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Discussion Starter · #1 ·
I'll try to include all info. Hoping this is a common issue so I don't have to start from scratch.

Sled: 2001 mxz 800
v3 v-force reeds
stock exhaust (Don't know if it had aftermarket exhaust before I got it, may have
and possibly bigger jets still???)

Ok here's the story. When I bought it, someone had stolen the gas cap off so I didn't even get to hear it run. It had been raining so I siphoned the gas out of the tank and put in fresh gas (and dry gas). It fired right up and idled a little below 1000 rpm. A buddy adjusted the idle as we were checking it out. We did a comp check. 140lbs per cylinder. At that point, we noticed I needed new plugs. I replaced the plugs before going north for the weekend. When I arrived up north, I purchased some 2 stroke oil. I had no idea what was already in the tank, but I bought the brp vps synthetic. It had been smoking a lot more with the oil that was in there.
After I had run about a tank and a half of gas through it, it started running rough. That's when I remembered the left cylinder plug wire felt funny when I changed the plugs. I looked inside the boot and noticed the metal clip was mis-shapen. So I cut the boot open and re-shaped it so I could finish the weekend. I also changed the plugs again. It still seemed to be skipping though.
During the next ride, it started idling at about 3800-4000 rpm. Right before the clutch kicks in on mine. When idling that high, it didn't skip. It doesn't feel like the cables are sticking. If I "snap" the throttle real quick it will idle down. But only if I snap it real quick. Sometimes if I get it to idle down, it will run rough.
Somebody told me something about some switches on the mpem that may need to be continuity checked or reset.

What do you guys think. I know it sounds like it may be running lean, but looking at the plugs it's on the real fat side of normal. Some of that water frozen inside? Junk hanging up the slides?
 

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700GSE said:
I'm not sure, but I think that's just the nature of the beast - all series III with flatside carbs do that... If there is a solution, please fill me in, cause it's damned annoying!
[snapback]683165[/snapback]​
My 01 Mxz 800 does the same thing. With the vforce reeds it seems to idle real high until i hit the throttle. Always have to use a little throttle to start it when its warm. My brothers 02 does the same thing.
 

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I'd clean the carbs, making sure your pilots are clean. Then check your reeds. I know you said they were V-force but I've heard they have been known for having the reeds crack, and the cages warp from the heat, beeing they are plastic. Just my $.02. Good luck, and let us know!
 

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I got a coupla pieces of data on this. First, the 3-series engines are jetted pretty lean at idle, prolly for emissions purposes. That'll raise the idle speed. Then, I just recently discovered that my oil pump doesn't return to full "home" position unless I do the "quick snap" of the throttle thing that you described. Upon this discovery, I adjusted my technique at coming to stop signs, etc., waiting for traffic to cross a road, continually ensuring that the throttle (and the oil pump) "snaps" shut. This, alone, decreased my oil consumption from about 23:1 to 35:1.

Bottom Line: the high idle is kinda the "nature of the beast".

My Sled: 2001 MXZ700, stock, Amsoil AIO.

Mark
 

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Discussion Starter · #7 ·
Well, here's what I did.

I replaced both spark plug boots. Probably nothing to do with it, but they were bad.
Fixed leaking coolant line. It was getting coolant on the coil.
Added carb cleaner to gas and used the spray cleaner. Hoping the spray cleaner started the job and the additive will finish it. Douched the linkages on carbs with wd-40, and also the coil that was getting wet.

Doing a lot better now. Everybody I talked to kept telling me it was normal for these to rev high, but they weren't quite understanding what I was trying to say. I understand it's normal for them to be reving high after you come to a stop, then they idle down. Mine was STAYING at 4000 rpm and not "shifting" down because of the high revs. It's a lot better now. When I come to a stop it's in the high 2000 range to 3000 rpm, then idles back down to under 1000. I had turned it down when it all started now I need to re-adjust it. It's also "shifting" down properly now.
The other annoying thing it was doing when I had this problem was the need to hold the throttle open when starting. I think I mentioned that, but anyway no more of that either. This spring when riding season is over
I'll strip everything right down, including carbs, and thouroughly clean and inspect everything. Keep it looking and running brand new. The previous owner did a good job maintaining this thing and I'll continue. Once it starts looking or acting like a rat, I'll sell it and use the money for a down payment on a RevX 800 H.O.
 

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Discussion Starter · #10 ·
Yeah I had turned the idle down out on the trail when the problem started. That was my other clue that my particular situation was unique. It effected idle speed in no way, unless I snapped the throttle. And even then it was still higher. Oh well going normal again now.

