Jesus christ, after dealing with the same problem as you have for months, i just now (literally just got back from the garage) have fixed the problem... i too had my brakes feel spongy on somedays and great on others.... it was more noticeable when i pushed the lever in slow... i bled the brakes a million times from every f@cking possible place lol.... i decided today to take everything off!!!! I started with the master cylinder..... i took off the brake lever, which i have done before, but i gave it a good look this time and on the inside of it, the contact point between the lever and the master cylinder, there was a lot of grime and wat seemed like corrosion.... i cleaned the sh%t out of it and put it back on to see if that did the trick, AND IT DID!!! The brakes feel great!!!! What a stupid little thing to miss ..... maybe this is what your problem is too, worth a look... hopefully this helps mate... good luck

 

Dblock,
Thanks for the suggestion. I have tried almost everything so it cant hurt to try the lever.

 

yea, figured id post it up to help as many ppl as possible... the inside of the lever is not really the first place you look.... hopefully this helps!! keep us posted.....

 

I've only used honda fluid and pads on my f4i since it was new to 42,000 miles now. The brake lever was always softer then most bikes but the brakes still worked great. I recently put stainless line on and they made a huge difference with both feel and power and I don't see the need to upgrade them anymore. I can already outbrake almost anyone in my group [B]at the track every time I go.

 

Prior to repairing the master cylinder, all other brake components were cleaned, inspected, lubricated, and replaced (new pads)as needed. Being a life long mechanic, it is rare that brake issues trouble me. I have encountered one of those phantom brake issues. Specifically, the front brake lever initial engagement sometimes feels initially spongy. or the lever itself actually compresses what about three times the normal amount. Example, after a bout of hard riding, the bike is parked in direct sun, mid day, ambient temp about 90f. While previously riding, the brakes felt fine even when coming to the final stop. After an hour in the extreme heat and sunlight, I get back on and the initial squeeze of the lever is way low but hard as a rock when it finally bites, prompting me to inspect the brake fluid level and lines immediately. But pump the handle three times and it is fine. What i found was that in hot weather it was more common, but could happen any time actually. Bike is an 01 with 30k on it. All honda parts used even pads. The fix, a master cylinder rebuild, which consists of a spring and a few seals / o-rings. My theory, is that the ambient heat and sunlight expanded the master cylinder and the most used worn part of the master cylinder was insufficiently sealing and when it reached the portion of the master cylinder bore that was rarely used it worked.. because the problem occurred rarely but more as time went on and it got warmer. Cheap easy fix. Unfortunately one of those things that scares the crap out of you but doesn't like to replicate itself.