suggestions on jetting a 2004 fe450

timoteo · Apr 27, 2009

I have just purchased an 8 hour old '04 FE450. Bike was purchased new in '07, ridden several times, and then garaged. At a minimum, the pilot circuit is plugged. So the carb is coming off.While it's off,should I rejet?. Based on the posts I've read, there seems to be little consensus on what the best jetting spec is. I'd like to get your opinions/beliefs on the best recipe.

Northern California
1000 - 8000 feet
30 - 90 degrees F.
Always low humidity

First though, some of my thoughts:
Could the manufacturer, with their countless hours of testing and knowledge get the jetting specs so wrong?
If I owned/managed Husaberg, I'd deliver a product with the best possible performance, knowing the benchmark is perfection (honda crf's).

I own a 525exc and 400exc. For the most part, there seems to be consensus on what works for the KTM: stock needle with clip lowered, OCEMN, and JD Jetting kit. I've tried all. All work well. The stock needle seems to be the least affected by altitude changes.The E taper smooths the power delivery of the 525. The only other jet that gets changed is the pilot. But I don't know anyone who changes the air jets. As far as I know, the KTM's come jetted lean in order to meet California/USA emissions requirements.

So now some questions:
Is there a secret to extracting the carb from the bike?
Is there a way to access the top and bottom of the carb without removing it?

Now, your jetting recommendations please.

Thanks,

Timoteo

cypher · Apr 27, 2009

Any manufactures no matter what bike tends to set the jetting on the safe and average side so that it covers all. whether they are crfs or whatever.

always find getting the carb off a pain in the ***. tend to pull off the tank then rotate the carb. you can just about do it with the tank on but if your in the shed you might as well pull it.

ned37 · Apr 27, 2009

you need to pull the starter before you can get the bowl off.
i ran my '04 with stock jetting at those altiitudes for a year. only thing i did different was put in an adjustable pilot fuel screw. ran sluggish at 8000 though.
these bikes were jetted weird for emissions. they ran a lean needle and overcompensated with fat pilot and especially main.
there's a lot of work in the pages of this site. do some searching.

Johnf3 · Apr 28, 2009

timoteo said:
Northern California
1000 - 8000 feet
30 - 90 degrees F.
Always low humidity

First though, some of my thoughts:
Could the manufacturer, with their countless hours of testing and knowledge get the jetting specs so wrong?
If I owned/managed Husaberg, I'd deliver a product with the best possible performance, knowing the benchmark is perfection (honda crf's).

Thanks,

Timoteo

Please put in for management of Husaberg then, because then it sounds like you would develop magic jetting that worked at all elevations and temperatures. I can't believe the Husaberg engineers couldn't do that (oh wait they can, it's called EFI--maybe you should check out an '09)

Back to your question. Since you prefer the perfection of Honda, do a seach or two by member name Buzzard. He set up his Husaberg based on Honda jetting, and his bike runs very well (I've ridden it). He has a few very detailed posts on what he did if you want to go that way.

buzzard · Apr 28, 2009

Timoteo, The manufacturer has to get by the EPA and other air sniffing agencies. I have a 2006 FE450, and sought to improve the jetting. I did look at how Honda jetted the CRF450R, as well as the CRF450X. The X model has to meet EPA specs, whereas the R model does not. I jetted my bike similar to the R, and after several slight mods, have a bike I'm happy with. From the Honda, I used the needle, acc. pump diaphragm kit, float bowl with bleed jet, and basic jetting. The answers to why are in an thread I named "$40 FCR Spruce Up", as I recall. Good luck!

timoteo · Apr 28, 2009

RE: Re: suggestions on jetting a 2004 fe450

Hi John,

How about responding with what jetting specs you use, and what characteristics they provide? And, why you changed the jetting from stock?
My goal is to have a bike that runs properly. While I've got the carb apart during recommissioning, I hope to make any changes that will enable me to meet my goal.

Thanks,

Tim

ned37 · Apr 28, 2009

RE: Re: suggestions on jetting a 2004 fe450

tim, take the time to do some searches as buzzard says. review the owners doc located at the left margin.

Johnf3 · Apr 28, 2009

Re: RE: Re: suggestions on jetting a 2004 fe450

timoteo said:
Hi John,

How about responding with what jetting specs you use, and what characteristics they provide? And, why you changed the jetting from stock?
My goal is to have a bike that runs properly. While I've got the carb apart during recommissioning, I hope to make any changes that will enable me to meet my goal.

Thanks,

Tim

I'm running a custom needle, splits the difference between the D and the E tapers--3rd clip usually. Stock pilot, limited AP squirt (Honda Diaphram) and around a 168 or so main jet, plus or minus depending on elevation. Very near perfect for 3-4K feet.

Oh, why I changed the jetting from stock? This was a set up I ran on a KTM RFS before I saw the light, and it transfered over very well.

suggestions on jetting a 2004 fe450

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