was way to big 0.875 dia.the actual bike is aprox. 0.562.With thanks JG.

[Ian C]

Don't take this as gospel as these parts books can have errors, but the part numbers for the ball and spring are the same for both the B25 and B44, but the threaded cap is a different part number. I can only assume that the spring pre-load is different between the 250 and 441cc engines due to the different big end oil pressure requirements. In view of this fact it may be that the caps are drilled to different depths to give the necessary pre-load for each type of engine or that the threads are a different size perhaps?.
The B44 screwed cap is part number 67-1505 and there is someone selling NOS ones on eBay.. but I must add this DISCLAIMER.. If you don't spec the correct parts for your bike you may have problems!!
I've also attached pictures of the B44 threaded cap FYI.

[LightningAndStarfire]

Would be interesting to know what the price difference was between a Starfire and a Shooting Star when new in the sixties. Perhaps the Starfire could have been almost bullet proof at little extra cost with the roller bearing big end and steel conrod.

I certainly intend to install an oil pressure gauge on my Starfire

[J Greenhagh]

Ian C. I will check it out ,with thanks JG