Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: paulbaker1954 on July 31, 2020, 07:58:10 AM

Title: Throttle movement amount
Post by: paulbaker1954 on July 31, 2020, 07:58:10 AM: A friend of mine has a UK K0 bike and I have a USA K0 bike and there is a big difference in the angle of movement from 0 to full throttle. On his UK bike I reckon it’s about 120 deg but on my US bike it’s more like 90.

The 120 movement makes his UK bike a pain to ride so was wondering if anyone knows any more.

The only variable I can think of is the diameter of the nylon bit the cable wraps round in the housing may be different
Title: Re: Throttle movement amount
Post by: Erny on July 31, 2020, 08:24:25 AM: I'm surprised there is difference - did you check spare parts catalogue what is different (or what shall be different)?
I know there are different handlebars, trottle cables, upper brake hose and wiring loom (all because of higher US bars) and switche(s).
Title: Re: Throttle movement amount
Post by: K2-K6 on July 31, 2020, 08:32:46 AM: "The only variable I can think of is the diameter of the nylon bit the cable wraps round in the housing may be different"

Yes, this is the normal part that is varied to change throttle linearity/ ratio etc. Whether Honda produced them differently I'd not know, but having a quick measure with a caliper should give you an insight as to what they've both got fitted to them.

I guess it's possible that one has a non std (perhaps from another Honda) fitted to make it different, either intentionally or by mistaken substitution.
Title: Re: Throttle movement amount
Post by: Erny on July 31, 2020, 08:50:03 AM: Quote from: K2-K6 on July 31, 2020, 08:32:46 AM
I guess it's possible that one has a non std (perhaps from another Honda) fitted to make it different, either intentionally or by mistaken substitution.

I suspect the same
Title: Re: Throttle movement amount
Post by: Bryanj on July 31, 2020, 09:03:50 AM: :Dthat sounds to me like the typical US owner peeing about with bits
Title: Re: Throttle movement amount
Post by: SteveW on July 31, 2020, 04:26:49 PM: You can get quick action throttles for modern sports bikes, so maybe it’s something like that.
Title: Re: Throttle movement amount
Post by: bobv7 on July 31, 2020, 05:58:36 PM: That's the one thing that annoys me most. It was the same when I had my 400/4; too much rotation from closed to open. Needs a throttle tube with a higher cam.
Title: Re: Throttle movement amount
Post by: Nurse Julie on July 31, 2020, 06:15:46 PM: Quote from: bobv7 on July 31, 2020, 05:58:36 PM
That's the one thing that annoys me most. It was the same when I had my 400/4; too much rotation from closed to open. Needs a throttle tube with a higher cam.
Agree, 400/4 throttle rotation is the worst ever, I'm sure it's not far of 360° from stop to stop. On my 550/4 it's about 180° max.
Title: Re: Throttle movement amount
Post by: K2-K6 on July 31, 2020, 06:35:02 PM: "Agree, 400/4 throttle rotation is the worst ever, I'm sure it's not far of 360°" ;D ;D ;D

It's possible that something like the 750 F2 has a different twist grip geometry that would fit and make it less travel.

Or some of the early eighties Hondas as they started to use CV type carbs with butterflies.
Title: Re: Throttle movement amount
Post by: bobv7 on July 31, 2020, 09:56:59 PM: That's a sound idea so if someone could do a quick measurement of the cam height and length from the handlebar there might be some relief for those suffering from over extended wrist action. Stop giggling at the back! :o

I checked mine and it's 10mm x 24.75mm near as damn it.
Title: Re: Throttle movement amount
Post by: cliff7 on August 01, 2020, 09:27:25 AM: Most peculiar! My 400/4 has about 100 degrees stop to stop and I'm sure it's getting full throttle. More investigation needed.
Title: Re: Throttle movement amount
Post by: Bryanj on August 01, 2020, 02:38:38 PM: I thought they were Oddjob, just too lazy to confirm it this time
Title: Re: Throttle movement amount
Post by: robvangulik on August 01, 2020, 05:54:46 PM: Quote from: cliff7 on August 01, 2020, 09:27:25 AM
Most peculiar! My 400/4 has about 100 degrees stop to stop and I'm sure it's getting full throttle. More investigation needed.
On my 400 too, easy to go WOT, not even a half turn.
Title: Re: Throttle movement amount
Post by: Nurse Julie on August 01, 2020, 06:46:10 PM: OK, I was exaggerating when I said I got 360° turn from stop to stop on my 400/4.....it's actually 90° 😊😊😊 It must be because I have very small hands, it just feels a lot further than ¼ turn 😁😁😁

Photo showing full extent of rotation

[attachimg=1]
Title: Re: Throttle movement amount
Post by: bobv7 on August 01, 2020, 08:23:04 PM: Yep, 90 degrees is right for the 500 too.
Title: Re: Throttle movement amount
Post by: bobv7 on August 05, 2020, 02:16:49 PM: I've bought a new throttle pipe off eBay that says it it fits a wide range of classic Honda models. It fitted OK and the lead lift of the ramp looks a bit longer than the old one. It did feel a bit better to me although it's still 90 degrees closed to open.

https://www.ebay.co.uk/itm/Honda-Push-Pull-Throttle-Tube-AND-GRIPS-53141-300-010-CB-350F-400F-550-CX500/303243856707?hash=item469abe0b43:g:~qoAAOSwAqhdnNIL
Title: Re: Throttle movement amount
Post by: robvangulik on August 05, 2020, 02:43:16 PM: I think you shouldn't want to have much less, it will be harder to (hold) open and also harder to dose the throttle, long ago I tried speed gas on my 750 for a while, but went back to standard after a couple of months. That was mainly useful to ride full speed all the time, and doing that on the street, well you know......