anybody ever tried this?

Gil Gallad · November 04, 2019, 02:57:46 PM

i usually build suzuki gt250's, but apart from water cooling one, i've done just about everything i can with them. so, having just aquired a pair of rd250 air cooled barrels and cylinder heads at a very reasonable price, i thought: why not fit them to the gt250 bottom end to give me [another] mongrel gt250 reed valve engine? i know it will be a lot of work, such as filling and redrilling the bolt holes, but i've done it before to fit some gt250a barrels on a ramair bottom end. also had them bored out to 58mm to give me a gt285 8) so i know it's do-able. don't ask why i should want to do such a thing, it's because i can [and mad as a hatter] - and hopefully nobody else has done it

cheers, gil.

teazer · November 04, 2019, 06:37:10 PM

Go for it. I did try to convince someone to fit a pair of RD 350 or 400 barrels on a set of 315/350 cases. That has to be an easy path to 60hp at the rear wheel.

m in sc · November 04, 2019, 10:03:35 PM

it has been done. you can fit 350 cyls as well if you can fly cut the case.

Gil Gallad · November 05, 2019, 07:46:26 AM

hi mate, thanks for that. if there's a write up to it anywhere then i'd love to read it. it's not as easy a conversion as it was at first glance, but should keep me out of trouble for a while. main problem being the stud spacing. ;D
cheers, gil.

m in sc · November 05, 2019, 08:30:39 AM

i was asked to do it about 12 years ago, i never saw the benefit over remounting an rd motor in a gt chassis, but its been done (not by me, wasnt worth my time). or reeding a GT250 topend and porting the snot out of it. .

Gil Gallad · November 05, 2019, 08:35:59 AM

hi mate, the original plan was to convert the gt250 top end to reed valve, using [cheap] rd350 reeds and rubber carb manifold, plus a couple of lumps of ali, milled out to take the reeds. but in my infinite wisdom i decided that using the rd250 top end was an easier choice. perhaps i ought to go back to plan 'a'?
cheers, gil.

m in sc · November 05, 2019, 09:52:27 AM

i would, tbh, its easier i think in the long run. I've milled a set of GT250 cyls for reeds for another guy,(Tom Garcia) he used some 8 petal snowmobiles reeds on it, supposedly worked out great.

Gil Gallad · November 05, 2019, 05:00:58 PM

hi mate [again]. do you have any photo's of the gt barrels reed conversion? just to give me an idea on where to start. many thanks if you can ;D
cheers, gil.

m in sc · November 05, 2019, 05:09:06 PM

i might have pics of me milling the back off them, maybe. i didnt add the reeds, tom did that himself.

Gil Gallad · November 06, 2019, 08:52:58 AM

any pics would be welcome before i start milling chunks out of a good set of barrels, or even a drawing would help. the only bit that baffles me atm is the gt inlet port, which is standard at 26mm and round, which reall won't be condusive to good flow from the reeds' thanks again for your input ;D
cheers, gil.

m in sc · November 06, 2019, 10:19:41 AM

i only have the 2 pics. i just milled the back flat, he did the porting and addition of reeds. i know he added tranfer ports and opened it up quite a bit.

note the intake oiling hole is still intact.

teazer · November 06, 2019, 04:01:59 PM

Here's one I grabbed from Tom's thread way back when

Gil Gallad · November 07, 2019, 04:36:56 PM

thanks for the photo's - much appreciated. i came up with a different idea. don't know why i never thought of it before, but there's a stockist in greater manchester somewhere that sells aluminium square box section in 60mm x 60mm x 5mm wall. that makes the i.d. 50mm and the reed valves are 50mm square - the reeds themselves. cut to right length and angle, make the end flanges and have them welded on. job's a gudun as they say. it will save an awful lot of milling out. just hope they'll let me buy just a short piece and not a 5 metre length minimum :P i have emailed them with my plea, so fingers crossed. it will cut the machining time down by hours. i could have used 57mm or 21/4" in imperial, with 3.2mm wall, but can't find anybody that stocks 21/4 square and 10 swg wall. i'll keep looking, if this wifi stays on. waiting for it to come back on so i can post this. why don't my wifi work properly when it's raining? (rofl)
cheers, gil.

m in sc · November 07, 2019, 04:47:25 PM

i mean, it only took like 15 minutes per cyl in the bridgeport, wasn't hard to do.

thats cool you have that pic, i lost it a long time ago. he just told me 'mill it flat' i was like 'ok' and chips went flying.

Gil Gallad · July 13, 2020, 08:56:29 AM

dead thread revisited ;D after 7 months this is what i came up with. and this morning it ran properly for the first time. i installed it in an old gt250 frame, wired it up and fitted a temporary fuel tank. all that's left now is everything else. photo is mid build, until i can find the later photo's 8)
cheers, gil.

gt250 ramair reed conversion:

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anybody ever tried this?