Today I went for a go on an ATV (quad). Not because I’m going to buy one but so that I could try out the thumb throttle arrangement. Some of you will know I damaged my wrist in an accident and now have limited movement.
The ride proved that I can use a thumb throttle without it hurting my hand or wrist. So I think I’ll get one, fit it to the V7 and see how I get on. I’ve got to replace this.
It might mean that I have to move the choke control and I will have to move the winker switch as I won’t be able to flick it with my thumb. I’m used to riding without winkers but this is only really possible with a throttle damper. The thumb throttle will close as soon as I let go of it so the winkers will have to remain.
I would have to get someone like Venhill to make up a throttle cable etc but it seems do-able. My reservation is that the throttle will be too stiff when opening 2 VHB Dellortos but I can only give it a try. I was assured that there is enough travel in a thumb throttle to pull the carbs fully open. I need about 32mm.
It’s unlikely anyone else has done this to one of these but can you see any pitfalls?
If you haven’t already, light springs for the slides will help a lot. Also mine’s using a 1-into-2 splitter (Superdweam twistgrip only accepts 1 cable) and was surprised how much lighter that makes it too. You wouldn’t think two long parallel cables would have so much friction… unless they were just old and knackered…
There’s already a cable splitter. I’ll likely get all new cables to make sure they’re as good as they can be. Are lighter throttle springs safe? I have heard mixed views on this. I understand the original springs were 2kg and you could get 1.1kg replacements but these days they are getting hard to find.
If by “safe” you are alluding to slides sticking open, has never happened to me. (Yet!) Light springs have been in my VHB’s must be over 20 years by now.
Yeah, that’s what I meant. I’ve never come accross anyone who’s had them stick yet but I’ve been given grave warnings. I think these have mainly come from the USA where the threat of being sued is more of a worry.
I did have the throttle stick open on a Yamaha RD400 many years ago. I laughed about it afterwards but not at the time! Luckily that had a kill switch but the slowing from 60 with the engine off was not nice. Of course, there’s no kill switch on the V7.
You’ll need some ATV grips as the twist grip and throttle tube will become redundant. Indeed, become a hindrance and possibly a hazard. Carb’s, a friend of mine swapped out the carbs on his Cali 3 for some Bing carbs off a BMW as they gave a lighter action.
I’ll use a plain grip to replace the old throttle. I’d heard that Bing carbs may be a viable alternative but I want to alter the bike as little as possible. I’ll just try a thumb throttle first. If it’s too tough to pull I’ll try the lighter springs. Hopefully this will be enough. There is an alternative which is a “convergance throttle”. This is a type of thumb throttle you operate by wrapping your thumb around the lever and pulling it in toward your palm, a bit like making a fist. It’s pretty pricey and looks rather modern but I’m told it puts less strain on your hand. http://www.inoveli.com
One of those throttle assists won’t help me - I’ve actually got one somewhere.
My problem is that I can’t bend my wrist much. I can just about turn a twist grip 60 degrees and that takes some effort. Most people can turn their wrist in 90 degrees and back something approaching the same amount, although that can reduce as you get older. My right wrist can do 45 degrees one way and about 30 the other. My left can do 90 and 60 'cos, in the past, I’ve damaged that one as well!
The simplest option is actually to make a hole in the grip on the twist throttle and then move the twist grip to the left bar with the cable coming from the outside tip of the bar. That way the throttle turns the right way. Clutch control can then be awkward (though not impossible) so I’d need to swap the front brake and clutch over - easily done as they’re both cable operated - then pop the other grip on the right. Probably I’d need a longer throttle cable. I don’t think I’d have any problem using a left hand twist throttle but, in an emmergency, I think I’d likely pull the clutch hard and not the front brake - a reflex after nearly 40 years of riding.
I think if you find the spring pressure too great you could try a longer thumb lever. The vintage boys will be using longer ones for their various controls - although you could end up paying a premium for something of that era I suppose. I’ve ridden snowmobiles with a thumb lever, and wished they had twist grips - but then my wrists still have most of their movement. Conversely I’ve had a go on some old hand change bangers and thumb throttle works much better on those I thought. Have you seen/considered this kind of thing? - http://www.webbikeworld.com/t2/motorcycle-cruise-control/brake-away/brake-away.htm
John…I had abig 450 single quad with a thumb throttle…I wished for a twistgrip…
my loop has a very lite throttle…on my lemons I usually cut and pull the throttle springs…yes…on a good motor you can have probs with it not shutting off…thats why I always test stuff !
On the bike I raced I had a TZ 750 Â quick action throttle…a bit like an on off switch on a powerful motor…but manageable and usable for you on a softer engine ?
Thanks for all the input. I’ve been looking again at quick action throttles but I’m not sure if I understand the descriptions properly.
For instance, on Mead Speed’s site they have a quick action throttle http://www.meadspeed.com/products/honda/rs125/throttle - Single pull, max. stroke 82mm (36/66 degrees). Does this mean it pulls 36mm in 66 degrees of turn? If so it could work as I think I need about 32mm of pull which I reckon would be about 59 degrees. This might still be a bit much for me to manage although, how often do you ride with the throttle wide open?
There is an even quicker throttle http://www.meadspeed.com/products/honda/throttle/very-quick-action - Max stroke 66mm (36/52 degrees). If I’ve got this right, then that would pull 32mm in about 46 degrees which is about half what it is now with the Super Pratic B throttle. Might be a bit like a switch and could be heavy.
Trouble is there aren’t any bike shops around here where I could try out a quick throttle. I’ll have a look on M & Ps site to see what they sell. I’ve got to go to Swansea on Wednesday so could call on them after my hospital appointment. - edit - as usual they don’t appear to have anything.
The throttle on my loop doesn’t feel that light. Could be that the cables need some work. Mine is a single pull throttle going to a splitter. Then 2 cables to VHB29 carbs. Is yours the same Kate?
Thanks Kate. I think my throttle is the same but is definitely stiff. Looks like a new set of cables is in order.
As I had to make the 110 mile round trip to the hospital in Swansea on Wednesday, I called in at M & P. As usual there wasn’t much I was interested in but I did try the throttles on the Kawasakis on show. I was almost able to turn a 90 degree throttle so I must have more movement than I thought. However, the throttles on modern bikes are nice and light as they only have to open a FI throttle body. I’ve been in the garage today and can actually manage a bit more of the loop throttle than I could! Think I’ll order a quick action throttle and see how I go. It means I wouldn’t have to make any other changes and, who knows, I might be able to change back after a while.
I was discharged by the consultant on Wednesday and he gave me the go ahead to get back on the bike. I saw the physio the following day and told him what I intended to do. He basically said to “use it till it hurts” but not to over do it. He thinks a twist throttle may be a good thing and help improve the wrist movement.
Hi John, don’t know where else you’ve been looking but I just did an eBay search and found all these ~ some of the levers are quite long, so giving better, er, leverage…
I’ve found that I can just about use the throttle that belongs to the V7Sport. It turns 90 degrees to fully open the carbs while the loop one takes 120 degrees. I can just get a similar throttle of a single pull type. No nasty thumb throttles and the need to change other controls. Also the return springs in the carbs should be ok.
Just to say, I finally got round to fitting my new throttle. It’s one from Domino. I had a new cable made by Speedy Cables as I needed more free play.
This takes just less than a quarter of a turn to open fully and is not too heavy to use. It’s better than my V7Sport possibly because it’s got new, nicely lubricated cables. In the photo it’s got no cables!