I'd like to try those venturi dividing gizmos out. They are kind of expensive. Anybody know someone who has tried them?
 

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Ksmith said:
700GSE said:
I'm not sure, but I think that's just the nature of the beast - all series III with flatside carbs do that... If there is a solution, please fill me in, cause it's damned annoying!
[snapback]683165[/snapback]​
My 01 Mxz 800 does the same thing. With the vforce reeds it seems to idle real high until i hit the throttle. Always have to use a little throttle to start it when its warm. My brothers 02 does the same thing.
[snapback]683324[/snapback]​
your jets might be pluged up or carbs need to be cleaned.
 

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Sparky8370 said:
I'll try to include all info. Hoping this is a common issue so I don't have to start from scratch.

Sled: 2001 mxz 800
v3 v-force reeds
stock exhaust (Don't know if it had aftermarket exhaust before I got it, may have
and possibly bigger jets still???)

Ok here's the story. When I bought it, someone had stolen the gas cap off so I didn't even get to hear it run. It had been raining so I siphoned the gas out of the tank and put in fresh gas (and dry gas). It fired right up and idled a little below 1000 rpm. A buddy adjusted the idle as we were checking it out. We did a comp check. 140lbs per cylinder. At that point, we noticed I needed new plugs. I replaced the plugs before going north for the weekend. When I arrived up north, I purchased some 2 stroke oil. I had no idea what was already in the tank, but I bought the brp vps synthetic. It had been smoking a lot more with the oil that was in there.
After I had run about a tank and a half of gas through it, it started running rough. That's when I remembered the left cylinder plug wire felt funny when I changed the plugs. I looked inside the boot and noticed the metal clip was mis-shapen. So I cut the boot open and re-shaped it so I could finish the weekend. I also changed the plugs again. It still seemed to be skipping though.
During the next ride, it started idling at about 3800-4000 rpm. Right before the clutch kicks in on mine. When idling that high, it didn't skip. It doesn't feel like the cables are sticking. If I "snap" the throttle real quick it will idle down. But only if I snap it real quick. Sometimes if I get it to idle down, it will run rough.
Somebody told me something about some switches on the mpem that may need to be continuity checked or reset.

What do you guys think. I know it sounds like it may be running lean, but looking at the plugs it's on the real fat side of normal. Some of that water frozen inside? Junk hanging up the slides?
[snapback]682808[/snapback]​
well is your air box right next to your throttle cables. cuz if it is take your air box off and if your idle drops then with the sled running move your throttle cables around. i have a mx 470 liquid that was doing the sametheing until i lossened my throttle cables up on the carbs. so i would check that.
 

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Sparky8370 said:
I'll try to include all info. Hoping this is a common issue so I don't have to start from scratch.

Sled: 2001 mxz 800
v3 v-force reeds
stock exhaust (Don't know if it had aftermarket exhaust before I got it, may have
and possibly bigger jets still???)

Ok here's the story. When I bought it, someone had stolen the gas cap off so I didn't even get to hear it run. It had been raining so I siphoned the gas out of the tank and put in fresh gas (and dry gas). It fired right up and idled a little below 1000 rpm. A buddy adjusted the idle as we were checking it out. We did a comp check. 140lbs per cylinder. At that point, we noticed I needed new plugs. I replaced the plugs before going north for the weekend. When I arrived up north, I purchased some 2 stroke oil. I had no idea what was already in the tank, but I bought the brp vps synthetic. It had been smoking a lot more with the oil that was in there.
After I had run about a tank and a half of gas through it, it started running rough. That's when I remembered the left cylinder plug wire felt funny when I changed the plugs. I looked inside the boot and noticed the metal clip was mis-shapen. So I cut the boot open and re-shaped it so I could finish the weekend. I also changed the plugs again. It still seemed to be skipping though.
During the next ride, it started idling at about 3800-4000 rpm. Right before the clutch kicks in on mine. When idling that high, it didn't skip. It doesn't feel like the cables are sticking. If I "snap" the throttle real quick it will idle down. But only if I snap it real quick. Sometimes if I get it to idle down, it will run rough.
Somebody told me something about some switches on the mpem that may need to be continuity checked or reset.

What do you guys think. I know it sounds like it may be running lean, but looking at the plugs it's on the real fat side of normal. Some of that water frozen inside? Junk hanging up the slides?
[snapback]682808[/snapback]​
try putting the original jets in it see if that makes a differance cuz it might i dont no.
 

