I could use some help…

[Mid pack “B” class]

Howdy everyone,

I’ll get right to the point with my question but I’d quickly like to say thanks to the many contributing members that help others with questions and problems, I’ve learned a ton reading the many threads from this community of KDX fans

I’ve owned a 2004, KDX 220 for about 3 years now, I purchased it as a complete running (although not well) bike
knowing that it would be a project.

I’ve spent a fair amount of my 52 years spinning wrenches on all kinds of machinery, and felt confident that I could get the bike in good running condition again

My issue is the bike is running way too rich,
And before we go right into replacing the jet block gasket let me explain the short list of all that has already been done.

Many updates were done to the chassis.

The engine was removed, jug and head were sent to Fredette for porting and mill work, the lower assembly was sent to a reputable 2-stroke only shop in Nebraska, the case was split and all seals, gaskets, bearings were replaced .
Crank and rod were also replaced.

New piston and rings installed after both assemblies were returned..

The carburetor is a BRAND NEW Keihin 35PWK/AS
This is not an EBay carb, it was purchased from a mom n pop shop that still has some inventory, I have set the float height at 18mm, main jet is now 145, pilot is 45…

I’ve replaced the CDI in hopes of rendering the issue..
The factory ignition coil still Ohms very close to spec. It is slightly high on the primary side but throws a 1”- 2” arc while grounded with the boot removed

I’ve tried multiple non-EBay NGK plugs and all are soaking wet when removed..
The V-force 3 reeds are brand new..
I have also tried swapping them out with the factory reeds just to verify they are not the issue. Bike runs the same either way..

Gnarly pipe, factory silencer
Brand new air filter after meticulously cleaning the air box..

This has been a lengthy 3 year project, and after a lot of time and money I’m just ready to ride the bike..

Many other things have been done but wanting to give an idea of what has been performed up to this point

The bike has roughly 5-10 minutes of run time since reassembled

What am I missing guys ??

Is this a KIPS issue ?
The timing marks are aligned and appear correct..
While viewing though the access cover it does advance when throttle is applied..


Any advice or suggestions are appreciated

Thanks everyone…

[KDXGarage]

Welcome aboard.

How clean is the inside of the pipe and spark arrestor?

I would start at the pilot, get it sorted, then needle, then main. Getting the Iar Striker means it will not be the same jets as the stock carb.


Thanks for explaining what you have done. You have eliminated a few things for sure.

[Mid pack “B” class]

Thank you for the response
That’s good advice on the carb..
I’ll need to order some smaller jets as everything I have is currently larger, but I will start with the pilot and work from there..

The pipe was degreased and power washed inside and out,
Same for the silencer, I would say it has a normal amount of pressure from the exhaust while running, however I have not tried removing the silencer to see how it runs with only the pipe

[Chuck78]

I second that notion that PWK Air Striker jetting will be notably different that stock original carb jetting requirements... That's the whole point of the Air Striker's design improvements, alter the fuel delivery/atomization in a positive way.

[SS109]

IMO, the first place to start is to do a leak down test before anything else. Just because it was rebuilt by a reputable shop doesn't mean everything is good.

You said the plug is wet. Wet with what? Fuel, coolant, or transmission oil? I assume you meant fuel but have you checked to see what it is for sure?

Jetting seems really odd. Unless you are above 8000ft asl I would say the main is way too small and the pilot way too big. Go through the jetting process found here (viewtopic.php?t=1156) and get that sorted.

[Mid pack “B” class]

Thanks for the response guys !

Yes, the plug is very wet with fuel, I’m running non ethanol 91 with Amsoil 40:1

The new PWK came installed with factory jetting for the 200’s I believe.. The main was 160, and 48 on the “slow” jet..
I started there and have systematically worked down through all of my jets trying to get it running correctly..

I am about 500’ above sea level..
No shortage of oxygen here.. lol

I cannot get the bike to idle either, and it makes no difference adjusting the idle screw, which leads me to believe the “slow” jet is too big.. But honestly my gut tells me something else is wrong..

