08 -Nytro-MCX-Would not start??

This a bit of a long story and this my first Yami and first boosted sled. I have owned numerous sleds but this is new territory.

Was riding for about 5 hours Sunday (first ride on the nytro) about +5c set up snow. Sled pulled so hard I couldn't even think about looking at gauges as the snow was pretty set up. At the end of the day was turning donuts and tipped it over on its left side. Was on its side for about 40seconds before I could get it straighten out. Leaked out approx 700ml (3/4 quart). Got oil all over the belt and clutches. Cleaned it up as best I could. After that sled was definately coughing and not pulling full boost. Seemed to clear up a bit on the trail ride down. Was not smoking oil at all.

Next day up the trail (boulder) it was still coughing a bit but cleared up and was pulling hard throughout the day. Around noon was doing a few pulls working the sled somewhat hard then came down parked it in the shade as it was closer to +8c and not a breath of wind (behind turbo hill-whatever the elevation is there). Parked for close to 1/2 an hour. After lunch fired up the sled and within a sled length was coughing and sputtering. and after about 100 ft it bogged then idled down and finally quit. Hit the key and it would start (without touching the throttle )then cough and sputter and slowly loose RPMS then die. Did this a few times no improvement. Nothing on the main guage no codes no lights. MCX just comes with a boost gauge.

Pulled the panels off and had a look no leaks and nothing disconnected. Oil was full and lots of coolant. Pull the power lead off thinking it may reset something electronic?? Checked the hose coming to the mcx box nothing inside no water. After about 20 min fire it up and died again.........tried once more seem to be idling turned it around drove 100ft and seemed to running again?

Put the panels back on and headed closer to home. Once closer to the cabin did some testing and again it seemed to coughing at WOT and was pulling approx 13lbs boost instead of 15. Max I could seem rpms was 8000. Now when it was pulling harderI know it was hitting 15lbs and no idea what RPM because it was my first weekend and was pulling like an ape!

Once back to the cabin let it sit again for about 20 min or so and on the trail ride down seemed to be better but very hard to test. It would pull 15 lbs but could not see the RPMS but did "feel" like it was pulling hard. Again it was downhill most times and hard pack trail.


It really felt like it was starving for fuel, my guess was a blocked fuel filter or failing pump?

Good fuel 91 from shell with 4 gallons of AV fuel.

Could this all be from fouled plugs from tipping over the day before?

Did the sled get so heat soaked that it just needed time to cool off without any panels?

When the sled failed to start I was WTF do I even check?

I will post more as I think of it just looking for some advice for what to check and once I get a chance I will do some field runs and see what its pulling for boost and rpms.

mcx stage 1- purple primary with shockwave. 74 daltons in primary with b-w-b

Thanks

Tues.

NytroDL said:

I ride 08 MCX T-Nytro with shockwave & @ about 7000' (hillclimb @ Allen Creek) it runs 15lbs @ 9200 rpm (pre-boost was 8250 rpm) also 3/4 of litre of oil seems like a-lot .......

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It did run for a few secs then quit.

sledskiing said:

A/F Readings?

Would you hit 1/4 throttle then it would fall on it's face?

Are you riding at WOT or at Boost then shutting the sled off?

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MCX didnt come with A/F gauge.

I am not even sure it would make 1/4 throttle then fall on its face....that would be max for sure.

Before I shut it off it did a long pull but not at max boost....idled across the ridge 300 ft. coasted down to the bottom of the bowl then about 200 ft at the bottom of the bowl idle it over behind the tree. So approx a min from the long pull until I shut it off. It was extremely warm out though with no breeze at all.

sledskiing said:

I would def look into adding an AFR gauge. It's hard to trouble shoot without one.

Sounds like you had the same issue as me. Could be Vapor Lock. Read This

http://www.snowest.com/forum/showthread.php?t=114447

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I am leaning towards the fuel in the lines/pump? getting to hot after sitting for 30 min after working the sled so hard. It would help explain why it would come back to life after having all the panels off. When it was running so poorly I did not try very hard to lug/idle it along that too may have clear it up. When 2 strokes are having any sort of problem always best to stop ASAP!

However doesnt fully explain why it wasnt pulling full boost for about 2 hrs after the incident. Maybe I had a bit of moisture in the boost lines and just took that long to clear out. As about 3 hrs after problem it seemed to be back on track?

