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xBRIANx

Another few noobie questions

10 posts in this topic

Okay, so 'Adjustable Fuel Screws?' what do they do for the bike?

I mean, is there a performance gain?

Is it like a different way to adjust the idle? Sorry for my ignorance, but it is exactly that.

Ive seen everyone talking about getting them, Im just wondering why?

Also- Re-Jetting the carb? Should I do that after I get an ajustable fuel screw? is so... Why?

And removing the air box cut outs?.. Im assuming after your cut them up, you use like screen to cover up the air holes + (pantyhose i would imagine would work good to on top of the screen to allow minimal dirt in) But I tend to sometimes ride through creeks and what not, will this be dangerous with these cut outs removed? Either way, is it a pretty good performance gain?

thanks boys:ride:

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Adjustable fuel screws give no performance gain but they allow the mixture to be regulated with a gloved hand without having to loosen the carb joints and turn the carb as was required when adjusting the standard screw.

It is nothing to do with idle.

Re the airbox cut outs, it depends what model of WR you ride.

I have an 05 with electric start and removing the cutouts did nothing (as far as I could tell) in terms of performance gain because of the location of the battery box for the electric leg.

I read elsewhere on this forum that decent gains are achieved on the non- electric start models because no battery box exists allowing a much better flow of air.

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Yeah, I have the 06 WR450FV (electric start). SO let me get this straight tho, Adjustable fuel screw is like.. basically rejetting it sorta? Say if its runing to rich, or to lean, can you fix it by adjusting that?

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Fuel screw is used to tune the pilot circuit, that is, the Pilot Jet. Use it to determine if you have the correct size pilot jet.

The following paraphrased from the Eddie the jetting dude:

With bike warm and idling turn the fuel screw in till the idle drops/ misses.

Then turn it back out till it peaks / smooths.

This should be bewteen 1-2.5 turns out on an FCR carb.

If you end up at less than 1 turn you nees a smaller pilot jet.

If you end up at more than 2.5 turns you need a bigger pilot jet.

It is not gonna have any effect on the operating range of the needle / main jet, so no it cannot be used just as a fix for all lean / rich situations.

Personally I reckon they are a great idea, but make sure to check the aftermarket screws regularly as some have a habit of working loose.

Make sure the spring, o-ring and washer come out with the old screw and go back in in the correct order with any aftermarket screw.

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They are great for changing weather conditions.

I just set mine for the quickest throttle response.

I just open the throttle just a bit for a little BRAP.

Whatever setting gives me the best BRAP is the one I use.

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It really is easy and it really does make a big difference in throttle response.

When you put the screw in put a little grease on the o-ring so it doesn't fall off.

I put a shop rag under the carb so if anything falls off I can find it again.

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They are great for changing weather conditions.

I just set mine for the quickest throttle response.

I just open the throttle just a bit for a little BRAP.

Whatever setting gives me the best BRAP is the one I use.

I'd not thought of that, always used it for perfecting the idle rather than the BRAP. I'll give it a shot tomorrow.

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