08 450 exc

[klxguy 0]

I am not sure if the jetting is right on my bike. I have put about 5 tanks of gas through it and am getting only 60 miles to reserve with the stock tank. When warm the bike is hard to start it acts like it is flooded, needing full throttle to start. There also seems to be a bit of a lag when giving it the throttle. Could this be a jetting issue? I don't really want to pull the Carb if it could be something simple. I clean the air filter after every ride.

[Joliet 0]

What does your sparkplug look like.

[racerbill 0]

JD Jetting, the kit fixed my 07

[bikeslut 1]

agree with Joliet... start with reading the plug... sounds rich, although there may be more to it than that

[christi20 0]

I have the same bike, and I get 90-110 miles on a full tank. Must be something wrong. Does sound like jetting to me, but I am no expert. RJ at All American did mine.

[TrophyHunter 15]

If u don't get it sorted out by Sunday, drag it down to the Tech Day.

[kellymac530 0]

Jd jet kit, but dont go with the recommended blue needle in the kit...use the red needle that comes in the kit in the 5th clip position down from the top and i think it was a 45 pilot and a 172 main...i used the heaviest rubber o-ring on the linkage and the accelerator pump spacer mod in the kit and my bike ran crisp and clean. I ride fairly heavy throttle and have gotten 120 miles before needing reserve, but normally about 110 mi.

you cannot just change the jets and get it right, it requires a needle cahnge and the linkage mods....remeber it is a street legal bike and needed crazy stuff to get the bike to pass smog and requires crazy fixes to get it to run like an MX 450...but it will

[bikeslut 1]

kelly touched on what I was getting at... the bikes are lean from the factory, to meet emissions...so

"fatten it up", right? well... no... you just dump a bunch of fuel in to the carb, and it gets burnt up without providing power. The needles help determine how the power is delivered... o ring mods, etc. Even fairly docile bikes like DRZs and XRLs need these mods done to get it normal, and they are still nowhere near a 450 KTM power wise.

So; if the previous owner just put in a bigger main, he only is making a different issue.

I would suggest getting a jd kit, and running down to trophy's get together... ask the right questions, and you MAY even have an appropriate jet assortment meet you there.

I would still look at the plug, cuz I will assume it is rich

[klxguy 0]

Here is a picture of the plug. I don't know much but it looks rich to me. Does the JD jet kit come with everything I need. Or do i need to order some other stuff.

[dirt dame 559]

Hmmmmm....somebody needs a nice manicure.

[kellymac530 0]

i dont see a pick of the plug....to properly check a plug, you cannot just take it out and look at it.

That will only tell you how it was running when you shut it off....like if it was idling or putting back to your garage.

The right way to check it is warm up the motor and ride it around, then do a full power pull and while at a strong throttle, kill the ignition. let cool and pull the plug this will tell you if it was lean or rich at rpm.

Bikeslut is right, just changing a jet does NOT necceisarily fix a lean or rich condition. it is much more about metering the rate the fuel is delivered and various throttle openings....thus changing the needle or...METERING needle is a very important part of jetting...

for 75 bucks i would order the JD jet kit. you can probably get the kit in by sat if you order it now and have it installed on sunday at TH's gathering....

if you ride primarily at lower elevations like OW you might want to use the blue needle...your best bet is to order the kit and it will give you the suggested settings...BUT CALL them for your specific application, they are very helpful.

I personally think plug reading is a tough art with todays electronic ignitions and and variable rate curves and horrible gas and ethanol and oxygenization..it is not like it used to be in my humble opinion but still a valid tool...im a seat of the pants tuner myself.

if your bike doesnt already have one...GET a gnurled knob air/fuel mixture screw....they are VERY sensitive to air adjustment and a pain to get to with the electric starter right under the carb....you NEED an adjustable screw for sure...i like my moose brand, but there are many options for 20 bucks ish.

i hope this helps a little

[kellymac530 0]

i see the pic of the plug now, and yes it looks rich and WET...if that came right out of the motor you are way out on something...

[bikeslut 1]

That does not look very rich to me... may just a bit; it's definitely not lean

kellymac; help a brother out... the kit comes with two needles, right? KLXguy... the kit won't include the o rings, I don't believe... that is a "trick" people use.

It'll normally come with a spring, some jets, two needles. You need to address everything at the same time.