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Ksmith said:
700GSE said:
I'm not sure, but I think that's just the nature of the beast - all series III with flatside carbs do that... If there is a solution, please fill me in, cause it's damned annoying!
[snapback]683165[/snapback]​
My 01 Mxz 800 does the same thing. With the vforce reeds it seems to idle real high until i hit the throttle. Always have to use a little throttle to start it when its warm. My brothers 02 does the same thing.
[snapback]683324[/snapback]​
hey try cleaning your reeds and adjusting your throttle cables and you might be running to rich or lean.
 

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Sparky8370 said:
Well, here's what I did.

I replaced both spark plug boots. Probably nothing to do with it, but they were bad.
Fixed leaking coolant line. It was getting coolant on the coil.
Added carb cleaner to gas and used the spray cleaner. Hoping the spray cleaner started the job and the additive will finish it. Douched the linkages on carbs with wd-40, and also the coil that was getting wet.

Doing a lot better now. Everybody I talked to kept telling me it was normal for these to rev high, but they weren't quite understanding what I was trying to say. I understand it's normal for them to be reving high after you come to a stop, then they idle down. Mine was STAYING at 4000 rpm and not "shifting" down because of the high revs. It's a lot better now. When I come to a stop it's in the high 2000 range to 3000 rpm, then idles back down to under 1000. I had turned it down when it all started now I need to re-adjust it. It's also "shifting" down properly now.
The other annoying thing it was doing when I had this problem was the need to hold the throttle open when starting. I think I mentioned that, but anyway no more of that either. This spring when riding season is over
I'll strip everything right down, including carbs, and thouroughly clean and inspect everything. Keep it looking and running brand new. The previous owner did a good job maintaining this thing and I'll continue. Once it starts looking or acting like a rat, I'll sell it and use the money for a down payment on a RevX 800 H.O.
[snapback]685451[/snapback]​
you might have an air leak spray carb cleaner down around the carbs to see if your idle drops cuz if your idle drops then you have an air leak.
 

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ride&die said:
Sparky8370 said:
Well, here's what I did.

I replaced both spark plug boots. Probably nothing to do with it, but they were bad.
Fixed leaking coolant line. It was getting coolant on the coil.
Added carb cleaner to gas and used the spray cleaner. Hoping the spray cleaner started the job and the additive will finish it. Douched the linkages on carbs with wd-40, and also the coil that was getting wet.

Doing a lot better now. Everybody I talked to kept telling me it was normal for these to rev high, but they weren't quite understanding what I was trying to say. I understand it's normal for them to be reving high after you come to a stop, then they idle down. Mine was STAYING at 4000 rpm and not "shifting" down because of the high revs. It's a lot better now. When I come to a stop it's in the high 2000 range to 3000 rpm, then idles back down to under 1000. I had turned it down when it all started now I need to re-adjust it. It's also "shifting" down properly now.
The other annoying thing it was doing when I had this problem was the need to hold the throttle open when starting. I think I mentioned that, but anyway no more of that either. This spring when riding season is over
I'll strip everything right down, including carbs, and thouroughly clean and inspect everything. Keep it looking and running brand new. The previous owner did a good job maintaining this thing and I'll continue. Once it starts looking or acting like a rat, I'll sell it and use the money for a down payment on a RevX 800 H.O.
[snapback]685451[/snapback]​
you might have an air leak spray carb cleaner down around the carbs to see if your idle drops cuz if your idle drops then you have an air leak.

[snapback]686165[/snapback]​
it is not normal for these sleds to rev high like that cuz my cousin has a 2001 mxz 500 and i only idles at 1500 rpm and that is the normal rpm.
 

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It's it's a lean idle condition, when tuned right the rpms will fall back to idle speed quickly when cold and hang for a few seconds hot, also when correct it will usually require a little throttle to start when hot.

two things (maybe 3) can cause this lean condition. #1 is the setting of the mixure screw, it may need to be richend a tad by turning it out, try 1/4 to 1/2 turn.

#2 is the actual height of the slides at idle, this is adjusted with the idle speed screw. It's a big player in the "idle hangs high thing" because if the slides are high more air is flowing and the idle mix circut has a hard time supplying enough fuel to mix with it (goes lean). Since RER seems to work better with the idle higher doo idle calibration are set on the high side, which is partial reason why everyones fighting this. This is true with all carbs it just seems the flats are more sensitive.

Bottom line is get the slide heights low enough for the mixure circut to work, and adjust the mixure screw as needed.

The 3rd reason that you hear bantered about is the air leaking past the slides. The product linked above might? help, but Im not convinced. If the air leaking past the slide was consistant (it should be) then you'd be able to tune for it. That's why I wouldn't point a finger at it as a cause but maybe? something that adds to it. A little oil in the fuel goes a long way in keeping slide wear in check BTW.
 
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