Can-Am ATV Forum banner

1 - 20 of 28 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #1
Looking for carb experts...2007 outlander 400 max xt. The carb is a Mikuni BSR33-49. Just disassembled and cleaned carb (not my first time) due to off and on idle issues. It was just time. After assembling, I Installed it on bike and it started right up and idled no problem.
However, if you jab throttle it stumbles and nearly stalls...let go of throttle it goes right back to idling. If you slowly press throttle it will gain rpm to about 80% throttle, then it stumbles. Does this indicate a particular thing I did wrong or isnt cleaned well enough? Where do I start?

If you look at video, you can see the slider move on throttle, but it looks to me like too much gas is coming out?2007Outlanderidling
 

·
Registered
2015 Outlander XMR 650
Joined
·
3,594 Posts
Knock on wood I haven't had to resolve any types of these issues with my carb, other than that "last chance" screen giving me fits.

Jungleman will be along soon, I bet he's got some useful advice for ya (y)
 

·
Registered
Joined
·
11 Posts
Discussion Starter #3
Thanks Bombardierbomb, this one has me stumped. It's not the first one I have cleaned, and was pretty confident doing it. It wasn't even that varnishes inside. I'm after taking it apart and putting it back together like 5 times.

The diaphrambis good, sealed good, jets all spotless, air fuel mixture at 2 turns back, slide does rise and fall with throttle....and it idles perfectly.

DAMN IT
 

·
Registered
2015 Outlander XMR 650
Joined
·
3,594 Posts
I don't see where you specifically mention removing/cleaning the screen underneath the float- have you?
 

·
Registered
Joined
·
11 Posts
Discussion Starter #6
So I did have the screen out and it was clean.

I also find that too much fuel, and coming out in spurts. Yesterday, I did take the needle out of the diaphragm and checked it...its on slot 3 as it should be. Maybe I should adjust it down?
 

·
Registered
Joined
·
2,080 Posts
If it's where it was before you cleaned it , no .
Is the float height correct ? / unchanged ?
 

·
Registered
Joined
·
11 Posts
Discussion Starter #8
The float wasnt adjusted initially, but after this issue I did adjust it to specs.

So I just discovered that I did have the starter jet (80), and main jet (133.8) switched by accident. I just corrected that, but it only made it worse. The bike wont even idle now and is literally spitting gas everywhere. I will post some pics below to see if you may be able to see something I did wrong...(the last pic shows the main and starter jet removed. You can just see the tip of the needle)
 

Attachments

·
Registered
Joined
·
11 Posts
Discussion Starter #13
Thank you Bonzo..I believe I have found the issue, after hours of staring at a parts diagram. If you look at the below pic, #34, the needle jet that sits under the main jet and jet holder.....well that's not in my carb right now.. I am thinking it fell out and was missed when I disassembled the carb. It looks like it just sits in there, does not screw in....now to start scouring the garage.
 

Attachments

·
Registered
Joined
·
11 Posts
Discussion Starter #15
Taking a close up pic, there does seem to be something way down in there, but it certainly doesnt have a small hole that you would think would affect the needle at all. Its wide open. You can even see that the needle isnt centered at all.
 

Attachments

·
Registered
Joined
·
1,414 Posts
Did you figure this out?
Im trying to remember what the needle seats into...I have another carb I can pull apart and check...

Plus one on the whole rebuild and the dynojet kit eventually, but something mustve happened to make it worse rather than better with a cleaning.

Lemme know, I'll tear into the backup spare carb.
 

·
Registered
Joined
·
1,414 Posts
That o ring on the main jet looks thrashed.
97781


Is that it down there in the hole after removing the main jet?
97782
 

·
Registered
Joined
·
1,414 Posts
That cant be good if it is.

There is a brass "guide" down in there but it doesnt come out of the carb, its pressed in.
97783
97784
97785

97786


It looks like the needle seats into the main jet and thats it...
97787


Only thing I can think of is the diaphragm needle isnt seating, make sure you have all the parts in order on the needle, especially the little spring on the back part of the white part, opposite the pliers.
97788


I know you know but that white part needs to be pushed in just right with that spring centered on the needle top.

I dunno, sounds like either the needle is not seating in the main or your float needle is sticking open.
You can check the float needle seat for burrs with a q tip or just visually.

Maybe operator error?
Ive been known to drop the float needle once or twice lol

Looks like the diaphragm is working properly, just fyi you can check it while its out by shooting a blast of air into the big brass fitting
97789


Hopefully you got it and this is tmi but Id make sure I had the needle assembled correctly then check the float needle.
97790

97791
 

·
Registered
Joined
·
1,414 Posts
Also thinking, Ive learned the hard way to only make one adjustment/change at a time.

If you adjusted the float before trying it with the jets in the right place...the float level may be off, thats a lot of fuel.

"Spec"
Is subjective on these imo. It doesnt take much to be way off.
Heres a great vid on getting it close.

Best of luck
 
1 - 20 of 28 Posts
Top