02 Cr 250

[SoCalMatt]

02 CR250 Jetting Help Needed!

Hello all! I need jetting help. Overall, my bike runs strong, except the low end is a little weak but it's a Honda. The mid to top rolls on very smooth. The problem is that I have oil spewing out of my silencer/spark arrestor and it is getting all over my swingarm, brake caliper and my gear and it's pissing me off. I have atleast 30 rides so far and have never fouled a plug and the bike starts on the first or second kick. I just had the top end done a couple of rides ago but it has always been spraying oil. I purchased this bike used so I dont know if it has stock jetting or carb. Please help, oh moto masters!

Here are my details:

I normally ride at 2500-3000ft altitude in 90 degree temps
I use Maxima SuperM premix at 50:1
92 Octane pump gas or VP C-12(depends on wallet)
NGK BR8EG
VForce reeds
FMF Turbine Core 2 silencer/spark arrestor
FMF Fatty pipe

I'm hoping to find someone who has gone through the same problem with an 02 CR250 to find out what jetting changes they made. Once the jetting is set I would like to know what setting to adjust for temp changes. Thanks in advance! :cool:

 

[john3_16]

At that altitude with VPC12 you're probably running pretty rich.Is there any way you can ask the person you bought it from if he messed with the jetting ?

If it is stock I'd try to go one step leaner across the board.

 

[SoCalMatt]

Thanks for the reply. I bought it from a dealer. I'm hoping that someone just knows what settings I should set the carb to.

 

[CR Swade]

do what many of us do, punt the Mikuni and put on a Keihin PWK. The Mikuni is nearly impossible to get tuned consistently on the 02. On my 01, I got it dialed but on that 02...do yourself a favor and go PWK

 

[newbikekiller]

PWK's are great carbs!

 

[SoCalMatt]

After installing the PWK, what jetting specs should I be using for the specs below? Did you guys install this on your bikes? Is the PWK a Yamaha carb?

I normally ride at 2500-3000ft altitude in 90 degree temps
I use Maxima SuperM premix at 50:1
92 Octane pump gas or VP C-12(depends on wallet)
NGK BR8EG
VForce reeds
FMF Turbine Core 2 silencer/spark arrestor
FMF Fatty pipe

---Matt :)

 

[SoCalMatt]

Also, do you know if Service Honda sells custom jetted carbs for certain specs and needs? Looking for an easy way out :)

Thanks!

 

[soulmate33]

Read This -----> http://dirtrider.net/forums3/showthread.php?t=86427

Aloha...

 

[SoCalMatt]

Wow great thread. It looks like I will be going with the PWK swap in the near future. :) I'll keep you posted. I really apprecite your help guys.

Where is the best place to get the Keihn PWK? CPW or Service Honda?

 

[Dragmeistr]

Order one off of a 2000 CR250. The CPW one comes with extra jets, but is pricy. On my 03CR250 tis is what I ran until I had it ported:

#7 slide
50 pilot
175 main
DGK needle
32:1 HP2 oil
VP Ultimate 2 fuel

 

[chavez27]

go to fmfracing.com and see what main, pilot and needle fmf recomends for your bike with that kind of pipe.

 

[john stu]

my bike runs great with the stock carb but it sure took a lot of tuning (lots) do a search on the s8 nozzle and start with tha,t it helps the most

 

[CR Swade]

go to fmfracing.com and see what main, pilot and needle fmf recomends for your bike with that kind of pipe.

and then buy a Keihin ;)

 

[SoCalMatt]

Haha, everyone is saying to go with the PWK. I think I will eventually do that however I would like to torture myself a bit first with some jetting changes on my Mikuni. I'm gonna try the S8 nozzle first, because it's cheaper and because my local shop said they have had good luck with this. If that doesn't work out I'm going to the PWK if my wallet has anything in it after the holidays... :)

Thanks for the help!

 

[mtk]

OK, if you like to abuse yourself, get the S8 nozzle and give it a try.

You'll end up on the Keihin eventually. I've got the whole assortment of jets for the Mikuni and the S8 nozzle and I'm putting a PWK on my 02 very soon.

 

[ProMed]

I have an 02 CR250 (PC pipe/silencer, Vforce) with the stock Mikuni, the S-8 and the help of my local track owner we have it jetted pretty much perfect. I have my needle sizes written down somewhere, when I find them I will post. I normally have no trouble jetting bikes, but trying this one myself quickly became a pain, but if you can get someone with good experience you can knock it out pretty quickly.