Author Topic: Throttle needs death grip (Read 5654 times)

DaveInTexas · « **on:** June 18, 2006, 06:58:36 PM »

Finally getting some riding in.
Finding after 20 mins my hand is cramped, the vessels bulging and it aches from trying to hold throttle in. Compared the return spring tension to my pal's Harley and mine was much much stronger.

I notice a hole in the bottom of the throttlegrip retainer, could this be some type of tensioner to reduce the wrist strength required to hold the throttle open?

If that is 'just the way it is', someone else told me about a product you velcro to the throttlegrip, it provides more leverage for your palm(?) --- heard of this??

merc2dogs · « **Reply #1 on:** June 18, 2006, 07:11:56 PM »

many of the older bikes had a spring over a screew threaded into that hole, I believe it was for setting tension on the throttle. Not sure if it was a plain steel screw or a nylon tipped one, and no idea how it affected wear on the throttle tube.
There are a few attachments made to fit over the grip that allow you to maintain position with your palm, instead of strength of grip. one I looked at was basically just a loop that slid easily one direction, but locked in the other so it was simple in operation.

sometimes you can put a lighter spring on the return, or use a small lock ring between the spring and the mount at the top to reduce tension.

ken.

Bob Wessner · « **Reply #2 on:** June 18, 2006, 07:20:08 PM »

Here's another I looked at. It has the ability to be folded out of the way.. according to the manufacturer anyway. Can't personally vouch for it as I've never tried it.

http://www.wolftrax.com/products/wr/

Tim. · « **Reply #3 on:** June 18, 2006, 07:43:10 PM »

Check the springs on your return. My bud's 750 had what must have been suspension springs from a go-kart on them - they were that stiff. Oh, and there were a couple of them. Previous owner must have really worked his right hand out a lot

Attack the problem from the source (the spring) before you buy gadgets to make turning that beast easier. BTW - does the throttle snap back into place when you release it? How new/old/lubricated are the cables?

Bodain · « **Reply #4 on:** June 18, 2006, 07:52:03 PM »

It should not take a gorilla grip to hold the throttle open. If you have a cable problem it can be found very easy. Just remove the cables from the carburator. Now turn the throttle. Does it move freely? If yes look elsewhere. If no. You found your problem.

DaveInTexas · « **Reply #5 on:** June 18, 2006, 08:59:33 PM »

The throttle snaps back easily - if anything, the cable and apparatus is all working too well!
If the cable was hanging up, I'd think I would have to use less force to keep it open.

I guess I will look into the screw/spring thing on the parts manual or on another bike (anyone looked at the bottom of theirs?). I have no way of telling if someone replaced my springs with valve return springs! or not, they look 'fine' to me. That is they appear to be appropriate in size and shape, all that.

Or maybe I will just get one of those wrist-exercisers!

HondaMan · « **Reply #6 on:** June 18, 2006, 09:07:22 PM »

Honda was overly cautious about safety on the world's first Superbike, and learning to ride sidesaddle for leverage, just to keep up the speed, was part of the riding process for a while.

I take out the springs and measure the closed throttle distance, then subtract the closed spring length from that. Then, I PERMANENTLY overbend the first 3 or 4 coils of the spring to make up 60% of that distance and reinstall the spring. The result is a less-stiff spring that still reliably returns, with good cables.

There should also be a length of rubber hose over the spring, about 1.25" long or so, that helps the rider maintain a given throttle setting. If yours is gone, install a new one. I think the large size vacuum hose at Checker Auto will fit.

Also, throttle grips with larger diameter handles will help. I use ones that are sort of "swelled" in the middle and tapered toward the ends: these work well for me.

Update 6/20/06: I got a shot of mine for you, while it's apart for rebuild. This shows how the spring has been stretched, and shows the rubber "holder hose" still in place. This is a 2-finger throttle on the highway, with good return characteristics.

