Question:
My daughter wanted to do her science fair project on something to do with the bikes this year. We hashed around several things, she had pretty much settled on weights of the various bikes, but then we got speaking about gas and how I mixed it etc. so the Science project evolved.

You see the question.

The procedure will be to take the Pizza bike of John Isherwood fame. (never rebuilt to my knowledge) Ish? (02 Sherco 125)

Take the 4 samples of fuel all mixed at 64 to 1 with Maxxima K2.

Bring bike up to operational temp as evidenced by the operation of the cooling fan.

Do a straight forward Dyno run for tourqe and HP and print the graph.

Drop tank and drain, ride bike around with fuel line disconnected to drain carb, refill with next sample of fuel, run to operating temp again and redyno.

Probably run double runs to look for consistency in measuring while a particular fuel is there.

So,,,,,, What do you guys think the answer will be?

Choices:
87 Octane
93 Octane
75% 93 Octane 25% 110 Octane race gas
110 Octane race gas
No difference

 

This message has been edited. Last edited by: Alan Bechard,

Please post the results when you get them. It will be interesting to see how much HP teh 125 puts out. How about a run with your 290?

Dang Alan! Choice number 3 actually requires higher math. And I told the teacher I'd never use that stuff again.

John

PS The calculator puts it at _ _.25 octane.

Terry, it will probably make an appearance across the Dyno while I am doing it as I am always a bit curious, Dean's 80 may well find it's way on there as well depending on how late in the evening it is!

OK, we did the runs to get the Science project done.

We added in 100 LL Avgas at the request of some on the RYP board.

87 Octane produced the most HP at 7.5
The Avgas, 100 LL was the lowest Hp at 6.78 I think it was.

The others were in between.

So,,, what do we learn, probably not much to be honest.

We did one run on each fuel, I would have felt a lot better, and more scientific if I could have done at least 2, preferably 3 runs with each. Unfortunately, I was supposed to be there at 10, we ended up there at 2, the Shop was jammed with customers, and for some reason the Dyno kept loosing communication with the computer. It just figures sometimes.

Also thinking about it, the most HP may not be the actual critical factor, and the Dyno run is not really representative of how we ride. We get it rolling in 4th gear, then do a tap to wide open and then shut off and read max hp. While that gives an accurate represantaion of that test, it is not really how we ride. Things like knocking, pinging etc. did not really come into play as they would actually out riding in the day. And while you could probably eliminate or minimize most of that with proper tuning, jetting, timing etc. you would very likely loose the HP gain.

Anyway, ask away. It was fun, man is that thing rough on tires, it is a little disconcerting running that thing, but nothing like when they had the Hayabusa on there!!!!!

The mix I normally run came in #2.

Ran out of time to run mine or Dean's. Might pull up there one evening just to see.

Unless I'm mistaken the HP is nothing but a torque reading at 5250RPM. It's all a calculation. I think the torque values would give a better seat of the pants feel for what a trials bike needs to do. Any big torque differances? Torque curve stay steady?

Cool project. Did you get a chance to make a pull with the 290? I'll take a guess at 17.5 HP. Sounds like the results were what was expected. Sure beats making a volcano for a science fair project!!!!!! Any pictures of the Pizza Bike smoking the tire??