It doesn’t have a ton of power the little that I’ve rode it ..


I will do a compression/leak down and report some numbers hopefully this evening..


Really appreciate you guys taking a minute to share your thoughts..

[bufftester]

Second doing a leak down to verify the engine is healthy in that regard. Then get your pilot dialed in. My hybrid is a 220 motor and I run a 42 pilot on a stock pipe and no port work, I would expect the AS to be smaller. Regardless, arm yourself with a variety of jets and go through the process only changing one thing at a time. Yes it is a slog, yes it takes time, but it does work.

[Chuck78]

One other thing to add, did you mention what slide cut away size was in the Air Striker? I believe they come stock with a 4.5 slide. You said stock 200 jetting but you didn't say stock 200 slide, and even if it did have a stock 200 slide, the Air Striker airfoil wings for the air jet intake area will completely change the pilot jetting requirements even if running the stock slide cutaway.
Instead of running stock jetting for a stock 200 carburetor, on an Air Striker with a ported cylinder and modified head, you should first reference what other people with similar setups have ran. This forum is a wealth of archived information on various setups and current forum users' current setups.

If you play with the chatting further and still can't get it to run anywhere near properly and make proper power, I also absolutely recommend the leak down testing. That's always an excellent recommendation even if you think everything is perfect. Especially since you had one shop do the bottom end and another shop to the top and, and presumably you assembled the top end yourself.

[SS109]

Yeah, I run a 38pj and I'm at 1600-2200ft asl. I would suspect that bike should be a 40 or 42pj and probably a main around 152-155.

Checking to see what slide you have is a really good idea as well. A 4.5 would not run well in the KDX.

[Mid pack “B” class]

Ok,
I’ve got about 162psi on compression,,

I’ll have to make a different exhaust plug for the leak down test. I’ll try and get that done yet tonight.

And I pulled the slide to double check and you guys are right
It has the 4.5 in it..
(I never thought to check it) my, bad

What are most guys running on modded 220’s ?

Can’t thank you guys enough for your input on this project for me..

[Mid pack “B” class]

Doing some more searching and reading on here now that I have some ideas from you all ..
I’m thinking I need the the #7 slide for the 35 PWK to work..

If for some reason any of you think this is tragic waste of $$ please let me know !
Lol

[SS109]

No, not a waste. It's just going to take a little sorting out and we're to help as much as we can.

On the slide, there are tutorials out there on how you can modify that 4.5 in to a 7.

[Mid pack “B” class]

Ok great !
I’ll do some looking into that
From what I understand it’s the cutaway portion on the slide

I will report any updates on this thread to keep you guys in on the progress..

[jamiethegiraffe]

you could also try a DEL needle which is slightly larger on the straight diameter that your carb most likely came with- that would help accomodate the 4.5 slide. I believe farmandsandtoys.com has a few in stock right now

[kdxdazz]

Unless I missed it there is no mention of the needle, the needle effects everything from idle to wide open throttle

[Mid pack “B” class]

Ok great suggestion !
I’ll check out that site with the needles !
Thank you

I double checked and the needle it came with is the DEK..

I also emailed the mom n pop shop I purchased the new carb from to see if they might have a #7 slide that will fit but haven’t heard back from them yet

I do still have the original 220 needle from the old 33PWK but I can’t make out the numbers on it anymore unfortunately

[kdxdazz]

Ok this is an easy one, DEK is incredibly rich right across the board, from memory 2.69mm straight diameter compared to stock 2.73mm diameter then the taper adds another dimension to richness, stock kdx220 needle is 1173l
Don't switch to a number 7 slide, this is a common myth that's been doing the rounds for donkeys years, you cannot change the slide as a work around solution for something else that is badly jetted, going to a larger slide makes throttle response and atomisation at idle worse although yes it will lean it out

[brademan76]

I know this doesn't help with your carb settings, and it's not a cheap alternative, but a lectron has helped lots of guys who were having problems getting their carbs tuned correctly, myself definitely included.