Jet kit for 2003 crf230f

[lawnandorder]

i have been looking online to get a jet kit for this bike, but all i can find is for 06-on, anyone point me in the right direction

[230Fstroker]

This is what I did.

2007 CRF230F7

120 main

48 pilot

03-05 needle clip 4th from top.

(by the way the stock needle for 2007 has 2 notches, with the clip on the second notch it's one notch higher than the 4th notch on the 03-05 needle.)

t-handle idle screw.

Check this link out.

http://rickramsey.net/CRF230Fcarb.htm

[VortecCPI]

230FStroker has recommended exactly what I would have.

Part Numbers:

+ 16016-KCY-670 – Slotted mixture screw ($11.87)

+ 16012-KPS-901 – 2003-2005 needle ($18.15)

+ 99103-KPS-0450 – 45 Pilot jet ($7.91)

+ 99113-GHB-1200 – 120 Main jet ($5.37)

Most of the time a 45 pilot will work just fine. It seems the later models, like mine, like the 48 pilot. If you're riding high you can use a smaller main jet.

You MUST remove the intake restrictor of the 120 main will be way too rich.

BE SURE TO CHECK FOR PROPER FLOAT LEVEL WHILE YOU'RE IN THERE!

Edited February 16, 2012 by VortecCPI

[230Fstroker]

230FStroker has recommended exactly what I would have.

Part Numbers:

+ 16016-KCY-670 – Slotted mixture screw ($11.87)

+ 16012-KPS-901 – 2003-2005 needle ($18.15)

+ 99103-KPS-0450 – 45 Pilot jet ($7.91)

+ 99113-GHB-1200 – 120 Main jet ($5.37)

Most of the time a 45 pilot will work just fine. It seems the later models, like mine, like the 48 pilot. If you're riding high you can use a smaller main jet.

You MUST remove the intake restrictor of the 120 main will be way too rich.

BE SURE TO CHECK FOR PROPER FLOAT LEVEL WHILE YOU'RE IN THERE!

I notice my bike was alittle rich until I took care of the restrictor and added the UNI filter.

Good luck with your jet kit and do your research for your own situation. ?

[230Fstroker]

? There's plenty of jetting info on here, do a search. Edited February 16, 2012 by 230Fstroker

[Professor XR]

You MUST remove the intake restrictor of the 120 main will be way too rich.

BE SURE TO CHECK FOR PROPER FLOAT LEVEL WHILE YOU'RE IN THERE!

Hey Vortec, Mike Coe told me not to mess with the stock airbox, so I left the snorkel in and the bike has been fine with his jetting and the stock airbox/air filter. Should I reconsider and try uncorking the airbox a bit?

[VortecCPI]

Mike probably meant not to mess with the airbox itself (i.e., Perimeter). In other words, don't bother cutting open the top of the box like MXers do or adding a bunch of holes on the sides. The stock 230 just doesn't need all this extra area for air flow.

I just can't imagine Mike recommending you leave the intake restrictor installed but you should check with him to be sure. All his dyno work I've read about was done with the intake restrictor and exhaust baffle removed.

You won't hurt the bike by leaving the intake restrictor in with a 120 main jet. It will just be too restricted and rich at the top end and you will give away power.

Double check with Mike. If he says something different, please let us know.

[Professor XR]

Hey Vortec, I dug up a bunch of emails from last year when I was talking to Mike about jetting. He said this about the airbox:

"I did airflow and airbox/filter tests when doing my development years ago. Don't waste your time with the airbox. The stock box and air filter will flow more than required for my full race 250cc engines. Many claim to experience significant gains by removing the screens and making changes. IMO, its not necessary to mod the airbox in any way."

I've got a lot more info from Mike about jetting that I can post in a separate thread if anyone's interested, but he's the main reason I left my airbox snorkel in.

Edited February 16, 2012 by Professor XR

[VortecCPI]

I still don't believe the airbox snorkel should be left in. I assume by "snorkel" you mean the plastic device that's wedged inside the rubber rim around the opening at the top. Check out this quote from Mike:

"This is what I recommend for your bike and all others with stock engine with exhaust baffle and airbox snorkel removed. I ride my stock bike from 0 - 6500+ elevation with no changes in jetting between the desert and mountains.

