The infamous powder bog

I was thinking more along the lines of High Temp + High Humidity = Low Density Air. Your thinking High Temp + High Humidity = High Pressure. Got it.
 
Oh I forgot I ran the sled the hole time with the carb heaters off so that didn't seem to make a difference for me!!!!! :o| But what ever works for you keep doing!!!!! ;):D
 
Hi guys!. I haven`t read all post thorougly but I just wanted to write a few words.
I ride a mountain viper with an aftermarked canister, dunno what brand. I havent experienced any bogging problems yet, went riding in some pretty deep stuff last season, and no bogging. Although I guess you guys may have more powder in certain places in USA, but like I say I havent been able to trigger the powder bog yet.

We have a set of triple pipes lying around at work, but my boss said that I would probably get some powder bogging issues with them because they did when they tried them on a Viper ER. So, I stepped away from the deal.

I remember on my SRX, I had huge bogging issues. I got a deflector, cold air kit, pre filter, but I still got some bogging. Eventually I taped off all the air vents in the hood and then the sled did run better. But the bog was still there.

Can the difference in exhaust pressure from a single pipe where all the exhaust from three cylinders are gathered and then pushed out, have something to do with it?. But why doesn`t the cat`s have bogging problems?. Or maybe they do?.

I hope someone finds a cure for this because I know how annoying it is.. .
 
gild said:
What I Believe is that steam is increasing underhood pressure which in turn pressurizes the float bowls causing sled to go rich. It has nothing to do with air intake density. If the vents are plugged hood pressure will increase. On the older sleds SnowTech mentioned that the SRXs under higher speeds went rich because of the change in under hood pressure. I am not sure but I thought the Viper was vented to the airbox so any underhood pressure spikes caused by steam would enter through the drain holes and pressurize the airbox causing an instant rich condition which causes the bog.This only happens witha totally covered hood and a shot of steam that is why with no hood there is no change in airbox pressure no matter how much steam is created.Then you have an air snow injestion problem.
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It could be under hood pressure, but with all the vents in the hood and foot wells, I do not see how it could pressurise (sp?). Make sure your Air box is well sealed to the hood. Like I said before I never bog. Is everyone who is bogging running after market painted triple pipes? I just rode with two friends with stock singles and me with ceramic triples. We rode 30+ miles breaking trail, over the bumper and or hood most the way (36 of new powder) no bogs at all. :dunno:
 
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My 01 MM 700 powder bogs but only when carving hard to the right.
It did it with the stock exhaust and with ceramic coated Bender triples.
I does not matter if the hood is covered or packed with snow, it will only do it when hard carving to the right. This makes me think my issue is exhaust.
I have an exhaust deflector but without removing it I don't know if it makes any difference or not.
 
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M-Max said:
My 01 MM 700 powder bogs but only when carving hard to the right.
It did it with the stock exhaust and with ceramic coated Bender triples.
I does not matter if the hood is covered or packed with snow, it will only do it when hard carving to the right. This makes my think my issue is exhuast.
I have an exhaust deflector but without removing it I don't know if it makes any difference or not.
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I have one friend with the same problem, we are still working on a solution. He throws it right and boooog, swings left instant power.l
 
Sorry, I just remembered this.

There is a guy here in town that has an atv/snowmobile repair and mod shop. He basically fixes them or puts on whatever mod you desire. Three years ago he had an 03 Mnt.Viper. He triple piped it the first season and rode it that way. It had the bog, but only about as bad as what my sled does (has to be pretty light "fluffy" snow). Before the next season he stretched it to a 156", different tunnel, MPI head, anti-ratchets, NOS, handle-bar risers, and put on a mesh lightweight hood. The screen hood is going to be like no hood at all as far as underhood getting pressurized. He sold it in the middle of that season. He said it made the powder bog soooo bad that it would barely stay running when he got off the trail, and it wasn't just "fluffy" powder anymore. I told him the screen hood was what made it so much worse IMO, but he said he was too disgusted to even bother trying to fix it.

To me, this enforces the idea of not letting any snow get under the hood. His screen hood allowed even more snow to enter, and made the bog even worse than it was with the factory hood.
 
I agree 100 percent with you mod.....there is something going on either with the pipes cooling or the humidity under the hood or both that make these #$%&* bog. I also think that on an 121" srx the deflector makes a difference, from my testing. :o|
 
OK guys I did a little testing for you this week! I took the first part of my airbox off and I taped my drivers side ram air vent closed with duct tape.In 3 ft or powder I got tons of powder bog all day. So when I got home I put the top of my airbox back on and went out and ran it again.! BOOM ITS ALL GONE! it ran perfect. SO I think it has something to do with the air box! I have hauck painted tripple pipes. and mech steel vents, so the powder is always hitting my pipes and no bog, it all has to do with the air box.. ohh and my carb heat was off, and my my hood was covered with powder all day! ok thats my.02.. good luck!
 
