Engine Bog @ 1/8 to 1/2 Throttle

L

Little Boy Blue

New member
Joined
Dec 29, 2003
Messages
4
Location
Canada
Hi everyone,

My 2001 MM 700 has a small problem. When running powder at 1/2 to full throttle the machine acts fine. However, when you back off the gas to 1/8 through 1/2 throttle and attempt to go around something, the engine loads down and does not want to pull. Snap the throttle open and the engine will clear itself and it will run to 8300 rpm. On trail running is good throughout the throttle range. When in powder with the engine acting up, just find a previously run track and the engine clears up.

The sled is stock with the exception of reed spcers. Clutching and jetting is set for sea level. I ride at 0 to 3000 feet. Track is a yoko 1.1 "

Any suggestions.

Chris
 
I've heard of reed spacers causing various bogs.

Couple questions:
How old is your belt? If your deflection is off, it can cause low speed bogs.

How long ago were the carbs cleaned? If it's teh carbs, it's probably a problem with your pilots, but it's hard to tell if it's lean or rich over a computer. My guess would be that it needs more air.

Does it bog from a standstill?
 
A buddy had the same problem, we pulled the pilot jets out and cleaned the crud out of them. Looked like it might been belt dust. Those pilot jets have pretty small holes and can get plugged pretty easy, when theres a little dirt in the carbs.
 
The belt was installed late last year. It has roughly 500 to 600 miles on it.
However, I have not checked deflection. I will make a point of doing this over the weekend.

I completly strip my carbs and clean them before the start of every season. They were cleaned this year and I have run 300 to 400 miles.

Low speed running on packed snow is perfect. Its only when I'm running in powder that there appears to be problem.

From a standstill to full open throttle the machine runs great. However, work the throttle a little before you punch it and she hesitates.

My first thought was the same as yours - more air required.
If this i so, where would you suggest I start?

Thanks Mtnviper, vmaxjohn.

Chris
 
To check if your bog is lean or rich do this... at idle flip on the choke for 2-3 seconds, flip it off and punch the throttle. If bog is worse its a rich bog, if bog is near gone you have a lean bog and the extra fuel from the choke helped. To fix you need more fuel early in the circuit (fuel screw out/ bigger pilots/smaller air jet).

If you only get bog when in the powder, you may be choking off the exiting exhaust on the right side, or sucking in snow into your airbox somehow.

Do you have pipes or modified airbox?

I had a prob once with primary clutch sticking, replaced bushing all was good.

Hope this helps.
 
I am having the same problem. Did you solve it? If so what did you do?
Also, is it normal for the clutches to get real hot in the powder?
 
It's 3 am, and I just got back from riding, so maybe I'm too sleepy to make sence, but could it be that it is just not backshifting enough, causing a "bog"? Try tightening your secondary 10 degrees or so and see if that helps it. Usually deep snow will let your track over spin, and if you let off the throttle and get back in it, the clutches might not have back shifted enough yet, causing a bog. Good night. I have to get up in 3 hours to RIDE SOME MORE! YEAH!!!! :D :D (I think I have a snow-boner)!
 
A couple of people told me that the snow dust is getting on the clutches causing them to slip and sucking the belt down in the secondary causing it to bog.
Im going to duct tape off my hood vents and see what happens.
 
KISS principal = Keep It Simple Stupid. Eliminate the simple first!

You might check that you don't have excess powder in the filter and air box causing breathing problems. I've also seen a lot of powder sleds with a deflector in front of the exhaust outlet to keep excessive back pressure from building up while in the deep stuff. Not sure if your's has it.
 
As suggested by Venture500 and InTooDeep, you might try an exhaust deflector. This is a common addition to Mountain Vipers. It clears a path for the exhaust to exit in deep snow.
 
You must log in or register to reply here.


Back
Top