Scooterotica

Hi a mate of mine has offered to sell me a barrel, jap piston, crank, exhaust and barrel that he had with a racer that he bought off ebay. We are not sure of any details but barrel is 200 stud spacings with sleeved down bore. Through the frame exhaust. Large 6 petal reed manifold.
Guessing this was built for 150 specials class. Wondering if this has a normal 58mm stroke or is it short stroke with larger bore hence being used on 200 engine. Any thoughts or ideas please. PS want to put this in a road going cutdown

i never raced 150 specials/standards but rode a few in practice 20 yrs ago they all seemed very gutless low down with very narrow power bands so not that good on the road also most race barrels have such wide ports that the piston rocks as it passes in effect droping in very slightly this will cause them to wear quickly on the road also the piston to bore clearances could be wrong were in the uk/world are you as your local dealer might be able to help another thing is some of these pistons could now not be available if yours is kaput

Thanks for your reply, this is exactly the info I was after. I'm in shropshire, piston is for reedvalve engine with windows cast into it. Maybe off a jap crosser??? Think I'm going to pass on this as it's going to be too hard to ride on road..... then again may be fun around town!

most things are worth a try at the right price theres so many of the shelf kits that offer near race spec performace compaired to those 80,s 90,s race barrels its not really worth it like i said the right price allways worth a go or why not ask if anyone on here wants it

can you please post some pics of the parts ??

ive had a go on a 150 wasnt a special as it was full frame, that used to be raced it was a sleeved down ts1 with 58 stroke and it was fast as f@@k, it got used for grasstrack in the end and was pretty unbeatable with the loon riding it

could go ether way if its 57 bore it will run 58mm crank.
if its 60mm bore it will be for 54mm crank.

I got my hand on Ian Franklands old group 5 bike a few years ago,it was an an Autisa 158.It did run a bit shitty at low revs but why do you use low revs on the circuit.It wasnt practical for the road but it was ace to race about the village where i live.I would dig it out of the garage on a Sunday and go for a quick blat around the village as ive never seen the police on patrol on a Sunday morn.I remember this mother grab her child and pull him away from the curb as i got near to them.It was pretty mental as the power was just on/off and had trouble getting out of 2nd gear in the village so it must of sounded loud as f@@k at about 10000rpm

i think if some of you rode dave websters group 5 bike years back you might change your mind. cheers all.

mick-h wrote:i think if some of you rode dave websters group 5 bike years back you might change your mind. cheers all.

Change mind about what?