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Post by veg on May 8, 2023 11:38:12 GMT 1
I’m aware that 400 barrels fit the 250 bottom end, do the widely available 350 barrels that you can buy new fit the 250? Anything else I’d need to know?
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Post by 4l04ever on May 8, 2023 21:03:18 GMT 1
350 will fit. 400 ones are for a longer stroke.
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Post by dusty350 on May 9, 2023 7:46:49 GMT 1
Are these the Indian made barrels Tim ? Think there is an issue with the porting/liners, but have read they can be improved with some professional input. Pete will probably know more  Dusty  |
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Post by veg on May 9, 2023 10:46:21 GMT 1
That’s the ones dusty think they are around £180 a set. Which seems like a bargain. I’ll do some research on them. 👍
Thanks both.
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Post by chrisg on May 9, 2023 12:41:00 GMT 1
400s can be made to fit but there is a lot of machining (read expensive). There is a guy in the us that sells new 350 cylinders that are ported correctly for the UK. The Indian version are tuned "down" to give longevity, so not a performance upgrade. www.ebay.co.uk/itm/284771396485You will need longer cylinder studs, up-jetted carb, some folk fit the drive gear/pinion from the 350 and dont forget the oil pump. Depending on the model, you may need 350 down pipes or fit expansion chambers. The carbs dont naturally line up with the air filer rubbers, so a bit of joggling is required. There is a thread on the aircooled site search project X |
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Post by veg on May 9, 2023 13:58:33 GMT 1
Thanks Chris exactly what I was after. Head wise what do you use? Can you still get those radial heads?
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Post by reedpete on May 9, 2023 14:31:03 GMT 1
The third generation barrels come from the factory now with Japanese spec port timing , a modified cast over liner that can’t slip or rotate and dowled fins ( where as the earlier ones didn’t have the OEM style fin stabilisers).
The majority you see for sale ,particularly the cheap east ones, are early spec that are now being ‘dumped’. The link that Chris posted are early ones.
there’s quite a bit on the Aircooled site about them including the work Dan did on his track bike using the second gen ones.
I’m putting some latest (3rd gen) ones on a bike just at the moment although the build has stalled a bit as I’ve been sidetracked by this and that..
Alan has some too.
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Post by guiri on May 9, 2023 14:54:58 GMT 1
I had some brand new 350 indian_chinese or who knows what barrels on my rd250f race bike ten years back kindly donated to me by Bryan H, Tony at aj´s in hull ported them for me and I raced the nuts off it for a few seasons with no trouble.
I still have a set of genuine Yam 350 ac barrels stitting on my shelf on 0,5 over.
Would probably be a good time to move them on as they seem to be fetching strong money.
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Post by chrisg on May 9, 2023 15:36:27 GMT 1
Thanks Chris exactly what I was after. Head wise what do you use? Can you still get those radial heads? I used a set of 350b cylinders and heads from the US, £120 all in. Rebored to .5mm os. Not sure if radial heads are a thing. Ive only ever seen them on 400s Edit: make sure that you use 350 little end bearings, there a bit wider that the 250. |
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Post by reedpete on May 10, 2023 23:50:00 GMT 1
I had some brand new 350 indian_chinese or who knows what barrels on my rd250f race bike ten years back kindly donated to me by Bryan H, Tony at aj´s in hull ported them for me and I raced the nuts off it for a few seasons with no trouble. I still have a set of genuine Yam 350 ac barrels stitting on my shelf on 0,5 over. Would probably be a good time to move them on as they seem to be fetching strong money. John, as well as the port work, did Tony pin the liner? |
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Post by abar121 on May 11, 2023 18:59:39 GMT 1
The third generation barrels come from the factory now with Japanese spec port timing , a modified cast over liner that can’t slip or rotate and dowled fins ( where as the earlier ones didn’t have the OEM style fin stabilisers). The majority you see for sale ,particularly the cheap east ones, are early spec that are now being ‘dumped’. The link that Chris posted are early ones. there’s quite a bit on the Aircooled site about them including the work Dan did on his track bike using the second gen ones. I’m putting some latest (3rd gen) ones on a bike just at the moment although the build has stalled a bit as I’ve been sidetracked by this and that.. Alan has some too. Hi Pete, How do you spot the newer gen barrels, any links? Thanks. |
