No midrange or top end

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KDXMainer
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No midrange or top end

Post by KDXMainer »

Ok my last question of the day. I bought a 2006 KDX200. The previous owner smashed up the expansion chamber(header). I have never ridden a KDX before so I have nothing to compare this bike to. The bike seemed a little wimpy at first but once I got on the tight trails I had a blast with it. My other bike is a 2011 KX450 wheelie machine powerhouse. But I have to admit I have never had more fun on a dirtbike in my life(I'm 53) than I did on this bike. It is the closest thing to a trials bike you can get but it has a seat.

So I ordered the FMF knarly woods pipe and a new no toil air filter. After installing it and taking it for a test ride I was disappointed. The starts right up idle's fine. If you rev it it reeves right up with no hesitation what so ever. But the bike won't wheelie at all. Has no hard pull. It just tacks right out but there's no muscle. I felt like I was riding a little kiddy 100 or something.

After reading all the success stories I know this can't be running right. I'm 6'1" 250 pounds. I'm in southern Maine so pretty much sea level. It's 70 degrees. The bike seemed to run better with the smached stock pipe.

Today I unscrewed the round kips cover and that turned fine when reving the bike. I checked compression and it was way up ther over 160 with just a few kicks. I pulled the carb and the needle was on third clip. The main jet is 160 and the pilot is 48. FMF recommends these or the lower 155 45. Would switching to these make that much of a difference? Should I order those and try them? Also the plate between the carb and head says V Force reeds so I assume those have been changed and that's what's in there. Should I unbolt those to see if reeds are broken? If not should I change them to a different brand? Would removing the snorkel and puting a new plug in make all the difference? The plug looked ok. Need some input for these questions. Thanks Mike
2006 KDX200
1998 KDX220
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Re: No midrange or top end

Post by KDXMainer »

Anybody?
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Re: No midrange or top end

Post by KDXGarage »

It could be a few things. Since you have a 2011 KX450F, maybe you got spoiled on power. Have you adjusted the air screw?
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KDXMainer
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Re: No midrange or top end

Post by KDXMainer »

Ya I thought about that. Wish I had another KDX to compare it to. Still 2nd, 3rd,4th.... Nailing the throttle and pulling on the bars and getting nothing just can't be right. The air screw is 1 and a half turns out. Also why is there a hole in the bottom of the air box? Can I plug that? I wouldn't want water and mud coming up threw that hole.
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1998 KDX220
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Re: No midrange or top end

Post by KDXMainer »

Is the 160/48 jets make it run leaner or richer? What size jets did this have when it was stick?
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Re: No midrange or top end

Post by KDXGarage »

It is a drain for water in case it gets splashed in there.

MAN. I guess comparing the two is kinda funny on mechanics.
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Re: No midrange or top end

Post by KDXMainer »

Figured it was a drain. Would rather have hose than that big hole. Would you switch to 155/45 jets would that make a difference? Can I unbolt that intake housing to look at the reeds and just bolt it back up?
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Re: No midrange or top end

Post by KDXMainer »

I'm not gonna take the intake housing off. I looked in there and it's nothing like my snowmobile reeds. It's just a thick horizontal piece and two thin vertical pieces then a screen above that a screen below . Nothing like a snowmobile read. Again going down to a 155 45 jets give me the midrange it should have?
2006 KDX200
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Re: No midrange or top end

Post by jeswinehart »

I would recommend a leak down test on crank seals before getting to deep into jetting work.
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Re: No midrange or top end

Post by KDXMainer »

I doubt it's crank seals. I've found that it's usually something simple. I'm just gonna clean the carb, put a new plug in it and remove the rubber snorkel. If it doesn't improve I'll bring it to the dealer and let them ride it and see what they think. Again does anyone think going down to 155 45 would make it run better?
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No midrange or top end

Post by jeswinehart »

Yeah man,,, I sure hope it is as simple as jetting. As far as what numbers to try,,,, ???
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Re: No midrange or top end

