Lightweight TS250/350 - Cycle Guide article.

[YUMASTEPSIDE]

.......currently available from France.....80.25mm Beamish pistons 215 Euro/$308 AUD

Its a '72 TS250,TF tank,TM250 carb, RM/PE airbox rubbers and filter/cage, alloy airbox, TM rear wheel, PE seat, DT250 head and a long way to go!! 

                               Roger 

[EML]

I was told the Beamish RL had a Massey Ferguson piston and a vent hole drilled through to the exhaust port to stop dieseling on trailing throttle.

[OverTheHill]

TS400 is 82mm, bought an RT2 yam cylinder that had one in once with bushed gudgeon holes in the piston to bring down to size, must have shortened the inlet side or drilled reed holes but would have worked regardless--too long ago but worked as it was. Thinking though that hell--80mm would be bigger than the standard liner outside [or close] so by the time it's sleeved to take an 80 piston do you need to bore the cases a bit to fit sleeve overhang down into. Must take away some of the transfer size up the side too. Cheated doing something similar [as i've written] but used 360 yam cases & cylinder with 250 crank 80x64, always wondered what i'd built but sound like 322cc. Love odd ball projects & hope it works out for you. Cheers. ps, not sure where i was heading but probably that RT1 Yam is 80mm & 'no reed holes' & may work for you. Thinking in reverse, if my TS400 piston was bushed to fit the Yam pin then you might need to say find a needle roller with bigger rollers to fit the yam piston to suzy rod--or bore the gudgeon eyes out. Anyway---

[LWC82PE]

This is from the 1974 Webco catalogue

[djr]

I don't know if this is helpful or relevant , but I have a July 1972 motorcyclist magazine with a 4 page article about a 322cc conversion to a DT1 using an RT1 80mm piston.
I don't know how to post photos on here , but happy to scan and email to someone who can if anyone is interested
 

[David Lahey]

The 320 Yamaha Majesty motor is a TY250 motor with a bigger sleeve, machined head, machined cases, modded transfer ports, RT3 piston and additional flywheel weight.
The "works" trials 360 motor was RT3 piston, cylinder and head matched to machined TY250 cases. TY250 crankshaft with crankpin relocated (same stroke as RT3), longer conrod and much more flywheel weight.
There was also a motor developed that used the DT400 cylinder but I don't know anything about it.

[LWC82PE]

DJR,  can post it but i will put it in the Yamaha section.

[Mick D]

Love threads like this, and all the info that comes forward,,

Great looking result on this thing YUMASTEPSIDE

[pokey]

MMM Beamish. should have pic of that above every marital bed and do the lil blue pill guys out of business.