Lean vs Rich - 4T vs 2T methods....

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Lean vs Rich - 4T vs 2T methods....

Postby Davenay67 » 01:51 pm Mar 03 2016

I have been a 4T guy all my life. Every one of the many bikes I have owned (aside from a brief, disastrous and forgotten about venture with a RD350LC a very long time ago) have lived by the suck, squeeze, bang, blow mantra.

My KDX is my only long-term 2T ride. I am having fun learning more about 2T's as I go along, but jetting remains a bit of a mystery, and I think some of my 4T background may be hindering me..??

4T lean - blip the throttle from idle at rest - the bike revs soar quickly and they hang, taking their sweet time to return to idle.

4T rich - blip the throttle from idle at rest - the bike bogs instantly, and depending on how rich, either stalls or clears its throat and then revs rise.


Does the same apply to 2T engines?
I am using the jetting guide here on the site.
I think my pilot is right, or really close at least. I recently replaced my jet block gasket in case this was causing any issues that make jetting extra hard. Once the weather improves I can see if the bike is behaving better, or whether it's the same-old-same-old.

Any advice or comments are really welcome. :grin:

Dave.
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Re: Lean vs Rich - 4T vs 2T methods....

Postby BlackMist » 07:44 pm Mar 03 2016

Look up plug chop testing, and colors your plug should be.
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Lean vs Rich - 4T vs 2T methods....

Postby Tioli » 05:29 am Mar 04 2016

Hi Dave.

I know what you mean but can't help with the translation from your knowledge to what a two stroke is singing and that's the point. You have to learn its song. Thick and thin. Thin is the way to go but it will take you to leaning out the motor with negligible power loss.

You know how some motors give, well I think the KDX motor is a giving motor. To get the most out of it with reasonable effort you could do what I did or
Basically RB modes, pipe of choice, port clean up vforce teeds, full advance.
2001 KX125 with a 1997 KDX Tioli Hp motor

My KDX journey starts at the bottom of this page:
http://www.trials.com.au/forum/viewtopi ... &start=160

Trials.com.au / Forum / All about...me! / My long time friend the prancing horse / page 9
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Re: Lean vs Rich - 4T vs 2T methods....

Postby Jaguar » 10:43 pm Mar 04 2016

Telling you haw to properly jet your ride would take a full hour. There are many tutorials on the net to help you with that.
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
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