Author Topic: My right hand's tired... (Read 2625 times)

jawntybull · « **on:** June 21, 2011, 01:27:37 PM »

Now now, this is a bike forum...

I've just got my CB750 going and taken it for a couple of test rides. Its my first old bike, and my other bikes are modern ('07 bandit and '09 DR) so I'm not sure if the controls on the CB should be as stiff as they are. The throttle spring seems really stiff and the previous owner had only one throttle cable linked up; the return cable is missing. The brake is also quite firm and really has to be cranked to get the bike to slow down.

So my question is - is this normal for a 35 year old bike with single caliper single disc and four carbies, or should I look into the controls a bit more? Happy if its to be expected. As it is I'm replacing the cables and putting a return throttle cable in. I'm wondering if I should fiddle with the throttle return spring (try to unwind it one turn off the linkage?) and pull the pads and roughen them up a bit. Pads look in good shape though.

dave500 · « **Reply #1 on:** June 21, 2011, 01:40:15 PM »

gday jaunty,roughen up the disc with a large sharpeneng stone,take the glaze off it,if the pads are of unknown age replace them aswell,the return spring is firm,ive just used a softer one,make sure it does return fully though and good move on fitting the push cable aswell.

gnarlycharlie4u · « **Reply #2 on:** June 21, 2011, 01:53:50 PM »

I wouldn't mess with the return spring until you get the throttle cables replaced. It may make all the difference.

As for the brake... firm is usually good. That is unless you have a stuck master cyl piston. Does the bike have a hard time stopping or is it just hard for you to pull the brakes?

octagon · « **Reply #3 on:** June 21, 2011, 01:59:29 PM »

before you buy new ones, you can try taking your old cables off and working light oil into them.
take the tank off and check how they're routed as well. with the tank off you can also move the cables around and see if that makes a difference.

gnarlycharlie4u · « **Reply #4 on:** June 21, 2011, 02:36:24 PM »

Quote from: octagon on June 21, 2011, 01:59:29 PM

before you buy new ones, you can try taking your old cables off and working light oil into them.
take the tank off and check how they're routed as well. with the tank off you can also move the cables around and see if that makes a difference.

but definitely replace the lack of a return cable.

octagon · « **Reply #5 on:** June 21, 2011, 04:18:13 PM »

good point

TwoTired · « **Reply #6 on:** June 21, 2011, 04:27:43 PM »

Honda Cables are teflon lined. Oiling them make the teflon polymer break down.

I've used a product called Dir-slide. It's a moly and graphite suspension in an evaporative carrier fluid. Whatever solvent it has, evaporates and leaves the graphite and moly behind. I've only ever had to use this once.

I don't think the motion pro cables are teflon lined. Might be what makes the cheaper.

Cheers,

WarwickE36 · « **Reply #7 on:** June 21, 2011, 04:33:35 PM »

Motion Pros Site says this...

Black vinyl coil-wound housing
Meets or exceeds O.E. quality (Debatable)
Inner nylon sleeve for longer life and smooth operation

TwoTired · « **Reply #8 on:** June 21, 2011, 04:39:08 PM »

Just to be clear. Teflon is not the same as nylon.

Cheers,

jawntybull · « **Reply #9 on:** June 21, 2011, 05:01:24 PM »

Quote from: gnarlycharlie4u on June 21, 2011, 01:53:50 PM

I wouldn't mess with the return spring until you get the throttle cables replaced. It may make all the difference.

As for the brake... firm is usually good. That is unless you have a stuck master cyl piston. Does the bike have a hard time stopping or is it just hard for you to pull the brakes?

Its a bit of both; the lever is firm (not really a problem) but the bike is also a bit hard to pull up - probably just me moving from double disc double piston brakes to singles?

I just bled the brakes and they have braided lines fitted, so I'd expect them to feel firm. My question is more to do with how quickly the brake pulls the bike up

TwoTired · « **Reply #10 on:** June 21, 2011, 05:27:00 PM »

I guess you are complaining about the stopping power of 35 year old brakes?