Bob Wessner · « **Reply #7 on:** June 19, 2006, 02:09:07 AM »

Quote

Finding after 20 mins my hand is cramped

Dave,

That is a short time in which this is happening. One other thing to consider, along with the other suggestions, is what type of material is in the palms of your gloves, more to the finish. Does it provide a good grip as in rough vs. smooth? That too can make a difference. I guess I am making an assumption you are wearing gloves.

toycollector10 · « **Reply #8 on:** June 19, 2006, 02:45:34 AM »

I bought a new pair of winter weight gloves on Saturday and had the same problem. Absolutely no purchase on the throttle. When I got home I got some black electrical tape and wound it, sticky side up, around the grips and secured it by doubling the ends back on themselves. Works a treat so far but looks a bit fugly. Once the gloves are broken in I think it will help with the problem..TC

Terry in Australia · « **Reply #9 on:** June 19, 2006, 03:14:35 AM »

The early CB750's (the best ones, IMHO) had friction screws between the cable bosses on the throttle assy, but these disappeared after the K2, from memory. They were more for adjusting the idle at warmup, but must have been a leftover from the mighty K0 with the cable carbs, that incidentally had a much nicer throttle pull, even with 4 seperate springs, compared to the single heavy bastard on the linked K1-K6 carbs.

Hondaman's idea is good, (as usual) or just go to an engineering supply store and buy a lighter spring, the rubber sheath didn't appear (from memory) until the K3, so don't be surprised if yours doesn't have one, as you know, our bikes went through a steady progression of mods to fix minor "flaws" (character traits?) right up to the last incarnation, the K6.

I just missed an auction for a set of Keihin CR's for my racer project, so I'm gonna bite the bullet and order a new set, anyone know what the throttle pull on them is like? Cheers, Terry.

Bob Wessner · « **Reply #10 on:** June 19, 2006, 03:32:17 AM »

Quote

Hondaman's idea is good, (as usual) or just go to an engineering supply store and buy a lighter spring, the rubber sheath

Terry,

The screw adjuster on my K0 is long gone. I'm having trouble visualizing where/what this spring/sheath assembly is. Can you clarify?

Mark M · « **Reply #11 on:** June 19, 2006, 03:43:20 AM »

Terry,
With my CR's they were fine, but I used a throttle and cables from an nc30 (same as lots of recent Honda sports bikes) the only
thing I found was getting the carb spacing spot on so that they closed smoothly.

78CB750F1 · « **Reply #12 on:** June 19, 2006, 03:52:21 AM »

Terry - I have just installed a set of Keihin CRs - the throttle spring is quite strong and snaps closed very firmly! A good feel to it though. The CRs have a rubber hose over the spring. Installing the throttle cables takes a bit of patience to prevent them binding because the throttle linkage is much higher on the carb bodies and very close to the top bar on the frame.

Terry in Australia · « **Reply #13 on:** June 19, 2006, 04:56:05 AM »

Quote from: Bob Wessner on June 19, 2006, 03:32:17 AM

Quote
Hondaman's idea is good, (as usual) or just go to an engineering supply store and buy a lighter spring, the rubber sheath

Terry,

The screw adjuster on my K0 is long gone. I'm having trouble visualizing where/what this spring/sheath assembly is. Can you clarify?

G'Day Bob, on your (magnificent) K0, you have four individual cables (one per carb slide) that go into a "one into four" splitter, with of course, just one cable exiting the throttle assembly. Underneath the throttle assembly there should be a threaded hole for a 6mm (I'm guessing, I've never measured it) screw with a knurled head and spring (to stop it falling out) that you can just wind in until it's snug at whatever idle speed you want to warm it up with. Old BMW's were the same, and some guys used these screws as "cruise controls", but I wouldn't unless I was crossing the Nullabor Plain, ha ha! (very long straight stretch of highway here in Oz)

On the later CB750's, which had carbs operated by a central linking system (which is great for keeping the carbs in synch, but not much else) there were no individual carb slide springs, but one heavy helical spring (sometimes with a rubber sheat to stop it snagging, depending on the model) located between carbs 3 and 4 which closed off all four slides. The spring is so strong you could use these carbs for cigar cutters, or guillotines for mice, or maybe for multiple circumcisions, ha ha! I get off my K1 and hop on my Suzuki GS1000S with a bank of single cable CV carbs and (without thinking) pull on the throttle on that thing so hard I've almost launched it through my side fence at times, the difference between the two bikes is that great. Cheers, Terry.

