Brake problems

I have a problem with my front brakes on my cb 400n, when i pump the leaver, the pressure bilds up, when i release the leaver, all the pressure dissapears and i have to pump the leaver several times to make the brakes work. Anyone have any ideas on how to fix this?

Take the master cylinder top off and check the fluid level. Give the brake system a clean, new fluid and bleed them. If that doesn't work the master cylinder may need rekitting. Carefull you don't get brake fluid on the paint work and use the correct type of fluid specified in the workshop manual. While you're at it check all the brake hoses for cracking. They may be worth replacing considering their age, two options-braided lines or more modern rubber type.

Yep, sounds like air caused by one or more of the things that Bonez covered.
Every 6 months I clean out the brake m/c's and flush new fluid through on all my bikes as part of routine maintenance. You get quicker at it each time you do it and a self bleeder device from Repco or Supercheap makes like a breeze.

using clear hose to bleed the brakes should tell you if there may be air in the fluid. unless it's trapped in the splitter (if you have one) or in the area of the mc banjo bolt - which is the case on my GS so i always bleed the brakes at that banjo bolt as well - pump the lever a few times and tie it to tthe throttle grip as tight as possible, then slowly undo the banjo and quickly tighten it again...

you change the brake fluid every six months!!??.....I stand to be corrected but I understood only modern brakes systems are suseptable to moisture in the brake fluid, not these old fossils we ride...never changed mine ever on any bike...ever....ok i will say for you all.....yes i hardly need brakes anyway...

All brake fluid (other than synthetic) is hygroscopic, and needs to be changed at regular intervals. Generally a two year interval is sufficient to keep the brake system in good order, but more frequently does no harm. It doesn't have anything to do with the age of the vehicle unless it's fitted with cables or rods instead of hydraulics . . . .

i don't do anything i can't spell

hygroscopic = absorbs water.

Every 6 months I clean out the brake m/c's and flush new fluid through on all my bikes

You'll wear out your brake lever doing that all the time - the brake lever on my bike is completely original because I never use it. If I replaced my brake lever then the bike wouldn't have matching numbers and it'd be worth nothing.

I figure if I do them all it uses the whole bottle of fluid which I crack a new one each time. Keeping a half empty bottle for years is not good practice either because the same hydroscopicing can occur as in the brake system to a smaller degree. Also every time I five them a flush there are impurities coming out. Fluid is cheap. Supercheap and Repco have specials regulary and their brands are slightly different colour so it's easier to tell when the new stuff comes through the system.

I've had rust block a brakeline bango on a brake caliper on one side on the GSX750 at one time. Used a small nail to clear it . The CBX750 when I got it the hydraulic master cylinders, brake and clutch, were full of crystilised /jellyfied "fliud".

Of course the CX just gets neglected because the brakes are useless. Having the aerodynamics of a barn door seems to slow it down ok though. I think the weight helps too and drag through the drive train. Bah!!, you don't need brakes to have a good time.

Agreed. Good brakes are over-rated.

Dodgyiti - Yesterday, 20:06
Yep, sounds like air caused by one or more of the things that Bonez covered.
Every 6 months I clean out the brake m/c's and flush new fluid through on all my bikes as part of routine maintenance. You get quicker at it each time you do it and a self bleeder device from Repco or Supercheap makes like a breeze.

Geez Dodgy.......................... poor old Cheap Bastard will be having nightmares reading of this frivilous over expenditure!

yeah brakes are over rated.....with the XS i just have to let the throttle go.........

speaking of brakes...are you a one finger...two finger or hand kinda guy......and don't be rude dodgy.......

I'm more a let go the throttle, grab a handfull and foot guy myself.