Banshee carburetion blues

[ssanddemon]

Pulled my '03 Banshee out of mothballs this weekend. I'm going from Portland, OR to Glamis next month for a week and I wanted to do a shakedown and get the 'sitting around' bugs out. She has been languishing in my garage for the last 6 months or so, ran fine when I rode her last. Initially, she wouldn't start. Shot her with starting fluid and she fired right off, but idled real high. UH- OH, gotta clean out the carbs. Did that, and pulled the fuel petcock out, as flow looked low. The strainers were full of $#&*, so I cut them off since I run an inline filter anyway, and cleaned the tank. Carbs looked fine inside, and I blew the ports out with carbkleen and compressed air. Fired right up, but idled super high, like 3000 rpm. Took the idle screws out (no TORS) and got it lower, to a nice burble. Got max idle rpm with the bypass screws at about 2 1/2 turns out. Went to Sandlake today and found her still running crummy. She holds a higher than idle rpm for a second or two after letting off the throttle, then dies after about 3 seconds. The left cylinder is cutting out at idle and middle rpms, but has fair to good power on top. Both spark plugs look good with brown deposits. Fuel is super (92) with Benol @ 60:1. I know this is in the carbs, but damned if this symptom is setting off any bells with me.
Bike has case matched cyls with stock porting, .008 off the head, Toomey TR 6's, Pro Flow intake with V Force reeds, dual K&N's. Carbs are stock, jetted @ 300 mains, needle on the top clip, stock pilots. Any help appreciated, I hate to throw much $$ into these stock carbs since I'll be going bigger after the porting gets done.

[bradley300]

you say you checked your plugs, is it possible one of your wires did not set back on the plug as well as you think?

this happened to my 300ex once, the wire wasnt on the plug well and made it hard to start and ran like crap low end since the spark had so far to travel, top end the spark was powerful enuff to arch the longer space and it ran fine

[ssanddemon]

Thanks for the reply, but no, the plug boot was on firmly. I had plugs out a couple of times yesterday. Played with gaps and switched plugs side to side. No difference.

[F-16Guy]

Did you take the pilot jets out of the carbs? There may be some varnish or crap built up in the holes (most pilot jets have multiple holes). You may also want to blow some carb cleaner through the passages while the jets are out. It sounds like one or both (most likely the left) of the idle circuits/jets are clogged. If there's any doubt, it may be worth the $7 to replace both pilot jets. If it otherwise was fine when you parked it, I would put my money on a fuel system problem.

[ssanddemon]

F-16, I did not remove the pilots when cleaning carbs, just blasted thru with carbkleen then compressed air. I will yank them out for inspection tomorrow, as well as a general disassemble of the carb and inspect of the reeds. Maybe a compression test as well.

[TRX300X]

The problem most people have with cleaning carbs is that they aren't thurou (sp?) enough. You've gotta blast out every orfice and every jet and spent a lot of time on them. Sounds to me like you're running lean. When a 2 stroke runs lean it won't idle down. Pull em down and go thru them again.

[crandles]

Check all the rubber boots for cracks also. If there is a crack that will cause a lean condition also.

[cals400ex]

when my buddy had stator problems we actually thought it was jetting. it was hard to start, idled a bit weird and had a low power output.

[ssanddemon]

Update here; found the carb problem, it was a leaking grommet on the Pro Flo boost bottle. It's a crappy system, I got to thinking that this had happened once before, and I threw the damn thing away and put the factory balance tube back on. Easy enough, now it idles down. Still cuts out on the left cylinder, however. Has decent enough power on top end, and the left side cuts in and out at idle, but absolutely nothing in the middle rpms, just weak puffs of smoke. Swapped carbs side to side, reed cages and ign. wires side to side, no diff. New plugs help for a second or 2 until it loads up and cuts out on the left again. Checked for spark while running thru the rpm range with a test spark plug, nice consistent blue spark. My two good riding buddies are mechanics like me, and we can't come up with anything except possibly a broken ring or leaking crank seal. I'm leaning toward the crank seal, as compression looks ok @ 150 or so lbs. I'll update again when the cause is found.

[stevo3176]

Just a though, do you have the tube that runs between the two carbs hooked up (looks like a fuel line)? Lots of people forget to replace that when they put the carbs back on. But this causes lots of problems with banshees. You should also post on banshee HQ they helped me out when I had a banshee.

[ssanddemon]

Yup, choke hose hooked up. Thanks for the HQ site tip.

[R3Concepts]

My freinds banshee was doing this exact same thing, I mean virbatem... Its the throttle override caps, if you move the idle up higher on the left side, if thats the side that cuts out, then it wont cut out anymore, or at least I got his bike pretty close by doing that.

[ssanddemon]

Got rid of that damn TORS crap about 3 minutes after I got her home from the dealer. Thanks for the suggestion, tho. Pulled down the topend and found some erosion damage along the upper edges of the piston, L. side; the top ring groove hogged out also. I guess when it ran lean due to the leaking boost bottle grommet, it did a bunch of pinging and hurt the piston. I am still mystified as to why compression was decent, but I have a complete top end set coming and we'll see what's up after that. Luckily, both the cylinders are in mint condition, so no machine work to be done other than a little porting I am going to do while I have the jugs off. Thanks to all you guys for the advice!:D