Help ZX 800 bog at WOT

[Vertical-Extreme]

My zx seems to be bogging at wide open throttle. i am going to start with the easy stuff first, new plugs, drain old fuel, ect. this is at a low elevation but i thought the DPM was supposed to compensate. it has jaws twins that A & E set up ( according to the previous owner.) it starts first pull and ildes and runs fine all the way up to about 3/4 throttle.
anyone have any sugesations on what might be causing the bog?

 

[Thunderr]

I had an 01 800 that bogged when I hammered it. Turns out the carb boots were falling off. Easy fix.

Cheers

 

[OVERKILL 19]

My 02 800X did that when I first bought it. The sled had sat for 2 years with the same fuel in it. Dumped it, and put in good Prem fuel and never looked back, but it took awhile to clear out the lines of that old stuff.

 

[Vertical-Extreme]

My 02 800X did that when I first bought it. The sled had sat for 2 years with the same fuel in it. Dumped it, and put in good Prem fuel and never looked back, but it took awhile to clear out the lines of that old stuff.

I'm hoping that is all it is, I bought the sled in september and i don't know how long the fuel sat in it, so it is going to get syphoned out and filled with new stuff. it that doesn't work i will start lookin at the boots and taking the carbs apart and cleaning them. i think it is the fuel though.

 

[sirzones]

Had my buddies do that last year. try cracking the gas cap to see if it clears.
His had pinched vent hose on fuel tank,very easy fix

 

[Pappillion]

May have to adjust your carb needles. Some times that will give you a mid range bog.

 

[mountainbigbull]

Does it bog just at altitude and runs ok at lower elevations? If so check the DPM tubing going into the carbs. My ZX tubes deteriorated and were loose on the push on fitting on the PTO side carb causing a rich mixture when I really worked it in deep snow. I think the clutch heat deteriorated the tubing over time. When I change all the tubing she ran really good!

Also there is a o-ring on the needle valve on the carb I heard that can leak and cause a rich condition.

 

[mountainbigbull]

Hey Summit_VLP we are from the same town I can come over and have a look at it if you want?

 

[Modman]

May have to adjust your carb needles. Some times that will give you a mid range bog.

But he's bogging at wide open throttle, he'd have to change main jets anyway.

How low is the elevation and what are your pipes set up for? My Jaws twins are the high alt ones and they do not do well below 3000 ft. Does it only do it at low alt and how long have you owned the sled? Did it just recently start or has it always been like this? If you have run it before and it was fine and then all of a sudden it is starting to bog, then I wouldn't suspect the previous setup or jetting. If it has always been like this then you will have to work the setup. If A&E set up the sled for lower elevation and you're running higher up in the hills, you might need to drop jet sizes if the baseline is too fat, regardless of the DPM compensation, a fat baseline is a fat baseline.

Hope that helps!

Happy Holidays Everyone!

 

[Vertical-Extreme]

Hey Summit_VLP we are from the same town I can come over and have a look at it if you want?

it seams to be better, at elvation. it is just sputtering through the middle a little bit but once it cleans itself out it goes good, or if you ease into full throttle it is fine. it is just a touch fat through the midrange. I will check my dpm lines today (im in whitefish right now).
it might need a needle adjustment, or a good carb cleaning. it is just 4-5 seconds of sputter, so it is still ridable but....
merry christmas

 

[mountainbigbull]

it seams to be better, at elvation. it is just sputtering through the middle a little bit but once it cleans itself out it goes good, or if you ease into full throttle it is fine. it is just a touch fat through the midrange. I will check my dpm lines today (im in whitefish right now).
it might need a needle adjustment, or a good carb cleaning. it is just 4-5 seconds of sputter, so it is still ridable but....
merry christmas

Check you exhaust power valves almost sounds like they could be sticking and are slow to react.

 

[Vertical-Extreme]

Check you exhaust power valves almost sounds like they could be sticking and are slow to react.

i have a few things to check when i get back from whitefish before i go to fernie on the second. if i don't have it solved maybe we can have a look at it when i get back to airdire.
cheers
Trevor

 

[mountainbigbull]

i have a few things to check when i get back from whitefish before i go to fernie on the second. if i don't have it solved maybe we can have a look at it when i get back to airdire.
cheers
Trevor

For sure just let me know how you make out. I will be leaving on the 31 to the 5th of Jan. Going to Revelstoke/Sicamous!!