Need Help! Tuning issue 98 KDX200

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zepplin153
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

Karl, One other thing that may be useful, It flattens out right at the top of mid range. Never even makes into high end. Its like as soon as the power band hits it goes flat.
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Need Help! Tuning issue 98 KDX200

Post by Julien D »

It does take some time after a new piston for the rings to seat, however, it shouldn't be totally flat up top. I would still double/triple check the KIPS valves, and pick up a 155 main.
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

OK,
I have an update:

I raised the c-clip on the needle all the way to the top and it made a huge difference. Its not flat any more. But it runs rough all throughout range (even idles rough). I followed the jet sticky and I had to spin the air screw out more than 2.5 turns to get it to idle well. I am picking up a 155 main this weekend.

Now I am left with a few questions:
1. will I likely need to change the needle i get the new main?
2. it struggles to idle and runs rough all throughout, but i am getting up in RPMs now, so can I likely rule out PVs?
3. based on the pilot jet test should I get a smaller one in addition to my main. or will I need to test the pilot again once I change the main?

By the way, I am really thankful for the replies. I am learning a lot and this will certainly help me out on the trail once its all set right.
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rbates9
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Need Help! Tuning issue 98 KDX200

Post by rbates9 »

Have you checked the tank valve for good flow? It might be worth making sure that the gas flow from the shut off is good.
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Need Help! Tuning issue 98 KDX200

Post by scheckaet »

Just to confirm:
sitting on the bike, the RIGHT subvalve has the groove on top and goes with the rod that has the Oring.
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Need Help! Tuning issue 98 KDX200

Post by KarlP »

I was worried that you had 10 minutes on this new motor, not an hour. You are well past rings seating.

It sounds like you are on the right track
Now I am left with a few questions:
1. will I likely need to change the needle i get the new main?
2. it struggles to idle and runs rough all throughout, but i am getting up in RPMs now, so can I likely rule out PVs?
3. based on the pilot jet test should I get a smaller one in addition to my main. or will I need to test the pilot again once I change the main?
Your needle does not have to change. If you mean clip position, then yes. I'd go back to mid way.

Still not sure about the PV's but it is looking better

Yes and Yes. There is some overlap between main size, needle clip position and pilot size.

Are you running the stock silencer? I had one of those get half plugged up on me. I did not realize it until after a rebuild.
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

yeah silencer is stock. and we have 5-star mouse hotel in our garage. I will check.
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Need Help! Tuning issue 98 KDX200

Post by KarlP »

Funny story.....

I had been feeling my 220 was a bit down on power. The change is gradual, it had been at least two years and many hours since I had done anything to that motor.

I had RBD do my head and carb while I did a new piston and rings.

I put it all together and it would not go at all. Ron had supplied a 155 main, I got it down to a 140 before it would run right at all.

I called Ron on a Sunday afternoon and he asked me to pull the seat. Nope, no rag in the air box. He had me pull the air cleaner just to be sure. No rag in the carb. He could hear the bike over the phone and said rev it up a bit and look at the exhaust. It was as obvious as could be at that point, my exhaust stream looked about like smoke curling off a cigarette.

I put a spare silencer I had on and that bike flew!

It was a pretty expensive way to realize my silencer was plugged.
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

very funny story! A bikers life for me right?

Well my silencer seems to have decent flow but I am going to check it again tomorrow. when you talk about your "cigarette" smoke, was that at idle or even when you reved it up?
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Need Help! Tuning issue 98 KDX200

Post by KarlP »

At idle.

It wasn't much better revved. That sucker was stopped up.

Too many miles of single track, I guess.
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

I think everyone is right about the PV's. I am back to them. But, i cant get a good pic of the valves through the exhaust to show. does anyone have a good pic I could look at as a reference (i cant find one).

But it looks like one sub valve is part way closed.

I owe everyone an apology if it is PV's. I was just very resistant to the idea. I wanted it to be Carb.
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Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

scheckaet wrote:Just to confirm:
sitting on the bike, the RIGHT subvalve has the groove on top and goes with the rod that has the Oring.
The manual I have reads: "the left sub valve has a groove and the right exhaust valve rod has an O-ring for identification."
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Need Help! Tuning issue 98 KDX200

Post by Julien D »

Yup, sounds like you got the backwards manual. You'd be able to tell with the exhaust removed, and the KIPS actuator held to the OPEN position, the slots in the subvalves will not line up with the ports correctly. Won't do much good that way! When you install them, pay more attention to the position of the subvalves as viewed through the exhaust opening as opposed to the timing marks on the valves. When holding the gear to the full open position, the slots in the subvalves should be lined up with the exhaust port openings.
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

Yeah, I checked this morning. Looking in there when the valves are in closed position the sub valves look like they are open. and one looks partially closed. and when I open them (turning the gear) they close. Waa waa waa waaaaaaaaaa.

So those sub valves should be closed when the valves are in closed position (like I should see the back side of the subvalves and not the grooveed or ported side of them)?
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

for anyone searching this problem in the future I found a great source for PV timing.
http://www.thumpertalk.com/topic/657765 ... to-kdx200/
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Need Help! Tuning issue 98 KDX200

Post by Julien D »

Yup. Seen that before. Sean did a great job with it.

I guess i need to contract someone to put us one together for here. I can do the E series one soon, when I re-assemble my engine. Want to snap some pics of yours for the H series edition?
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

I would love to. let me know what pics you might want and I will do my best. I will help any way I can! I will be working on the PV's tonight. I am leaving in a few min. anything specific you want me to shoot?
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Re: Need Help! Tuning issue 98 KDX200

Post by Julien D »

Just installation and proper timing pics, along with something to illustrate the difference between the left and right valves.
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

OK,
Sorry bro. No pics. couldn't focus to get any quality pics. I only have a crappy camera.

But, I have some interesting news. Got the engine out, swapped and aligned all PV's, and got it back in. They were in ass backwards. I made for absolutely sure they were perfect before I put the engine back. The sub valves were closed when in the resting (idle position) and they were open in the full throttle position. They moved in unison. It was perfect.

BUT its stil not right up in the top end of the RPM.... EXCEPT, I turned off the gas and right before the bowl emptied, BAAAM It ran like a Million Bucks and then died. So Its right I just got to get my fuel right.

I have ordered a step down in the main and pilot (45/155). but after this incident I think I may only need to adjust my float height.
Should I adjust my float height down to reduce the amount of gas in the bowl? And, How much should i adjust it?

It Never Ends! I cant wait to get this thing dialed in. :mad:
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Re: Need Help! Tuning issue 98 KDX200

Post by Julien D »

When you lean the bike over to the left does fuel leak from the overflow? I doubt adjusting the float is your answer. Jets will help.
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