The wifes 03 recon doesn't like wot. At every other throttle position it runs fine. but, if you just pin it from a stop it will die. if you pin it a little slower, it starts to go, falls on its face and almost dies then takes off ok. if you slowly go from idle to wot it seems to do ok. it had a 95 jet in it, and i think the other settings were stock when I bought it (at 1400 ft). took it to my house at 5450ft. installed a 93(?) jet and lowered the needle one setting, and adjusted the mixture till the idle was at the highest point, then set the idle. we ride between 8-12,500 ft. a lot of riding about 9,500ft. it has an oiled foam filter in it, and I did open up the intake tube. this weekend I put the 95 jet back in it, and lifted the needle one setting, the re adjusted the mixture. it seems to not want to die as easially at wot. looking at the plug after normal riding, it does look a little lean. i just thought that being at such a higher altitude it would need a smaller jet. now it is looking like it needs to be bigger? i also cleaned the carb really well. on a side note, no matter where the fuel shutoff valve is positioned, it will still run. the arrow doesnt seem to line up with the names of the positions as it should. any constructeve input is appreciated.

mike

 

My typical high altitude ride is from 4,000' in the valley up to ~12,000' in the mountains (eastern Sierra)....but we also do desert rides at and even below sea level!

I learned long ago that constantly messing with the jetting for large altitude changes was nothing but an exercise in futility! I did myself a favor and install Thunder TPI valves in my airbox lids (engine jetted for sea level). I open them for ascents, and close them back down again for descents. Above ~9,000', I just pull the lids off altogether.

This is indeed a rejet (!), but insead of adjusting the amount of fuel, you are just adjusting the amount of intake air. In the end, you accomplish the shame thing....and you can do it on-the-fly!!!

Thunder Products - Performance carburetor and clutching for snowmobiles, motorcycles and ATVs.

One note, it may be difficult to fit the TPI in the Recon/250EX airbox lid, because the air fiter is so close to the bottom of the lid, plus the lid is on the small side. In this case, I use the 1" UNI round airbox vents and arrange them around the periphery of the lid. It is a bit of a pain, but I use duct tape over the openings and remove/replace the duct tape during ascents/descents.

 

A 4 stroke is not affected by altitude near as much as a 2 stroke.

With that said, I would check your float level. Sounds like it may be way to high. When you hit WOT quickly, it sounds to be flooding out. Over time bouncing down rough trails and jumping can bend the float tab and cause the float level to rise. I check mine on my snowmobiles every year. I usually set them sightly to the lean side.

 

As far as the fuel shut-off not working, don't know how long you are letting it run. When you shut it off and at a idol, it will take forever for it to run out of fuel. When I drain my snowmobiles ever spring, I usually let them run till the lines are empty. Some times it take 10 to 15 minutes for them to run out of fuel.

 

I always run the carb dry when I put mine away. It usually takes about 5 minutes of idling before it dies out.

 

So, you think that it is too rich at wot? It fires right up after it dies - doesnt run rough or anything.

Do I set the float level with the carb flange?

The fuel shut-off: since its off about 90* off of where it should be, I set it to where I thought on would be. ran it that way for a couple of days. put it on the trailer one day and turned it to where I thought off was. forgot to turn it back to on, and ran it off all day (20 miles). since it didnt make a difference I've been running it that way all summer.

Mike

 

One thing you need to do is make one change at a time. If you change the needle and the main jet at the same time you will never know where the issue is coming from. Also, with that much of a change in altitude you need to go lower on your main jet. Go to Jets R Us JETSRUS and pick up a couple smaller and maybe one more bigger than the 95 since they are only $3.

 

There is a small tab in the center of the float that sits on the needle valve to open and close it as the fuel level drops and raises. You can use a pair of needle nose pliers to bend that tab either direction. Won't take much. You will have to remove the carb from the machine and remove the float bowl.

For a leaner condition the float should hang down (oh so slightly) when holding the carb right side-up.

I know you said you cleaned it, but double check the pilot jet for cleanness and while you have the carb off......blow it out again.

 

I cleaned the carb again today using a bunch of carb clean. Made sure that nothing was plugged, etc. Didn't find any dirt in the bowl. Checked float height and found that the floats were level with the bowl flange. The entire assy is made of plastic, so it doesn't look adjustable anyway. The float needle didn't really have any wear on the rubber. Put it back together and it was no different. All of the vacume lines look good. I pulled the choke out about 90% and nailed the throttle wide open and it did not want to die one bit! Pushed the choke back the the run position and nailed the throttle wide open, it just flat died. This is with the 95 main, 38 pilot, and needle in the middle slot at 5450ft. I dont understand, souldn't I be quite rich at this elevation with a 95 main? By the way it is acting I'm going to need a 105-110 or so main jet to get it to go when I mash the throttle? I also noticed that backing the mixture screw out the idle doesnt get to the highest point unil it is pretty much all of the way out. I can see the threads when the idle starts to slow. Since this adjustment is pretty much at its maximum adjustment does that mean that I need to go to a different sized piolt? Thanks for the input.


Mike

 

So, I tried throwing a 110 jet in it just to see what would happen, and really no different (as far as just mashing the throttle wide open in neutral). Didnt ride it at all. Is that an accelerator pump on the carb? Could it be causing problems (took it appart and nothing looked messed up). Anybody know who could answer my questions???

Mike