HondaMan · « **Reply #14 on:** June 20, 2006, 10:06:11 PM »

If someone wants one of these screws, I can make one with a nice (but plastic) thumbscrew on it. The tip should be rounded. Inside the throttle grip there is a flat, folded spring plate that this screw tightens against, providing friction against the rotation of the throttle. There needs to be a spring around the screw (on the outside) to help it stay in place. Lots of them are lying about on the highway (or stuck in someone's tire!) from riders who set them too loose, letting them fall out and....gone! These disappeared by DOT law in 1974, most K3 and later were missing them. The signature change was with the 90-degree OFF switch on the right side: factory units that came this way in mid-1973 and later had no screw, nor a hole for one.

And, it makes a SUPER cruise control at speeds of 80+.

Terry in Australia · « **Reply #15 on:** June 20, 2006, 11:07:24 PM »

Quote from: HondaMan on June 20, 2006, 10:06:11 PM

If someone wants one of these screws, I can make one with a nice (but plastic) thumbscrew on it. The tip should be rounded. Inside the throttle grip there is a flat, folded spring plate that this screw tightens against, providing friction against the rotation of the throttle. There needs to be a spring around the screw (on the outside) to help it stay in place. Lots of them are lying about on the highway (or stuck in someone's tire!) from riders who set them too loose, letting them fall out and....gone! These disappeared by DOT law in 1974, most K3 and later were missing them. The signature change was with the 90-degree OFF switch on the right side: factory units that came this way in mid-1973 and later had no screw, nor a hole for one.

And, it makes a SUPER cruise control at speeds of 80+.

Put me down for a couple mate! Cheers, Terry.

cbjunkie · « **Reply #16 on:** June 21, 2006, 06:13:53 AM »

A-HA! I knew I must be missing something (the PLATE) as mine has never seemed to work properly...

Is this a spring steel item, or could I fabricate it out of a bit of stock?

dusterdude · « **Reply #17 on:** June 21, 2006, 07:04:40 AM »

its the spring,mine is the same way.gonna replace that sucker one of these days.

cbjunkie · « **Reply #18 on:** June 21, 2006, 07:07:37 AM »

no, I mean is the PLATE made of spring steel...

I have the original screw and spring (exterior), but not the plate (interior - to the handle)

crazypj · « **Reply #19 on:** June 21, 2006, 07:26:35 AM »

The hole is to let water out so dont block it up. Thre friction adjuster switches had a small boss cast in if memory serves me correctly and were fited to 500 as well as 750
PJ

clarkjh · « **Reply #20 on:** June 21, 2006, 07:44:48 AM »

I lost the friction plate when I had mine appart, (didn't know any better). Ended up making one out of Maple. Works like a charm.

James

cbjunkie · « **Reply #21 on:** June 21, 2006, 07:51:45 AM »

i have a block of teak - sounds like the trick...
hmm...i wonder what else i could replace with wood...

hcritz · « **Reply #22 on:** June 21, 2006, 09:08:18 AM »

I've got a 77 750 and the throttle spring is major death grip...
Mine has a piece of rubber inside the return spring...doesn't seem to help much...cables are good and properly adjusted...and it snaps back to idle quickly.
I made a much lighter spring to use on the highway...which make distance riding OK...but It doesn't snap back to Idle very well...make that consistently. And, it's a pain to have to pull the tank to change the spring anytime I'm going to make a ride longer than 30 min too. Might be worth the effort to look into an off center pull on the spring to give variable resistance as the throttle is opened...
Anyone tried that direction???

cbjunkie · « **Reply #23 on:** June 21, 2006, 09:16:40 AM »

critz - we are talking about the spring on the throttle handle itself - NOT the spring that causes the cable to return to idle...

look underneath your RH handle - there is a large hole, threaded, there is supposed to be a screw with a knurled grip on the end and a spring around the shaft of the screw...

when tightened, this screw, or at any rate the plate inside the handle, presses against the throttle slide to keep it from snapping back - this screw can be tightened on the fly and used as a "cruise control", as HondaMan stated...

hcritz · « **Reply #24 on:** June 21, 2006, 09:26:42 AM »

Hey Junkie....
They deleted that little device before mine was built...Not even a boss on the bottom of the switch assembly where you could drill and tap for one...
Though about one of the simple mechanical cruise units...not sure exactly how safe those are!?!
Guess for 15 bucks or so might be worth a try.
Still thinking that off centering the spring where it has more leverage as the throttle nears Idle and less as it is opened might be the ticket.

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Author Topic: Throttle needs death grip (Read 5654 times)

78CB750F1