Low down torque

Got questions? We got answers....
Post Reply
RyanFury86
Member
Posts: 5
Joined: 01:32 am Jan 29 2014
Country:

Low down torque

Post by RyanFury86 »

hi all, my kdx seems to be lacking some low end power, say when i'm driving in 2 nd or 3 rd and you open the throttle it bogs down then jumps into power band, same when you gear it through power band, it will start bogging from 5 th then suddenly pick up. I've cleaned the carb but not sure on jet sizes, it's got a fmf fatty and power core 2 on it, airbox top is removed, filter seems a bit dirty and havn't removed the spark plug yet. i also just set the air jet to 1.5 turns from closed and float level is at 16mm. it's got a bigger sprocket at the back, but not sure about amount of teeth. it's got 4700 kms on the clock and starts without the choke and really little smoke on it. can you guys please give me input as to what to look at or change?
spl383
Supporting Member I
Supporting Member I
Posts: 143
Joined: 06:05 am Apr 02 2013
Country: United States
Location: Carrollton, TX

Low down torque

Post by spl383 »

What KDX do you have?
RyanFury86
Member
Posts: 5
Joined: 01:32 am Jan 29 2014
Country:

Re: Low down torque

Post by RyanFury86 »

it's a kdx 200, watercooled, in the range of 2000 -2004 model, I don't know where to check the year model
User avatar
bufftester
Platinum Member
Platinum Member
Posts: 3455
Joined: 06:03 pm Oct 31 2012
Country: USA
Location: University Place, WA

Re: Low down torque

Post by bufftester »

Has it been rejetted since the installation of the pipe and removal of the airbox lid? This is a very typical jetting issue.
avgKDXjoe
Member
Posts: 44
Joined: 11:40 pm Dec 02 2012
Country:
Location: Woods

Re: Low down torque

Post by avgKDXjoe »

Look at the head tube for year. There should be a sticker that will display the year. If it's not there look at the VIN that is stamped on the head tube. The tenth digit is the model year.
Y = 2000
1 = 2001
2 = 2002
3 = 2003
4 = 2004
5 = 2005
6 = 2006

I would put a clean air filter, new plug, and play with jetting before changing anything too dramatic.
'04 KDX 200
'01 KDX 200 (current project)
User avatar
Gotanubike
Supporting Member III
Supporting Member III
Posts: 898
Joined: 01:00 pm May 22 2013
Country:
Location: Ontario, Can

Low down torque

Post by Gotanubike »

Sounds like a pilot malfunction to me...did you double check that your pilot jet is free of debris?
1990 KDX200
Bike Profile -> http://www.kdxrider.net/forums/viewtopi ... 61#p136315
Suspension Overhaul(Shock+89-92 conventional forks) -> http://www.kdxrider.net/forums/viewtopi ... 15&t=15255
96'-98' RM125 Showa 49mm fork swap -> http://www.kdxrider.net/forums/viewtopi ... 04&t=16994
KDXrider world map! -> https://www.zeemaps.com/map?group=186158
avgKDXjoe
Member
Posts: 44
Joined: 11:40 pm Dec 02 2012
Country:
Location: Woods

Re: Low down torque

Post by avgKDXjoe »

I'll also suggest cleaning the petcock and try new fuel line. I had an O ring disintegrate in my petcock, the bike acted a lot like you are describing. It was just starving for fuel.
'04 KDX 200
'01 KDX 200 (current project)
ecojbr
Supporting Member II
Supporting Member II
Posts: 239
Joined: 09:16 pm Aug 04 2010
Country:

Low down torque

Post by ecojbr »

I would lean toward power valve stuck open
04 kx220 hybrid
03 kx 250
05 kdx 200
MCKDX220
Member
Posts: 109
Joined: 01:17 pm Apr 25 2013
Country: United States
Location: Roseville, CA

Re: Low down torque

Post by MCKDX220 »

RyanFury86,

1st of all let's start with where are you located ???

You gave the clue of being able to start w/o the choke.

If you live in a warm climate, that is somewhat normal.

If you live in a cold climate, that is not normal.

If you live in a cold climate, you are way to rich on pilot and would test backing the air screw 1 full turn to see if that helps a bit before going any further.

Michael
87 KDX200 / 02 KTM 520 EX/C / 87 XR 200 / 90 XR 200
RyanFury86
Member
Posts: 5
Joined: 01:32 am Jan 29 2014
Country:

Re: Low down torque

Post by RyanFury86 »

I stay in south Africa, freestate to be exact, pretty warm climate here. the petcock does not work anymore and leaks when you move it to the closed position, the feul line goes from the petcock to a normal open and close valve that was put into the line, I checked also no fuel filter in the line, the pilot jet I checked and that is a size 48, I cleaned the carb about 100 km ago as it was very dirty and also the float level was at 14mm which caused it to run out of fuel at wot, I changed that to 16 mm and also adjusted the pilot jet to 1.5 turns, I think it was at about 2 or 2.5 turns open when I got the bike. the kips etc all is in good working condition. i''ll take the carb off again tonight and clean the jets etc, also replace the plug and filter.
MCKDX220
Member
Posts: 109
Joined: 01:17 pm Apr 25 2013
Country: United States
Location: Roseville, CA

Re: Low down torque

Post by MCKDX220 »

You can service the petcock by removing the 2 screws and checking for debris and gunk that have accumulated around the rubber gaskets and concave washer.

If you are strapped for funds, I would recommend removing the petrol tank, drain tank and remove the petcock and clean it and put grease on the rubber gaskets before reinstallation.

I would use a Qtip (Cotton swab) and clear grease to clean up areas. Keep applying until you can not see anymore debris, or discoloring.

This should stop your fuel leak at the petcock.

If they are torn, time to replace them, there are several kits on Ebay, for gasket kit replacements.

Strain petrol through and old T Shirt before putting back in tank and think about getting an inline fuel filter.

Disassemble carburetor and spray carburetor cleaner in all the orificices and soak the main jet and pilot jet in carburetor cleaner for the recommended time.

Michael
87 KDX200 / 02 KTM 520 EX/C / 87 XR 200 / 90 XR 200
RyanFury86
Member
Posts: 5
Joined: 01:32 am Jan 29 2014
Country:

Re: Low down torque

Post by RyanFury86 »

Thanks for the input, I tested the airbox theory and made a lid from a icecream bucket and sorted all the problems out, nice low down torque, quick into powerband and much more smooth power. I ordered a airbox lid, seal and snorkel and will be putting it back on, never liked the idea of it being open. thanks again for all your help
Post Reply