Ts250/1 barrel swap with ts250

[DAVIDGUEST123]

I don't know if anyone has tried this but what I'm trying to do is swap a supa 5 250 barrel with a ts250 barrel. Long story short ,seized,(see previous posts) rebore wrong size, piston slap, barrel has fins broken, good ts250 barrel bought(also one size oversize) hoping the two are interchangeable..here is what I've discovered.

Both barrels have the same casting number

Ts 250 barrel at the to[p has no lip

250/1 has a lip at the top

Basically the differences that I can see is..
1)The bore sizes. Both barrels are one size oversized yet when measuring the bore with and old standard size ring the 250/1 gap is around 2mm and the ts250 is 0.5mm. Even with my rudimently grasp
of maths that doesn't seem right.
2) The lip at the top of the barrel where it meets the head. 250/1has a square casting and a lip but the ts250 is round with no lip.
3) There is a small 'H' stamped under the exhaust outlet were as on the ts250 it's a 'M'

So the big question is ..If I take this ts250 barrel and get it rebored(to the correct 0.04mm clearance) and stick it on my 250/1 Supa five will it work?

As ever many thanks in adavnce.
Dave

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[Guesi]

Hello

The TS 4 gear and 5 gear cylinders are interchangeable.

But the one without lip is not an TS 250 4 gear but an ES/2 cylinder.
The lip was to center the cylinderhead in relation to the cylinder

The ES cylinderhead was centered by the long cylinderhead screws.
So there was no need for a lip.
The TS 250 models had another cylinderhead with smaller holes for the Stud bolt for cylinder fastening. The head also had the function to hold the engine in the frame.

So your cylinder without lip is NOT interchangeable. It is an ES/2 cylinder.
As the mould for the cylinder is the same on both models, the spare part numbers are the same.

That is why I asked for a picture of the intake side.
You can see on the right cylinder on the picture above that there is a sprue on the left side where the intake is.
This is because on the ES models there was a cover for the carburetor. And this cover should touch the cylinder where the sprue is.

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[DAVIDGUEST123]

Thanks for all the input chaps.

Just to be clear.The old barrel with a broken fin from the bike which is a TS 250/1 Supa 5 from 1982, the barrel I was hoping to get rebored and fit to it now turns out to be an es250 barrel.

1972 Es250 barrelwith the carb shroud supports shown

and these to barrels cannot be swapped

1982 TS250/1 Supa 5 Barrel from the bike

I also think that although the barrel has been stamped as if it was one it's first rebore it is in fact standard

Looks like it's back to the drawing board for now.

Many thanks Dave

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[DAVIDGUEST123]

this is the barrel orginally on the bike note the damage in blue

Above is the one incorrectly rebored form the bike

ES250 (so I'm told) bought from ebay

This is the one that will not fit, due to fitting of the head bolts..shame

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[DAVIDGUEST123]

Hi .
Yep I'm now sure that the nice es250 I bought (not the one in the eaby add), although it looks very much like a ts250 barrel apart from the carb shroud supports. It will not fit
my bike. This comes down mainly to the mating up of the head. The conculsion is that although port and barrel positions are indentical the lip at the top serves two purposes
One being the easy locating of the head but also to help support the engine without moving as the ts motor is 'Hung' from the frame by it's head. Were as the ES is supported
in the frame.
Had I gone ahead and fitted the ES barrel I'm pretty sure it would have run. I would of however have had possible problems with the join betwwen the head and the barrel and as I'm planning a
long old trip this summer everything needs to be right.......at least beore I set off.