jms61uk Posted June 11, 2012 Report Share Posted June 11, 2012 Hi everyone, I have recently got hold of a triumph 3TA twin engine basket case. This will eventualy be slotted into a royal enfield 250 crusader trials frame to make the popular TriField or Tri Enfield machine. Has anyone out there built one of these bikes, and if so what would be the best engine specification to go for - 350 or 500, There are a lot of tuning options from stock 350 to Daytona 500. etc Any info and advice greatly apreciated. Jon Summerfield. Quote Link to comment Share on other sites More sharing options...
big_red_bike Posted June 11, 2012 Report Share Posted June 11, 2012 Hi Jon it all depends on what sort of power you like .A standard 3ta or 5ta will be soft and easy to ride,i have a t90 engine in mine which is pretty lively but i ride it like a modern bike on the clutch.A common mod is a 350 bored out to 400. Quote Link to comment Share on other sites More sharing options...
bashplate Posted June 11, 2012 Report Share Posted June 11, 2012 hi BRB, do you know what pistons are used for the 400 twin? Quote Link to comment Share on other sites More sharing options...
jms61uk Posted June 11, 2012 Author Report Share Posted June 11, 2012 So what pistons are used to get to 400cc? And is the bottom end left alone - I know that to convert to 500 the 350 steel conrods need to be swapped for the alloy 500 items. and also 500 barrells and head. I need to get the motor re bored anyway, so if a 400cc jump just needs pistons and rebore, it sounds like an easy and cost effective way of getting a bit more grunt with minimum outlay. Jon Summerfield Quote Link to comment Share on other sites More sharing options...
big_red_bike Posted June 12, 2012 Report Share Posted June 12, 2012 Hi i think the pistons are from the triumph tiger cub.Try dc classics in yorkshire they sell all the parts you will need to build a trials twin,primary and gearbox sprockets etc. Quote Link to comment Share on other sites More sharing options...
cvgmmartin Posted June 14, 2012 Report Share Posted June 14, 2012 I have been riding a 500 Triumph for many years here in Canadian vintage trials. We let anyone ride that wants to, and don't have a pre-65 or similar class, so don't worry much about the types of rules/regulations that are so well discussion on this forum. This means that my bike would probably not be well received in the UK other than as a special, however I have written about the engine modifications I have made and some of these may be of interest to you (eg cam type and valve timing). If you are interested you can find this in Charlie Prescott's Otter forum under the Readers Page. Mick Andrews was complementery about the engine when he tried it. Quote Link to comment Share on other sites More sharing options...
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