686 Stock carb blues
#1
686 Stock carb blues
My new 686 runs great when it runs . I take that back the engine runs great the carbs suc!!!!! I fought them all weekend. Let me give you a run down and see if any one can help. I have a 102mm 12:1, stage II hot cam and springs, Some cleaning up of the ports,A good free flowing exhaust, and a Proflow with no air box. Right now It has 25 pilot jets 3.25 turns out, 190 and 195 mikuni jets, and the needle on the fourth clip. The needle is not the stock one the stock one was way way to lean. the bike wouldn't even accelerate past 1/4 throttle.
Here is what it's doin With those carb settings....[img]i/expressions/face-icon-small-disgusted.gif[/img]
It ran totally perfect all around throgh out the throttlr range but when holding it WFO for a long straight period it would stall out. So I checked the tank petcock,replaced fuel line,Checked needle valves in the carbs. Didn't change any thing.[img]i/expressions/face-icon-small-confused.gif[/img]
So I had a few beers and thought about it for a while and then raised the float level to about 5mm from the factory setting. It doesn't run out of gas on top end anymore.[img]i/expressions/face-icon-small-happy.gif[/img] But It only runs right from Idle to 1/4 throttle and WFO nothing in between , cutting out chokeing and if you stab the throttle it takes off like a Banshee (Just a lot faster) Ha Ha....
This is all Ive done this past weekend at sand mountain I Didn't even get to meek up with any fourum members (RaptorJay) Couldn't find him in the sea of 10,000 people at the mountain. I saw a very clean raptor at the mountain sounded really nice. Then I heard the Turbo sound from that beast, That thing was fast, awsome acceleration from that bike. Any ways any help would be great from the 686 crowd that has went through this before.
I just want a reliable set-up, I'm to the point now that this thing is about as tempermental as Alcohol/Nitro mix. I know this shouldn't be a problem, Right? This set-up in general should be reliable I would think. Please help a fellow Raptor owner that almost just doesn't want to ride it anymore..............
Here is what it's doin With those carb settings....[img]i/expressions/face-icon-small-disgusted.gif[/img]
It ran totally perfect all around throgh out the throttlr range but when holding it WFO for a long straight period it would stall out. So I checked the tank petcock,replaced fuel line,Checked needle valves in the carbs. Didn't change any thing.[img]i/expressions/face-icon-small-confused.gif[/img]
So I had a few beers and thought about it for a while and then raised the float level to about 5mm from the factory setting. It doesn't run out of gas on top end anymore.[img]i/expressions/face-icon-small-happy.gif[/img] But It only runs right from Idle to 1/4 throttle and WFO nothing in between , cutting out chokeing and if you stab the throttle it takes off like a Banshee (Just a lot faster) Ha Ha....
This is all Ive done this past weekend at sand mountain I Didn't even get to meek up with any fourum members (RaptorJay) Couldn't find him in the sea of 10,000 people at the mountain. I saw a very clean raptor at the mountain sounded really nice. Then I heard the Turbo sound from that beast, That thing was fast, awsome acceleration from that bike. Any ways any help would be great from the 686 crowd that has went through this before.
I just want a reliable set-up, I'm to the point now that this thing is about as tempermental as Alcohol/Nitro mix. I know this shouldn't be a problem, Right? This set-up in general should be reliable I would think. Please help a fellow Raptor owner that almost just doesn't want to ride it anymore..............
#2
686 Stock carb blues
I've got a VERY similar setup as you and mines runnin good on stock carbs cept a few stumbles that I'm tryin to work out. I've got my carbs setup like this: 195/200 mains, needle 3rd notch, 27.5 pilots, and air screw out 2.75 turns. I also have no airbox and a pro-flo kit and I think that is whats making it really hard to get rid of those stumbles. Everything in my carbs are stock makuni supplies in other words no dynojet stuff, only makuni parts. If I were you I'd go back to the stock needle and put it on the 3rd or 2nd notch, that might help the mid range at least start working. The stumbles I'm having are it being to rich in the mid range and when im crusin in a higher gear (3rd is worst) at a low rpm and wanna throttle it it doesnt want to rev and just pops and cuts out alot then itll take off. This only happens when I hit the throttle hard, if I ease into it slower it doesnt cut out. Try setting your carb up like mine and see how it runs. Like I said, you have a very similar setup as me and I think it might work. Good Luck!
#3
686 Stock carb blues
Thanks for the info, I'll try that. What are your float levels set at? Mine are a little higher than stock and I think when I raised them It richened the needles a lot . I'm gonna go back to the stock ones and try that. Mine even when it is sputtering you can hit the trottle and it just takes off. And that's what makes me think the midrange is rich. The plug is a little on the rich side but not enough to turn the electrode black. Just the base ring is on the dark side.
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#9
686 Stock carb blues
I've got that setup too. I am running the mikuni needles on the fourth slot, 185/190 mains ( a little lean ) and 25 pilots 3.5 turns on the airscrews. The quad pulled very well at sea level no problems felt a little weak off the bottom but as soon as I got rolling the power was immense. I'm about to try 190/195 mains and last slot on the mikuni needles. I think the aftermarket needles are what's killing you. I'd simply experiment with different slots on the stockers.