jon v8 Posted December 20, 2015 Report Share Posted December 20, 2015 (edited) I have to say at times I've I wondered if it is worth building a full 500,you only need to look at how successful Barry Barthorpe is on his 350, my 350 AJS is never short of power and grips like no other bike I have ever ridden...(Too late,bought all the bits) The Mick Dickenson barrels are 85mm in their unfinished state if that's any help. The piston I am going to use is an 86mm XT500 - genuine one. If there is enough crown thickness when we measure it I'll take material off the top to keep the compression down,and use a plate under the barrel as well.My aim is a chuffing steam engine at low revs that will pick up and shut down quickly.Remember also that the finished bike will be alot lighter than the originals,so less power is required to make it move Deryk, I think now mags can be an expensive option,espcially if you are building from scratch.A new BTH electronic will arrive in 48hrs and be ready to use.Buy an old Wader off Ebay,get it serviced ... Thats a couple or three months.(Both will cost about the same in total) If I could get decent quality service parts I would consider using them again.But now the BTH and Electrex etc ARE reliable,and are far more accurate than a mag could ever think of being.I've scoped both running them on the lathe,there is no comparison.The electronic advance is smooth,I can easily start my Ajay by hand,then go straight into a section only needing to balance,steer and control the throttle.OK,its cheating... But it is how it seems to be now, modern tyres grip so well manual advance is not needed,a reliable smooth motor at low revs is vital for the tight turns we are asked to ride now. I believe it really doesn't matter which way you build it,or what you use - it will be another Pre unit bike being ridden.Whilst there are not hundreds,there are enough that clubs need to bear them in mind when marking out.That is the key,keep the sections sensible - as I have said,and will keep saying... Edited December 20, 2015 by jon v8 3 Quote Link to comment Share on other sites More sharing options...
collyolly Posted December 21, 2015 Report Share Posted December 21, 2015 Hi Jon, my short stroke uses the XT350 piston and the MDP barrel without a plate or modification to the piston. I need to use full retard to start ( I still use a TT mag) or I get either a no start or a big kick. But, I would not say she runs like a chuffing steam engine, in fact due to the lighter 350 flywheels there is minimal flywheel effect compared to a long stroke 500 motor. You can't have both a fast turn on and off and chuffing steam engine, I like the way it rides like a lighter bike and responds better to the throttle for our now obligitory over tight sections. In fact I have often run with slightly higher tick over to stop her from stalling and ride with a good clutch to ensure the reliable bite point gives me every advantage ( never knew with the old clutch when the engine was going to get loaded and hence the occasional stall, which the long stroke motor would just pull through ) Quote Link to comment Share on other sites More sharing options...
drake Posted December 21, 2015 Report Share Posted December 21, 2015 (edited) Not sure if it's of any interest to any of you, but I have decided to scrap my project. As a result I am selling my 500 short stroke engine with MD barrel,XT350 Wiseco forged piston, all new bearings, cam followers etc and cylinder head completely restored and sorted by Roger Taylor at RTS. Brand new build as in un used. Will sell after Xmas If interested contact chamber66@sky.com John Edited December 21, 2015 by drake Quote Link to comment Share on other sites More sharing options...
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