rd250lc top end transplant

[Gil Gallad]

i tried a search, but i ended up with just one page of rd and rdlc info, so not what i was looking for. i'm sure i've seen it on here - or maybe the old site? - but somebody transplanted a rd250 top end onto a suzuki gt250 bottom end. i'd love to be able to find it and see how he went on with it 
cheers, gil.
p.s. i'm thinking of transplanting a rd250lc top end, so i've got a reed valve and water cooled gt250 to go with my reed valved gt250 

[m in sc]

you would need to flycut the cases and reposition the stud holes. I looked into it at one point.

[teazer]

How about a set of 3 RD400 top ends on a GT550 crankcase?  Or perhaps one and a half CPI top ends on a GT750 bottom end.  Now I'm going there, would a CPI top end on a T500 bottom end make a TR500 (XR05) replica of sorts?

Just asking for a friend.

I did look at a couple of those and filed them under "Anything is possible with enough time and money".

[Gil Gallad]

thanks mark, i'd looked at doing that and it's hardly mega difficult. the original plan was to use rg250 barrels and head. now that was way out of my league. not least cutting and welding for the crankcase induction for the reeds. unfortunately i bought a top end and offered it up before i got that omg, what the fk am i trying to do here feeling 
teazer, unfortunately 350/400 top ends, 550/750 bottom ends are stupid money here in frosty england, so i went for the cheapest option. there was a bloke on fb with a gt380 and what looks like a yam top end on it - can't make out what barrels as i'm not up to speed with yam 2 stroke engines. if i can find a photo i'll tack it on the end of here 
cheers, gil.
p.s. i'm waiting for the green light off a mate who wants one of his spare gt550's turning into a 636cc using ts185 pistons. there again after 2 years of umming and ahhing i'm not holding my breath.

gt380 plus:

[teazer]

That looks neat.  Are those RG250 barrels?  they look like they have early Suzuki style crankcase induction.

[Gil Gallad]

i can't work out what barrels they are. plus i can't find the original posting on fb, which didn't give much info anyway. the only thing i can remember is it's way over 371cc, more like 470, but the barrels look nothing like my rg250 barrels. i've got mk2 and mk3 {power valve} top ends and those look totally different. with 10mm ali plate under them and crankcase induction i would have gone for rg250, but i googled rg250 and 500, all the rd's and just couldn't find any barrels that matched those. btw, the bike is actually ridden. it looks a bit of a shed and he obviously spent all his money on the engine, but ran out for the bike itself. as you say, it's pretty neat though 
cheers, gil.

[teazer]

We had an early RG many years ago (pre digital camera) so no pics to go back and check against.

The crankcase reeds yell SUZUKI and the stripes down the barrels match the Mk! RG pics I found on line. So the question is what pistons did he use?  57mm gives 413cc and 58mm gives 428cc and those numbers are achievable.

I see rearward crankcase extensions under the lift plate and an HPI or Electrexworld ignition and TM carbs.  Not a cheap conversion.

[Gil Gallad]

hi teazer, after over an hour of searching i found it on the interesting and rare page. bloke that built it is called ian reid, but he gives little info on it, apart from it's shed built, 460cc, 80bhp and he's even raced it at a classic 2 stroke meeting at donnington. i've sent him a friend request, so hopefully he'll accept and i can pick his brains. you never know, i might go back to plan 'a' and use my mark 2 rg250 top end 
cheers, gil.
p.s. i uploaded more photo's if you want me to post them?

[teazer]

Pictures are good.  The more the merrier.  I did find one poor quality pic of that motor on my hard drive, so any info on it would be interesting.

The Barton water cooled "500" triple was based on a GT380 IIRC. What's not to like.

[Gil Gallad]

hi teazer, there's a bit of info on the barton motor etc here: http://yorkshireferret.blogspot.com/2012/02/barton-motors-sparton-phoenix-and-more.html
here's a few photo's of the 380/460 bike and engine 
cheers, gil.

380x1:


380x2:


380x3:


380x4:


380x5:


380x6:

[Gil Gallad]

teazer, you were dead right about the barrels. they are rg250 mk2 and if i'd have looked at mine properly i would have seen they were the same. anyway, after half an hour on the phone to ian who built the 460 i came to the conclusion that it was way beyond me using a rg250 top end and i'd stick with the rd250lc top end. i sourced a decent top end on fleabay at a decent price and just waiting for them to arrive. after talking to ron at fahron he's going to mill the crankcase mouths out for me - the rd liners are bigger than the gt. bought some 8mm aluminium round bar, which i'm going to thread and plug the original 8 stud holes up, ready to redrill and tap them to take the yamaha barrel studs. hopefully by this time next week i might have moved along a bit - but at least i've made a start 
cheers, gil.

[Striker1423]

This is excitin'.

Can't wait to see these franken-bikes come alive!