RH 250 barrel on a TM 250 motor

[oldfart]

Is there any gain to be had fitting a RH barrel to a TM motor using RM 250a pistons
RH  has 3 bolt holes on intake where as the TM has 2
Exhaust outlet is shorter by 15 mm   ....   pipe sort of matches
Pic of inside RH bore

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[Hoony]

big ports on that sucker !

[oldfart]

exhaust port

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[Doc]

Stew, I have it on good authority that you will need to modify the TM250 bottom end to fit an RH barrel. From memory I believe a few of the studs are slightly (about 5mm) different but I'll be talking to the guy in the know today so I'll get back with more specifics. If the TM base gasket matches then this imfo is wrong. Not sure whether you'll notice much improvement running an RH barrel as the barrel is only a part of the original RH setup. RM250A slugs are supposedly the same as the earlier RH pistons  will email you tonight with more imfo  Part number for the base gasket on an RH250 is 11241-40000 whereby the TM250 part number is 11241-30001 but they both share the same part number for the head gasket.

[oldfart]

Spent last night trying to research into the RH engine parts to find out exactly what was different before I go into this blindly . Have not been able to find a parts book related to the RH ? is there any such thing .
Will bit the bullet and take the barrel off today and see if it's a goer

[oldfart]

Doc . Yep your spot on as usual  front studs match up , but rears ( intake ) are 4mm inwards each side which poses no problem as there is plenty of meat to play with
As you can see in pics the ports are massive and no way match up with cases  too much frigging around in that department
On the plus side the bore is standard plus the crank feels good ( not bad for 30 years ) biggest supprise finding a needle missing on top roller 


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[Maico31]

Hey Oldfart i have a couple of RH250's and the motor is basically the same as an RM250a without the reed valve. They are totally different to a TM250 and probably too hard to adapt the RH barrel to the TM motor.

[Hoony]

would i be right in saying that RH 250 barrell is NOS.

anyway i think Suzuki 211 is your man when he gets back to inform on all things RH/RN

[brent j]

What about the idea of porting the TM barrel to match the RH?

I remember an article in Trail and Track in the 70's where they ported, I think, a DT400 to match a Maico 400 with supposedly good results. This would save trying to match odd studs and such

Brent

[oldfart]

What let Lozza loose on me barrel  remember him talking in a post 60 Hp out of a Tm 400  WTF

At this stage I will rebuild the top end ( new piston -rings -pin and roller )

Hoony..... yes it's NOS came with Std piston n rings plus first O/s piston and  rings.
Lucky find a couple of weeks before xmas break in Briz-Vegas 
 Thought it was worth a try .... Shit happens . It's packed back in box for another day .

I will catch up with Dave Tanner as He lives just a few Klm away in the New Year , just love the sound the RH makes

[211kawasaki]

Guys
the thing will bolt on to TM cases but better to mod the left hand transfer port on the case as its a lot larger on the RH, so while your there get both sides matched up; as well, the exhaust leaves at a different angle to the TM so a pipe will be needed. TM head will fit fine.
Stick to a VM36 mikuni at 290 main 45 pilot run the ignition at 2.6 BTC and it will go like stink

any other tips let me know
211Kawasaki aka Suzuki

[oldfart]

A spare set of cases is the long term plan  now , then I'll have a play . The bike is sort of a goer so will ride it and have fun 
211..... I will Definately need more tips on set up            later on 

[Lozza]

Stew
I could make the TM barrel out perform the RH, modding the case and the TM barrel auxlilary transfer would improve scavenging.The real weak point is the abysmal T exhaust port.

[Freakshow]

Lozza will the institute be sharing these mod'S ?

[Lozza]

Hmmmm I think my will states that all spec's be locked in a box and buried with me