11 replies to this topic

[Bigbird TT Bronze Member]

I have a 2009 250X that I put a big bore on along with other things.  I also changed the "fixed" fuel screw to an adjustable (MSR) one.  My problem started when I was riding and had a hard time starting the bike.  In checking, I saw the fuel screw had vibrated out almost completely, so I did some trail maintenance and cranked the screw back in full closed using a pair of needle nose pliers since I couldn't get my fat finger in to do it by hand.  I then adjusted it out 1 3/4 turns where it was idling well before, but now I got the hanging idle problem.  I rode as it was for a few hours then went home.  There, I pulled the fuel screw out to check it without my glasses so I really couldn't see the details of the screw clearly.  I cleaned everything up, put the screw back in and experienced the same hanging idle that didn't vary no matter what the adjustment was.  I pulled the screw out again, this time with my glasses on and noticed the tip of the screw (the really fine point of it) was missing.  It may have broken off an fell out at some point, but my fear is that it is jamed up in the orifice.  Does someone know if the small hole in the venturi is straight through to the fuel screw orifice?  In other words is that little tip of the fuel screw jammed up in there, and if so, what would be a good way to get it out?

The diagram of the pilot circuit in the Honda manual seems to indicate that there is a passage through from the fuel screw adjuster to the venturi of the carburetor, and I have jammed the broken part up in it when I made the field adjustment.

Thanks for the help.

[keviwa TT Silver Member]

Dang that sucks. You can try to run a soft wire through the opposite direction but you need to go slow and be carefull you dont tear up the inside of the passage.
When you get it out. Buy a BRASS T-handle screw. The Aluminum ones are crap and have been known to have this type of failure. Good luck.

[Bigbird TT Bronze Member]

SUCCESS!  Thanks to Ramsey's counsel I was able to extract the broken part of the fuel screw.  His suggestion was to use a sewing needle.  The kind you sew buttons on, and as small as possible.  The work at the center of the venturi hole using pressure to push the piece out the bottom of the hole.  It took me a few attempts of careful and steady pressure and it popped out.  

Here are some don'ts I learned:

Don't use an aluminum fuel screw, at least in a 250X.
Don't use pliers to tighten in the screw.
Don't overtighten the fuel screw.

[MasterT2000 TT Bronze Member]

The lessons you learned are correct. #1 being, never use an aluminum screw.

[MX Tuner TT Bronze Member]

I think "not using pliers to tighten the fuel screw" is probably a good clue as to what happened. That and clean, lubricated threads will prevent any problems.

[102dals TT Member]

Where can I get a fuel screw that isn't aluminum? I haven't seen a brass one.

[keviwa TT Silver Member]

102dals, on 01 March 2013 - 10:03 AM, said:

Where can I get a fuel screw that isn't aluminum? I haven't seen a brass one.

Check the parts section on this board. The TT store carries several of them.

Edited by keviwa, 01 March 2013 - 02:04 PM.

[carters2 TT Gold Member]

Screw the brass t-handle one as well.  With the starter located where it is t-handle fuel screw is essentially impossible to adjust without burning the shit out of your hand and I am not able to reach in there with a glove on.  Swapped my t-handle with the R&D Flex Jet and have never looked back.  Quick adjustments on the trail is a breeze.  This is a must have item for the 250x

[backyard hack Get Help Now]

Yeah , I have the Flex Jet on both my bikes , great product

[prplhzeit200 TT Bronze Member]

carters2, on 01 March 2013 - 03:30 PM, said:

Screw the brass t-handle one as well.  With the starter located where it is t-handle fuel screw is essentially impossible to adjust without burning the shit out of your hand and I am not able to reach in there with a glove on.  Swapped my t-handle with the R&D Flex Jet and have never looked back.  Quick adjustments on the trail is a breeze.  This is a must have item for the 250x

I looked at one of those yesterday. I changed my pilot jet to a 42 and it seemed to help alot. I warmed up my bike yesterday and went for a short ride, but it still seems to have "hanging idle". If I rev it, it idles high for about 5 to 10 or 15 seconds then settles in to a normal idle. Will the flex-jet fix that or should I go to a 45 pilot?

[DeadSpider TT Newbie]

prplhzeit200, on 16 March 2013 - 07:47 AM, said:

I looked at one of those yesterday. I changed my pilot jet to a 42 and it seemed to help alot. I warmed up my bike yesterday and went for a short ride, but it still seems to have "hanging idle". If I rev it, it idles high for about 5 to 10 or 15 seconds then settles in to a normal idle. Will the flex-jet fix that or should I go to a 45 pilot?

You might just need to richen the fuel screw by turning it out.  The R&D flex jet just makes it easier to adjust as it allows easy access.  Start by turning the fuel screw in all the way until it seats, counting the number of turns.  Then back out the fuel screw, counting the number of turns.  If you go beyond 2 1/2 turns out I would certainly replace the slow speed jet with a 45.  That hanging idle certainly indicates lean mixture at the pilot!

DS

Edited by DeadSpider, 17 March 2013 - 04:01 AM.

[prplhzeit200 TT Bronze Member]

The tech at the shop told me not to go more that 2 turns on the fuel screw so that is where I stared. I turned it out another 1/4 turn but havent ran it yet.