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Hi everyone. I have a Honda crf230f and have recently done the "power up" mod with both baffles removed, 132 main and a needle that says "C30F". I was having issues after the mods and after reading several topics it seemed that the problem would be fixed by installing a #48 slow jet. I've done this and the problem persists.

What happens is at 1/4 throttle it starts to run poorly revving up and down like it's bouncing off the rev limiter and backfiring upon releasing the throttle. I've tried the needle in all clip positions and the problem persists. I think it maybe running lean because of the backfiring and how quickly it warms up.

Does anybody have any ideas and recommendations on what part I need to change and how?

Thanks.

What is the fuel screw setting??

I've had it at positions from all the way in to all the way out with no change so I put it back to 1 and 5/8 turns out as the service manual says.

Thanks for such a quick reply!

What is your elevation???

That power up set up is for sea level applications.

If you are high up you are way rich and loading up.

However,
The backfiring on decel IS indicative of a lean pilot circuit as well as getting hot quickly.

O right, I forgot to mention I live at 9,300ft and ride up to around 13,000ft. I figured the parts were for sea level elevation, but never found documentation saying so. Which part(s) will I need to change to make the mixture correct? I think I'll probably need to decrease the size of the needle jet?

Wow. You are super rich. (not wealthy, just gassy)

Try this set up:

Main: 128
Pilot: 40 (stock is 42)
Needle: Honda Power-up kit part #16012-KPS-921 (clip in 4th position)
Pilot screw: 5/8 turn out

Alright, will do. Thank you very much ~! You're a great help! I've read many of your other posts for other questions I've had. I'll post back how that works for me when I get the parts, but that may be a while as I live 45min away from civilization and 1hr away from the the closest motorcycle shop.

Also, I'll be going Moab, UT for a dirtbike trip later this summer. Will I be able to modify the settings of the jetting parts I have or do I need to get different parts? The elevation of the city is 4,000ft and I'd guess the surrounding terrain varies at most + or - 2,000ft.

Thanks again!

The jetting should work for Moab. Won't be optimal, but should still provide way more power than stock. You will have to open the fuel screw a bit as you go down in elevation. maybe to 1 1/4 or 1 1/2.

Ok good to hear. I like not having to buy more parts.

Could I bug you with one more question?
My brother has a crf150f (stock) and I'm trying to get him to do the "power up" mod as well. I know what parts he'll need if he was at sea level, but he lives at the same elevation I do so what would you recommend? Also, how do you know what parts - experienced intuition or is their a formula?

As always, thanks!

The spec for the 230 is from DaveC. He lives in Colorado Springs and rides above 8000'. He says that's the hot ticket.

The 150 uses a different needle and jetting.

CRF150F Full Power Needle 16012-KPT-921

#112 Main Jet 99113-GHB-1120

Set up the needle and fuel screw as you would on your 230. Should be pretty close.

Will do. Thanks, you've been a tremendous help!