does master cylinder bore matter
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Joined: Aug 2008
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From: kentucky
does master cylinder bore matter
iv been doing alot of research on converting my hand controls to a 96+ i found a great deal on a kit.http://www.bkrider.com/bkrider/skuse...iteria=SA30109 i have never messed with the master cylinder befor so i dont know what is on it . i have a 92 will this kit work or do i need a 9/16 bore.
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From: NW AR
All other things being equal, different size bores in the MC work like this:
Larger bore give you a firmer pedal (lever in this case) and will require more physical force to achieve the same braking effect (less leverage). Harder to modulate.
Smaller bore will give you a softer pedal (or lever) and will require less physical force to achieve the same braking effect (better mechanical leverage). Easier to modulate.
Now, is the difference enough to be a problem in this case? Probably not, but you will likely have to get used to the new "feel" afterwards.
Larger bore give you a firmer pedal (lever in this case) and will require more physical force to achieve the same braking effect (less leverage). Harder to modulate.
Smaller bore will give you a softer pedal (or lever) and will require less physical force to achieve the same braking effect (better mechanical leverage). Easier to modulate.
Now, is the difference enough to be a problem in this case? Probably not, but you will likely have to get used to the new "feel" afterwards.
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From: NW AR
You can't go wrong with the bore size the MoCo put on the bike to run whatever brakes you have on there now. That is, if they put a 5/8" MC on with the calipers you have on there now, then you can't go wrong with a 5/8" bore. If they put a 9/16" on with those caliper(s), then stick with that.
But, like I said, the difference in actual feel between 5/8" and 9/16" may be fairly small and not really noticeable. Do teh maths on the volume and stroke differences between those sizes and you might get an idea. You are talking 1/32"^2 * pi * stroke volume difference. There's always a certain amount of trial and error too.
But, like I said, the difference in actual feel between 5/8" and 9/16" may be fairly small and not really noticeable. Do teh maths on the volume and stroke differences between those sizes and you might get an idea. You are talking 1/32"^2 * pi * stroke volume difference. There's always a certain amount of trial and error too.
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Joined: May 2008
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From: Picayune, Ms.
Actually it will be the length of the "stroke" of the piston that counts. A smaller bore in the master cylinder would require more movement in the brake lever to achieve the same "pressure" on the caliber piston to do the same amount of "work". Thus you don't have to squeeze harder/softer but longer/shorter.
Make sure that the lever is capable and has enough "travel" to do the work. And don't forget that the mc lever also activates the brake lite. So if you would go to a larger bore the brake caliber's pucks may be in full contact with the rotors before the switch is activated. I don't know but the switch position may be adjustable.
Think of it as changing sprocket sizes on the output shaft of the transmission. Go to a smaller sprocket and the engine has to turn more RPM's to get you down the road for the same mph's. And of course vice/verse.
Make sure that the lever is capable and has enough "travel" to do the work. And don't forget that the mc lever also activates the brake lite. So if you would go to a larger bore the brake caliber's pucks may be in full contact with the rotors before the switch is activated. I don't know but the switch position may be adjustable.
Think of it as changing sprocket sizes on the output shaft of the transmission. Go to a smaller sprocket and the engine has to turn more RPM's to get you down the road for the same mph's. And of course vice/verse.
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From: Coromandel Peninsula New Zealand
Actually it will be the length of the "stroke" of the piston that counts. A smaller bore in the master cylinder would require more movement in the brake lever to achieve the same "pressure" on the caliber piston to do the same amount of "work". Thus you don't have to squeeze harder/softer but longer/shorter.
Make sure that the lever is capable and has enough "travel" to do the work. And don't forget that the mc lever also activates the brake lite. So if you would go to a larger bore the brake caliber's pucks may be in full contact with the rotors before the switch is activated. I don't know but the switch position may be adjustable.
Think of it as changing sprocket sizes on the output shaft of the transmission. Go to a smaller sprocket and the engine has to turn more RPM's to get you down the road for the same mph's. And of course vice/verse.
Make sure that the lever is capable and has enough "travel" to do the work. And don't forget that the mc lever also activates the brake lite. So if you would go to a larger bore the brake caliber's pucks may be in full contact with the rotors before the switch is activated. I don't know but the switch position may be adjustable.
Think of it as changing sprocket sizes on the output shaft of the transmission. Go to a smaller sprocket and the engine has to turn more RPM's to get you down the road for the same mph's. And of course vice/verse.
If you fit a hydraulic brake light switch at the master cylinder banjo it overcomes any issues....I don't fit the stock switch any more....the hydraulic one is vastly superior to the stock switch.
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Joined: Jun 2007
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From: Bedford UK
In essence any small-bore master cylinder intended for Harleys is for single disc, the larger size is for twin disc. As the link says, that 11/16" is a twin disc set-up. It will even do twin rotors.....
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