That all being said; I've done this stuff on my DRZ and XRL, but never on a pumpkin... so I may be speaking out of my ass...

on the DRZ, to get it right; you replace all 3, and cut a hole in the airbox

on the XRL, you put a spacer under the needle, rejet and drill the slide.... each bike has it's shortcuts, and I don't really know that bike

[kellymac530 0]

yes the JD kit comes with the orings in 3 different thicknesses for different accelerator pump action...the kit comes with everything for that bike...

[klxguy 0]

Just ordered the kit.

[racerbill 0]

GOOD, that'll fix the problem.

[hobiee 28]

I cannot believe the dealer let the bike roll of the floor without setting it up to at least run correctly? Guess i am spoiled.

[Joliet 0]

Here is a picture of the plug. I don't know much but it looks rich to me. Does the JD jet kit come with everything I need. Or do i need to order some other stuff.

It does not look like it has been running rich to me. However it does look wet, which is never good. Is it gas or oil that is making the plug wet? When the bike us under a load, what color is the exhaust? Has it ever run well with the current setup? If it is just a hard hot start problem, and it bogs on quick acceleration, your AP might just be set so it is squirting way too much fuel. Your jetting might be perfect, I would deal with the accelerator pump first.

[bikeslut 1]

I cannot believe the dealer let the bike roll of the floor without setting it up to at least run correctly? Guess i am spoiled.

blame the EPA and CARB not the dealer... granted; some dealers will sort that out for you, but most won't (and feel they CAN'T)

it'll be ok- you ordered the kit; installation is pretty straight forward (not that I am a mechanic), and if you get it by Sunday, you'll have a lot of knowledgeable people around... they won't be helping you, they'll be drinking beer and cracking jokes, but they'll be around

[klxguy 0]

Here is a picture of the plug. I don't know much but it looks rich to me. Does the JD jet kit come with everything I need. Or do i need to order some other stuff.

It does not look like it has been running rich to me. However it does look wet, which is never good. Is it gas or oil that is making the plug wet? When the bike us under a load, what color is the exhaust? Has it ever run well with the current setup? If it is just a hard hot start problem, and it bogs on quick acceleration, your AP might just be set so it is squirting way too much fuel. Your jetting might be perfect, I would deal with the accelerator pump first.

Actually the first day that rode the bike it seemed to run perfect then after that the performance started dropping off. When I pulled the plug it smelt of gas.

[kellymac530 0]

If the power is dropping off, there is a slight possibility that you could have a valve issue...not likely on the Xc4 motor, their valves are rock solid, but if it came with say an exhaust valve set too tight, it could be tightening more as the motor breaks in causing the valve to stay open a bit dropping compression and killing power...

Easy to check the valves on those bikes...you already have the tank off likely, just pop off the cover and feeler gauge the rockers...use the method in the manual...i personally dont prefer the 1/6th method.

if a valve is tight, then check compression to make sure a valve is not hung open...do CT either way cant hurt...if there is any issue ktm has a warranty so have them fix it.

really check your carb for debris when you do your jet kit, i know its new, but in the build process i have seen plastic particles fom the tank or hoses get into the fuel system....

likely something simple

[paulmbowers 236]

use the method in the manual...i personally dont prefer the 1/6th method.

I realize you own a BMW now, but I have to respectfully disagree. As the rockers and the valve stems wear, they tend to cup on the rocker side, and mushroom on the valve side. If you slip a feeler gauge in between those surfaces, you'll get an inaccurate gap, and the feeler gauge is flat and does not bend to fit the mushroom/cup arrangement. In that case, the 1/6th method works better.

New, yes the feeler gauge.

[Joliet 0]

Out of adjustment on a valve will not make a plug wet with fuel. Bring it to the maint. day, it will get sorted out. Ken

[kellymac530 0]

HAHAHA fakey....i havent even gotten the bmw here yet and im already on the outs with you ehhh...

on the Xc4 motor fakey they use shim buckets, not adjustable rocker tips like the RFS motor you have.

Completely different animal, besides the bike is brand new...but on the Xc4 a feeler gauge is still more accurate...when you upgrade to a truely modern motorcycle fakey, then you can argue with me

OF COURSE IM KIDDING...no need for everyone to PM me what a jerk i am again

it is more than likely just the carb...but for the 15 minutes a valve check takes on an XC4 motor its worth a quick check...

[klxguy 0]

I will check the valves this Sunday. For the record, I bought the bike with 16 hours on it and I have put a little over 20 hours on it since then. Practically new but not quite. The baffles have been taken out of the pipe will that affect the JD Jet kit?