Scooterotica

I don't know about anyone else but I wouldn't re-jet just to compensate for the weather (unless it was for a very long journey), I'd just ride a little slower to keep the temps down and realise that max speeds on an antiquated 2 stroke is a Holy Grail that's only ever available under ideal conditions.

I'm not talking about long rides Coaster I'm talking about my sprinter. I actually do understand the theory a little, I'm just trying to pull information out of people to see if my thoughts are correct

I'm thinking that when the motor is running at its best which can be found through trial and error and multiple plug chops that an Ideal running temp for max performance can be found. When at this ideal temp/rpm the exhaust is in tune with the rest of the motor and pulsing at its best, at this point the exhaust pulses are are traveling at a certain speed.

When the external temperature changes the air density changes, higher temps cause lower air density and lower temps cause higher air density.
The lower the air density the richer the a/f mixture the higher the air density the leaner the a/f mixture. So high temp = Richer and Low temps = Leaner A humid day also makes the a/f mix richer.

If things go lean the EGT temp will go up and the opposite if things go rich the EGT will go down.
If either of these happen the temperature variations will alter the local speed of sound in the pipe which in turn will alter and the rate at which the pulses are returned. This in turn will knock the tune of the pipe out of sync.

So my theory is that when the temperature increases, the air density becomes lower, the a/f mixture gets richer, The EGT gets lower, the pipe gets out of sync, max power is lost.
A re jet with a lower number to lean things up is required so the temp can return to normal, the pulses return to their normal speed, max power is again acheived.

Well thats my theory, I havent used one yet Ive just read up a bit or multiple things in the past. It may well be b@11@x though

I have a digital Stage6 one on order and I'll fit it at the weekend to my sprinter. Testing my theory shall comence in 2014

Can anybody help confirm or shoot me down. either way I'll be happy

Ah a sprinter, that explains it then, does the stage 6 offer any form of data logging? just thinking you'll have a lot to think about on your runs

coaster wrote:Ah a sprinter, that explains it then, does the stage 6 offer any form of data logging? just thinking you'll have a lot to think about on your runs

No but If you know a bit of kit that logs as much stuff as possible let me know. I love plugging scooters into laptops. I used to spend hours revving my Rotax powered smallframe watching the powervalve open and close on my laptop. Just because I could Love gadgets me . . . . . . . . Love em!

Have you been in the fast scooter forum Wayne?
There is a bit if kit that can data log, but the name slips my memory they use them on race karts, but the fast scooter guys would be able to help

soulsurfer wrote:Have you been in the fast scooter forum Wayne?
There is a bit if kit that can data log, but the name slips my memory they use them on race karts, but the fast scooter guys would be able to help

I was a member on there years ago, I'll go and take a peep, cheers mate

I remembered!
http://www.aimsports.com/products/mychron4/

I use mychron data loggers.
Designed mainly for use in karts. Good bit of kit. Got a 3 on my Rotax and a 4 for the sprinter.
The 4 can give 2 temp readings, head and exhaust. Also good for replaying sprint runs as I wont be riding it I'll be able to see gear change points/revs ect.

OzOAP wrote:I use mychron data loggers.
Designed mainly for use in karts. Good bit of kit. Got a 3 on my Rotax and a 4 for the sprinter.
The 4 can give 2 temp readings, head and exhaust. Also good for replaying sprint runs as I wont be riding it I'll be able to see gear change points/revs ect.

Hey up Oz

So Did you find one at a nice price, I've just been on the link above and downloaded the software. There's some sample data. Looks good. Let me have think fromn where you bought yours from please mate

soulsurfer wrote:I remembered!
http://www.aimsports.com/products/mychron4/

Cheers for that by the way