andy m Posted December 17, 2010 Report Share Posted December 17, 2010 (edited) I am gathering together the parts to build a Bantam trials to ride the BMCA trials,I have frame/engine and hubs, does anyone here have any pointers on what can be done with the frame, head angles or raising the engine etc. Not sure what forks to go for, I won't be winning any medals out there but I want a rideable bike. Up to now I know the gearbox mod to do, going for the 185 conversion from Rex Caunt, pvl or electrex cdi , 12 tooth g/box, f spkt and 60 r wheel. Anything else worth considering, all info much appreciated. Edited December 17, 2010 by bo drinker Quote Link to comment Share on other sites More sharing options...
broony Posted December 17, 2010 Report Share Posted December 17, 2010 Bo Drinker,I'm in the middle of building Evo 2 Bantam at the moment.I have some drawings that I got from a member on this site which gives all the dimensions for dropping the top frame tube(bracing for the headstock),rear subframe mounting/subframe dimensions.Also swing arm mods.I've got a set of Suzuki GS125 forks/yokes(just cut off the lugs for the caliper-only Quote Link to comment Share on other sites More sharing options...
toyboy2 Posted December 17, 2010 Report Share Posted December 17, 2010 Hi if you are looking at a 185 convertion try Mick Dickinson on 01709874956 for a barrel these have been made to suite trials abd not racing Garry Mitchel also has new gears the same as the works used. Garry can be got on 07766265766 Quote Link to comment Share on other sites More sharing options...
andy m Posted December 18, 2010 Author Report Share Posted December 18, 2010 Thanks for replies. Any ideas which best way to go for the swing arm?? Mod the existing or go for a Cub arm ?? Quote Link to comment Share on other sites More sharing options...
b40rt Posted December 18, 2010 Report Share Posted December 18, 2010 (edited) Thanks for replies. Any ideas which best way to go for the swing arm?? Mod the existing or go for a Cub arm ?? I thought Cub arms were a bit narrow as well ? Have a look http://www.trialscentral.com/forums/topic/29911-modified-cub-rear-swing-arm/ Edited December 18, 2010 by B40RT Quote Link to comment Share on other sites More sharing options...
ferret1964 Posted December 18, 2010 Report Share Posted December 18, 2010 Theres a chap who rides the BMCA trials, Steve Jones who has a company called progressive classics, he does frame/hub and swingarm mods for bantam trials and he is good. Jim Pickering also rides with BMCA and he builds Bantam trials. also very good. Quote Link to comment Share on other sites More sharing options...
broony Posted December 19, 2010 Report Share Posted December 19, 2010 Been doing a wee bit work on the Bantam and found out the following.Some of it is old information but it might help-starting with the frame:-the top tube can be lowered and the subframe mounting repositioned and the subframe narrowed/shortened.the swing arm can be extended by 1 inch(2 ways to do that extend at the slotted end(put in a fillet) or extend the tubes,if using an early (narrow) swingarm the right hand tube needs to be reshaped where the tyre/wheel runs for clearance.Front forks either standard heavyweight or fiddler type,rear shocks about 13" what you can afford(using road ones at the moment but even on there softest setting are a bit hard),Rims-front 21"xWM1 and rear 18"xWM2.Engine:- plenty can be done but its all down to the coin,with any two stroke a crank rebuid,big bore"don't laugh" the most common way to go is a Suzuki TS185 piston(standard =187cc,+2mm=198cc),the only prob is the small end is a different size(needs a bit of work),noticed that Rex Caunt does oversize pistons(big Bore).Todd head or later center plug head.Gearbox:- swapping second and third gears around makes the box close ratio,fitting a 12 tooth primary crank sprocket.Gearing 13 tooth front and 68 rear.Amal concentric with carb spacer/manifold and K and N style filter.Exhaust ,its recommended that the silencer has a volume of about 2litres and that it is close to the engine also that the exit is half the area off the inlet.Then you have various ignitions to choose from.Hope this is a help to fellow Bantam owners. cheers the noo Brian Quote Link to comment Share on other sites More sharing options...
andy m Posted December 19, 2010 Author Report Share Posted December 19, 2010 Thanks Brian, that gives me a good start. PS I received the drawings you pm'd me. I will sort the engine first as it seems straight forward and then go from there. Quote Link to comment Share on other sites More sharing options...
monty_jon Posted January 26, 2011 Report Share Posted January 26, 2011 Does anyone have a drawing for the frame modifications? (D7 type) Also any idea where to get a cub wide swing-arm from? (failing this I will have to modifiy the standard one) Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted January 26, 2011 Report Share Posted January 26, 2011 Does anyone have a drawing for the frame modifications? (D7 type) Also any idea where to get a cub wide swing-arm from? (failing this I will have to modifiy the standard one) Sammy Millers used to do a wide swing arm. Might be worth giving Richard a call to see if he has any left? Quote Link to comment Share on other sites More sharing options...
monty_jon Posted January 26, 2011 Report Share Posted January 26, 2011 Sammy Millers used to do a wide swing arm. Might be worth giving Richard a call to see if he has any left? I Quote Link to comment Share on other sites More sharing options...
jamestee Posted January 26, 2011 Report Share Posted January 26, 2011 You could do no better than talk to Jim Pickering, mentioned already in a reply above, his tel is 07850 836571. He will be at Wrighty's show in Telford in a couple of weeks if you can get to it. I'm in the process of building up a Bantam courtesy of Jim P who provided me with most of the bits and I can highly recommend him as a real good lad, provides good gear and is very helpful. Quote Link to comment Share on other sites More sharing options...
andy m Posted February 5, 2011 Author Report Share Posted February 5, 2011 You could do no better than talk to Jim Pickering, mentioned already in a reply above, his tel is 07850 836571. He will be at Wrighty's show in Telford in a couple of weeks if you can get to it. I'm in the process of building up a Bantam courtesy of Jim P who provided me with most of the bits and I can highly recommend him as a real good lad, provides good gear and is very helpful. Thanks, I will be going to Telford, there are a couple of localish people who are doing a lot with Bantams, Jim, and Rob Homer I hope to see them and pick their brains.. http://www.classicrider444.com/2011/01/10/rob-homer-bsa-bantam-special/ Quote Link to comment Share on other sites More sharing options...
bilc0 Posted February 5, 2011 Report Share Posted February 5, 2011 http://www.classicrider444.com/2011/01/10/rob-homer-bsa-bantam-special/ Very nice. Quote Link to comment Share on other sites More sharing options...
andy m Posted November 19, 2011 Author Report Share Posted November 19, 2011 Spent a few Quote Link to comment Share on other sites More sharing options...
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