bad gas mileage & tailpipe seeping oil '97 kdx 200

[thefriends03]

any tips on how to cure awful gas mileage? i have a '97 kdx 200 with a 240 big bore kit. i know the change in bore cuts down on the gas mileage, but i am only getting about 30 miles (if i'm lucky) on a 3 gallon tank. jetting seems to test fine.

as for the tailpipe. i have an fmf turbine core ii that just seeps oil. i just repacked it the other day, hoping that would help. i am running a 50:1 mixture in it. again, the jetting tests fine right now.

any suggestions?

 

[adam728]

Tons of spooge and drinking gas like a big block Chevy? Jetting, jetting, jetting! Could be as simple as a high float level (bike will run rich, and dump fuel out the overflows while riding), or you may need to start right over and jet jet jet.

What jetting are you running now?

 

[thefriends03]

haha, yes. i am hoping it is the float level. i am in the process of getting that checked. main jet is a 145, pilot is a 42, needle is stock and clip is in highest position. i am at about 4500ft, and it was jetted last summer. main jet test results good. however, most of my riding is done in between 1/4-3/4 throttle. rarely am i ever wide open. i am wondering about the needle too. plug is turning up dark brown after a normal trail ride.

 

[whenfoxforks-ruled]

Crazy, seemingly jetting, spooge, and a 97? Replace the float valve and seat if applicable. A leak down test will confirm its not the bottom end seals. Then try and jet it. Who did the big bore?

 

[thefriends03]

kustom kraft out of glenwood springs, co did the big bore. the float valve and seat are in great condition. thanks for the help. keep pointing me in the right direction.

 

[digifox]

Wait what 30MPG?

Dude i wouldnt be complaining! its a 2-stroke with a 145 Main for Christs sake!

 

[thefriends03]

I wouldn't be complaining if it was 30mpg. I am complaining because I said I am getting 30 miles per tank. It's a 2.9 gallon tank, so that is about 10mpg. That is a problem.

 

[whenfoxforks-ruled]

Kustom Kraft, Danny Schunamen?

 

[thefriends03]

kustom-kraft.com. don't remember the name of who i dealt with.

 

[dmerc]

10mpg? DAMN!!! That doesn't even seem POSSIBLE!!

It can't all be going thru' that poor li'l motor! Gotta' be leakin' out the overflow, leaky tank, neighbor siphoning gas for his lawnboy?? :laugh:

 

[digifox]

I wouldn't be complaining if it was 30mpg. I am complaining because I said I am getting 30 miles per tank. It's a 2.9 gallon tank, so that is about 10mpg. That is a problem.

Oh...lol oops i mis-read that :whoa:

So about 10MPG, WHOA i dont think thats possible....
As dmerc Said

 

[mudpack]

Ten mpg sounds completely feasible in certain riding conditions. The fact that friends03 rarely uses full throttle tells me he probably is doing a lot of first- and second-gear riding; technical trails, mud, sand, hills, etc.
If the bike is running good...as he says it is...then jetting is good.

Friends0s, fill up the bike, then run the tank empty on fireroads/two-tracks/open country where you are in fourth- and fifth-gear 90% of the time. I'd bet a set of swingarm bolt caps your mileage will be double the 10mpg you are getting with your current riding.
I.e. there may be nothing wrong/out of the ordinary/unusual with your bike. :cool:

As far as spooge goes; it's a two-stroke. Spooge comes with the territory.

Mud

 

[whenfoxforks-ruled]

You can not "look" at the float valve, and figure its good. It gets replaced once a year, or when you have screwy jetting/spooge problems. Push the float up and it shuts off, nope, you replace the valve.

 

[kdx200 h1]

kdx 200 95

my kdx 200 95 goes thou the 12L tank in 60 ks on aftermaket fmf pipe. thats in third and four gear reving the snot out of the beast. in enduros and trail rides

gears 13/48

it leaks a bit out of the overflow pipe but hav been fine tuning the foat level to stop it from leaking.

if this helps...

