155 main, 3rd clip on the needle, 42 pilot, 3 turns or 18 clicks on the choker knob
an with the cooler weather today  the bog was way worse....ill get a fresh plug tomorrow but not the 30 bux one...

Okay, mine is an 01 and might be different jetting but this where I am and my only issue is I am a little lean on the bottom but no bog at all. I have 46 pilot, 162 main, last clip on the needle 12 clicks out and 1 1/4 to 1 1/2 turns on the air screw depending on the temp.

Another thing where do you have your power valve adjuster set. I know I played with mine once and found by turning it in too much it ran like a turd. so I have mine set at just enough tension on the spring to keep it from the valve from flopping around loose.

the pv is at one turn of tension like the manual says .... so the bog is a rich condition right?

Which needle do you have in it?


Booger2

I would try to move the needle clip up. It leans out the bike from the 1/4 to full throttle. If that doesn't help it might not be a rich condition it might be a fuel starve condition so I would look at the float height. You say you can creep up slowly to full throttle right...so if you hammer it and it bogs there might not be enough fuel in the bowl to supply the jets. get my meaning?

yea i ordered a float level tool a week ago im still waiting for it ...yea imma check my fuel tank strainer too...hey how hot does ur bike run... say at the top of the rads ir on the cylinder head? any ideas?

My bike gets good and warm but you can't fry a egg on it or nothing.

Yamajeb10-31-2008, 11:35 PM
I talked to a carb parts distributor and here's what I've learned. Indeed it's another way to adjust air/fuel mixture at lower throttle openings. Effectively you can adjust (turn) this knob and get a change similar to the airscrew adjustment. Note I state similar, not the same because apparently it impacts a slightly larger throttle range opening from zero to just under half-throttle. Overall, it works WITH the pilot or slow circuit.

The parts guy said the idea with the thing was in concept a great idea. The problem was that too many people were confused by it and didn't use it correctly so on newer models they discontinued it's use.

So I 'sperimented. After I warmed the bike up pretty well I changed it by three clicks at a time (BTW 45 pilot jet and at these temps A/S is a little less than 1.5 turns out so slow jetting is fairly good). My test was to get it going only fast enough to keep from stalling in 2nd then wick it open fairly quickly. I started out at what I'll call the baseline at 12 clicks out from completely clockwise (two full turns out).

From baseline I tested after three clicks out (2.5 turns out total), six clicks out (3 turns out total), nine clicks out (3.5 turns out total). I noticed improved throttle response at six clicks out from baseline but at nine clicks out it was starting to develop a little bit of what I'll call a lean bog, not bad but noticeable when I wicked it open quickly. Snap was best at six clicks out from baseline.

Then back from baseline three clicks in (1.5 turns out total), six clicks in (1 turn out total). No need to go any further because throttle response was breaking up.

In effect by turning it out (CCW) I was leaning out the pilot circuitry and by turning it in (CW) I was richening things.

Tried one more test. I got enough momentum to motor along in 3rd gear on a slight incline then tried wicking the throttle. This helped to gauge the difference without having to fight to keep the front wheel down. Best response about 6 clicks out.

Please note that there may very well be older models or other bikes that use the choke knob in a different way or it may be a different design - built in idle adjust or something . . .

but if you have the stock carb on an '01 or '02 250 and your pilot is jetted well this knob ought to give you some easy tuning - give it a try!! I'll be fiddling with it for sure, beats fooling with a little tweeker on the A/S.

kewl thank u ...

I finally got my solenoid replace and it took care of my pinging as well.

What about the pulsing?  Is that gone too??

Nope, I forgot to mention that. I still have it. I am guessing that the seal on the clutch side must be leaking??? I am going to try a new set of reeds and richen the choke knob down. I have it already turned it in at 8 clicks now. Didn't seem to make much of a differenct from 12 clicks. I figure I will run it in another four and see what it does.

I did a leakdown test on mine and absolutely could not find the leak with soapy water.  It's definitely not holding air.  With the amount of smoking I had I am convinced it's the case gasket
leaking/sucking from the transmission.   When I first built this bike I used mis-matched cases - right side is the original '00 and I replaced the left side with a '96 case from Ebay.
I found a set of matching cases on ebay for 150, so I bought 'em.  This time I'm sending the crank out for rebuild and replate-ing the cylinder.  A total rebuild done right.  That should fix the damn thing!!

I haven't measured it.  The exhaust smells like burnt motor oil rather than sweet 2 cycle.  I've never been comfortable with the mis-matched cases anyways.  Found a matching set for $150 and junped on it.  Plus, it won't hold air for even a few seconds on the leakdown test.