New steed

[Friedom]

Right on.
Got it running yesterday. Very strangely, though. Would sometimes idle, once warmed up. No chance of kick starting it. Had to bump start down our steep driveway, very erratic running. I swapped in the carb from my 92 and the symptoms didn't change. I will be inspecting the reeds soon(should have already), but last night when I
picked up a frame for my 92 from SS (it will live again!) he happened to mention o rings at the exhaust port around the pipe. I had never seen any such thing, but I'm expecting they'll make the difference in getting a good closed loop. Mine were missing on both bikes. Things should run a whole lot better now.


Crawl Wheel Drive

[Friedom]

Soo......
It runs, but I still have to bump start it going down the steep driveway. Got it idling pretty smooth once it warmed up. Idle will fluctuate about every 10-15 seconds, just minor changes up and down.
Riding it is getting fun, but if I get past half throttle it bogs/misses/fails and sounds like it's begging to shut off. It'll pull the wheel up easily in an early gear before I get to that drop off, but the joy is over quick.
So I just read a few pages of people's jetting on ThumperTalk, but most are H series bikes, so I'm asking for some help dialing it in.
Here's what I know so far:

93 kdx200
Left kips valve is shut - gear broke off and was removed. Rest of the KIPS works great. (Steel valves on the way)
Brand new looking piston, though I don't know what type.
Stock Reeds, look new.
New FMF Gold pipe
Stock silencer with a cobra screen spark arrestor
2600'
New NGK Br9es plug
150 Main Jet, 48 PJ
Brand new UNI filter
40:1

I'll be changing the plug for another new one soon, now that I'm closer on jetting and can idle.

So far I only ride it up and down the driveway and to the end of the street. Can't take it into the dirt because I need to have pavement to bump start it if it dies. No hint of starting with the kick yet.

Wisdom to share? Anyone? How do I know if I need to go bigger or smaller on MJ if it is totally missing above half throttle? Anything else I should check? Why can't I kick start it?

One more thing - 87 octane. Does it or does it not need higher octane? Head looks unmodified.

Crawl Wheel Drive

[SS109]

That is way fat on the PJ. What I was running and was pretty spot on. 152 on the main, a 40 pj, CEK needle on the 3rd clip position.

[eprovenzano]

Not really knowing the getting for these beasts yet, I'd agree that yours is far too fat... A 48 pj (to me) seems huge. I'd drop to a 40 or 42 and the see if you can kick start it


Sent from my iPhone using Tapatalk

[Friedom]

That makes sense! Yes! Looks like it's time to order some jets.

I have to take a look at the needle and clip position too. Haven't pulled it yet.

Fun Wheel Drive

[SS109]

Yeah, I know you ride a lot of the same areas as I do so I would definitely go down to the 42 PJ and try that with the main you already have and see how it runs. I would probably order a 152 and 148 mains along with a 42 and 40 PJ. Find out what needle you have in there before thinking of replacing it.

[Friedom]

I'll get an assortment so that they're available for both carbs.
Wait, I'll see what is in the other carb, maybe I'll get lucky!

Fun Wheel Drive

[Friedom]

Ok guys, I put in a 42 PJ and a 152 MJ. Stock needle on middle clip.
Bump started it on the hill as there was still no hope of kick starting. Got it to warm up enough that I could hold the throttle to keep it running, then adjusted idle screw to keep it going. Finally got it into neutral without killing it to check. Air screw is at about 2 turns now, definitely running better than at the .5 to 1 turns recommended by FRP.
Kept dying though, so once I got it kind of stabilized I put a new plug in. I was able to kick start it ONCE.
Still runs pretty choppy above half throttle. My main has gone up a size and my pilot down 2, but it seems to fire intermittently at 1/2 to full throttle, where before (on 48/150) it wouldn't fire at all above half throttle.
Maybe that means it needs a bigger main still? Or perhaps I should stick the 150 back in. I have an assortment here from 150 to 158 now. Should have got a 148 this morning when I was getting my pj.

