Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: Bioflex on August 03, 2011, 01:05:37 AM

Title: Dyno tuning 2 strokes?
Post by: Bioflex on August 03, 2011, 01:05:37 AM

I may be lucky enough to be able to get myself a chassis dyno, as it can be completely written off as a business expense and I have access to one cheaply.

Firstly, I am assuming a dyno designed for cars should be universal enough for bikes? ( I do realise there is such thing as a bike only dyno but that would be quite restrictive), however my main concern is about the oil burnt by 2 strokes.
I remember years ago having a rotary on a dyno, the owner complained a lot about it gummng up his o2 sensor, with a 2 stroke being a lot more oilythis issue could be a lot worse.

If anyone has had experiences running 2 strokes on dyno's and the use of o2 sensors with them Id appreciate any input

Title: Re: Dyno tuning 2 strokes?
Post by: 2T Institute on August 03, 2011, 04:39:44 AM

Heaps of experience.You never get any useful or reliable info from an O2 sensor on a dyno. So don't bother with it.Problem solved. I'm not certain if car dynos are any good for bikes, important thing is the drum/roller braking system.

Title: Re: Dyno tuning 2 strokes?
Post by: Bioflex on August 04, 2011, 04:42:26 AM

Cheers, I thought you'd be the guy in the know here.
I'm confused though, if an o2 sensor isn't used how can an effetive air/fuel ratio be found and thus an optimum tune?
Surely there's a more refined method than just doing a plug chop?

Title: Re: Dyno tuning 2 strokes?
Post by: 2T Institute on August 04, 2011, 06:35:53 AM

Yes there are ways and that's why I get paid the big bucks  ;D ;D ;D ;D
Truth is you don't need it and a EGT probe is best for WOT tuning

Title: Re: Dyno tuning 2 strokes?
Post by: scotty dog on August 13, 2011, 09:43:53 AM

On the dyno subject, i noticed an add in the paper about a dyno for bikes here now and it got me wondering if that would be a good way to get my CR tuned to its maximum and what does it roughly cost? 

Title: Re: Dyno tuning 2 strokes?
Post by: 2T Institute on August 14, 2011, 12:11:18 PM

Depnds where you go and the operator. Unless you have a big pile of pipes, heads and cylinders you can really only change jets and move the stator around and fiddle with the timing.
Most places charge $80 a run which is a complete WOFTAM, you need to find a place you can hire by the hour, half or full day.

Title: Re: Dyno tuning 2 strokes?
Post by: scotty dog on August 14, 2011, 07:15:29 PM

Yea ok, i just wondered about getting it jetted perfectly really, might have to look into it,
Cheers for the info.