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Hey guys so I’ve thrown the kitchen sink at my bike and I’m at a loss now. My 04 outlander 400 runs like a bag. When you snap the throttle it almost stalls and on a gradual acceleration it misfire and backfired just sluggish to get to the top end. When it’s at the top end of rpms she runs smooth as a whistle and easily does 90k/hr. So I have cleaned the carb, changed the carb to a new one, put a new plug, good used ignition coil, swapped crank sensors (which mine and the test one is at 930 ohms), changed the fuel pump, swapped cdi boxes, swapped voltage regulators, tested the resistance of the stator, and checked to make sure my kill switch wasn’t shorted. I can get it to run good when I adjust the carb but it will eventually after a short time of either sitting or sometimes even just running go back to doing the same thing. Fuel supply from the tank seems to be good, and the fuel is clean also went through two different tanks of fuel with two different stations. I really don’t know anymore. I have two videos of when it’s running good and running like a bag. Any ideas would be nice. I’m back to being suspicious of the crank sensor because according to the manual it’s out of spec.



hopefully the links work but basically show what I’m dealing with. Thanks in advance.
 

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Welcome to the site.

The crank sensor could account for those issues, but I thought the check engine light would illuminate, if it was working intermittently...... maybe not.

I otherwise would point the finger at the "new" carb, even those aren't tuned the best, out of the box, but it sounds like you've dealt with that. Running strong and fast at the top end typically rules out any fuel delivery issue, so fuel pump, last chance screen in the carb, prefilters in the tank, all should be cleared of contribution.

Hate to tell you to just go throwing money at it, but yeah, if those crank pos sensors aren't specing out according to the manual, gotta resolve that first.
 

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Discussion Starter #3
Thanks I appreciate the advice. I don’t think I have a check engine light on my cluster as it’s an 04 could be wrong though. The issue actually occurs with both the cleaned out original carb and the new carb. At this point I’ve thrown the kitchen sink at it so I’m gonna completely eliminate my fuel supply with fresh fuel and gravity feed the carb. If that doesn’t fix it. gonna buy an oem crank sensor and see what happens. Kind of running out of ideas at this point. My gut is telling me it’s the crank sensor as well so I appreciate it.
 

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Did you ever try running it off the reserve side ?
If memory serves , that will pull fuel from a separate filter within the tank .
 

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Discussion Starter #5
Did you ever try running it off the reserve side ?
If memory serves , that will pull fuel from a separate filter within the tank .

Hey there thanks for the response. Yes I have tried reserve and on position. Same issue is occurring.
 

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Discussion Starter #7
You're welcome .
Fuel pump diaphragm comes to mind then if you haven't already looked into it.
Thank you, for the response. Fuel pump has also been changed. I actually completely bypassed the fuel system and gravity fed the carb. Same issue is still occurring. When I snap the throttle it pretty much stalls out before a series of misfires and back fires as it revs up. I’m super suspicious of an ignition problem. Gonna put a crank sensor and update the thread.
 

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I just watch both vids,,,, after typing this reply ...
the first vid the engine has whats called a hunting idle & miss fire
then i noticed your muffler ! BACK PRESSURE !! fix or replace your muffler
these engines are designed to run with back pressure from the exhaust .
this is your first problem even a highly tuned hot rod with headers is designed with some back pressure in mind .





you may have gone through most of these ideas but throwing $$ at it will just piss you off.
remember that every system works in conjunction with each other.
eliminate the easiest one before moving on to the next one.
as you describe its flooding out as you pin the throttle.but runs fine at hi rpm to me this is a carb adjustment issue / spark plug issue or a CPS issue try adjusting or cleaning this first
reading spark plugs can tell you a lot about carb and engine condition issues.
is it flooding with fuel or leaning out ?
hows the plug after it stalls is it covered with fuel ? whats the plugs porcelain colour ? black too rich & if its wet = flooding. & if its light brown & dry its choking for fuel . after hi rpm run whats the plug look like ?
how is your air filter ? filter box ?
spark system are you getting good spark ? gap correct ? correct plug ?( dont trust new out of the box plug gaps )
is the plug wire / lead shorting out somewhere ?
timing = Could it be timing is slightly off ? parts worn or timing chain worn ? Crank pos sensor faulty. ?
hope this helps ..
 

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Discussion Starter #9
I just watch both vids,,,, after typing this reply ...
the first vid the engine has whats called a hunting idle & miss fire
then i noticed your muffler ! BACK PRESSURE !! fix or replace your muffler
these engines are designed to run with back pressure from the exhaust .
this is your first problem even a highly tuned hot rod with headers is designed with some back pressure in mind .





you may have gone through most of these ideas but throwing $$ at it will just piss you off.
remember that every system works in conjunction with each other.
eliminate the easiest one before moving on to the next one.
as you describe its flooding out as you pin the throttle.but runs fine at hi rpm to me this is a carb adjustment issue / spark plug issue or a CPS issue try adjusting or cleaning this first
reading spark plugs can tell you a lot about carb and engine condition issues.
is it flooding with fuel or leaning out ?
hows the plug after it stalls is it covered with fuel ? whats the plugs porcelain colour ? black too rich & if its wet = flooding. & if its light brown & dry its choking for fuel . after hi rpm run whats the plug look like ?
how is your air filter ? filter box ?
spark system are you getting good spark ? gap correct ? correct plug ?( dont trust new out of the box plug gaps )
is the plug wire / lead shorting out somewhere ?
timing = Could it be timing is slightly off ? parts worn or timing chain worn ? Crank pos sensor faulty. ?
hope this helps ..

thanks for the response. The thing is I have got it run fine with the exhaust the way it is. It’s kind of hard to find a muffler for these things that isn’t 500$ plus but I may look into trying that. So far it has had 4 plugs out of the box new since I started this diag. All black after I’m done with them and put another one. Like I mentioned I managed to get it to run right with the carb adjustment but then go back to it and it’s running like trash again. The fact that I intermittently have gotten it right tells me something as static as timing or valve adjustments are out the window.

I do have a new development though, I have managed to get the bike to stall when spraying intake cleaner or brake cleaner around the intake flange. So I may have a vacuum leak there. Going to throw in a new carb boot again, a new intake flange and gasket then update. I will also take your advice and see if I can Find an affordable muffler. Thanks again for the advice much appreciated.
 

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Discussion Starter #12
So quick update. New intake manifold, gasket, and I McGivered a muffler on it. Still doesn’t run good. Now I discovered if you turn the adjustment screw all the way in closing off the fuel it still runs. I’m wondering if my adjustments on the float in the carb are off and that’s what’s causing me all this headache along with everything else that was wrong. Anybody know if the float height is adjusted too high if that would cause my problems?
Thanks in advance
 

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The engine would/should still run for a few minutes on the residual fuel left in the bowl, even after turning off the fuel petcock. Not sure if that's what you're experiencing or not. There are some good videos on youtube that show you how to set a float "level", but usually in a new carb, that's good enough to get you running right, with maybe only some fine-tuning of the jets needed, to really optimize it.
 
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This guy has some excellent carb clinics and yeah it sounds like shes flooding out but so many variables....
Youre on the right track just keep doing one thing at a time when tuning the carb.
Once its good you can go back to diagnosing other possibilities/causes/symptoms.
Fyi, I ran a long hose on the overflow and ran it out at my left foot so I could see if it was overflowing the bowl when test riding.
Soooo many ways to set float level.
I found this one got me the closest.

 
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