Scooterotica

eden wrote:

holty wrote:ive looked at lots of cylinders, i realy would prefer liquid cooled, and just wondered if anyone had ever fitted a gasgas 250 cylinder on a lambretta, looks like they use a 60mm stroke which would make port timings suitable depending on rod length and compression height of the piston, i know i will have to alter the casing to suit the shape and height of the barrel, any thought folks?
holty

Mate of ours has transplanted a gas gas engine into a lambretta frame and put it on the dyno a few weeks ago... 10 bhp but s**t loads of torque.

oh dear, thats not realy many bhp is it, dont suppose you know what size engine that happened to be please ?

many thanks,

holty

doesn't ride like its only got 10 bhp, it got 10 after having an expansion grafted on, it was under 9 with the standard pipe on lol.

9 or 10 bhp is still very low, i might have to have a re think, i have seen an aprilia 240 cylinder that might be better i think its 72mm bore, and its made by rotax, which is the make of cylinder it was supposed to have had fitted a long time ago, i guess it was air cooled, but i would like water cooled.

holty wrote:9 or 10 bhp is still very low

Depends. Was it a MotoX, Enduro or Trials bike engine?

SF

i think the gas gas engine is an off road engine designed to have lots of torque for climbing hills etc, not realy meant as a road engine i think. i do like tourqey engines though, i remember a friend of mine having one of rayspeeds 250 engines in the 80s, it was the one where rods were brazed to the fins, then it was bored right out to accept a liner, and had a 72mm piston, he had a 48mm vw clubman on it, and a big amal, sx200 gearbox, it was an arm ripper, didnt rev much, but it pulled like a freight train, sounded very nice, old school, what was the saying, no replacement for displacement !

Eden, the lad who did the dyno had a modern race bike with a Rotax 250 cylinder on a (I think) Aprillia engine, did he say he got 45hp out of his. think it was an ex cart top-end (watercooled). I had a look at it but didn't ask him.

http://i245.photobucket.com/albums/gg56 ... 53c44e.jpg

I was going to use a Gas Gas 321 cc barrel ,it was a 60mm crank
but i am doing something more exotic

GP240 wrote:Eden, the lad who did the dyno had a modern race bike with a Rotax 250 cylinder on a (I think) Aprillia engine, did he say he got 45hp out of his. think it was an ex cart top-end (watercooled). I had a look at it but didn't ask him.

is that the same eden that posted earier ?

No, not the gas-gas, the guy who run the dyno had a modern street bike/racer under a cover. I think it was an Aprillia based bike but the engine had a Rotax 250 top-end grafted on it. The owner said he had 45hp out of it.

Eden will fill in the gaps.

The gas-gas in the Lammy frame is/was a trials engine, it also had the original small box pipe, didn't rev high but the low down grunt was big. As Eden mentioned before, the owner of the dyno pulled out an aprillia RS expansion which they adapted for the gas-gas but did not do as expected due to the tune of the barrel (up from9 to 10hp). Be interesting if he could find a more revvy barrel for it tho.

GP240 wrote:No, not the gas-gas, the guy who run the dyno had a modern street bike/racer under a cover. I think it was an Aprillia based bike but the engine had a Rotax 250 top-end grafted on it. The owner said he had 45hp out of it.

Eden will fill in the gaps.

The gas-gas in the Lammy frame is/was a trials engine, it also had the original small box pipe, didn't rev high but the low down grunt was big. As Eden mentioned before, the owner of the dyno pulled out an aprillia RS expansion which they adapted for the gas-gas but did not do as expected due to the tune of the barrel (up from9 to 10hp). Be interesting if he could find a more revvy barrel for it tho.

ye the engine in the blokes Bike was a cart engine and it was very compact. he spent a while telling me all about it, and it wasn't expensive either