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thanks thumb doc! ive read alot of your posts here, you have been a big help for ALOT of us folks.
i will run these tests you mentioned and get back to you.
a few things to remember:
in cold or warm weather the sled still act this way, BOGGS at higher rpm/speed.
once started the sled runs good for anywhere from 5 minutes to 1 hour then it starts to BOGG at high rpm.
the first thing we did was go thru the carbs, clean and even replace and adjust jets.
(after the carb work we did ,the sled still acted up the exact same way.)
the compression should be good, because the entire engine has now been totally rebuilt.

forgive me though if i sound like a rookie ( GUILTY )
my buddy works on sleds alot he's doing most of the work for me.

anyway i really appreciate your input cuz you obviously know a lot about sleds.
I'll run these tests and post the results soon.

Thank You!
BiLL[/b]
Bill,

Never assume that since it's been looked at that nothing was over looked. Most of the stuff I recieve is in boxes that "mechanics" had their hands in. I will be asking you to over see some of the operations because if you want it done right DIY. Get back to me with the Carb stamped numbers (in respect to MAG & PTO sides) main jet numbers, pilot jet numbers and take out the float needle seats and see if you can look straight through the fuel line connection to the hole that the float seat screws into. If there are screens, ditch them right away. I will also need some photos of various components along the way. Let's hope this trip is a short one.
 

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Discussion Starter · #24 ·
Rob : Thanks for the input bro. thats something i never did think of. i will try it!
it may at least give me a few clues or leads.
im guessing tho (in my case) this wont be the source of the problem but like i said before i am a ROOKIE at sleds (but not cars). but I was thinking because i have one plug getting a little wet that the problem isnt from lack of fuel but instead from either lack of spark or too much fuel?
Thanks Rob, i will post the results soon.

THUMB DOC:
Great point about DIY if you want it done right. i do totally agree with that.
Again, Thanks so much for your time, i really appreciate your help my friend.

Let me know which components , i will get you the photos.

Also i will soon post the Carb stamped numbers (in respect to MAG & PTO sides) main jet numbers, pilot jet numbers and take out the float needle seats and see if you can look straight through the fuel line connection to the hole that the float seat screws into.

I have already ordered the new coil (and plug wires), but in the mean time i will try to get as much of the info as i can from your previous post to see what you might make of it.

We did the compression test = 150 both sides (very good i think?) as it should be after the rebuild.

this sled ran great for a long time. then one day it started having the BOGG @ high rpm/speed problem. i took it to my local sled repair shop. the first thing they did was:
change plugs.
cleaned the carbs (new jets) (adjustments/settings).
and i think they also cleaned the clutch.
new belt.
all that and possibly a few other tune up things i may be forgetting about.
and still the sled had the same bogging problem.
so we rebuild the engine crank and everything. (had over 5,000 miles on it.)

Still had Bogg problem.

Then i took it to my buddies (he knows quite a bit about sleds anyway.)
he inspected the secondary clutch SPRING ,it didn't appear stretched or twisted/bent in any way.
replaced stator.
check all wires and wiring harnesses ,fuel lines.
tested for spark (good).
compression test 150/150.

Still Bogg.

Next will be install the new coil and get thumb doc the info on my carbs he mentioned.

i like this sled alot.
when it was running good it was VERY FAST and fun too ride.
its gonna be a lot of fun to ride if i can get this problem solved.


BiLL
 

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Bill,

One common problem would be the fuel pump diaphram being pierced. It would cause the crankcase side that the fuel pump pulse line is connected to to run rich in the low end and starve both carbs at high speed. Here is a link to another post which I explain fuel pump operation.

http://www.snowmobileworld.com/forum/index...st&p=576654
 

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My first POST!
I've read so much here, ALOT of great info and peeps here seem very cool and willing to share info and ideas. Thank You for that!

anyway, i own a '98 MXZ 670 Rotax. (i love it!) but maybe not for long.
one day it started Bogging at higher speed (top end)
and seemed to do it more when the sled gets warmed up.
it wouldn't always bogg but most of the time it did, again only at higher speeds like 35 mph and up..
so first i had the carbs and clutch cleaned. NO GO.
then, top half engine rebuilt. NO GO.
then, crank seals replaced bearings all checked out good. NO GO.
then, spring in secondary clutch we looked at it (it didn't look bad or stretched or twisted?)
and now we are thinking about getting the STATOR rebuilt :(
next will be coil?

Its starting to cost a lot of money but i really like this sled, when its running good it has a lot of (BALLZ!).So im really hoping the STATOR will be the solution. i read a lot of good ideas from you all here in the forum. Would love to hear from you if you got any advice or suggestions or SUPPORT :(

Thank You.
BiLL
:bash: :bash: :bash: :bash: :bash: :christmas: :christmas: :christmas:[/b]
Repalce your fuel filter and see what happens. You are probably not getting enough fuel due to restriction in the fuel filter.
 

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how about your fuel lines? make sure that you dont have a kink in them, also there are on some skidoos there are small filters when you take the gas line off of the carb, there is a small sock filter small white one check that see if thats not gummed up?[/b]
His sled is a '98 which I think was the only year that 'doo used them. I pulled them out of my MXZ500. Bro didn't take them out of his wife's Formula 583DL & a few winters later they gummed up on their trip up north. Got to a dealer, left it w/ them & the mechs' there knew what the problem was & yanked them out. Sled never had a problem in all the years she had it other than that.
 

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Discussion Starter · #28 ·
The problem seems to be that the clutch side cylinder is not getting enough spark or getting too much gas at HIGH END / RPM ' s , because the clutch side plug is the side with the slightly wet plug and the side that is bogging i guess. Could a gummed filter cause this?

we havent changed the plug wires yet ,
and havent replaced the cdi box yet (but i heard when they go out they go out completely meaning like the sled would not even run or Die alot. mine doesnt do that.

next week im taking the sled into another shop to have a guy there check it over and look at the carbs.



P.S.
The Coil didnt Work. Still boggs.

BiLL
 

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The problem seems to be that the clutch side cylinder is not getting enough spark or getting too much gas at HIGH END / RPM ' s , because the clutch side plug is the side with the slightly wet plug and the side that is bogging i guess. Could a gummed filter cause this?

we havent changed the plug wires yet ,
and havent replaced the cdi box yet (but i heard when they go out they go out completely meaning like the sled would not even run or Die alot. mine doesnt do that.

next week im taking the sled into another shop to have a guy there check it over and look at the carbs.
P.S.
The Coil didnt Work. Still boggs.

BiLL[/b]
Check your main jets. They should be 310 PTO and 290 MAG running at sea level and -20C operation. What is your altitude and temperatures you ride at? Make sure the carbs are cleaned in all the passages including the main and pilot jet circuits.
 
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