KDXRIDER.NET

I probably don't have my jetting correct, so I'll get that out in the open first. (I haven't had a chance to do a plug chop yet but that is on my 'to do' list.)

I'm currently running stock carb (no RB mod yet), 150/40/1174-mid clip position, AS=1.0 turn out, 40:1 Maxima K2 with 93 octane pump gas. Throttle response seems good, but hey, when you never ride anyone else's bike, how will I know???

I repacked and cleaned out my S/A two weeks ago. It doesn't matter whether I'm putting around or screaming the bike, I get a trail of spooge down my S/A. The problem is that the spooge is dripping onto my swingarm and rear brake caliper, soiling the brake pads.

I know I'm not supposed to jet for spooge, but what can I do here? I imagine the spooge is not good for the pads.

By the way, Wibbens recommendation for the Yamaha Combustion Chamber Cleaner for the S/A was EXCELLENT; that stuff dissolved everything in the S/A and I didn't have to heat it or anything. Thanks Wibby!

I'd try dropping the needle one clip position....also check reed condition.

Indawoods wrote:"Worn reeds will mimic rich jetting"

Checking the reeds would be a good idea as Indawoods suggested.

I would open the air screw a 1/4 turn at a time until I had a slight hesitation then turn the air screw in about 1/4 turn. Then I would look at the needle clip position.

I had a similar problem. Mine was'nt getting onto my brakes but it was running down the S/A and onto the swingarm. I dropped my main jet size and tried a different gas mix. I went with and still use BelRay Synthetic race oil at 40:01 ratio mix. It really cut down on the spooge but I'm still getting some. Just enough to screw up my riding jerseys. So I've dropped the main some more and put new packing in my S/A also. It really has improved the performance. I need to do a plug chop now also. I'm looking into a needle adjustment maybe also. Depends on what the plug looks like after the chop. But the first main jet change made the biggest difference so far. We'll see what the second main jet change does.

Jon.

Thanks guys, I never would have thought about the reeds. Maybe it's a good time for a DF3?

Jafo, what main are you running now? I used BelRay H1R when I first got the bike, but all the BelRay haters on the "other site" scared me away from it. I had a lot of spooge back then but my jetting was so close to stock (aka wrong) I can't blame the oil for that. Mobil MX2T had the least spooge of any oil I've tried, but of course I can't buy that anymore, so I'm back to Maxima.

Rider1: 152/40/TV5/OEM needle clip3...cleans his airfilter, then oils it by immersion into filter oil, gently squeezes out excess oil, dries it..goes riding.

Rider2: 152/40/TV5/OEM needle clip3...cleans his airfilter, then oils it using an aresol, lightly spraying and works it in by hand to an even color, dries it...goes riding.

The two won't be 'jetted' the same at all. Not even close.

Wow CC, I didn't know that. That is interesting.

BTW, I use NoToil on my filter (detergent, oil, rim grease).

Fuel isn't 'sucked' into the incoming airstream, but pushed into it by atmospheric pressure. The greater the pressure differential, the more fuel is pushed into the carb. The less air pressure is in the carb, the more the pressure differential. The harder it is for the engine to get the air it needs (restrictive intake) the richer it will run. That's why airbox modification is popular on the KDX...well, and most other engines, too!

This past weekend, my wife's Banshee developed a 4-stroking burble right about needle slope time. Very consistent. Took off the outerwear (filter sock sorta thing), tapped it clean from some fine dust...problem sawved!!

Towit: Increased restrcition on the intake will make an engine run more rich.

That's what a choke plate does on common auto carbs. There is no choke 'enrichment' circuit as the Keihin PWK has, just a restricter plate than makes the A/F mixture more rich.

Thanks CC, that makes perfect sense! I thought the fuel was "sucked" into the airstream, but now that I think about your explanation, I agree with you. Now I understand why the reeds can make a difference (or, I think I do).

Can't it be said that, ideally, you want maximum pressure drop across the carb's venturi to create maximum airflow into the engine? If so, then a clogged air filter will create a large pressure drop across the filter. Since there is only so much pressure available, the pressure drop in the carb is reduced by the amount dropped across the filter. Since more differential pressure = higher airflow, this reduced differential pressure in the carb causes the airflow to slowdown, thereby reducing the amount of fuel put into the engine?

k

I'll tell ya, that Canyon Carver(canyncarvr) is something else. It is sooo true though Brad.

Sorry..I missed any notification I had gotten on this thread...

A couple of things...

re: maximum pressure drop

I assume you mean the drop at the ventui is the larger (largest?) of any other drop in the airstream...in which case, yep.

It's not a matter of a 'maximum' anything otherwise..it's just a matter of it being there. The pressure would drop more if the venturi was smaller..but at some point in time it's going to be an impediment to the whole process.

It's true there is only 'so much pressure' to be dropped..but where the airfilter becomes a problem when IT impedes airflow (and so drops pressure) and IT is not part of the air/fuel mixing process. The carb does that..outside of its operation, things that have a direct impact on the 'signals' it needs to work properly are going to screw it up. Call it 'garbage in, garbage out'. GIGO!

It's an INCREASED pressure differential that gets your more fuel pushed into the airstream. The total of the air filter drop plus the venturi drop equals MORE drop than there should be..thus the carb loses its ability to accurately meter fuel.

re: more differential pressure equals higher airflow

Not necessarily. Take a vacuum cleaner..put your hand over the hose. You get maximum 'suck' on one side of your hand, atmospheric pressure on the other, or maximum differential......and no air movement whatsoever.

Somewhere along the line there is a balance between pressure differences and the ability to flow air given a particular sized orifice..'more' is not always better.

How's that fit with what makes sense to you?

You're prolly in trouble...cuz it makes perfect sense to me!!!

..and it's the way it works, too!!!

Cheers!