 

[mudpack]

There is one correct float level, and it pertains to engine tuning, not to controlling spooge or carburetor leaks.
Adjust the float to the correct setting, and then take care of the other issues at their source.

 

[whenfoxforks-ruled]

There is one correct float level, and it pertains to engine tuning, not to controlling spooge or carburetor leaks.
Adjust the float to the correct setting, and then take care of the other issues at their source.

Very well put, I wish I could do that?

 

[dirt bike dave]

FWIW, I had a 240 big bore in an '84 KDX, and it used much more fuel than the stock motor, but I still got at 15+- mpg in normal trail riding after getting the jetting dialed in.

The big piston sucks in air at a much higher velocity through your carb - so it picks up much more fuel even with the same jetting. IMO, you will want to put in a leaner needle - maybe 2 steps leaner than your stocker. And see if you can find a leaner pilot, too.

A slide with 1mm more cutaway will also lean you out down low.

 

[sr5bidder]

wonder what the plug would "read" if you where to run 40:1 or 30:1

Also 145 main and 42 pilot are what we down here at 0-1000ft altitude are running with good cross the board results
4500ft is way up there

 

[thefriends03]

most of my riding is done in 3rd gear. i am not a really aggressive rider. i want to try a different needle. the next size needle that is leaner is a BGQ. that is just one step leaner. they don't make a longer one than that without going smaller on the diameter or changing the taper. not sure if that one step change is going to make a huge difference. as for the float valve - it works like a charm. no leaking thru it at all. thanks for the input and keep it coming.

 

[whenfoxforks-ruled]

wonder what the plug would "read" if you where to run 40:1 or 30:1

I do not believe, any "tight" engine, and jetted properly, would "read" any difference between 20:1~40:1. IMO. How it feels, and how long it lasts, another story. I did get an email back from Kustom Kraft, Tom Schunamen sold the company when it moved out west. And he bought it without the simons forks! Back in 81, new water cooled and plated 250 Honda's was not getting the life span I was figuring out of the top end. Tom punched out the bore and put sleeves in. It seemingly worked, but, I was never happy with the bike. Fast forward, I sure wish replating was mainstream back then? Its way to difficult/impossible to get the liner to match exactly to oem or better specs. And, the dynamics of the engine are compromised, IMO. Now I know its not an MX race bike, but, when you have shady issues? Look to the jury rigs and basics.

 

[josefmd]

wonder what the plug would "read" if you where to run 40:1 or 30:1

Also 145 main and 42 pilot are what we down here at 0-1000ft altitude are running with good cross the board results
4500ft is way up there

\

You have a 200 right? The main seems really lean at a 145. I have dropped mine down to a 150, and I ride at the same alt as you 900-1200 ft above SL. I am also running a 42 pilot, clip at #2, and I might drop that down to a 40, raise the lower the clip to #3.

 

[whenfoxforks-ruled]

\

You have a 200 right? The main seems really lean at a 145. I have dropped mine down to a 150, and I ride at the same alt as you 900-1200 ft above SL. I am also running a 42 pilot, clip at #2, and I might drop that down to a 40, raise the lower the clip to #3.

Not too hard to figure at all. There is no science to all bikes jetting being different? Well, there is one! Then you introduce variables: altitude, barometric pressure, temperature, inherent casting differences, FUEL, and not to mention the "mods?". Jetting IS easy! Done the basic method, and as long as the engine is mechanically sound. Sleeved or "eye candy ported", or NOT mechanically sound? Probably NEVER get it jetted properly. Good enough or better than it was, maybe?

 

[dirt bike dave]

He has a 240.

Overbore bikes often require leaner jetting, as they generate much more vacuum when sucking through the same size carb as a stock bike.

 

[whenfoxforks-ruled]

Yep, I have 2 buddies with EG big bores, and they run great on stock jetting. Stock they did not run good on stock jetting?