2003 900 cat question

Halman · Jan 1, 2008

my buddy owns a 2003 900 cat and has problems when he gets into deep powder. on the trail, it is fine and runs great, but as soon we jump off the trail it bogs down. I'm thinking the motor is getting starved by the snow and it cant breathe, so to speak. is there anybody else with this issue who fixed it and/or anyone with some insight or advice for him. Would prefilters be better than the air box or is there some way to cut vents so it can breathe? Or is this even the problem. It is completely stock. any help is much appreciated! THX

cmantle1 · Jan 1, 2008

common issue

before the m chassis, this was a very common problem. See if his sled has a exhaust deflector, if it doesnt, make one. there are lots of threads on hrre about them, and they make a huge difference. if the problem persists after you install the deflector, try a cold air intake kit. Both of those will definently solve the problem

cmantle1 · Jan 1, 2008

thread to help.

heres the thread about the deflector and intake system

http://www.snowest.com/forum/showthread.php?t=48251&highlight=spank

good luck and hope it works out

wastedeep · Jan 1, 2008

my 03 800 had the same issues
in the deep it would bog
i built a shock well secondary exhaust pipe
in the deep snow the stock exhaust get restricted even with the deflector
with this extra pipe the back pressure has some where to go
good luck
HNY

Halman · Jan 2, 2008

Thx for the advice

i appreciate all the help fellas...i did go look and the sled does have an exhaust deflector but not a very good one, i think it might need a bigger one....hey WASTEDEEP what in the world is a shock well secondary exhaust pipe? Is this a whole new exhaust or a add on...im a little lost, sorry....Also where would you guys get a cold air intake mod from....SLP or do you guys recommend somewhere else???? once again thx a bunch

cmantle1 · Jan 2, 2008

wastedeep is talking about re routing your pipe(s) to the shock well. basically this makes it like on the new m series. i found that this can be a good solution, but the air intake/deflector works really well too. you said the deflector on ther e now is small? mine was too so i made it bigger and it works well. As for the airbox, i have yet to do it to my 900. But, another memeber on here took a slp airbox and custum made a snorkel coming out the top. he said it works great and hasnt had a bog since. overall, i think both of the options work well, just mostly preference. rerouting the exhaust isnt exactly dirt cheap, but niether is a new airbox...im doing ok right now with just a big deflector, but the airbox is on its way...
goodluck!!

Sledbrain2 · Jan 2, 2008

Is it snow over the hood that does it? I on the air box on the mag side they put the boot half in and half out of the air box. There can be a gap there when the silicon deteroiates. As soon as a bunch of snow hits that gap it will starve the motor. It will also cause a lean condition on the mag side as well

Bill1010630 · Jan 2, 2008

03 900

My 03 900 did the exact same thing, carbs were icing up,04's have engine coolant flowing through the carbs to aleviate this problem. On deep powder days I would place duct tape on the inside of the belt side vents and it cured the problem.

Halman · Jan 3, 2008

thanks cmantle. sledbrain and bill.....ill try out the suggestions and go riding this upcoming weekend.....i really like the idea of rerouting the exhaust...ill look into it! once again thx

amery3 · Jan 3, 2008

In addition to the exhaust defletor, make sure to use lots of high temp silicone around the hole where the exhaust exits the belly pan. You can alleviate the problem just by making sure there is no way exhaust can go back under the hood. the issue isn't that snow is plugging the pipe, the snow, being packed around the bottom of the sled prevents exhaust from leaving the underside of the sled.

This creates a pocket of exhaust that has nowhere to go, it will take the path of least resistance, and if there is snow all around and there is a gap where the exhaust outlets, it is easier for the exhaust gases to go through that gap, and under the hood than it is to push through the snow. The exhaust deflector helps prevent this by creating a channel for the exhaust to travel throughout the back.

If exhaust enters under the hood, (via the gap that you didn't fill with silicone around the belly pan) it gets sucked into the airbox through the underhood air vent and you suck in exhaust fumes into the airbox and ultimately the engine that are low in oxygen. this makes the engine enter an overly rich fuel/Oxygen ratio and the engine bogs as a result.

wastedeep · Jan 24, 2008

its two pieces of pipe that are welded together
one fits on the tail end of the can (muffler) and the other end goes up to the shock tower
i used 1.5" dia tail pipe and a short piece of 2.5"
i think that holtz racing sells one like it
u can check there web site
good luck
sealing up the exits well it does help alot

JENSEN BROS · Jan 27, 2008

slp covers for the intakes by your foot wells. also make a rectangle of foam to cover the top of the carbs. keeps the snow off the carbs and keeps them warm. the slp intake grate covers work wonders. can get them from hi performance engineering for about 20.00 they say they come each but the pack is a two pack. purchase two sets in case you lose one. it is the fix for deep snow that everyone is missing. also make sure that your air screws are at 2.5 turns and the fuel screws are 1.5 turns or less. keeps the engine warmer at lower speeds and less touchy to water ingestion.

teammugad · Jan 28, 2008

So I have a 04 efi 900 and I have the same problem. I have the exhaust out the shock well, Pre-filters on the intake grates, I even put another layer of pre-filter on the intake on top of the airbox. The only thing I haven't done is seal the exhaust. It still bogs. What else can be done to COMPLETELY eliminate this bog?

Thanks,
Kory

teammugad · Jan 28, 2008

Anyone?

grayghost · Jan 29, 2008

The fix that helps this problem out the most is to get your jetting correct. If you are rich you will bog mid-range is critical to have spot on and this will cure your bogging issue.

LSB · Jan 29, 2008

grayghost said:
The fix that helps this problem out the most is to get your jetting correct. If you are rich you will bog mid-range is critical to have spot on and this will cure your bogging issue.

bingo

lean it out. I did this with mine and it helped clear this up quite a bit. I still might do an exhaust reroute but I almost dont think there is a need to anymore. You have to think that on most days when its super deep snow (enough to cause this bogging issue) its also snowing hard and generally a warmer day (as in 25-30 degrees). Your gonna be running rich in those temps anyway nevermind all the snow over your hood blocking airflow and keeping underhood temps even higher. LEAN it out

teammugad · Jan 30, 2008

What can I do to lean out an EFI?

Kory

JENSEN BROS · Jan 30, 2008

you can put heavier weights in to load the motor more and make more heat to lean it out. i run polaris weights 10-66 in the mountians. have a pipe, head, reeds, 2 degree timing advance key way and gutted air box. you may try the 10-64 to start. you can use yellow green or red primary and a red/white secondary spring with a 53 degree helix. this works very well on my brothers 900 efi. good luck.

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2003 900 cat question

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