rd400 rod with suzuki ts 250 piston

[tavspeed]

put a search into ebay you can get pattern ones for about £30,there is one on now genuine n.o.s for £24 buy it now,same for rd 400 rods about £33 for pattern rods,but you will have to source some bushes for the gudgeon pin as discussed earlier,the piaggio ape rod is the preffered choice but not as widely available,cheers all.

[the-brickie]

Where is the best place to source the piston (TS250) and jap con rod for this as Im about to start buying for this kit for winter..Is it me or is there a lot doing this..?

Well I'm having a go, got the converted 60mm crank with a 18mm eyed rod, old barrel ready for the re-bore and a TS250 piston, pin and clips in the post. As the saying goes... what goes around..

[tavspeed]

credit crunch engine

[J1MS]

My advice on these conversions is get the cooling air from the fan to head cowling delivery as good as it can be... any big gaps between Flywheel cowling and fan will cause the air to just spin around the mag flange and not make its way up to the head cowling... Get a close fitting head cowl with the fin fitted, to help cool over the exhaust port, as fitted to Italian GP 200's... As there is very little wrong with the power these kits make... As Sprinting times over standing quarters have always prooved... Speed or power has never been a problem using cast... But cooling is not as efficient as it is through Aluminium...

Compression ratios, Ignition timing, and ineffective cooling are the problems most probably, that will stop a cast iron barrel from running.... Therse conversions were very popular in the mid 80's... They wre popular because they could be very quick, and pulled well from low speeds.. I ported around 20 barrels for Suzuki TS 250 pistons between 83- 91... One of which was on Stans (From Garston, Liverpool) ended up on his sidecar outfit... Tuned for bottem end grunt, It would pull well in all gears. The barrel ended up on Stakeys scooter (from Birkenhead) then his wife Trisha ended up with it on her SX 200.. In My Opinion... Very reliable kit if care is taken on final setup...

[the-brickie]

Wise words JIMS, duly noted.

Due to the heat build up at the exhaust, as you say about the intenal fin to direct more air towards it, I wondering if a small air scoop under the barrel might be in order to force air around the manifold. A bit like, but maybe not as big, as the one used on Mr Edmonds race bike. (Thats not Blackadder by the way) After all, that cooling air is free!

[Andy Pickering]

I am going to use rapido 200 barrel (ally) re-bored to TS250 piston and have already got a proto scoop in the pipe line

[Rich_T]

A drawing of the top hat bush for TS250 piston conversion is here at the bottom of the page.
http://www.granturismo.pwp.blueyonder.co.uk/Tooling.htm I made mine from bronze, the ID is slightly under size so a perfect honed pin fit can be achieved. The OD is drawn to size so add a press fit tol. on top of this (I used about 0.04mm of the top of my head). This is a perfect job for scooter loopy John if anyone wants to make some.

[GP240]

Bringing this conversion back up to date,
I have a complete kit which I'm about to build to a casing.
Crank = 58/110 (Ape rod) with 18mm eye, TS250 70mm piston and barrel bored to225.
The piston came with a 16mm pin to fit a standard rod with brass top-hats/sleeve (18mm) which are fitted from the outside (unlike Rich T's), I am putting in the correct 18mm pin to go with the new rod/crank.
I need to know what length these gudgeon pins are/or where to get on from (Chislespeed need the length size).
Cheers Boo.
PS, prob go with VHSA/32 and a JL3/Variotronical Ign.

[GP240]

Just found it (me being a lazy arse)
cheers the-brickie
http://www.tkrj.co.jp/goods/m-AS0810X--30510.php
18X55 gudgeon pin.