Author Topic: stiff throttle  (Read 3381 times)

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Offline Dakotarider

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stiff throttle
« on: August 15, 2017, 07:48:25 PM »
How do I get the throttle return spring to loosen up?   I have a 78 cb750k with the PD carbs.
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Offline evinrude7

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Re: stiff throttle
« Reply #1 on: August 15, 2017, 07:57:30 PM »
take it off and stretch it.  don't ruin it just give it a good stretch.  night and day for me on my 750. 
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Offline MoMo

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Re: stiff throttle
« Reply #2 on: August 15, 2017, 09:32:01 PM »
other things to check:  throttle sleeve dirty, end of grip binding against handlebar, throttle cable binding from grit or improper routing or frayed, slides binding...Larry

Offline Dakotarider

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Re: stiff throttle
« Reply #3 on: August 16, 2017, 05:26:55 AM »
the spring is the coil type around the slide shaft, how to I stretch that? Everything else is smooth and free.
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Offline BobbyR

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Re: stiff throttle
« Reply #4 on: August 16, 2017, 05:36:45 AM »
other things to check:  throttle sleeve dirty, end of grip binding against handlebar, throttle cable binding from grit or improper routing or frayed, slides binding...Larry
Before I work on the spring I would be completely certain that cable is not fraying. This is common as the cables age. You get very tiny breaks in the strands that form "hairs" that scrape the walls of the sheath. These are not large strand breaks. They are numerous. If you lube the cables and everything smooths out, that is probably your problem. The lube is temporary. If you cables are old or original, they should be changed. Having a throttale cable break whicl you are our riding really sucks.
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline evinrude7

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Re: stiff throttle
« Reply #5 on: August 16, 2017, 06:21:33 AM »
the spring is the coil type around the slide shaft, how to I stretch that? Everything else is smooth and free.

ahh good question.  it's different on mine.  can you post a photo? 
cb750 k6 - ugly

Offline evinrude7

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Re: stiff throttle
« Reply #6 on: August 16, 2017, 06:30:57 AM »
i think i found a photo of it here.  http://forums.sohc4.net/index.php?topic=97319.0 however this is on a 550.  is it like this?  if so can the spring be "let out" a little while still offering "snap back" upon release?
cb750 k6 - ugly

Offline flybox1

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Re: stiff throttle
« Reply #7 on: August 16, 2017, 07:26:56 AM »
'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)
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"Knowledge without mileage equals bullsh!t" - Henry Rollins

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

Offline Dakotarider

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Re: stiff throttle
« Reply #8 on: August 16, 2017, 07:31:59 AM »
yes that is the type that I have in the picture.  The issue is that there is too much snap back, causing my wrist to tire even on a 20 minute ride.  I have smooth barrel type hand grips causing me to grip harder than I should need to.  I have other bikes and they don't have as much snap back as this bike.  I know I could get different grips to help, but it is still too much snap.  I want less snap.
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Offline flybox1

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Re: stiff throttle
« Reply #9 on: August 16, 2017, 07:39:34 AM »
Its a safety feature.  You WANT the slides to close like a guillotine.
Get a crampbuster or eat more spinach  ;D
'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 Dakotarider

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Re: stiff throttle
« Reply #10 on: August 16, 2017, 09:05:00 AM »
 The safest way to ride a bike is to leave it in the garage.   The older I get the more I realize that the joy in riding increases with the comfort level. The difference between riding an old bike and a new bike is the small details that make you feel like one with the machine. Well, the easiest fix is to get better grips.
If one bike is good, three is better!

Offline CycleRanger

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Re: stiff throttle
« Reply #11 on: August 16, 2017, 09:38:44 AM »
Its a safety feature.  You WANT the slides to close like a guillotine.
Get a crampbuster or eat more spinach  ;D

If the stiffness lasts more than four hours call your mechanic.... ;) ::)


But to be serious, larger diameter grips might help.
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CB750K5        '79 XL250s     CL350K3
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Offline lrutt

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Re: stiff throttle
« Reply #12 on: August 16, 2017, 09:39:33 AM »
Has to be in your cable or throttle sleeve. Those springs aren't all that strong.

