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Post by hopwheels on Sept 12, 2006 21:03:15 GMT -5
OK thumper kids, developed a weird prob with the rebuilt carb (have not yet installed the new #330 main btw). Last couple of nights, went out to start it, and no go. Both times, drained the carb float bowl, and it starts.
So why would that be happening?
Am I wrong in thinking that it is running rich if it's accumulating a lot of fuel in the carb? If it is running rich, all stock (except forgot to mention, moved the jet needle up one space during rebuild), how's that possible with the K&N? Shouldn't it be running lean? Confused, perplexed, bothered I remain...
Gary
Hopwheels
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Post by manxman on Sept 13, 2006 0:02:37 GMT -5
Maybe the petcock is leaking a bit and overfilling the float bowl. This would cause a flooded condition on start-up. ??
Dave
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Post by hopwheels on Sept 13, 2006 0:09:36 GMT -5
Hey Dave:
I had the lines off the carb at several points over the weekend with the tap in the "ON" position and a full tank, and nary a drop of petrol out of the line... if it were the tap, wouldn't it leak out the fuel line with the tap on?
Gary
Hopwheels
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Post by wotavidone on Sept 13, 2006 1:15:35 GMT -5
Assuming your carb is like just about every other carb I know of, it would have a needle and seat, which, if in good condition, will shut of the fuel flow to the carb when the float gets high enough.
If the float level is set too high, there will be flooding. So, at the risk of accusing grandma of not knowing how to suck eggs, (I hardly dare to ask the question) but here goes: "you did check the float level when you did this here carb up, didn't you?"
Mick
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Post by hopwheels on Sept 13, 2006 1:24:50 GMT -5
Hey Mick: Dare away! Nope... didn't do it. (The carb is the stock for 78-79 Mikuni 34VMSS btw). I am completely new to the engine and carb stuff, so how do you check the float level? I just put everything back together the way I found it (after a try or two) with a keyster carb kit. Sounds like the culprit. Maybe the old needle I put back in (new kit needle was incorrect) doesn't seat all the way? Maybe I should have cleaned it... if only I had a buck for the "maybe i should haves" and "if onlys" I've had on my project bikes  Off comes the carb again. Dang, I'm gettin' good at taking the carby off... Gary Hopwheels |
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Post by StewRoss on Sept 13, 2006 6:28:15 GMT -5
Hi, Gary, Mick, Yep first thing I'd be doing is checking the float height as well. Remove the bowl, not a fun thing on the ol' SR carby...turn the carby upside down, and measure between the mating surface of the carby body where the bowl seals onto...now you need to measure from the alloy surface, not with the gasket in place...to the upper (lower) surface of the float. Now a few things here: * You need to have the float just touching the pin on the needle (...needle and seat)...not depressing it...to get an accurate measurement. * Sometimes that can mean that you hold the carb body onto it's side a little bit...you'll soon get the hang of it... * To adjust the float height you carefully bend the tang that acts on the needle to suit...matter of feel. * Figures are - 22.5 - 24.5 mm (0.886 - 0.964)...as you can see it's not accurate to the last thou...but be accurate anyway. Good luck...see what happens then...one thing at a time. SR  |
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Post by medic09 on Sept 13, 2006 11:27:34 GMT -5
take a look at the link I posted under the thread 'carburators for dummies. he just reiterates what Stew wrote, but the illustration might help (or confuse things more ). I'm waiting to pick up the original carb I ordered, from the post office. Let me know how you installation turns out! |
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Post by hopwheels on Sept 30, 2006 18:04:21 GMT -5
Hey guys...
Got a chance today to get that carb off and check the float measurement. Looks pretty much right at 23.5mm or thereabouts (to the best of my ability to gauge). While I was at it, I went ahead and shaved 1.27mm (.05") off the slide as precisely as I could. Big difference! So now here's what I'm running for some feedback from you guys...
Stock airbox w/K&N filter
Stock exhaust
Stock carb with these mods...
#330 main jet
Needle clip 1 position lower (raising needle by 1 position)
1.27mm shaved off slide (went slightly less I think more like 1.1 to 1.25)
Everything else in the carb is stock
Started 'er up and let her warm up, still a small hesitation just when you crack the throttle, (after warming up to around 140°F) but no where near the original problem it was. Seems to idle more smoothly as well.
Is that little bit I went less than the recommended 1.27mm perhaps why it still has a slight hesitation?
Unless there's some other recommendation from you guys, I'm going to keep 'er set up like this and just ride...
Thanks for all the input lads!
Gary
Hopwheels
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Off comes the carb again. Dang, I'm gettin' good at taking the carby off...
