Help, turbo Nytro runs like crap!

JamesS · Oct 12, 2009

I have a 2008 turbo Nytro (MCXpress 240HP rear mount) and the problem I am having is that it pops/backfires (like it's hitting a rev limiter) when I get on the gas. Here's a video of it, it pops numerous times (sound in the video sucks sorry)
Turbo Nytro

XP8 · Oct 12, 2009

Mine did the same thing last year and it was the plug that went into the MCX box. Make sure it is fully plugged in. It solved the problem for me.

Motleyone · Oct 12, 2009

I am not familiar with the MCX setup but does it do this cracking and poping when you easy into the throttle and don't get on boost? Have you checked your fuel pressure? Have you checked EVERYWHERE for boost leaks? If you think it is hitting the rev limiter what is your clutching setup? What springs do you have in it, what weights? Those are a good few things to check.

BBNytro · Oct 12, 2009

Yeah that sounds like you not getting the extra fuel for the boost and it is leaning out causing the back fire. I tied the wire to the sled close to the box so that with jumps and bumps and flex it will not break connection or come unplugged. Also diaelectric grease is a life saver.

drinkwyo · Oct 12, 2009

Mine did this once.
Pull the fuel tank and inspect ALL of the vaccum lines. One of the plastic tees is most likely broken. Replace the tee and u should be good to go. If they are all good, keep hunting I guess

Washy · Oct 12, 2009

Sounds like lean pop, not enough fuel. Like montley says if you roll the throttle does it do it? That sled got a new MCXPress control box in Feb Last year. Check the wiring into the box. I am pretty sure that was the prolem with it in the first place. He had moved the box from by the battery to above the radiator and puled a wire out of the harness. I would check the wires going into the box. Also can you hear the turbo chattering , your BOV is not opening when you let off the throttle. The spring that comes in the MCX BOV is too stiff. It comes apart and put a lighter spring in it.

whittaker727 · Oct 12, 2009

My buddy just had to replace his entire exhaust because all off the welds and flanges had cracked, so make sure you check for boost leaks.

SLY · Oct 12, 2009

Sounds like it isn't getting enough fuel under boost. Check the wires going into the connector for the MCX controller very carefully. I have seen that a couple of times. As someone already said, you cannot have any stress on the wires going in, they are small and will pull out if you have tension on them. If that is not the problem I would check all the wiring first, then move onto all the vacuum (pressure) lines.

summitguy · Oct 13, 2009

Popping

Had the same issue when I froze up under the hood last year. Warmed it up real good and problem went away which tells me I had a frozen vacuum line or fuel line. Check all your hoses to make sure they aren't kinked and make sure the MCX box is mounted higher than the incoming vacuum lines to make sure water doesn't get in the box from condensation in the lines.

JamesS · Oct 13, 2009

I believe I found the problem, thanks! :beer;

JamesS · Oct 13, 2009

Do you know the sled Washy? Do you know what spring I need to put in the BOV?

Washy · Oct 13, 2009

PM'd you.

noob · Oct 14, 2009

james, looks like you taped the red wire and zip tied the wires together. that's what I was going to mention. from an outside appearance, the plug into the mcx looks fine. but the red power wire on my nytro wasn't seated all the way in creating the exact problem you were having. glad ya found it.

JamesS · Oct 15, 2009

She rips now! :beer;

. Also how hard are Yamaha primaries to clean and lube?
October 13 2009

up-high · Oct 15, 2009

Clean the clutches but don't lube them.

Motleyone · Oct 15, 2009

Use a soft green scotch bright pad and a little water. Clean up the residue and your done.

JamesS · Oct 16, 2009

How hard is the primary to take apart?

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Help, turbo Nytro runs like crap!

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