Great mid to top end BUT

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Greatbrit
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Great mid to top end BUT

Post by Greatbrit »

Ok so. Kdx 220 2001. Bike idles fine.
I changed the stock pipe to a rev pipe. Took the snorkel off. Needle clip at 2 from top. 45 main. 40 pilot.
Bike kicks over after 2. Fuel mix is 40.1.

Excellent throttle response and power mid to top end. Bike stalls coming into corners. (Bog)
Crappy throttle accelerating and coming out of corners. Always on the clutch to keep revs up.
Float level good. Spark plug good.
Shall i go leaner on the pilot to a 38?.
Please help
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Julien D
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Re: Great mid to top end BUT

Post by Julien D »

Pilot is not going to make much difference over 1/4 throttle or so. Try raising the needle a bit. With the rev pipe and the snorkel removed it's going to breath a bit better. You may be starving it of fuel.
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cornishwrecker220
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Great mid to top end BUT

Post by cornishwrecker220 »

I found that the rev pipe on my 220 shifted the torque curve & took away a little of the bottom end ( I changed to the "woods" pipe with better results ...
Try placing the needle to the 4th position first .... Then try the 3rd position but with a 148 main jet & see how you go .
I find the 220 jetting a little more sensitive due to the porting .
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Julien D
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Great mid to top end BUT

Post by Julien D »

cornishwrecker220 wrote:I found that the rev pipe on my 220 shifted the torque curve & took away a little of the bottom end ( I changed to the "woods" pipe with better results ...
Try placing the needle to the 4th position first .... Then try the 3rd position but with a 148 main jet & see how you go .
I find the 220 jetting a little more sensitive due to the porting .
You may be the first person I have heard say that they actually like the woods pipe better for the 220. Interesting. General consensus over the years has been woods pipe for 200, rev pipe for 220.
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cornishwrecker220
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Great mid to top end BUT

Post by cornishwrecker220 »

Pipe was actually a Pro Circuit platinum 2 ( pretty much the same as fmf desert/Rev ) I ride tight single woody trails & gnarly goat tracks...the power band on the 220 is narrow & falls flat quite quick , I found the platinum/Rev pipe only made it run out of puff quicker but it did pull stronger in the mid range . , perhaps if I had taller gearing it may of helped with staying power but tbh the 220 is a real woods bike with great bottom end & that's what I love so much about this bike ....I just didn't like what the PC did to the power curve .
Greatbrit
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Re: Great mid to top end BUT

Post by Greatbrit »

Julien D wrote:Pilot is not going to make much difference over 1/4 throttle or so. Try raising the needle a bit. With the rev pipe and the snorkel removed it's going to breath a bit better. You may be starving it of fuel.
you mean raise the needle to the top (1st position)?.
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Great mid to top end BUT

Post by cornishwrecker220 »

Raising the needle means lowering the clip position toward the sharp end , thus raising the needle in its seat , in turn this will richen the mix of fuel.... The 220 needle is half a clip richer than that of the 200 so try the middle clip & see how it runs....compare it to the fourth position & see if it runs better or not, you will find the bike will blubber a little more on low revs but it won't harm the motor ....maybe a little more spooge out of the tail pipe.
Greatbrit
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Re: Great mid to top end BUT

Post by Greatbrit »

ok. i did lower the pilot to a 38 and the bike is a lot crisper . it also idles better when warmed up. needle is still second from top. when i brake hard into a stop or a corner she still wants to die though. Should i lower the needle still or go up on main jet? thanks
Greatbrit
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Re: Great mid to top end BUT

Post by Greatbrit »

Greatbrit wrote:ok. i did lower the pilot to a 38 and the bike is a lot crisper . it also idles better when warmed up. needle is still second from top. when i brake hard into a stop or a corner she still wants to die though. Should i lower the needle still or go up on main jet? thanks
Also i dont want to run the bike too lean to cause damage. could i run change the fuel mix to counter it. im at 40.1 at the mo .
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Re: Great mid to top end BUT

Post by jjavaman »

Mine was doing that when I first got it, turned out the fuel valve in the carb was stuck. The plunger was not moving, I pressed it down a few times and it's been working ever since. It's worth a try.
97-220 with a PC pipe. 2015- RB carb and head mod
Greatbrit
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Re: Great mid to top end BUT

Post by Greatbrit »

jjavaman wrote:Mine was doing that when I first got it, turned out the fuel valve in the carb was stuck. The plunger was not moving, I pressed it down a few times and it's been working ever since. It's worth a try.
Yes the fuel valve works fine. im just wondering now if my jetting is too spaced out as in is it odd to have a 38 pilot and 145 main.
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Re: Great mid to top end BUT

Post by John_S »

i wouldn't worry about the 38/145 spread. Mine is 40/145 and could run a 38 with the air screw set richer. When it comes to jetting, not wanting to go too lean on a circuit means you'll never know what too lean is and likely will be too rich. Rich is safe though. I'm not saying take it out for for a day too lean. Too lean is noticeable and a quick 1 minute test ride (fully warmed up) with one size too lean main, one clip too lean needle, or 1/2 turn too lean air screw isn't going to blow it up. If it's lean it will act like its out of gas or start pinging at which point you LET OFF and just cruise back to your tools and make the next change.

