OK, here's my latest crack-pot idea, the critics and questioners will love this one........ha ha. :fb:
Right, for a whole host of reasons that aren’t good enough to waste time writing, I have decided to build a scooter that is a 3 trick pony, it will be a jack of 3 trades, but a master of none.......it has to be a compromise in each area if it is to do the following:
1) Run an ADS touring pipe, 30mm Delly, and 4.2 gearing for a low revving, road going scooter.
2) Swap and fit an ADS race pipe, 38mm TMX and sprint gearing to run it up the drag strip and Elvington for some 1/4 mile jaunts
3) Swap and fit an ADS race pipe, 38MM tmx and race gearing to enter a couple of street class races in 2011
Can one engine do all 3? Well, as I say.....not effectively as a class winner, but then I’m not a class winning rider, so does it matter? Its just one of those mad-hatter ideas, another scheme to keep me tucked away in the garage all winter, its just for the fun and the sport of the challenge!! lol
Anyways, the current power output of the engine we are using is 28.7bhp and I have an ADS fast road pipe which I have compared back 2 back with a JL4 and the results are very similar on both pipes, the ADS pipe does have a smoother top end BHP curve though, and the volume of the pipe really draws the gasses through, to the extend that it would need up-jetting in comparison to the JL4. JL's were my favourite production/off the shelf pipes up until now, but the price, quality and performance of the ADS pipes has won me over. So I was deciding whether to go the hooligan route on the road with this pipe, or fit the touring version and go for gearing based performance......and I’ve decided that’s what I’ll do. I have the ADS tourer winging its way to me as we speak, and as soon as that is dynoed I’ll post the graphs, I’m hoping for approx 24-26bhp and 22-24ft-lbs at around 6k RPM (ish)........but we shall see what happens, it might be better, it might be worse, but whatever it is I’ll gear it up accordingly, ride the f@@ker and post the results.
On top of all this, whilst building this engine, dynoing different pipes, thinking about gearing and so on, Sean and I had some conversations about this, that & the other, and Sean really wanted to experiment with the tuned length of a pipe on this motor. So what he did was asses the engines port timings, measure the tuned length of a JL4 pipe, and then reduce it by approx 2 inches. Ultimately this had the effect of pushing the power approx 1000-1200rpm further up the range, but more importantly it increased peak BHP by 2.3 to 31bhp, and gave a huge increase in area under the graph. This result is exactly what Sean predicted it would do..
Now of course this pipe is no good for what i’m doing as a road-going scooter.......its going in the opposite direction of what im trying to achieve...lol.....but still i thought it was an interesting topic for discussion and a fun experiment. I think the ADS Race pipe results will be almost identical to this shortened pipe, and as those pipes are of superior quality to a JL4 (with better clearance and less cracking etc) I’ll be running on of those from Chis when I sprint and race the scoot, and keep the touring setup for the road.
So thats what we're on with at the moment building a road scooter/engine for low revs and 4.2 gearing.....and having an option to sprint/race if i want to. Here's a pic of the scoot when it was at dry build stage, the bit we chopped out of the JL4 and the JL4 before (original) and after (shortened) dyno graph.
Below: BHP
Below: Ft-Lbs torque
No pressure then LOL. 
