Help had some engine trouble

[ger]

I had my first ride this year and on my second day it started to (hard to describe) hesitate , backfire and I had no power . It seemed like I was running out of fuel.
If I was under 6 grand it was good , give it a bit and it felt like I hit the rev limiter and then it would backfire.

After we sat for a meal or a rest on the trail it would be good for about 5-10 min then it happend again.

My only thought is bad gas or water in the gas . Any ideas?

Plugs looked good .

engine is stock other than green springs , and fuel shutoffs ( thought they could be restricting but it did not do it the first day only second day and once on the third day. :?:

 

[Mighty]

Throw in some new plugs.

 

[NY_SXR700]

What make is the shutoff's. If they are not a Yamaha made for a 1000cc engine with 4 carbs I would be careful. I say that because I think you RX guys have 2 fuel feed lines in there. I fell into that same trap on my sx700 motor. I got a fuel shutoff from a Doo dealer (Yamaha was out and I wanted one right now!!). He said it went on the 700/800 doo's. Well, it was starving me on long WOT runs. The outside was the right size but the insude was about 1.5mm to small. A 4-stroke will pop if you lean it out so it could be somethingto check. Doug

 

[redeye23]

Three weeks ago while riding in jackman I had the same problem for the first time on my sled (right around 3,500 miles). I went into Jackman Power Sports and the mechanic disconnected the TORS under the hood and ran the sled and the problem stopped. He took it into the shop immediately and after 15 minutes he came out and showed me that there is a switch for the throttle/TORS in the handle bars (throttle side) behind the plastic and if it gets wet in there it causes the sled to hesitate and back fire. He said he has seen the problem before on the RX-1 and he also changed the plugs but did say my old ones(original) all looked fine. We were riding in a foot of fresh powder and the where a few washouts we had to go through. I also buried the sled up to the handle bars off the trail in the powder and it was snowing for the first two days we were there. He recommended that I cover the sled when it is snowing (which is hard when you are riding it!!!) and that i take the cover off myself and occasionally blow it out with canned air. I rode another 200 miles after this and no problems at all.

 

[rx1mtn]

An other thing to look for is that your air box is fully seated on your carbs correctly. Very easy to over look, take top of air box off and look and feel that the rubber connectors are fully seated on EACH carb.

 

[vcrash]

I would check your carb vent hoses, might be pinched against airbox or possibly the tank vent!

 

[ger]

I did check the carb boots and all lines for pinching.
I wondered about the tors but it did not do the same thing as my last sled did when that acted up .

will water in the gas do the same thing.
As for the fuel shutoff , if they are too small it should do it on every WOT run , this would do it at 6000 rpm too . No they are not Yamaha ones but they are the correct size ( same as the line all the way through so if the line can flow the fuel so should the valve

 

[kmer]

Had similar symptoms as ger did. On the 'second day' ride I was breaking trail through powder (again).... for about 60 miles ..... then it started to act up.... it wouldnt rev over 8k at first then down to 7k then down to 6k..... we were crossing some pretty iffy lakes so i didnt stop right away...

When i pulled the air box lid off, the air filter was frozen to the airbox.... large accumulation of ice had built up and was causing restriction... the accumulation in the belly was also affecting steering...

Once i cleaned out the air box and belly it ran fine again.... my guess is that there was accumulation from the day before that i should have checked.

 

[ger]

Thanks Kmer , I never thought of lookin in there , I did the crank vint slit so I didn't think anything else would freeze in there.

I was in some deep snow the first day and there was alot of snowdust on the other days.

I still don't know why it would do it sometimes and not allways if it is something like that . I would think as long as it is restricted it would act up not the on and off like I had .

GER

 

[race24x]

What is this crankcase hose slit I found a cut in my hose and thought it was bad. From the airbreather inside the airbox. Am I wrong to order a new one????

 

[kmer]

I used to bring my sled inside to thaw it out after every ride last year. This year it's been outside all the time. It never had a chance to thaw out completely after 1000 kms in four days.

Also, the snow we just had was very light and powdery (and lots of it... 10" to 12" - more than usual in 6 hours). That's gotta have something to do with it. The RX was just 'loving' the powder... we usually switch off to take turns breaking trail but.... i was being a 'powder piggy' and stayed in front for about an hour straight. That's not normal 'trail' riding. The 600 MXZ doos were quite content to bring up the rear because the powder was hard-going for them. (We did the same run the night before.... i used 29L of fuel in about 130km of 'normal' powder... day 2 i used 32L wallowing in powder on the same run. The Rev 600HO used 40L on day 2. The F7 used 36L.... and they spent most of the time following.)

I'm planning on removing my toolbox (or make it easier to remove on the trail) just so that I can clean out the belly and keep an eye on things.

 

[kmer]

What is this crankcase hose slit I found a cut in my hose and thought it was bad. From the airbreather inside the airbox. Am I wrong to order a new one????

That's yamahas update/answer to a freezeup condition some experienced last year. Don't change it.

 

[Buckeye]

Slit hose

Race24x, the hose is supposed to have a slit. It is an 2004 update.