Author Topic: Anyone else have this dumb choke problem?  (Read 3183 times)

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Offline markreimer

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Anyone else have this dumb choke problem?
« on: October 24, 2016, 08:55:05 AM »
I've got a '74 cb750. The last two rides I've been riding along, everything is great, and then suddenly by bike starts to really bog down. Like on death's doorstep kinda thing. I panic for a second, then look down and realize my pant leg has snagged the choke lever and pulled it out to full choke!

Push the choke lever back down and the bike is back to normal, obviously.

I've never had this happen in the 6 years I've been riding the 750 until now. Anyone else have this annoying issue? Almost seems like the choke lever is slowly working itself outward as I ride, until it's sticking out far enough to grab my pant leg. But the choke lever on this style carb isn't under spring tension or anything like that, so I can't see what would make it work itself outward...

Offline harisuluv

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Re: Anyone else have this dumb choke problem?
« Reply #1 on: October 24, 2016, 09:46:43 AM »
I could tell you in a second if I had them in my hand, if the lever was bent, if the chokes were synced, etc. etc.  Without pictures it's very hard.

Offline markreimer

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Re: Anyone else have this dumb choke problem?
« Reply #2 on: October 24, 2016, 09:48:33 AM »
Lever isn't bent and I synced the choke last time I rebuilt the carbs. I can't imagine how they could become un-synced, but hey... worth looking at. I'll pull the airbox off and see if they are all sitting at the same height.

Offline flatlander

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Re: Anyone else have this dumb choke problem?
« Reply #3 on: October 24, 2016, 11:45:09 AM »
yes i've had this!
i have this choke lever on the 550f that can be pushed up (closed) if you're unlucky. happened to me once when i had the bike fairly new and i was like: dammit, did it just die on me? before i noticed what hat happend.
recently it happened again, i think the top of my boot's shaft must have gotten caught on it. i was running low on gas as well and switched to reserve while riding. that didn't help. only after stopping i saw the choke lever and was reminded of that first time it happened. must keep this in mind.


Offline ekpent

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Re: Anyone else have this dumb choke problem?
« Reply #4 on: October 24, 2016, 12:17:59 PM »
 I have been riding 750's since 1981 and have never had it happen.

Offline Duanob

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Re: Anyone else have this dumb choke problem?
« Reply #5 on: October 24, 2016, 04:14:22 PM »
I had that happen on my 550 once. Someone bought me a gremlin bell and after hanging it on the bike it never happened again!  8)
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Offline Deltarider

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Re: Anyone else have this dumb choke problem?
« Reply #6 on: October 24, 2016, 11:41:24 PM »
I had that happen on my 500 a couple of times. I've bent that lever somewhat inward and now it's over.
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Offline evanphi

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Re: Anyone else have this dumb choke problem?
« Reply #7 on: October 25, 2016, 08:00:55 AM »
Never had it happen on my CB750
--Evan

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Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

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Offline strynboen

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Re: Anyone else have this dumb choke problem?
« Reply #8 on: October 25, 2016, 10:13:36 AM »
hand choker on a k3 1978..some of the real good upgrates on the last cb"s..it can be locked in all posisions too... ..and give idel kontroll the first milimeter pull...
i kan not speak english/but trying!!
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Offline ekpent

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Re: Anyone else have this dumb choke problem?
« Reply #9 on: October 25, 2016, 01:41:33 PM »
hand choker on a k3 1978..some of the real good upgrates on the last cb"s..it can be locked in all posisions too... ..and give idel kontroll the first milimeter pull...
if the knob stay up. Had a 1977 I sold that had to be held, was a pain in the arse.  Love the simple stuff.

Offline Tim2005

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Re: Anyone else have this dumb choke problem?
« Reply #10 on: October 25, 2016, 03:18:13 PM »
Have you bought new riding boots recently? I've had that happen on the 750 - old set of boots used to catch on it occasionally, slightly shorter replacement ones are aok. 

