[sbronco68]

Hey guys just looking for some input on Pilot jet size. I have a 05 450R in southern California and I can’t lean it out with the fuel screw. It currently has a 42 pilot jet. I can’t see needing to go to a 40 at sea level. Any experience would be appreciated.

[SoCal450R]

I have a 06 450r i am running a 45 pilot jet from sea level to 4000

[sbronco68]

I have a 06 450r i am running a 45 pilot jet from sea level to 4000

Thanks for input. I put a #40 pilot jet in and still can’t get my bike to even run rough with the fuel screw turned all the way in. If I turn it all the way out it will almost die but not in. Any ideas?

Thanks Guys.......

[nminus1]

I have an 11. The previous one was 10, but mine goes to 11.

[Asmith]

I have an 11. The previous one was 10, but mine goes to 11.

Why didn't you just make the 10 bigger???

[sbronco68]

I have an 11. The previous one was 10, but mine goes to 11.

Ok now I'm lost. 10,11?? That sounds really small for a pilot jet.

[Asmith]

I have an 11. The previous one was 10, but mine goes to 11.

Ok now I'm lost. 10,11?? That sounds really small for a pilot jet.

Go to Blockbuster and rent the movie "SpinalTap".

There will be a test at some point in the future...

[sbronco68]

~ I read you instructions on how to set you pilot jet and fuel screw and I can't get my bike to die if I turn the screw all the way in. Please Help! I promise to go watch Spinal Tap.

[Asmith]

You are not looking for the bike to die, just a little stumble is all.

Almost like a V8 engine with an occasional miss.

Try turning the idle up a little higher than normal, the stumble will be more pronounced.

The 40 is awfully small, I would think that the 42 or 45 or even a 48 would be more inline.

The 42 would require the fuel screw@ 1 1/2 to 2 turns out.

The 45 would require the fuel screw@ 1 1/8 to 1 1/2 turns out.

[sbronco68]

Thank you ~. That makes a lot more sense. I think I will be pulling my carb back out today to put the 42 pilot jet back in or even bigger. Thanks again for the help.

[nminus1]

I have a 06 450r i am running a 45 pilot jet from sea level to 4000

Thanks for input. I put a #40 pilot jet in and still can’t get my bike to even run rough with the fuel screw turned all the way in. If I turn it all the way out it will almost die but not in. Any ideas?

Thanks Guys.......

Did you ever replace or remove the screw? A missing or hung up washer/o-ring will cause this to happen.

[sbronco68]

I did replace the screw. Should I just replace the O ring to be safer? The O ring comes right out though if you pull the screw all the way out. I don't think its stuck.

[nedirtbikr]

- 2006 450R
- 180 Main
- 48 pilot
- CRFsOnly fuel screw at about 1-1/8 out (1-1/2 in cooler weather)
- 1000'-2000'
- Typically, starts on second kick and runs like a raped....well, you know!

[nminus1]

I did replace the screw. Should I just replace the O ring to be safer? The O ring comes right out though if you pull the screw all the way out. I don't think its stuck.

If its like the X screw(which it should be) there should be a washer too, my point was that if they hang up the screw can't go in all the way, therefore no ability to shut off the fuel in the circuit, to cause stalling. Try putting the old screw back in, perhaps the new screw is the cause? Gotta try every poss cause to get it straight

[Asmith]

I did replace the screw. Should I just replace the O ring to be safer? The O ring comes right out though if you pull the screw all the way out. I don't think its stuck.

If its like the X screw(which it should be) there should be a washer too, my point was that if they hang up the screw can't go in all the way, therefore no ability to shut off the fuel in the circuit, to cause stalling. Try putting the old screw back in, perhaps the new screw is the cause? Gotta try every poss cause to get it straight

Good point.

Which screw did you replace the stocker with??

I have heard of troubles associated with the aluminum screws, ie Zip Ty, et al.

I like the CRF's ONLY screw. It is made of brass and is machined beautifully and will not corrode. The aluminum ones do not machine as well, will corrode and will bend easily.

The screw should have the spring, washer and o-ring installed in that order.