120 main jet (used to be 132)

45 pilot jet

Stock needle ('03-'05) with clip in fourth groove from the top

Accessory needle ("power-up") with clip in fourth groove from the top.

I have found that for low elevation riding, as in the desert, the "power-up" needle adds a touch better performance, but looses that same touch when riding in higher elevations of 4000 and up."

From reading what you posted I am convinced he is talking about the airbox itself. This is why he mentions the screen and air filter. Any restriction at the intake side of a carb will increase circuit signal and richen the mixture. It has the same impact as a partial choke setting.

I'd really like to see what you have posted in a new forum. I'm sure it will be very good reading.

Edited February 16, 2012 by VortecCPI

[VortecCPI]

I did a very quick calculation. A 230cc engine at 95% efficiency running at 9750 RPM moves 36 CFM of air. The openings in that snorkel are 22mm x 25mm. That yields an inlet velocity of 34.55 MPH. That's pretty fast and I'll bet the pressure drop across the edges of the openings along with a 90-degree turn in that restrictor is quite a bit.

The intake velocity with the restrictor removed is about 6.5 MPH. Twice the velocity is roughly four times the pressure drop. My old XL125 had a much bigger opening in the top of the air box.

Maybe I'll get by buddy to model it using STAR-CCM+ (CFD)...

Edited February 16, 2012 by VortecCPI

[Professor XR]

I did a very quick calculation. A 230cc engine at 95% efficiency running at 9750 RPM moves 36 CFM of air. The openings in that snorkel are 22mm x 25mm. That yields an inlet velocity of 34.55 MPH. That's pretty fast and I'll bet the pressure drop across the edges of the openings along with a 90-degree turn in that restrictor is quite a bit.

The intake velocity with the restrictor removed is about 6.5 MPH. Twice the velocity is roughly four times the pressure drop. My old XL125 had a much bigger opening in the top of the air box.

Maybe I'll get by buddy to model it using STAR-CCM+ (CFD)...

Wow, you know your stuff too! Yeah, by snorkel I mean that rectangular plastic insert that fits into the rubber gasket under the seat. I was assuming he meant leave that in when he said not to touch the airbox at all, but what you wrote also makes sense, and kind of contradicts what he wrote to me. He probably was writing with the assumption that I had removed it. I've got the seat off now since I'm doing some wiring, so I'll take the snorkel (restrictor) out and see how the bike performs next time I ride. My theory is that it can't hurt anything, right?

Edited February 16, 2012 by Professor XR

[VortecCPI]

As long as your float level is properly set you should be right on with Mike's 120 main recommendation.

I always inspect the float level externally as a sanity check. Replace the black bowl drain line with a clear one and loop it up past the top of the carb. Open the bowl drain screw and the gas will climb up the line to the same level as that in the bowl. It should be just below the bowl gasket. If it's low be sure to set the float level to 12.5mm or 1/2".

Many people overlook float level - It is very important for proper metering.

[lawnandorder]

ok, but is a kit for a 2007 going to work on a 2003? because dynajet only lists for a 2005-up,,

[VortecCPI]

Our 2004 and 2009 are identical except for the needle and maybe air bleed sizes. The parts from Dynojet should work but I suggest you just buy the two Keihin jets as the 2003 doesn't require a needle change.

Edited February 18, 2012 by VortecCPI

[crf-500]

here in canada a honda part number is a shure sighn your about to be severly riped off.sudco or carb parts wharehouse have proven to be the way to go. so far know i want an 03/05 230needle jet will anyone tell me the numbers on the needle ?and no i dont want the honda part number. for years i,ve often thought that a big wide ranging numericley progresive colection of needle,main and pilot jets to have on hand at my shop would be awsome to own. the local shops have a few jets but selection isnt good to say the least and ordering and waiting pisses me off.

[VortecCPI]

Everything you need to know can be found here: http://rickramsey.net/CRF230Fcarb.htm