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Rich at idle, lean off idle Fcr mx 41 husaberg 650

Joined Sep 2018
108 Posts | 13+
Italia
Hello. As written in the title I have this situation: Rich at idle, lean off idle.
Here is my set up:
MJ 155 Taper E (perfect from 1/2 to 4/4).
Length K clip 2 (perfect at 1/3).
Needle diameter R (perfect to 1/4).
PAS 1/4 = PAJ 45 the richest measure (lean to 1/8 ).
PJ 35 PS 0.5 the leanest measure (rich at 0/8 ).
If I mount richer needle diameter it improves to 1/8 but gets worse at 0/8 and 1/4.
If I mount a thinner needle diameter it improves to 0/8 but worsens to 1/8 and a little even 1/4.
The needle diameter covers homogeneously from 0/8 to 1/4, at least this happens on my bike ...
Clip height is not effect about 0/8 - 1/8.
The PAJ appears to have an effect from 0 - 1/3 with a marked peak at 1/8.
I will try to close the PAS further (less than 1/4 turn) to resolve the lean condition to 1/8 in order to have a homogeneous rich condition from 0/8 to 1/4 which I correct with more lean pins (diameter S or T)
 
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it is your E needle, they are too long on the straight before the taper begins. to prove it, lift the needle up one clip and your problems will be solved even though the midrange becomes rich as a result.

Try a D needle on and R or an S like a DMR or a DMS. your 3/4 throttle won't be as good though.

Taffy
 
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Thanks Taffy for your cooperation.
I feel the lean condition just out of idle: for example in 1st gear I can reach high revs with 1/8 throttle and hear the engine make a "oooooo" sound instead of "popopopopo".
At 0/8, however, it is rich because I can lower the idle, close PS and do not hear the engine die.
At 1/4 the mixture is right.
 
Hopefully you will follow this?
Try a DMS. and lower thre PJ considerably. it may even take a 38PJ?
Taffy
 

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Hi,

At first, apologize for using another thread, I can’t create my own.
I have a FE550 (2008 model) for a many years. In general bike always started very well. Same carburetor settings (yets, needle) three years. Suddenly weird problem appeared. Started a bike as usual with choke, but closed it almost immediately. Engine stopped and didn't start any more. When I kick, it almost starts (for a half a second) and then stops again. Changed the plug, opened a carburetor, looked yets, didn't see anything wrong and put everything back together - and as I thought, no changes. By kicking almost starts (by every single try). Opened a carburetor again and cleaned everything quite throughout (ultrasonic, carbclean, compressed air), changed the pilot screw gasket, back together - no changes. Have played with idle screw and pilot screw, no success. Checked the chain tensioner - seems working (chain quite fresh, 3rd click). During this second, when engine runs, it does not make any weird noise and no smoke or smell or something else wrong from exhaust. Checked the tappets, everything fine, but adjusted again just in case. Having double springs, as far as I can see they are not broken. Then opened the carburetor again, including mid body. Everything seemed ok, but still putted new gaskets (for mid body part only), additionally new choke and hot start knob, new vacuum plate gasket and just in case a new idle jet. No success. Measured the stator, everything within spec, measured ignition coil – it was a bit out of spec, so I replaced it with another used one which was within the specs. No success. Then played again with the screws. I could get it started for approx. 7-10 seconds when idle screw full out and hot start knob out as well. When it runs for this short time, there is no abnormal noises. I still have the feeling that its carb, but I can’t imagine what it could be. Every idea what could be wrong is welcome.
Please excuse if typos or poor wording have been used, not the first language.
Regards,

Toomas

P.S. Settings: on idle: air 75, pilot 40; starting original (85 I think it was). Main and needle don't remember, but very most probably it's not a reason, I really have had these for couple of years (I ride 500km per year and on road with FS wheels).
 
time to try another husaberg carburettor on your bike that is runnung fine. this will tell you if it is the carb or not?

cheers

Taffy
 
From my experience, if the bike, when cold, starts immediately and immediately turns off, it is because the carburetion is rich. It happens to me for example when it is summer, it is hot, and I try to start using the cold start (suffocation). I advise you to check if the pilot air jet is clogged, or simply the cold start is malfunctioning and does not remain deactivated. To start the bike try to increase the idle a little, with accelerated speed so that it does not turn off. From there, lower the idle gradually and check the mixture screw. We await updates
 

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