Author Topic: Carburettor throttle return spring  (Read 549 times)

Offline taysidedragon

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Carburettor throttle return spring
« on: May 18, 2021, 10:30:52 AM »
I find the throttle quite heavy on longer rides. (Arthritis in my hand doesn't help 😣)

The return spring seems a lot stronger than it needs to be, has anybody tried a slightly lighter spring to lighten the throttle feel. Obviously it still needs to be strong enough to safely close the throttle.
Gareth

1977 CB400F
1965 T100SS

Offline Athame57

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Re: Carburettor throttle return spring
« Reply #1 on: May 18, 2021, 10:42:06 AM »
I wonder if cruise control is an option, are these kits universal?
I brake for animals!
1978 CB400F2

Offline TrickyMicky

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Re: Carburettor throttle return spring
« Reply #2 on: May 18, 2021, 10:52:44 AM »
I had often wondered about this very same problem, ageing joints got me thinking that we possibly do not need such a strong spring as it is fitted with a closing cable as well.  Then just under a year ago, with the tank and seat removed, I was performing the ancient ritual of "If it moves, oil it" on everything within reach. I was checking on throttle action when it dawned on me that the cables were original, 44 BLEEDIN' YEARS OLD!!   The piggy bank was duly sacrificed, and a new set was fitted,  Oh! My right wrist hasn't had such pleasure in many a year.  The stupid part being that I replace the clutch cable approx. every two years, and yet the throttle cable is subject to the same weather elements and engine heat, yet requires much finer operation. Could be worth trying. Stay Safe. Mike.

Offline TrickyMicky

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Re: Carburettor throttle return spring
« Reply #3 on: May 18, 2021, 10:55:00 AM »
I wonder if cruise control is an option, are these kits universal?
Cruise control is only of any real use on a motorway. Who wants to take a solo bike on a motorway?

Offline Nurse Julie

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Re: Carburettor throttle return spring
« Reply #4 on: May 18, 2021, 12:51:24 PM »
I've fitted a less tight throttle spring on my 550/4 Mongrel because I found it a bit hard work after a few hours riding, it works a treat. I had to retain a bit of tension though as I don't have a return throttle cable fitted to this bike but this snaps back just perfect.
Im a Nurse, trust me, this won't hurt.....much !!!

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http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline taysidedragon

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Re: Carburettor throttle return spring
« Reply #5 on: May 19, 2021, 12:48:35 AM »
I've fitted a less tight throttle spring on my 550/4 Mongrel because I found it a bit hard work after a few hours riding, it works a treat. I had to retain a bit of tension though as I don't have a return throttle cable fitted to this bike but this snaps back just perfect.

Good to know. Thanks.
Tricky Micky, My cables are new and move freely when disconnected.
Gareth

1977 CB400F
1965 T100SS

Offline billywingnut

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Re: Carburettor throttle return spring
« Reply #6 on: May 19, 2021, 04:33:34 PM »
I think you really need that throttle return cable for safety reasons, there are four carbs if one should stick you would be in trouble, this strong spring ensures the engine returns to the correct idle speed when snapped closed,  the old cables ( 40 years old) on my bike would occasionally leave the engine running slightly faster than the 1200 rpm recommended.

Offline allankelly1

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Re: Carburettor throttle return spring
« Reply #7 on: June 01, 2022, 11:53:06 AM »
I've fitted a less tight throttle spring on my 550/4 Mongrel because I found it a bit hard work after a few hours riding, it works a treat. I had to retain a bit of tension though as I don't have a return throttle cable fitted to this bike but this snaps back just perfect.
Hi Julie

May I ask where did you source your spring from please

Would like to use a lighter spring on my CB400F as starting to do longer rides out +100 miles so would like to lighten up the throttle a bit if possible

Many thanks Al


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Offline Nurse Julie

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Re: Carburettor throttle return spring
« Reply #8 on: June 01, 2022, 01:40:12 PM »
I've fitted a less tight throttle spring on my 550/4 Mongrel because I found it a bit hard work after a few hours riding, it works a treat. I had to retain a bit of tension though as I don't have a return throttle cable fitted to this bike but this snaps back just perfect.
Hi Julie

May I ask where did you source your spring from please

Would like to use a lighter spring on my CB400F as starting to do longer rides out +100 miles so would like to lighten up the throttle a bit if possible

Many thanks Al


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Hi Al
I sourced it from a spring parts bin in the workshop 😂😂😂😂 I've no idea what model Honda Four it came from, all I can remember is that the spring tension was a little less than the one I had fitted and overall it was a few mm longer.
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline allankelly1

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Re: Carburettor throttle return spring
« Reply #9 on: June 01, 2022, 01:41:20 PM »
I've fitted a less tight throttle spring on my 550/4 Mongrel because I found it a bit hard work after a few hours riding, it works a treat. I had to retain a bit of tension though as I don't have a return throttle cable fitted to this bike but this snaps back just perfect.
Hi Julie

May I ask where did you source your spring from please

Would like to use a lighter spring on my CB400F as starting to do longer rides out +100 miles so would like to lighten up the throttle a bit if possible

Many thanks Al


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Hi Al
I sourced it from a spring parts bin in the workshop I've no idea what model Honda Four it came from, all I can remember is that the spring tension was a little less than the one I had fitted and overall it was a few mm longer.
Ok thanks for the reply

I will measure mine and see what is out there

Thanks again Al


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Offline Oddjob

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Re: Carburettor throttle return spring
« Reply #10 on: June 01, 2022, 02:53:37 PM »
This was discussed at quite some length in one of my posts, it was the considered opinion that using a small split ring (like off a key ring) is a good solution, just slip it onto the end of the spring and the post it supposed to hang off. It has to be a small split ring though, any beach fisherman has a few in his tackle box as they come in handy for beach weights etc
Don't play stupid with me, I'm better at it

Offline allankelly1

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Re: Carburettor throttle return spring
« Reply #11 on: June 01, 2022, 02:54:34 PM »
This was discussed at quite some length in one of my posts, it was the considered opinion that using a small split ring (like off a key ring) is a good solution, just slip it onto the end of the spring and the post it supposed to hang off. It has to be a small split ring though, any beach fisherman has a few in his tackle box as they come in handy for beach weights etc



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Offline Oddjob

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Re: Carburettor throttle return spring
« Reply #12 on: June 01, 2022, 03:00:06 PM »
I don't need to say this but just in case I think I should. The spring should still be under tension with the split ring fitted or everything just falls apart when the throttle is let go suddenly. A small 10mm ring should be good enough but test and see and if not go a little bigger until you get the spring tension you feel you can live at whilst still retaining positive throttle closure.
Don't play stupid with me, I'm better at it

 

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