Post by ohgood »

lol it will never pull like a kx450... it's a woods bike not a full on mx.

jet it and you'll get smoother power, Ave a little bit more of it. remember, WOODS not power :-)
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Re: No midrange or top end

Post by doakley »

I dunno. My 220 lifts the wheel easily in 2nd and 3rd, never tried 4th. What size sprockets do you have on it? (Long shot)
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Re: No midrange or top end

Post by Julien D »

Definitely check that the kips valves are installed correctly and functioning correctly. Definitely run through the jetting. Woods pipe is intended for low end grunt. If you want a snappier top end, the desert pipe would be a better choice. Either is better than the stock pipe overall, though.
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No midrange or top end

Post by canamfan »

It's simple get the desert pipe. It really does make that much difference.
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No midrange or top end

Post by chippy »

I would try going richer on the jetting. When I switched from a Desert to a Woods pipe, I had to fatten everything up to get it to run right. I raised the needle and started going up on the main. I settled on a 160 MJ (up from a 152) and a 42 PJ (up from a 38). I am running a much higher altitude than you are. (3000'-6000' above sea level) You may need to go much richer yet at sea level. I thought the Woods pipe was a dog until I started re-jetting. It woke right up! I now like the Woods pipe better for my type of riding. We ride mountain single track mostly with an occasional trip to the desert during Winter. (Moab Utah or Arizona) The Woods pipe also fits my bike MUCH better and tucks up out of the way. I like it.
Oh yeah, I too have V-Force reeds and the top is off of the air box, Moose air filter. There should be a hose with a one-way flapper valve on the air box drain. That keeps the crud out and lets the water drain.
Let us know how your bike turns out!
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Re: No midrange or top end

Post by Julien D »

If you're running at 6,000' and need a 160, something is up. The only thing that would easily explain that would be compensation for an air leak. You should not need to go up from a 155.
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Re: No midrange or top end

Post by chippy »

Let me clarify.
3000' at valley floor, cool Sept. morning temps (25-45 degrees F.) Trips down south during winter (lower elevations) = 160 main jet.
Most of the riding is at mid elevation. I should have said 3000'-4500' above sea level.
There are some 5000'-6000' trails, but they usually go up, and right back down. I would have to lean out the jetting to ride these a lot. Especially since they are only accessible during the hot months.
My point was that a 160 mj at sea level with cooler Maine temps and a pipe may not be enough.
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Re: No midrange or top end

Post by KDXMainer »

I took the rubber snorkel out and messed with the air screw. The sprockets are 13/49 and I just put a 50 on it last night and am going to try it today. The bike still doesn't wheelie but I'm happy with it. I think I need to get rid of the stock silencer. Once I do that that might make the difference. I can't believe how many kdx' are for sale right now in my area. I can get a really nice one with a full desert pipe for 1300. I way overpaid for my bike. I think it's safe to say I won't be selling this anytime soon. The only way I'll get my money out of it is to ride it for 10 years. I'm still looking for a KX that I can steal the front end off of. I'm looking at a 2001 kx250 2 stroke. The plastic the seat all look the same. Will it fit on my KDX? Is there a better bike I should be looking for to use as a doner bike? Anyone on here live in southern Maine and want to ride? Thanks Mike
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1998 KDX220
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Re: No midrange or top end

Post by KDXMainer »

I take back everything I said about this bike not having any mid or top end. Today this bike ripped!!! I did a couple things I hadn't done yet. I put a 50 tooth rear today. I chopped the throttle in 3rd and this thing scared the **** out of me. The front end went to 12oclock. It now wheelies anytime I want you just have to nail the throttle twice. I also held it wide open in 5th and 6th. It was like riding my old rm 250 . The back wheel started coming up beside me. I couldn't be more happy with this bike. Who needs the rev pipe. And I still have the aftermarket silencer, the carb mod and the head mod to look forward to. I might even sell my 450 and get another one of these. Loving life... Today anyways.
2006 KDX200
1998 KDX220
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