Quick re-cap:
We have a lovely new shiny friend called Michael, who likes to fanny around with a porting tool on Yamaha race bikes.....he's quite good at it apparently!
You can read more about Mick here: http://scooterotica.org/tempforum/viewt ... =12&t=4957Anyway, Mick wanted to branch out into scooters, and so asked if we had some old s**t barrels that he could use to f@@k about with and practice on. So we slung him a shite old cast iron 150 kit and thought no more of it. Anyway, next time i saw Mick, i asked how the practice was going, and to my surprise.....he had taken this:
And turned it into this:
I was shocked!
I actually thought....bloody hell, not a bad practice....we might actually run this cylinder for a cheeky test!
Anyway, long story short (really?) i couldnt find the time to get an engine built etc, so we offered up the cylinder FREE of charge to forum member 'Ove' to run for us if he wished, as his 186 kit had just expired and he had no funds to fix/replace.
So we posted the kit out, and all he had to do was source a cheap piston with rings that were less than the standard 2.5mm rings. Ove got hold of a cheap £30 piston (i think from AF? Not sure - he will reply hopefully) with 1.5mm rings and banged the kit straight on with a Clubman and 28mm Delly. Then yesterday, he rode up from darn-souf, and stopped over in a B&B so that we could see how the cylinder was getting on.
Now please bear in mind, that whilst Mick did a sterling job on putting in all sorts of weird n wonderfull boost ports, his work to the inlet and exhaust was minimal, and a lot more is still required there. This is because i advised him that we would be fitting a better piston at some point, and so he wanted to be sure where the ring pegs would be before he continued further.So we left it that we would let Ove source a piston, we would then dyno, and then Mick could complete the tune and we would give a final dyno reading at that point.
In the end, we have hopes for a 20bhp engine, if running a JL4 with 30mm delly......but whether or not that will be ridebale is debatable....maybe 15-17bhp would be more usable....but i just want to see how far it can go before its not a joy to ride anymore? Also note, that whilst the extra transfers are funky, you could probably get 80-90% of the results we will end up with, without them....Mick just put them in for fun when playing with this......its another Scooterotrica folly!
So straight onto the dyno with a cast iron 150, Clubman pipe and 28mm Delly, we got just under 10hp @ the back wheel (blue line):
This was quite dissapointing, but to be fair....quite reasonable given that the piston was completely standard, not even a cut skirt yet, and the inlet and exhaust port still need work to match them to the fancy work done to the transfers. So moving on, we stripped of the clubman, made no other changes and fitted a JL3 exhaust pipe that i had kept to one side for this test.....instant bhp increase as expected, just under 13bhp, but the best bit was the power delivery/curve shape....it was WORLDS apart from the Clubman (as expected! ;o) ) See the red line above for JL3 BHP curve.
Ove switching exhaust at the Scooterotica workshops:
The graph below shows the BHP and Torque curve for the JL3:
So with just under 13bhp at the backwheel, we dont see any problems getting another 1bhp (or maybe even 2bhp - if we are lucky??) using a JL4. So that will be an easy 14bhp from the old cast iron cylinder........and thats before we even cut the piston skirt, re-work the inlet, or finish the exhaust. Those 3 mods alone could be an easy 2-3bhp without going too far.....and then the scoot could still be rideable at 16-17bhp.....or a screamer if we fancy a 20bhp tune? But then its Ove that has to live with it ona day-2-day basis.....so we'll take our lead from him.
Either way, it shows that with a little thought and a nice man with a grinder, you can take a 150cc kit that most people throw away, add a £30 piston, and have some cheeky porting work done and you've got more power than a standard 200cc engine (12bhp quoted official figure - but we see approx 10bhp at the back wheel from most standard 200s and abit more when pie/carb combos are changed) and just as much power as some more expensve 186 kits that are out there for £350+. Everything has a purpose, and Ally kits certainly have benefits......but this simple, and cheap bit of sillyness that we've done, demonstrates for good things can be, even on a limited budget. And dont forget...this was originally just going to be a practice cylinder for Mick to junk, before it turned into this amusing thread!
Im certain future Mick Abbey cylinders will be even better. 
Anyway, i hope that gives you guys a healthy update for now? Ove headed back darn-souf today, and is going to post the cylinder and new piston back to Mick for the 2nd stage of the tune, and then will return for a Clubman/JL3/JL4 shoot out. If we hit 17bhp (i dont see any problems with that figure) then we'll ask Ove if he wants to run-round at that, or shoot for the big 20.....its his choice, and our pleasure to oblige in either case.
Cheers Chaps
Dan
..i realize it wont TS mid uummphh But be happy with Grunt.. 
, important thing is to me that it suffered a hell of abuse and when stripped down last month was as clean as a whistle, poss down to filtered tm24 carb. 