PE250N Jetting

[bretb81]

Has anyone had experience setting up the jetting on a PE250N. I have changed the main jet down too a 210, lowered the needle too it's lowest position and am still finding it too be running rich.

[BAHNZY]

BretB81,
Something is not right. I have a PE250N that has just has a complete rebuild 1.00mm over. It is fitted with a RM expansion chamber and an aftermerket muffler. I am running the standard pilot, 2.0 slide, the needle in the centre position and a 290 main jet. Cant remember what the Needle Jet or the needle is but i would be taking a guess that it is stsnadard. With the air screw out 1.5 turns, the combination starts hot and cold with no issue, idles fine and pulls like a train through the whole rev range. Motocross or single track riding and every thing is fine. Do you have any idea as to the condition of the cranks seals or centre case gasket? What plug are you running?

[LWC82PE]

What oil ratio are you using?

[lukeb1961]

PE250N Owners Manual
http://cid-407d7ef0965d3991.skydrive.live.com/browse.aspx/Pure%20Enduro/PE%20Owners%20Manuals

says:

Main Jet #250
Jet Needle 6DH3-2
Needle Jet P-6
Cutaway 2.5
Pilot Jet #37.5
Float height 13.9mm +- 1.0mm

I would be checking that float height.
Luke

[bretb81]

It had a 280 main, 2.5 cutaway, assume std needle. I have a spare carb which has the same setup from an 80 model. I have gone down in steps to 210 and it runs ok exept for 1/4 - 1/2 throttle. B8 plug instead of B9, new silencer, 40:1 fuel/oil. I'm tempted to increase the throttle cutaway but these are near impossible to get if I stuff it up.

[lukeb1961]

Go back to 20:1. Yes, really. Use std settings on everything - jets, plugs, etc.
Once you are back to totally standard, run it for a half hour, blow all the dodgy mix through. THEN let's start looking at the thing.

Luke

[LWC82PE]

yes dont use 40 to 1 in a PE. stay close to 20 to 1, start with standard jetting, use a minimum of 95 octane fuel ( specified in PE manual), higher is better, add octane booster if needed.

[pmc57]

Yes agree with all. At 40:1 you are in fact making it run richer. (more fuel per air because you are taking away the oil).