14mm master cylinder bore??

[snowbeard]

So I thought someone had advised me against using a 14mm master cylinder brake lever over our 5/8" bore. I can't seem to find it, and I just realized that the one I got on eBay is 14mm I've been asking so many people that I must have missed it. it's a nissin lever, in nice shape, and I think it would work, as it has an adjustment for lever pull distance...?

any experience? thanks!

[focus frenzy]

you will just have to put it on and see how it works (bleed the system good)
5/8th's equals right at 16mm so the one you picked up is 2mm smaller and will have longer lever travel.
you will have to try it and conduct test at different levels of brake application to see if it will provide enough brake effort with out coming to close to the bar.
you will get better leverage so lever effort will be lower.

[snowbeard]

hmmm. that's good enough, but it might be good to hear "no, it isn't enough fluid" before I rebuild this whole brake system... as of now, I just realized I don't know how to get a brake light switch onto the new lever either, as it isn't included. I hate to take apart what seems to be working all in all, just to try something that's going to cost a bit more money in parts and pieces... :?


grablegabbleghad!!!#@+#@@!

[Anonymous]

master

The effort applied to the calipers by the master cylinder is expressed in pounds per square inch, so if you go to a smaller piston then you are applying more pounds per square inch at a given applid lever pressure, look at it this way if you have a 1 inch piston and a lever force if 25psi then you have 25lbs. of applied force at one inch on the piston, now make the piston 1/2 inch with the same lever pressure 25lbs and you now have 50psi of applied piston pressure, it will make you brake application more sensitve

[snowbeard]

aha! thank you, so I will get more force for less effort, but it will require a longer distance, and more fluid pushed, to acheive that, right? more sensitive by way of having more degrees of movement to acheive smaller steps of force?

my only worry is when do I run out of lever pull, and that, I suppose must be anwered by trial... at least may as well since I've just about collected all the parts I'll need (or so I naively seem to think...)

Thanks!!

[Anonymous]

aha! thank you, so I will get more force for less effort, but it will require a longer distance, and more fluid pushed, to acheive that, right?

Lower lever effort - yes.
More lever travel - yes.
More fluid pushed - no.

The amount of fluid moved will be the same, as it is determined by the caliper piston movement. And that has not changed. By changing to the smaller M/C you have increased the leverage ratio, meaning more lever travel for the same caliper movement. But the amount of actual fluid motion has not changed.

For the brake light switch you can buy banjo bolts with a pressure activated switch in them. You simply replace the existing switch (which is a very poor design anyway) with the pressure switch banjo bolt and wire the banjo up. I have seen them sold for dual purpose conversions on dirt bikes and I bellieve someone here mentioned that Dennis Kirk or one of the other big aftermarket suppliers sells them as well.

Mark

[snowbeard]

great idea! I might get to go that route, but the cost may be prohibitive. I do have some momentary switches already, and wouldn't think it too hard to find a replacement, but you never know, I thought the nipple to the remote res would be simple too!! :roll:

Thanks!!