Edit: Video of idling. Thoughts?

http://s925.photobucket.com/user/cfgaef ... 0.mp4.html

Fun Wheel Drive

[david]

48/150 is the stock jetting. I tried 42/152, and while it was crisp, it had a lean bog when I would wick the throttle, and was fairly hard to start. I went to 42/155 and it was better but still had a slight lean bog. Then I remembered I had old fuel in it. Refilled with fresh fuel and the lean bog is gone and it starts better. Choke it, no throttle, kick it 4-5 times and it lights off. Let it idle with the choke out until it starts to idle down then take it off choke. After that, it starts with one or two kicks. Haven't gone back to the 42/152 with fresh gas, but with the 42/155 there is less spooge coming out of the silencer. I cleaned the drips off before my last hour long ride and it was still clean when I got back.

[Friedom]

Thank you. What's your elevation?

Fun Wheel Drive

[david]

430ft

[Friedom]

Whew. I'm starting around 2600. That'll make a difference.

Fun Wheel Drive

[david]

Most definitely.

[Friedom]

In starting to be concerned that there's something deeper amiss with this engine.
I was at a big annual dual sport ride event this weekend, and one of the guys brought a 91 KDX200. He was kind enough to let me ride it and I got to see what one that is working right feels like. They're fun! He had a custom 6" foam seat on it and a good 4" of rise on the bars. I couldn't even sit on the bike, lol, but riding standing was fun!

Now that I've seen a bike that just wants to keep running and is very forgiving, I'm concerned about what's going on with this 93 of mine that will only bump start, won't idle until it's warmed up, runs awful above half throttle, and generally seems unhealthy.
Reeds are stock, in good shape.
Top of airbox removed
New air filter.
Shiny new Fmf gold pipe
New oil(atf)
New piston
Head bolts just torqued to spec
42 PJ, 150 MJ, per SS recommendations running in the same location
Air screw 2 turns out
40:1

What's next, compression test?
I'll get it running and spray some carb cleaner around the carb to see if I have a leak.
I'm starting to be concerned there's a crank seal leaking. What else can I check?
I have steel valves on the way. Might have to dig deeper and split the cases (I don't want to) if I can't narrow down the problem to something external.

PO mentioned something about a weak spark, and the bike came with an aftermarket coil as well as the original. I guess I'll swap in that one and see if changes anything. I'll also try the coil from my 92. I've got lots of parts to swap out from the 92 if anyone has any ideas.

One thought: nothing is connected to the lighting wire, not even the regulator. Think this matters? I assume is a different circuit than the ignition circuit.

Fun Wheel Drive

[david]

You are correct, there is a separate lighting coil so that should not affect how it runs.

[Friedom]

Thanks. I'll probably get the 92 running. If it runs good, then I'll know the components are good and starting swapping them one at a time and see if anything changes, starting with the coil.

Fun Wheel Drive

[Friedom]

Update: the 92 build is running like awesome sauce. Now I have confirmed good components to swap out.
Today I tested the CDI and coil from the 93 in the 92. They're both good.
Also did a compression test and read a solid 150psi.
With a fresh plug against the head, I can see and hear a good solid spark.
Also discovered service stamps on the cylinder from 02 and 04. And there's a 1 stamped on top of the cylinder - does this mean bored 1 size over?
I guess all that's left is to check the wiring harness and Stator. But I've got a mag puller, so it shouldn't be too hard to swap them over, and inspect the wiring.
The 92 really cooks. I hope the 93 can keep up soon!

Edit: Found that the lighting coil is missing entirely.
Tested impedance on the ignition coil. Around 380 ohms, right within spec of 300-450 range listed in the manual(IIRC).

Both carbs work in the good bike too.

Starting to get narrow on remaining options.

Fun Wheel Drive

[SS109]

Might be time for a leak down test.

[Friedom]

I don't know if I remember how to do that - or ever knew on a 2t.

Fun Wheel Drive

[SS109]

I don't know if I remember how to do that - or ever knew on a 2t.

BTW, you can use pressure or vacuum. Just be careful with how much pressure or vacuum you use.

[youtube][/youtube]