« previous next »
Pages: [1]   Go Down

Author Topic: Sticking throttle  (Read 3974 times)

0 Members and 1 Guest are viewing this topic.

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Sticking throttle
« on: July 10, 2015, 04:52:42 PM »
Something I've noticed is that my throttle is sticking open.  It's difficult to rotate the rod at the carburetor, forcing me to close the throttle rather than having it snap closed on it's own.

Obviously it needs to be addressed, but the question - where should I look to address it?  Should I grease the places where the rod enters the carb bodies?  Or is the issue likely something that originates inside the carburetor - like on the needle slides?  This is a PD46a carburetor.

I guess I'm looking for likely places to start.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline madmtnmotors

  • When did I get to be a
  • Really Old Timer ...
  • *******
  • Posts: 6,110
  • Sunny Central Florida
Re: Sticking throttle
« Reply #1 on: July 10, 2015, 05:24:10 PM »
I'm guessing we're talking about the 77 550K in your sig?  ???

If so, is the external return spring in place? Honda part number of the spring is 16036-393-004 and it connects the idle stop bracket to the front stay plate (Honda part number 16119-393-004). It works in conjunction with the coiled return spring on the shaft.
Logged
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #2 on: July 10, 2015, 06:18:07 PM »
The spring is there.  Without the spring in place the shaft is difficult to rotate manually, like it's dragging on something.  I don't see any evidence that it's bent although it probably wouldn't take much of a bend or binding to prevent free rotation.

And yes, this is my '77 CB550.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline mpgholston

  • Full Member
  • *
  • Posts: 31
Re: Sticking throttle
« Reply #3 on: July 10, 2015, 06:41:38 PM »
Just to make sure, did you check the locking screw on the throttle handle to make sure it isn't engaged? I'm assuming a 77 has one. Also if the cable is adjusted to far out (at the handle) the cable can bind. Oh, while stuck try rotating the handle bar back and forth and see if it frees up. This happened to me once.
Logged
All Stock and All Spec 1974 CB550.
In my book, you either screw a guy out of tires OR upload pictures of yourself playing with your crank on the web.  Performing both will render absolutely horrible results. #brimmer.

Offline RevDoc

  • Hot Shot
  • ***
  • Posts: 556
Re: Sticking throttle
« Reply #4 on: July 10, 2015, 07:52:04 PM »
MPG may be steering you in the right direction. I had a problem with the throttle on Angie not dropping down to idle. Changed out the throttle cables and problem solved.
Logged
Dana

'78 CB550K--Angie
'82 CB750 Custom--Eva



As soon as you straddle a bike expect every other driver on the road to suddenly start competeing for the title "Dumbestsonofa#$%*inallNorthAmerica!!"

Offline mrfish2

  • I might be a
  • Hot Shot
  • ***
  • Posts: 679
Re: Sticking throttle
« Reply #5 on: July 10, 2015, 08:06:29 PM »
If it's sticking there are only so many places to look at. You've already said the spring is there and functioning correctly, so the only other things to check for are sticky slides, sticking throttle cable, or maybe the twist grip is binding up somehow. Just went through all this on my bike and it turned out to be a crappy aftermarket pull cable.
Logged
1976 CB550K            1979 XS1100
1980 CB650C - Sold

Quote from: crazypj on October 19, 2008, 09:14:45 PM
It's a little motor and likes having the tits revved off it.

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #6 on: July 10, 2015, 09:17:25 PM »
Alright, I'll quit jerking around then and start with the cables - bind it then see if turning the head will jar it loose.

I still suspect it's the slides, but no sense tearing it apart when I can knock out the easy stuff first.  Never actually thought of looking at the cables - which is probably why I had to ask.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline jayowen

  • Full Member
  • *
  • Posts: 42
Re: Sticking throttle
« Reply #7 on: July 10, 2015, 09:22:29 PM »
i had a sticky throttle and it ended up being the throttle tube that was super dirty underneath. i just bought a new one as it was cheap and boooom normal throttle.
Logged

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,301
Re: Sticking throttle
« Reply #8 on: July 10, 2015, 10:08:02 PM »
Throttle grip edge too close to control and rubbing? Gunk under your throttle tube?
Gunked push / pull cables?
Spray carb cleaner on all the moving parts at the throttle bell.  Carefully lube the moving parts.
Choke butterflies centered in Carb throats?
Logged
'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 eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #9 on: July 10, 2015, 11:05:48 PM »
Assuming it doesn't rain tomorrow, I'll take a real close look and report back, might be an "all of the above" situation.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #10 on: July 11, 2015, 08:28:09 AM »
Well, I suspect it is an "all the above" situation, however in this instance it looks like the cables are sticky.  Didn't see that coming.  I'll need to pick up a cable lube - since I don't have one.

I did release the screws that hold the slides firm on the rod and the #3 was a bit off-center.  Loosening them released a bit of pre-load in the rod - so I have that anyway.  But sticky cables it is.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline mpgholston

  • Full Member
  • *
  • Posts: 31
Re: Sticking throttle
« Reply #11 on: July 11, 2015, 08:50:53 AM »
Hey, doesn't sound too bad.
Logged
All Stock and All Spec 1974 CB550.
In my book, you either screw a guy out of tires OR upload pictures of yourself playing with your crank on the web.  Performing both will render absolutely horrible results. #brimmer.

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #12 on: July 11, 2015, 09:02:55 AM »
No it isn't, although sticky cables sure makes my ride a bit harrowing. :-[
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #13 on: July 11, 2015, 10:41:44 AM »
Some pretty nasty stuff came out of those cables, so even if ultimately it doesn't solve my problems 100% - it still needed to be done.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline links56

  • Full Member
  • *
  • Posts: 69
Re: Sticking throttle
« Reply #14 on: July 11, 2015, 10:44:21 AM »
It's crazy how much gunk can get in a cable sheath over the years.
Logged

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #15 on: July 11, 2015, 12:30:54 PM »
Actually I've reassembled the cables and Flybox had it correct - messed up throttle tube.

The cables were sticky, but ultimately it's the throttle tube that's dragging - I don't even think it's the right throttle tube for the bike since the grip doesn't cover the whole thing.

I have a new throttle tube on order, I'll replace it and be glad to have figured it out.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline Stev-o

  • Ain't no
  • Really Old Timer ...
  • *******
  • Posts: 34,355
  • Central Texas
Re: Sticking throttle
« Reply #16 on: July 11, 2015, 04:10:45 PM »
You're gonna need new grips too.   BTW - the tube can be trimmed if it is too long for a specific grip.
I love ProGrips, I get them at Cycle Gear or you can get em at Amazon....


http://www.amazon.com/Pro-Grip-Dual-Sport-Grips/dp/B001RTCPEW
Logged
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline eigenvector

  • Master
  • *****
  • Posts: 1,949
  • Member of the despondent public
Re: Sticking throttle
« Reply #17 on: July 11, 2015, 07:27:52 PM »
The grips will be fine, I can get them to slide off with a hose pick and compressed air.

I have stock grips on the bike, I use the pro grips you mentioned on my CB750 - and they are quite nice.
Logged
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre
Pages: [1]   Go Up
« previous next »