Be glad you don't have a Guzzi Lemans. Those 2 big Delorto pumpers will make you look like Popeye in no time.
06 Harley Sporster 1200C, 06 Triumph Scrambler, 01 Ducati Chromo 900, 01 Honda XR650L, 94 Harley Heritage, 88 Honda Hawk GT, 84 Yamaha Virago 1000, 78 Honda 750K w/sidecar, 77 Moto Guzzi Lemans 850, 76 Honda CB750K, 73 Norton 850, 73 Honda Z50, 70 & 65 Honda Trail 90, 70 & 71 Triumph 650s, 65 Honda 305 Dream, 81 Honda 70 Passport, 70 Suzuki T250II, 71 Yamaha 360 RT1B, 77 BMW R75/7, 75 Honda CB550K, 70 Honda CT70

Offline Dakotarider

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Re: stiff throttle
« Reply #13 on: August 16, 2017, 11:28:45 AM »
I knew there would be some comedic relief soon. ;D
The issue isn't the dynamic actuation of the throttle, twisting.  The issue is the static hold necessary to maintain speed.  Imagine one of those squeeze exercise thingy's, the kind with the hand grip and coil spring.  You could do that all day without taking a break, but wouldn't last long if you had to hold them closed.
I have already made certain that my throttle cable and throttle action is free and without bind.  Those are good.  If they weren't, then the throttle would be more sticky thereby decreasing the amount of grip necessary to maintain speed.  Kind of a built in speed control, twist it to the desired rpm/speed and let go.  I've had throttles like that. :)
I agree that the slides need to snap back into place, I just had a wish that I thought some else might have an easy fix for. 
Maybe i just go buy that wrist grip exercise thingy...
If one bike is good, three is better!

Offline flybox1

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Re: stiff throttle
« Reply #14 on: August 16, 2017, 11:33:16 AM »
Crampbuster !!!


...or a shakeweight  ;D
'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 Dakotarider

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Re: stiff throttle
« Reply #15 on: August 16, 2017, 11:36:51 AM »
shakeweight?
You're motorcycling all wrong! ???
If one bike is good, three is better!

Offline flybox1

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Re: stiff throttle
« Reply #16 on: August 16, 2017, 11:44:54 AM »
shakeweight?
You're motorcycling all wrong! ???
lmao  ;D
'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 lrutt

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Re: stiff throttle
« Reply #17 on: August 16, 2017, 01:19:33 PM »
Get those barrel shaped grand tourismo grips. Look good on vintage bikes and relieve a lot of that stress you mention
06 Harley Sporster 1200C, 06 Triumph Scrambler, 01 Ducati Chromo 900, 01 Honda XR650L, 94 Harley Heritage, 88 Honda Hawk GT, 84 Yamaha Virago 1000, 78 Honda 750K w/sidecar, 77 Moto Guzzi Lemans 850, 76 Honda CB750K, 73 Norton 850, 73 Honda Z50, 70 & 65 Honda Trail 90, 70 & 71 Triumph 650s, 65 Honda 305 Dream, 81 Honda 70 Passport, 70 Suzuki T250II, 71 Yamaha 360 RT1B, 77 BMW R75/7, 75 Honda CB550K, 70 Honda CT70

Offline BobbyR

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Re: stiff throttle
« Reply #18 on: August 16, 2017, 05:49:33 PM »
Get those barrel shaped grand tourismo grips. Look good on vintage bikes and relieve a lot of that stress you mention

+1 fat sticky grips you are only resting your hand on it.
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline RAFster122s

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Re: stiff throttle
« Reply #19 on: August 16, 2017, 07:51:27 PM »
There are the old barrel shaped design that has the rubber raised grid forming that barrel.  They do a job at isolatjng vibration.  I bought a set from a seller ibuy.isell and they were inexpensive, never used them  i think they are still being sold on ebay.  I currently have a grip which is the Performoance grip Gel grips that are pretty tacky and soft.  I believe that Randakk's sell them as his Ultimate grip or some such...

They are not a huge diameter grip, this is another way to help with that problem...another is to replace the throttle assembly with a quick action throttle that actuates in 100 degrees.
David- back in the desert SW!

Offline Dakotarider

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Re: stiff throttle
« Reply #20 on: August 17, 2017, 05:42:01 AM »
Grips it is.    Always a fine line between ridable and and looks.
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Offline lrutt

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Re: stiff throttle
« Reply #21 on: August 17, 2017, 11:34:49 AM »
emgo has the gran tourismo grips. Have those on about a dozen bikes.
06 Harley Sporster 1200C, 06 Triumph Scrambler, 01 Ducati Chromo 900, 01 Honda XR650L, 94 Harley Heritage, 88 Honda Hawk GT, 84 Yamaha Virago 1000, 78 Honda 750K w/sidecar, 77 Moto Guzzi Lemans 850, 76 Honda CB750K, 73 Norton 850, 73 Honda Z50, 70 & 65 Honda Trail 90, 70 & 71 Triumph 650s, 65 Honda 305 Dream, 81 Honda 70 Passport, 70 Suzuki T250II, 71 Yamaha 360 RT1B, 77 BMW R75/7, 75 Honda CB550K, 70 Honda CT70

Offline RAFster122s

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Re: stiff throttle
« Reply #22 on: August 17, 2017, 11:34:40 PM »
The name of the grip I described but could not recall the name of is a Bolton Grip.

Similar to a gran tourismo shape in the waffle style  surface.
David- back in the desert SW!