Measuring brake lines

scott s

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I'm doing a front end swap (Yamaha R6 on a CB550) and I'll be getting creative on the brakes. How much slack or give should you have in the brake hoses for suspension travel? I'll be getting new lines made, but need to know how much "give" I should allow.

Right now, I'm leaning towards a stock style master cylinder, Goldwing brake splitter (because that has the pressure switch that will plug right in to my harness and keep the bars clean) and two lower hoses. I need to know how much slack I should allow in the lower hoses.
For the upper, I can just run a piece of wire or string and get a good idea.
 
Put the bike on a stand or lift to where the front forks are fully extended, then measure from there. Routing cheap, clear tubing and attaching points with duct tape can make it easier to route and then pull out to measure.
 
irk miller said:
Put the bike on a stand or lift to where the front forks are fully extended, then measure from there.

Sound advice.... I once was told of a man who fitted braided brake lines to a fireblade and didn't consider this.

He only got to pull one wheelie on it and at the next corner the lever bit his other fingers and he wandered off into the scenery....

Once they are fitted do the same again. In their final orientation they should not be even slightly tight, at full fork extension from lock to lock.

If you want to mock up a measure then a piece of garden hose will give you a better measure than a bit of string as it will reflect the need for radiussing of any bends in the routing. Consider things like the front mudguard and how the hoses will (if at all) run through hose stays; and how it will come up around the yokes, headlight and wiring.

Either that or just buy the front line from the front end you've stuck on. I assume you are using the same handlebras, brakes and wheel??
 
No, that's why I need new lines. The R6 uses clip ons and I'm running handle bars. The stock hoses are too short. I even have some brand new Galfer lines for the R6. I'll be listing them, the clip ons and controls for sale soon.

I measured as described above and called Slingshot Cycles. I picked up a reproduction Honda master cylinder (14mm, just like the R6), black braided hoses (3 pieces), and a Goldwing brake splitter. Clean bars, stock wiring and a stealthy look!
 
Good arrows sir!!! If, when you've got to the testing stage, the front brake hasn't got enough feel then go to a 5/8 m/cyl. It works out to about 15.8mm and can often improve the feel of a twin 4 piston set up which uses the 14mm m/cyl.
 
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