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Post by reedpete on May 11, 2023 20:55:24 GMT 1
The third generation barrels come from the factory now with Japanese spec port timing , a modified cast over liner that can’t slip or rotate and dowled fins ( where as the earlier ones didn’t have the OEM style fin stabilisers). The majority you see for sale ,particularly the cheap east ones, are early spec that are now being ‘dumped’. The link that Chris posted are early ones. there’s quite a bit on the Aircooled site about them including the work Dan did on his track bike using the second gen ones. I’m putting some latest (3rd gen) ones on a bike just at the moment although the build has stalled a bit as I’ve been sidetracked by this and that.. Alan has some too. Hi Pete, How do you spot the newer gen barrels, any links? Thanks. The most obvious tell if there is a suitable camera angle is the fin dowl at the front corner of the top four fins. OEM have this and the 3rd gen have this. Thats more of a case of form over function, but it’s easy to see. Without it the top fin tends to easily bend although they can be straitened Out easy enough. It was interesting to hear John say he didn’t have any movement with the liners but Dan from the Ac club did a test and on two consecutive sets on his track bike and on both sets the liners finally slipped. He ended up pining them to keep them from dropping. The latest ones have a waist belt on the liner and are over cast so can’t move. Plus they seem now to be tartgeted at RD owners with a port map same as Yamaha, rather than the midrange map that the Rajdoot had. I’ve both types at home so can take some side by side pictures but I’m currently away, so can’t do till I’m back home. |
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Post by sidney81 on May 15, 2023 19:30:32 GMT 1
I'm now in progress in putting a 350 set of barrel's on my ac hybrid,I used a spear set of 250 heads I had them opened up and the domes machined to work with the barrels! The 250 heads are a bit wider so I just cut the outside fin off so they match up nice ! Can't wait to get it up n running.
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Post by veg on May 20, 2023 7:23:16 GMT 1
I did wonder if it was to do with the rajdoot weren’t they a de tuned 350b? (Showing my ac ignorance)?
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Post by reedpete on May 20, 2023 14:16:30 GMT 1
I did wonder if it was to do with the rajdoot weren’t they a de tuned 350b? (Showing my ac ignorance)? The aftermarket barrels were initially made for the Indian market not for the RD market. It’s best to think of the Doot engine as tuned for mid range and 50mph cruising fuel consumption rather than ‘de- tuned’. Yes, less peak Bhp but higher midrange torque……anyway that’s semantics… key point is that if you want RD port timing on the early barrels you need to buy them and then pay someone to port them. |
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signal
L plate rider.
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Post by signal on May 21, 2023 8:04:55 GMT 1
Reedpete, that is great news that the problems with the liners have been addressed as well as the porting. I have some experience with the older cylinders and the liners did slip even when pinned. I put another pin each side part way up the bore in the blow down area that is above the transfers and below the exhaust ports.problem solved.
We use them for a racing 700 and porting four rajdoot spec cylinders to race tune took a huge amount of work. Much less if they are already in US spec.
The repo cylinders transfer porting is straight and not bent like the originals so in that respect they were better.
We have found no problems with excessive wear in the bores,and the casting finish is superior to the originals.
I would be be grateful for photos of the new cylinders as I may get another set.
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Post by guiri on May 30, 2023 11:07:22 GMT 1
I had some brand new 350 indian_chinese or who knows what barrels on my rd250f race bike ten years back kindly donated to me by Bryan H, Tony at aj´s in hull ported them for me and I raced the nuts off it for a few seasons with no trouble. I still have a set of genuine Yam 350 ac barrels stitting on my shelf on 0,5 over. Would probably be a good time to move them on as they seem to be fetching strong money. John, as well as the port work, did Tony pin the liner? No Mate. |
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