Author Topic: Can't get my main jet to seat - HELP!  (Read 1364 times)

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Offline theofam

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Can't get my main jet to seat - HELP!
« on: February 12, 2010, 11:16:34 am »
My main jet isn't seating properly such that when I put my leaf spring on, it just flops - no pressure to hold on the main jet.  The main jet seems to be sitting about 1/16" too high.  I've tried tapping the top of the jet with a hammer, but I'm worried too much pressure will cause damage.  I used WD40 to lube up the o-ring before install.

Stuck in the garage awaiting expertise!

Offline Little_Horse

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Re: Can't get my main jet to seat - HELP!
« Reply #1 on: February 12, 2010, 12:09:55 pm »
I should have read this one first. The pressure to hold the jet in comes from the float bowl being screwed down. It should be loose in there, but the oring needs to be fully in. A sixteenth of an inch of jet should be out.
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Offline TwoTired

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Re: Can't get my main jet to seat - HELP!
« Reply #2 on: February 12, 2010, 12:36:12 pm »
The oring for the jet met be contained withing the carb body casting feature.  I will often use grease to aid that feat.  The spring clip holds the jet in only when the bowls are installed.

The O ring must be soft enough to conform to any irregularities and create a proper seal.  Soft orings will hold the jet in place while the bowl is being installed.

The Main jet rests on the emulsion tube in the carb.  This is pushed out of the carb from the where the slide sits.  It needs cleaning if the rest of the carb needs cleaning.  It is often overlooked.

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

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Offline theofam

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Re: Can't get my main jet to seat - HELP!
« Reply #3 on: February 12, 2010, 02:33:02 pm »
Cornandp, thanks for the info on how the leaf spring works.  Makes sense.

Twotired, Ecosse told me if I rubbed my tank three times and said your name at some time you'd chime in!  It worked!  So, about this emulsion tube.  Sounds like I pull the main jet, get a small socket or punch in there and knock it out into the throat of the carb?  Is that right?  And yes, you're right, until you mentioned it, it was about to be overlooked, yet again.

Offline fmctm1sw

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Re: Can't get my main jet to seat - HELP!
« Reply #4 on: February 12, 2010, 03:07:42 pm »
I've had good luck licking those main jets when they wouldn't go in the whole way. 

Standing by for ridicule...
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Dude is that a tire ? or an O-ring..??

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This is not a pod thread
This is not a #$%* on my vacuum gauges thread
This is a help or GTFO thread.

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Offline theofam

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Re: Can't get my main jet to seat - HELP!
« Reply #5 on: February 12, 2010, 03:15:46 pm »
fmctm1sw,  :D  Thanks for the good laugh!  That's usually how I clean my batteries!

Offline theofam

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Re: Can't get my main jet to seat - HELP!
« Reply #6 on: February 12, 2010, 03:27:46 pm »
Twotired, never mind.  I got the emulsion tube out by dropping a punch in from the needle/slide/top and knocked it out.  It was clean, but who knows about the other three.

Offline TwoTired

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Re: Can't get my main jet to seat - HELP!
« Reply #7 on: February 12, 2010, 03:37:09 pm »
Glad you got the emulsion tube out.  Don't be too aggressive with the punch, though.  That's the end that has the needle jet orifice.  Distorting that would be...

...bad.

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Kframe

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Re: Can't get my main jet to seat - HELP!
« Reply #8 on: February 12, 2010, 04:02:03 pm »
Oh crud I just read this about the emulsion tube. 
I missed those when I cleaned my carbs last autumn.   :( 
Bike seems to be running okay though, I haven't really run it around though as the tires are shot.  So I only have less than a hundred miles on it. 

Well, come spring if she's running rough I know where to look first, so thanks!
:)
-K
2007 Triumph Bonneville T100, ARK'd, Pods, TOR's, Napoleon's, Innovate G5 Air/Fuel Gauge, Ignition Relocation by D9, Stebel Nautilus, Avon Roadriders
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Offline TwoTired

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Re: Can't get my main jet to seat - HELP!
« Reply #9 on: February 12, 2010, 04:12:09 pm »
The emulsion tube has cross drilled holes in it.  These are used to premix air (from an air jet) with the fuel making a froth, or emulsion.  The froth is far easier to draw/lift into the carb bore, which helps throttle response.  Further, if the holes are plugged, the fuel economy gets worse, as less air is in the fuel mix.

Cheers,

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline theofam

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Re: Can't get my main jet to seat - HELP!
« Reply #10 on: February 12, 2010, 10:05:31 pm »
TwoTired, I was very careful with the punch on the emulsion tube.  It took a very minor tap to get them out.

Kframe, you may be fine w/o doing the emulsion tubes.  Mine didn't have any gunk in them.  I've my fingers crossed for ya.

Offline Kframe

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Re: Can't get my main jet to seat - HELP!
« Reply #11 on: February 13, 2010, 06:11:37 am »
TwoTired, I was very careful with the punch on the emulsion tube.  It took a very minor tap to get them out.

Kframe, you may be fine w/o doing the emulsion tubes.  Mine didn't have any gunk in them.  I've my fingers crossed for ya.

Thanks!
Now we just gotta wait for the snow to melt so I can ride more and find out for sure!
-K
2007 Triumph Bonneville T100, ARK'd, Pods, TOR's, Napoleon's, Innovate G5 Air/Fuel Gauge, Ignition Relocation by D9, Stebel Nautilus, Avon Roadriders
1984 Honda Shadow VT700c, Stock
1974 Honda CB550K, In rehab
1986 Honda Helix

 

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