Just thinking out loud to try help other peeps in the future if they have this problem.

Also my T-4S knowledge base is somewhat limited to start.

Most of my research on the beasts are related to coolant/oil leaks, air/boost leaks otherwise the yammi's run trouble free? Or is that a misconception?

Thanks for the input!

MCX data box-http://www.mc-xpress.com/ is this worth it or should one just look at a decent A/F gauge?

At 15lbs boost things are wizzing by pretty fast. Need a decent hill with soft snow to get a good look at the guages.

Update

Well with a few hours of research havent turned up alot of answers yet. This is apparently not a common problem.

So far it has been suggested to check the TPS-readout and the perhaps its just the sensor going bad?

Check the fuel pressure with an inline gauge.

Was also told it should leak very little oil and that the mini oil reservoir should have a long tube on it running down to the belly pan to prevent oil overflow. Mine has about a 2 inch long tube so I will extend that, he also mentioned trying an inline one way valve to prevent any oil leakage with roll overs.

I read somewhere about bleeding the fuel pump in case of vapour lock? How does one do that?

Seems some love the mcx databox and others feel its a waste of money unless you are going to be changing maps regularly for different conditions? say racing? A/F gauge would be nice but without the data box and software you could see the numbers but not be able to adjust anything.

Thoughts? Suggestions?

Got this email for mcx today:


Hi.
I recommend you to:
Bring the sled inside an let it dry.
Take apart some panels and maybe also the fuel tank and check all the vacuum hoses and fuel hoses so nothing is bent.
Also check the wires so they are properly installed against the stock wire harness and so the wires are all O.K in the connector to the MCX EFI-box.
Maybe change the spark plugs if you suspect them to be bad.
Best regards Erik Marklund

summitguy said:

Mine ran very similar one day after warm riding one day and then having it freeze over night in the trailer. Would fall flat on its face every time it was time for the turbo to make boost. Coughing and spitting and even stalled at speed. Would only start with the trottle being applied.

I put it in a heated garage for a couple of nights, let it completely dry out, put dielectric grease on all my fuel box leads and it hasn't missed a beat since. The turbo sleds like to get dried out at night I guess.... gonna have to get heat in the trailer.

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hmm.... on my day it was so warm with no fresh snow coming up so I dont think I froze anything but this does appear to be common issue.

I am still thinking the fuel was heat soaked from sitting. Then it cleared up once panels where off and cooled down.


I need to do some testing.

Install was done by Whitehorse Yamaha approx 1500km ago. I was not the original owner but they may give me some insight.

Did some testing today. Had the sled drying out in the heated garage for 2 days.

Cleaned up the inside/clutches/belt from that oil spilling out. I plan to put a longer tube on that mini oil tank.

Checked all wires/tubes/lines that I could see. Everything looked ok. Fluid levels where all normal.

I did approx 10 pulls around 1/2km. Snow had a hard crusty layer with a bit softer underneath. Depth would have been less then a foot. Temp was -11c and elevation was 2800ft. Highest I saw rpms jump to was 9000 but it would mostly hang in the 8600 area. Sled was quick to respond and no sputtering on the top end. Boost was jumping around as when you first hit it, it likes to spike. Pulling 13-14lbs boost.

So the problem I was having seems to have cleared out as I suspected coming off the hill on Sunday. For that elevation is the rpms too low and boost kind of high? I was expecting to see 8800 rpms at 11-12lbs boost. It is has about 30-40% AV gas so that should be safer but I dont want to taking chances either.

When I got back to shop I was surprise at how much moisture was inside. I think most of the moisture came from snow getting in on the throttle side of the belly pan down near the oil reservoir. When I pulled the the top section of hood off the windshield and bottom of the panel both had significant moisture on it.

I will check the TPS setting tonight and see what they are doing.

Never had a shockwave set up. I did spend some time looking at it but not 100% on how to adjust it. I already miss the key to open the secondary like on my poos/pol. Taking the belt off wasnt bad but putting it on there is not alot off room for my hands to open the secondary.

few pics

few pics

What are peeps doing for venting? I think all that prefilter is doing is holding the moisture in.

I think if I can take out the headlight and get some decent screening on it that should solve the problem of letting moisture and heat out.

I will definately be doing something with that lower oil side vent.

If you have some pics feel free to paste them so I can get a better idea of what is working.