Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: mad99mike on February 26, 2017, 04:17:49 PM
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Hi has any one converted one of these as it says cb250rs with ft500 engine some use xl/xr500
Engine mine has ft500 which has fixed timing and no decompressor also only has kick start pinks a bit on hills have to change down breaks your ankle if you use any throttle to start on the rs it had advance unit fixed Cdi the ft has variable Cdi will have to check tomorrow what I got under the tank
Has any one got any info on this conversion or I will have to go back to the two fifty motor
Regards mike
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Good luck with your search-i hope you find a solution.I've fancied one of these but previous experience of a sprained ankle on a Enfield 500 has put me off the conversion.
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but didnt the ft come with an electric start?
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Aye, I thought the FT was electric start only, and from what I heard, the electric start was its major weakness :-\
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Aye, I thought the FT was electric start only, and from what I heard, the electric start was its major weakness :-\
Yes,i think that's the problem.........
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I seem to remember reading somewhere that it is possible to fit a kick start to the FT - I think a starter pinion is under the crankcase cover but you have to swap the crankcase for another one (XL?) and get a kick start and associated gears.
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From memory the FT ignition has the advance retard built into the box, the RS as you said has a mechanical advance/retard and the box is fixed timing. I used a mechanical advance retard from an XL500S which went straight on the XL500RC crank but I had to slot the XL500S backplate to get the correct timing.
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When converting these machines from 250 to 500 you want to keep things as simple as possible, if you can get hold of the 250RS side cases which have the generator and the pickup then all you need is the 250 flywheel and the centrifugal timing advance/retard unit. You also need the automatic decompressor lever and you need to convert the rocker cover to accept the decompessor cam arm. The FT engine is basically the same as the XL500 engine but does have some small but significant differences, the electric starter is the obvious one but there are subtle differences like the oil pump and the bottom crank case has a deep sump. Good luck with the conversion and if you need any information just ask.