4 RX1M's cut out at same time!

I was out riding and skiing saturday with four other rx1 mountain sleds. It was a fairly warm clear day with spring snow conditions. We were riding between 7000 and 10000 feet making laps up and down to drop skiers off at the top. All four sleds were running strong all day and then about 2:30 in the afternoon it happened.

All four of us were headed back to the top. I was in the lead carrying a passenger. At about 9000 ft while climbing a moderately steep slope the engine started to cut out and miss. Almost died completely and I was forced to turn it across the hill and shut it down to avoid disaster.

As I sat there, I noticed the sled behind me had also stopped just below me. I thought maybe this person had just stopped to see if we needed a hand.

Then the third sled came by us. It was burbling and missing just as mine had. This rider managed to reach a gentle plateau just above us and was able the pump the throttle a little and get it to clear out.

The two of us who had shut down on the hill were able to restart after a few minutes and continue up to the top with no further trouble.

We dropped off our skiers and headed back down the hill only to find the fourth sled had died in exactly the same spot. This sled would not restart.
We pulled the plugs and they were not fouled or fuel soaked. Finally after about 20 min. we got it to start.

After a short break, we all rode up and down the same hill for the rest of the day with no more trouble. How does something like this happen to four different sleds at almost exactly the same time and place???

Three of the sleds were '03's; two with floatbowl updates and red carb springs, one without either. Needles and pilot screws all set slightly different.
My '03 had the carb heat shutoff and TORS is bypassed. the other two '03's and the '04 do not
have shutoffs. Fuel in each sled came from three different sources.

The real clencher is I went back and rode the same place yesterday. Rode all day with no trouble, and then died in the exact same spot at almost the same time of day. Another sled did also. Then no problem the rest of the day!

The only time my sled acted like this was before I installed float bowl update and carb heat shutoff. Have had no problems for almost 2 years.

Sorry for the term paper, but I wanted to get all the info down so you guys can help me solve this mystery.

Did you have the rubber flap over the carb or over the valve cover ??? seem to make a help when flip a head over the valve cover on the warm days

My flap was flipped forward over the air box, not sure about the others.

Are you sure you just didn' t get a little hot.

I'm sure they were running pretty warm, but no temp lights came on, and plenty of snow hitting the exchangers.

Weather station record shows air temp was around 51 F. All I can think is it must of been just the right combination of Altitude, temperature, humidity, slope angle etc. to create a condition that none of our machines liked.

I'm thinking that maybe that long of a pull up that steep of a hill you might start starving for fuel. Could possibly need a little higher float setting. Ken

That could be...still can't figure out why no trouble on passes before and after under nearly identical conditions.

Did all of you guys just get back on the sleds from taking a break? If so I'd say your fuel pumps got too warm and vapor locked. The progress you made up the hill before the sleds acted up was mostly courtesy of the fuel in the float bowls.

Remember the fuel lines pass a few inches over the exhaust header and when the fuel gets warm the vapor pressure goes up and the efficiency of the fuel pumps goes down. The diaphragms are much better pumping liquid then gas vapor.

Happened to me once in the middle of a big full throttle hill climb right after taking a break. Now on warm days I pop the hood when taking a break.

me and a buddy who ride a RX-1 m has almost the same thing in december.

Sled running great all day long, but suddenly, both sled wont rev over 8000 rpm, for about 10 min. And they burble , i think it'S a drop of barometric pressure, we where on a the lake at about 2300 feet, then we cannot take the lake at over 8000 RPM, sled rev 10000 then almost instantly drop 8000 and would'nt get any higher.

This last about 10 min. We where not high but pressure where we ride is somewhat strange. X-FILES......... ouahhhhhhhha :?

Saw a show on Discovery Channel about the Bermuda Triangle and the possible link to methane gas emissions from the ocean floor into the atmosphere. A 1% concentration of methane was enough to make a piston aircraft engine quit. Maybe you were riding through some methane!!!!!!

Interesting...could be an indication that the mountain is getting ready to erupt. Might be an alien disrupter field too!

Yeah, that sounds about it..... the spacecraft was gonna beam you all up after they used the disrupter field on you, something made them change their minds......LOL

Your jetting was rich. Running in warm temps at high altitude under load will really bring out this problem!!!

Do you have a coolant shu off for the carbs? If it was warm out with no coolant shut offs it will cause some problems.