You should have a hard lever. If you use all your strength, the front tire might squall a bit. I don't think the front forks are strong enough for stoppies.

The brake pad must be uncontaminated as must the rotor. Totally dry and never had any solvents, oils or silicone soaked into the pad or the rotor. Yes, they are microscopically porous. And, heat will bring any lubes to the surface to impede friction.

If you never use more than one or two fingers on the brake lever, retrain yourself to use all four fingers.

If your brakes are worse than I've described, and the pads have worn in make full contact, they need a workers attention.

Cheers,

BobbyR · « **Reply #11 on:** June 21, 2011, 05:43:44 PM »

As TT said you are applying 21 Century standards to middle 20th Century technology. When they say grab a handful of brake, they mean it.

Cables tend to develop little breaks in the outer strand over time and small steel hairs rub against the cable sheath. Lubing will help for a while. Also, under the handgrip is a plastic sleeve and the grease under that sleeve hardens and collects crap. You can slide it off, clean out the crud and use a good modern lube which will smoth things out a surprising amount. Welcome to the past.

splitt · « **Reply #12 on:** June 21, 2011, 07:36:33 PM »

Make sure that there are no sharp bends or kinks in the throttle cable also. If possible, the cable should make a single arc. These old carbs do offer a fairly stiff pull. Some have used lighter springs on the carbs also. If you decide to go that route, put that return cable on first. I have had great luck picking springs up at my local hardware store.

davesee · « **Reply #13 on:** June 21, 2011, 07:46:19 PM »

my cb is the only bike i've ever had, but when i twist other people's throttles they feel insanely light. that said, i couldn't ride for more than thirty monutes without one of these

http://throttlerocker.com/

gnarlycharlie4u · « **Reply #14 on:** June 28, 2011, 09:45:58 AM »

Related^^^
check this thing out:

http://www.scottoiler.com/uk/products/crampbuster.html

KingCustomCycles.com · « **Reply #15 on:** June 28, 2011, 09:49:39 AM »

Brakes should be very adequate, not noticeable to actuate and the throttle smooth as hot butter on zuccini. It isen't a Hyabusa but they do stop and go quite well.

Redrider969 · « **Reply #16 on:** June 28, 2011, 12:54:12 PM »

You've already received a lot of excellent advice. Here's my 2 cents worth anyway. The CB750 was the first production bike to use a disk brake. The disk was significantly more powerful than the drum brakes, especially in the wet, and Honda was afraid riders would have problems locking the front wheel, so they deliberately made it less powerful than they could have (at least that's the story I've been told). Sand the disk lightly on both sides, make sure your pads are good, that your hydraulics aren't leaking and have enough fluid, and with the braided lines, you've done all you can. Use four fingers and squeeze hard.

Make sure your rear brake is in good shape and properly adjusted. Since the front brake is not as powerful as those on the new bikes, there isn't as much weight transfer to the front wheel, that means there's more traction for braking available at the rear wheel

With respect to the throttle, I don't have much to add. I have the same problem. My solution is one of those thumb operated throttle stops. I use it so much that I don't even think about it, and it allows me to take my hand off the throttle every once in a while to "shake it out" and work the kinks out of my wrist and fingers.

jawntybull · « **Reply #17 on:** June 28, 2011, 08:05:17 PM »

All good advice thanks. The return cable has made a difference, and one of those crampbusters looks to be worthwhile. A few people seem to have them fitted. The small diameter looks the go - any suggestions on the thin or the wide style?

Stev-o · « **Reply #18 on:** June 29, 2011, 06:06:05 AM »

As said before, you can't compare these brakes to your other bikes. And ride the 750 accordingly.

I'd put new quality cables on it, bet it makes a difference.

wingman1946 · « **Reply #19 on:** June 29, 2011, 06:38:07 AM »

I go with the theory that if I wouldn't have bought the bike new with it acting that way then it should not be acting that way now. Regardless of age or prior technology.

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Author Topic: My right hand's tired... (Read 2625 times)

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