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Author Topic: running on 3 cylenders (up date)  (Read 1620 times)

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Offline irish44395

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running on 3 cylenders (up date)
« on: February 05, 2016, 01:38:14 PM »
Trying to get my 650sc NH running clean the carbs still not running on #4 getting good spark ,at first it was running on just 1&2 Then 3 started working ,I don't know were to look or do. air is blowing out the intake side of #4 along with gas.  can I have a stuck valve ? or is it the timing ?
Pete
« Last Edit: February 07, 2016, 08:15:29 AM by irish44395 »
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Offline flybox1

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Re: running on 3 cylenders
« Reply #1 on: February 05, 2016, 01:52:38 PM »
air
spark
fuel - carbs.  clean, clean, clean.
check fuel level in bowls using clear tube test.
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Offline irish44395

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Re: running on 3 cylenders
« Reply #2 on: February 05, 2016, 02:21:19 PM »
Thanks I'll give that a try,I get gas blowing back out the intake side of the carb. the floats are not adjustable on the 650,
Pete
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Offline flybox1

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Re: running on 3 cylenders
« Reply #3 on: February 05, 2016, 02:48:48 PM »
Quote from: irish44395 on February 05, 2016, 02:21:19 PM
the floats are not adjustable on the 650,
yes, but they may not be closing the float valve, causing your flooding. . . .
The only way to see if they are  shutting off fuel correctly, is with a clear tube.
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline therobbstory

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Re: running on 3 cylenders
« Reply #4 on: February 05, 2016, 03:00:33 PM »
Quote from: flybox1 on February 05, 2016, 02:48:48 PM
Quote from: irish44395 on February 05, 2016, 02:21:19 PM
the floats are not adjustable on the 650,
yes, but they may not be closing the float valve, causing your flooding. . . .
The only way to see if they are  shutting off fuel correctly, is with a clear tube.

Suffering from major brain rot after wrenching on my machine all day. I'm having a similar problem to OP with fuel in my air box. Could you briefly explain this clear tube test?
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Offline Gene

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Re: running on 3 cylenders
« Reply #5 on: February 05, 2016, 03:10:38 PM »
Quote from: therobbstory on February 05, 2016, 03:00:33 PM
Quote from: flybox1 on February 05, 2016, 02:48:48 PM
Quote from: irish44395 on February 05, 2016, 02:21:19 PM
the floats are not adjustable on the 650,
yes, but they may not be closing the float valve, causing your flooding. . . .
The only way to see if they are  shutting off fuel correctly, is with a clear tube.

I'm having a similar problem to OP with fuel in my air box.

You likely have a clogged overflow (thus the fuel that wants to leak is headed up to your airbox).  I had the same issue.  Clear tube method is - you attach a clear tube to somewhere the gas would come out of the bowls - drain plug, etc. - open the petcock - hold the tube up, the fuel should be a couple mm below the seam.  There are a hundred instructions on it in this forum.

Check your oil for gassiness smell and don't run the bike if the oil smells like gas.  Just do an oil change anyway, actually, just to be sure.
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Offline irish44395

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Re: running on 3 cylenders
« Reply #6 on: February 05, 2016, 03:51:28 PM »
I'll give it  go tomorrow, Now if its the over flow the gas will be higher or lower?
Thanks
Pete
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Offline Old Scrambler

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Re: running on 3 cylenders
« Reply #7 on: February 06, 2016, 07:34:02 AM »
Higher.................its the same principal as taking in a wee-bit too much Guiness ;D ;D ;D
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Offline irish44395

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Re: running on 3 cylenders
« Reply #8 on: February 06, 2016, 07:48:41 AM »
I checked the levels on all  four carbs they are all the same . I pulled the carbs off and will clean # 4 again .I got to have some thing clogged I think , I have to get more carb cleaner then back at it.
Pete
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Offline irish44395

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Re: running on 3 cylenders (up date)
« Reply #9 on: February 07, 2016, 08:26:50 AM »
After cleaning the carbs reinstalled fire it up still wasn't running on #4. just happened to put my hand on the taped cover and felt it rapping turned it off ,took off the cover and discovered the long screw was reverse with the short screw. the long screw was  hitting the tapped arm, reversed the screws and its now running on all 4. I hope it didn't muck up anything doesn't appear so but now I am going to start taking it apart and painting and cleaning
thanks for all the help I'm stilling learn and having fun hope to be able to  contribute to others like you all have helped me I'm sure I'll will need more too
Pete
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