jimmyl Posted September 10, 2008 Report Share Posted September 10, 2008 250 Beamish needs re boring, do I stay at 250 or remove the insert liner and go back to the original manufactured size of 325. If so what else is needed to be done. What difference will be felt if I switch to the 325? Anybody got any other tips to make a Beamish as competitive as possible? Quote Link to comment Share on other sites More sharing options...
tilertrialler Posted September 10, 2008 Report Share Posted September 10, 2008 make sure you can get a piston if you go 325 , there were very difficult to get a few years ago. Quote Link to comment Share on other sites More sharing options...
sherpatensing Posted September 11, 2008 Report Share Posted September 11, 2008 250 Beamish needs re boring, do I stay at 250 or remove the insert liner and go back to the original manufactured size of 325. If so what else is needed to be done.What difference will be felt if I switch to the 325? Anybody got any other tips to make a Beamish as competitive as possible? Put it back to standard. 325 pistons are available, look on the Beamish Club website. I would suggest that fairly tall handlebars are used (unless you are very short) as the standard footrests are rather high and lowish bars tend to make you lean too far forwards. Quote Link to comment Share on other sites More sharing options...
jimmyl Posted September 12, 2008 Author Report Share Posted September 12, 2008 I have seen the 325 pistons on beamish owners club web size, does the head need any mods if a bigger piston is installed. Any idea what oversize piston would be required after the 250 sleeve is removed. Ta Quote Link to comment Share on other sites More sharing options...
woody Posted September 12, 2008 Report Share Posted September 12, 2008 You need to speak to Nigel Birkett for a definitive answer. I was thinking of doing the same with a 250 I once had and I'm sure I was told the head would need work, strange I thought seeing as they were built as 325 and sleeved down to 250, so maybe the 250 was fitted with a different head. The 250 should go well enough if you take off the big crank weight on the clutch side which will allow the motor to spin up quicker, should you feel the 325 conversion is too much agro. Quote Link to comment Share on other sites More sharing options...
beamish owners club Posted December 16, 2008 Report Share Posted December 16, 2008 Don't go to 325! There was a very good reason that Beamish took the standard 325 and sleeved it down to a 250, the 325 is too much of a handful unless you are 18+ stone or have a sidecar. 250 pistons are easy to come by, all available 325 pistons were designed for another make of bike. The head on your 250 was skimmed when the barrel was sleeved but no-one knows by howw much so it would be trial and error to get the compression ratio back right. 250 pistons are everywhere and the bike will perform much smoother as a 250. 5.5" bars or 6.5" if you can get them and move the pegs if you don't mind spoiling the chrome for the sake of performance. Quote Link to comment Share on other sites More sharing options...
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