powder bog

Was out this aft wicked storm happening couple inches an hour at the time packing 3 ft of powder on a pond for the groomers first pass
across later this week.The steam is an issue but what would cure the bog right away was shaking the water and snow off the foam pre filter. When it's wet like that restriction makes it really rich plus with the steam.
Helix
 
mightymg said:
OK guys I did a little testing for you this week! I took the first part of my airbox off and I taped my drivers side ram air vent closed with duct tape.In 3 ft or powder I got tons of powder bog all day. So when I got home I put the top of my airbox back on and went out and ran it again.! BOOM ITS ALL GONE! it ran perfect. SO I think it has something to do with the air box! I have hauck painted tripple pipes. and mech steel vents, so the powder is always hitting my pipes and no bog, it all has to do with the air box.. ohh and my carb heat was off, and my my hood was covered with powder all day! ok thats my.02.. good luck!
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ok Test number 2! well seemd the bog wasnt gone,. I thoguht it was.. well the powder on the first test just wasnt deep enoguh so it was a combo pf two things im certain! first air box cant be open it needs to be sealed to the hood. 2nd deep snow riding means you must have a exhaust deflector. just like many of the posts on here say! whenever i sidehilled on my exhaust side major bog unles my rpms were up. whenever i stopped in really deep snow ( 2ft or more of straight fluff) i would have to clean the snow away from my exhaust out let or it wouldnt alow me to build rpm... as soon as I cleared the snow wiht my hand it ran perfect..

so in conclusion

#1 airbox sealed!

#2 Exhaust deflector... im gonna build one this week Ill update if that fixes it completely or not!
 
I forgot to mention I also put a prefilter on my underhood intake not on the air box, but on the hood its self. I have never had water or even heavy moisture build up on the top of my airbox. I have had enough steam coming out from under ther hood that it look like a engine fire. Still no bog.
 
Interesting, so you put a pre-filter across the openings under the hood that funnel under hood air to the box? Your not meaning the hood vents, correct? How did you attach the pre-filter to the hood? TIA
 
mightymg said:
ok Test number 2! well seemd the bog wasnt gone,. I thoguht it was.. well the powder on the first test just wasnt deep enoguh so it was a combo pf two things im certain! first air box cant be open it needs to be sealed to the hood. 2nd deep snow riding means you must have a exhaust deflector. just like many of the posts on here say! whenever i sidehilled on my exhaust side major bog unles my rpms were up. whenever i stopped in really deep snow ( 2ft or more of straight fluff) i would have to clean the snow away from my exhaust out let or it wouldnt alow me to build rpm... as soon as I cleared the snow wiht my hand it ran perfect..

so in conclusion

#1 airbox sealed!

#2 Exhaust deflector... im gonna build one this week Ill update if that fixes it completely or not!
Click to expand...

I've been following this thread closely since it started and since my first reply, nearly 1.5 months ago... i was hoping, maybe there was something else to this "bog" that is so familiar to my sled too...

seems maybe it is an exhaust backpressure problem after all...

my 02MM has a stock deflector installed and it doesn't help 100% of the time....
if you are building one, be sure to alter design from stock and make it more aggressive.... then post pics so we all can make one like it....

tj..
 
When my sled bogs when I first start it in deep deep powder, it bogs and I cant get the Rs up, but when I reach under the pipes and clear the heavy powder away the rs climb instantly like normal, so Im gonna build a bigger deflector to block the front and underneath, kind of like the king cat... And im gonna do your idea of the pre filters on the hood.... Ill let you know if it works...
 
Something new I'm trying this year that has made a difference so far. Is block off the underhood inlet air with a thin piece of aluminum plate. Then drill a bunch of 1/2" holes in the rear facing surfaces of the cowl. Also around the gauge pod mount. I have flowrites in it already, however the additional holes seem to give the motor the air it needs.
Also a couple of years ago I pulled the upper and lower LH screens. Then modified the lower RH screen so snow can fall though and keep the vents clear. This helps keep the pipes/underhood from getting to hot.
When I had the screens in and was working hard through the deep heavy snow. I actually dis-colored the ceramic coating on the pipes down at the area were the pipes run close together. Because there was no air flow around the pipes.
If you run without screens, pretty much need to block off the underhood air inlet to the air box, so the motor dosn't suck in any steam.
I also use an exhaust deflector.

Bill
 
new plug caps solved my probs, 98 xt 700 with triple haucks,cant beleive how much time i lost figuring this one

Pat
 
Plug caps keeps coming up, and I just read a thread in the general section that said the same thing. He put di-electric grease in his caps and put a wrap of electrical tape around the plug and cap...said problem was gone (SRX). This is also what Chevyracer68 said cured his. I still haven't rode yet...but finally got the sled out to start getting it ready, just have normal stuff to do. I guess taping up the plugs will be the first thing I try, and then go from there. I'm also curious about A K Mntviper's trick of putting pre-filter material in the openings in the hood where the under hood air passes through to the air box. Maybe letting the moisture collect there instead of on top of the air box filter is the ticket? We'll have to see.

I'm not going to rule out anything yet, but my bog isn't better/worse no matter which way I carve. I doubt that the exhaust deflector is my problem. It is specifically when snow hits the hood vents and enters the engine compartment. Those of you building a bigger one...be careful not to have it so low that you are hitting stuff with it and tear up your belly pan.
 
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