Air Box Mod Question

[Woody_393]

Ok, I'm modding my air box as we speak (working on it anyway), and have a question or 2.

1) On the little inlet things (the ones on the side # plates) do you just unscrew them and take them off, or do you just cut them down?

2) Did you have to jet richer?

Thanks guys.

[Roostman]

Ive been thinking about what to do with those myself (cut or remove). Im leaning toward cutting them a little bit and maybe cutting the hole in the #plate a little bit bigger. I dont really think its gonna make enough difference to worry about jetting changes.

[Roostman]

Im guessin you have an 02 CRF if your asking about unscrewing the little deflector inside the #plate, am I right? The 03s have bigger holes in the sideplate and a different inlet setup (straight shot to the filter). I wonder if they fit on the 02s? I dont see why they wouldnt, same frame.

[FFRacing11x]

If your CR was jetted right when you started, you will be fine.

[Woody_393]

Yeah, those are what I'm talking about. I'm thinking of just cutting them too, instead of removing...

Ok, thanks FFR, I'll leave the jetting as it is and go from there.

[strykmaster]

I just removed mine. If you just cut them down, they still block airflow from where you cut the airbox. I seached on TT also and most CRF riders just removed them too. I did not re-jet because I think I was a little rich to begin with. Will be trying the JD blue needdle (#3 position) to see if there is any improvement. I'll let you know what happens.

[VET393]

All I did was take the screws out and remove mine. I put rags in the plates when I wash it to keep the water out. I also trimmed the lip off the fender with a razor knife. Pretty simple.

[Woody_393]

Ok, I'll just remove them. That is certainly easier.

I'm doing the airbox trimming too & removing the backfire screen.

I have already installed the blue needle 4th position with the 178, though for my altitude he recommends a 175, but I'm going to leave it be for now, and then dial in once the air box mods are all done.

BTW, I'm going to take new pics so we can update the KB.

[Woody_393]

Originally posted by strykmaster
Will be trying the JD blue needdle (#3 position) to see if there is any improvement. I'll let you know what happens.

3 eh? Isn't your red one on 5? If so shouldn't you go with 4th? Though he does say #3 for race conditions is good???

My understanding was if 5th on red, then 4th on blue? is that not correct?

[strykmaster]

Originally posted by Woody_CRF
3 eh? Isn't your red one on 5? If so shouldn't you go with 4th? Though he does say #3 for race conditions is good???

My understanding was if 5th on red, then 4th on blue? is that not correct?

I just double checked the reply from JD and he wrote me that RED #5 is very close to BLUE #3. The blue giving better response off bottom, the red more response off top.

[Woody_393]

Ahh, okay, good to know.

I've decided to cut my little air scoop things instead of just removing.

[strykmaster]

I see little difference.......either way.

[Yardpro393]

just unscrew

[Woody_393]

LOL, ok, maybe I'll just unscrew them...

[strykmaster]

Originally posted by Woody_CRF
Ahh, okay, good to know.

I've decided to cut my little air scoop things instead of just removing.

Here's a quote from therapture from TT:

"Yep...you guys can thank FFRacing79 for this info. He says, on a dyno, that you can run a stock CRF450 and get a baseline. Now, remove the right side panel, gain a full 1hp...go figure! The vents are restrictive when the motor is cranking along! RTemove the vents, (and the screen) you accomplish the same benefit, more airflow at high rpms. Cutting the airbox is a smaller part but does make a difference especially for modified engines (like mine!) "

The vents are restrictive and I really can't figure out why there there in first place. So the dirt has to travel through a vent first?
The dirt and dust will still get to the filter anyway?

[Woody_393]

ok, i'm unscrewing them

[strykmaster]

Thought you would see it our way.

[Woody_393]

Yeah, I couldn't resist the powers of 2 Dirt Riding Surfer Dudes...

[strykmaster]

Originally posted by Woody_CRF
Yeah, I couldn't resist the powers of 2 Dirt Riding Surfer Dudes...

We are ALL POWERFUL. We tear up the surf and turf.

[Woody_393]

Both vents are removed, and the box has been shaved. Pretty easy when you heat the blade up with a torch