Offline Gordon

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Re: Anyone else have this dumb choke problem?
« Reply #11 on: October 25, 2016, 06:09:57 PM »
That's happened to me a couple of times on the 550, but never on the 750.  The orientation (front to back) of the lever on the 550 means that a pants leg flapping in the wind can smack it and push it to the closed position.  The sideways lever on my 750 would have to be hit from directly beneath, which just doesn't happen. 

I suggest getting some of those skinny pants the kids are wearing these days. ;) 

Offline Johnie

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Re: Anyone else have this dumb choke problem?
« Reply #12 on: October 25, 2016, 07:56:54 PM »
Never had it happen on a CB750. Maybe that choke linkage is a bit lose. Maybe snug up the choke nuts a bit. You should have a little resistance when you lift the arm.
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Offline daniel9441

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Re: Anyone else have this dumb choke problem?
« Reply #13 on: October 25, 2016, 10:52:34 PM »
Never had issues with the choke, but I almost fell over at a stoplight this weekend when my 500's kicker went up my pant leg. That was a little scary :0

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Offline strynboen

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Re: Anyone else have this dumb choke problem?
« Reply #14 on: October 26, 2016, 03:18:50 AM »
hand choker on a k3 1978..some of the real good upgrates on the last cb"s..it can be locked in all posisions too... ..and give idel kontroll the first milimeter pull...
if the knob stay up. Had a 1977 I sold that had to be held, was a pain in the arse.  Love the simple stuff.
it have to be  turned clockveise to Lock solid...(like on old cars).mine had run 75,000 km...so a lot of km on the clock..and still Work ,,even it are a bit Loose in the plastic
i kan not speak english/but trying!!
http://forums.sohc4.net/index.php?topic=60973.0
http://forums.sohc4.net/index.php?topic=144758.0
i hate all this v-w.... vords

Offline evanphi

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Re: Anyone else have this dumb choke problem?
« Reply #15 on: October 26, 2016, 05:55:05 AM »

I suggest getting some of those skinny pants the kids are wearing these days. ;) 

Or some tight leather pants.


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1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline markreimer

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Re: Anyone else have this dumb choke problem?
« Reply #16 on: October 26, 2016, 07:17:52 AM »
As good as tight leather pants with rhinestones sounds (and oh boy, does it sound good), I don't think it's actually my pants catching the lever anymore.

FYI - I have the choke lever that is activated by pulling it directly outward, not the version that pulls up and back in-line with the bike.

I was trying to figure out how my pants might have been catching the lever and I just don't see how it could happen. The lever is too far in, even when it's sticking out a bit, to catch. And the lever is quite high up, so I'm not sure how my boot would grab it. but it's happened to me 3 of the 4 rides I've done this week now!! I have never had this happen for the first 4-5 years I've owned this bike.

I checked to see if the fuel line, throttle cables or anything else around the carb might be rubbing on the choke linkage and pushing it open. Came up empty though.

I thought maybe I had bumped it myself while adjusting the idle screw (it's real cold here right now, I usually give it an 1/8th turn when I start up, and turn it down a couple minutes later), but then it happened totally out of the blue.

This is the strangest gremlin I've chased on the 750 yet. If I can't track down the source I'm going to have to fabricate a little latch or magnet or something to hold the lever down.

Offline wallym

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Re: Anyone else have this dumb choke problem?
« Reply #17 on: October 26, 2016, 12:45:27 PM »
Had this on my 500 four k2. The choke is sprung to an on position and when in off position there is a ball that is spring room
 and pops in a recess to hold it there. That was worn so I tightened it up and worked.

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Offline Gene

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Re: Anyone else have this dumb choke problem?
« Reply #18 on: October 26, 2016, 04:11:31 PM »
I thought maybe I had bumped it myself while adjusting the idle screw (it's real cold here right now, I usually give it an 1/8th turn when I start up, and turn it down a couple minutes later), but then it happened totally out of the blue.

I've done this without realizing it. No way that lever should be moving up on it's own UNLESS the mechanism itself is so worn it's moving around sloppy there.
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