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In the 2 years of ownership of my Berli, I have gradually improved the way the engine performs:- new Weber 32/36, various tweaks and adjustments to the usual areas including ign timing, valve clearances, a check on valve timing.
I identified the camshaft as a Piper 270, and that might account for a slightly lumpy tickover. The only real problem remaining is a flatspot when revving up from tickover to drive away. Unless I get the revs up to 1500rpm or so, the engine can temporarily 'die' and then leap away from standstill. This is no problem with the typical Grand Prix start, but in traffic this can sometimes can be a bit awkward.
My Weber supplier "Fast Road Cars" was helpful in suggesting various adjustments and jet sizes. He sold me a 'pulse jet' which is really just a well-made brass gubbins that is inserted in the dizzy to carb vacuum pipe. This jets down the 5mm ID pipe to around 1mm or so, and delays/reduces the sudden change in vacuum applied to the dizzy when opening the throttle. I had already experimented with homemade versions, so this one was much the same but made to a higher standard.
Although the pulse jet helped, the flatspot had not disappeared entirely. The only area left to experiment with was the carb injector pump. My carb supplier was unable to locate any alternative jet sizes, in particular a slightly larger size that I thought might do the trick. Although the fittings on the side of the carb look like they could be tweaked, there is no obvious direction to go in there. Change the spring or alter the mechanism in some way?
I would be grateful to learn of a supplier of injector pump jets, or got any other ideas to sort out my flatspot?
Cheers
Mike
I identified the camshaft as a Piper 270, and that might account for a slightly lumpy tickover. The only real problem remaining is a flatspot when revving up from tickover to drive away. Unless I get the revs up to 1500rpm or so, the engine can temporarily 'die' and then leap away from standstill. This is no problem with the typical Grand Prix start, but in traffic this can sometimes can be a bit awkward.
My Weber supplier "Fast Road Cars" was helpful in suggesting various adjustments and jet sizes. He sold me a 'pulse jet' which is really just a well-made brass gubbins that is inserted in the dizzy to carb vacuum pipe. This jets down the 5mm ID pipe to around 1mm or so, and delays/reduces the sudden change in vacuum applied to the dizzy when opening the throttle. I had already experimented with homemade versions, so this one was much the same but made to a higher standard.
Although the pulse jet helped, the flatspot had not disappeared entirely. The only area left to experiment with was the carb injector pump. My carb supplier was unable to locate any alternative jet sizes, in particular a slightly larger size that I thought might do the trick. Although the fittings on the side of the carb look like they could be tweaked, there is no obvious direction to go in there. Change the spring or alter the mechanism in some way?
I would be grateful to learn of a supplier of injector pump jets, or got any other ideas to sort out my flatspot?
Cheers
Mike
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