Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board 1970 Firebird

Fired up the Firebird for the first time in around 40years. 1970 US model with end feed and roller conversion. It has an old style pressure relief which seems to work fine. It also has a ported Thunderbolt head and 34mm carbs. Oil pump is stock. It's not very hot as idle pressure will drop a little more when it is.

I went up the drive way and back. And it seems good, good response. Carbs seem close at slow settings. Yet to run in and test the rest.

https://www.youtube.com/watch?v=gFqWcDC6nYM

Sound good Mark.

That must be the nearest thing to a stock A65 that you own

Yea, it's pretty stock except for a few bits and the head. It feels like it will go pretty good, lots of response low down. First thing I've ridden up the drive in a while. It's going to be interesting on the road when it gets there. No balance tube between carbs makes them easier to set and I sort of fail to see the point?

Can only think long twin cables moving about might upset stuff. This has a short splitter and with side by side carbs, could be a bell crank, though this set up is good.

looks good Mark!

I can't understand why the factory didn't do the twin carb bikes like this, would have saved a fortune on head castings, could have used a commando style airbox/filter also.

If they filled part of the pushrod tunnel they could port them like this and not break through, and you could make them for bigger ports as well, Just adjusting one part of the pattern.

A t'bolt head convert eh?