I think Julien and cornishwrecker had the best advice. Richen the needle (raise the needle=lower the clip) one clip by going to the third clip and see what happens. It could be starving for fuel with the flow of the new pipe. I would've tried that first because sometimes all it needs is one clip to make all the difference. If you're bike idles great and runs good at 0-1/4 throttle it's time to mess with the needle.

Best thing to do would be to follow the jetting guide. Get it good 0-1/4 throttle on the pilot, THEN 1/4-3/4 on the needle, THEN wide open on the main, one thing at a time and no skipping around. Don't change your fuel ratio to try to fix the jetting.

How many turns out is your air screw? Did it run great right before the pipe swap and that was the only change?
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Re: Great mid to top end BUT

Post by John_S »

The best quick test for jetting that I know of is all started with cruising in third gear with the throttle 1/8 or so open.

Pilot jet- if it cruises along no matter how long you hold it there you're good, if it slows down and loads up your rich, if it sounds like it's running out of gas or pinging you're lean.

Needle- roll onto 1/2 throttle. If it picks up smooth you're good, if it crackles or stutters and doesn't clean up by the time you get to 1/2 throttle you're rich, if its down on power, sounds like it's running out of gas, or pinging you're lean.

Main- third gear cruising along like the pilot and needle, whack the throttle wide open. If you have a face full of handlebars and it wants to flip over backwards its perfect, if it crackles and stutters you're rich, if its down on power, sounds like it's running out of gas, or pinging you're lean.
Greatbrit
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Re: Great mid to top end BUT

Post by Greatbrit »

It ran ok with the stock pipe but still died when hot at idle.
i put tbe rev pipe. and power core silencer and boysen reeds in. the air screw is about 2 turns out. needle 2nd clip. throttle response is pretty good right the way through now. it was always good from mid to full anyway.
Thanks for all the help guys. Bike needs a good run and will post results.
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Julien D
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Re: Great mid to top end BUT

Post by Julien D »

Greatbrit wrote:ok. i did lower the pilot to a 38 and the bike is a lot crisper . it also idles better when warmed up. needle is still second from top. when i brake hard into a stop or a corner she still wants to die though. Should i lower the needle still or go up on main jet? thanks
Your pilot jet has very little effect on anything above idle. For the mid range circuit where it seems you are having issues you need to look at the needle and the main jet. Since you have plenty of room to play with the needle, drop the clip down one notch to raise it up, and see what that does. If it's improved, go another notch. If that does not help, we need to look at the overall jetting. Bog is usually lean, blubbering / stumbling is usually rich.
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david
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Re: Great mid to top end BUT

Post by david »

Julien D wrote: Your pilot jet has very little effect on anything above idle.
The pilot is EVERYTHING between 0-1/4 throttle and it continues to feed the engine through the entire range. So saying it does little above idle is incorrect.

Greatbrit, in your very first post you say float level=good. If it idles good and has good throttle response, but is dying when braking or going into corners, I would look at the float level again. It sound too high. I know all the specs say 16mm+-, but at 16mm my float is resting on the carb and can't go any lower (when the carb is upside down). I had to adjust it to 17.5mm to see that it still has some movement available to depress the spring loaded center pin of the fuel valve.
'81 KDX 175
'90 KDX 200
'07 Vulcan 2000 Classic LT (totaled 4/25/15)
'82 Honda GL500 (sold)
'96 ZXi 1100 JetSki
'98 STX 1100 JetSki
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Julien D
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Re: Great mid to top end BUT

Post by Julien D »

david wrote:
Julien D wrote: Your pilot jet has very little effect on anything above idle.
The pilot is EVERYTHING between 0-1/4 throttle and it continues to feed the engine through the entire range. So saying it does little above idle is incorrect.

That is true, obviously, but the overall effect at wider throttle openings is minimal as compared to the MJ. If the bike idles well and has crisp response at low throttle with a considerable bog when cracking the throttle under load (as described here), I would still suspect incorrect needle setting or main jet. My primary goal with that statement was to try to shift the focus off the pilot jet, because I don't think that's his issue here.



Greatbrit, give this a thorough read


http://www.kdxrider.net/forums/viewtopi ... 105&t=1156
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david
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Re: Great mid to top end BUT

Post by david »

Julien D wrote: My primary goal with that statement was to try to shift the focus off the pilot jet, because I don't think that's his issue here.
I agree
'81 KDX 175
'90 KDX 200
'07 Vulcan 2000 Classic LT (totaled 4/25/15)
'82 Honda GL500 (sold)
'96 ZXi 1100 JetSki
'98 STX 1100 JetSki
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