95 FE600 off idle hesitation/dies

Have you tried cleaning your carb? Sounds like some little thing in the adjustment. The carb isn`t a VHSB is it? Check also for a air leak on the intake but more than likely it is what I think. Good luck.

sweet41k said:

The stock Delorto carb has been completely disassembled, cleaned, blown out and reassembled. No change. I even bought another stock used carb, thoroughly cleaned it out and installed it. Still the same. It may run fine for 10 acceleration, but the then the next one just pops and dies just as you open the throttle. Starts right back up fine but if you open the throttle, pop and die. If you ease into the throttle very very slowly it will be fine. Once the rpm's are above 2000 (est) it's fine. I even temporarily installed a Mikuni 38mm flat slide. Acted the same way. COULD IT BE AN IGNITION PROBLEM???

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Check the plug cap for tightness along with the wire going to the coil. They can work loose. Get some carb cleaner (spray can) and with the bike running spray around the rubber intake, if there is a leak you will know it. Check your wires good, clean contacts and connections and try a different plug. Good luck.

as you have a spare slide i would thoroughly recommend that you remove .5mm off the bottom of the slide. if you check under the slide body it will say 50 in a circle or 50/1 or 2 or 3. that means the cutaway is 5.0mm.

taking away .5mm makes the ar rush through a smaller hole and meanbs the bike picks up fuel better. it won't stall.

try it. you've got two!

regards

Taffy

Gave me nightmares reading your post and remembering all the grief I went through eliminating the same problem from my 96 FC 501. Flame outs usually occur because a lean mixture hasn't burnt completely and is still doing so at Exhaust TDC. With the valve overlap on high performance cams through early intake opening, fuel ignites in the carb, sometimes blowing it off the manifold. A hot spot can also cause this. With the Husabergs ignition sparking at Compression TDC and Exhaust TDC, matters are worsened. This is why Husaberg shortened the duration and steepened up the opening ramps on the newer cams (resulting in increased valvetrain wear I must add).
A hot spark to ignite things correctly is important. Keeping the engine cool helps as well. I replaced my waterpump impeller and ran water wetter. Also set my intake valves a bit loose on the intake side to delay intake opening and assure they were closing (tight intakes can cause leanness). All this helped in small increments. The big gains came from carburation changes in the 0-1/4 throttle opening range. A needle has a straight shank for approximately the first 10MM (up to approx 1/4 throttle) of slide opening. Raising the needle won't help in this area, but a richer slide (as Taffy mentioned) or a larger needle jet will. I went up on the needle jet a size. Also, the pilot jet doesn't simply supply fuel to the idle mixture screw, but also to an orifice under the front of the slide that affects the mixture under 1/4 throttle. A larger pilot jet also helped.
Well, after all this, it was liveable but still a problem. Eliminated the problem by installing a smaller carb off a 98 FE400 (Round slide 38mm not the 2 stroke style flat slide). With higher velocities through a smaller carb, the fuel generally atomizes better at lower RPMs and burns more efficiently. Bingo! No more flame outs and cussing while trying to start the bike in a tight corner on a 100 degree day. I did lose a bit of top end power, but such is life. Hope my past agony can be of help today.
Dan

Removing material from the bottom of the slide as Taffy described actually leans the overall part throttle fuel mixture, which helps to alleviate off idle stumbles or hesitations in many cases. I had somewhat similar jetting problems with my '96 FE600 in that I was never able to get it dialed in perfectly. I finally replaced the flatslide Dellorto with a 41mm flatslide Mikuni with 100% better results....Go figure!

chas

a smaller cutaway should richen small throttle openings up to 1/4 throttle + a bit.

i didn't realise that it was a square slide dell orto we're on about here. they were known on road bikes as the biggest pile of poo known to man!

by the time they're old i would think it would be enough to do your head in.

look at e-bay. there are loads of round slide carbs going on there and all the knowledge is here to get it dialled in.

regards

Taffy

Taffy,
Yes a smaller cutaway would richen the part throttle mixture, however removing material from the bottom of the slide would make the cutaway larger thereby making it leaner....wouldn't it?? I can see where the greater air flow would suck more fuel in, however the overall mixture still should be somewhat leaner. I am used to working over the slides of flatslide Mikuni carbs and I am assuming that the same principles would apply to the FCR carbs....perhaps not a correct assumption??

Chas said:

however removing material from the bottom of the slide would make the cutaway larger thereby making it leaner....wouldn't it??

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i know that you meant "taking more out of the slide cutaway".

just to recap
if you make the arch higher you let air through a larger hole so it goes slower, creates a weaker signal and picks up less fuel.

if you remove from the base of the slide, thus making the height of the cutaway smaller, you have made the air go through a smaller hole and speeded it up. this creates a far stronger signal and and gets far more fuel. this is therefore richer.

for a period i ran a 3mm cutaway and my PJ was #33 AND too rich!!!!

i confess i panicked, put a file across the cutaway and took it back to 3.25mm. later i changed the needle and other things and i'm back at 38/40PJ.

so i could theoretically have gone back to 3mm slide cutaway and a 35PJ or thereabouts.

i come from the school of clean, crisp and sharp jetting. this is most obvious in my PJ's. i think it's the mark of someone who test rides rather than dyno's his bikes.

just my opinion.

regards

Taffy

You have proably all ready tried this, if so please bear with me. Have you tried resetting your air screw on the carb, might be a shade bit off. There is a little hole on the lower side of the carb where the boot from the airbox fits can get plugged. That was part of the problem with mine. Once clear, it ran good, no sudden burping and dieing. It is more than likely in or around the carb. Hope this helps.

sweet41k said:

I'm tempted to cut away the throttle slide opening .5mm, but that's one of those "can't put it back" once it's done jobs. I do have an extra carb though, so I may try that. Any suggestions?

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yep i have one!

first tell us what you meant coz that ain't english you just spoke? 0.5mm more off the cutaway to make it taller or 0.5mm off the base?

yes you can put it back!!! read the above post from me! and did you read and grasp what thew cutaway does?

have you drawn on a piece of graph paper (supplied by the nipper) a simple line of the two needles?

it's an absolute doddle to do!

you simply draw the width up the side. the taper start point from the bottom and the nose width at the end of the graph.

until you do this you don't know what you've done.

reference charts are available of all needle codes from dell orto.

regards

Taffy