Went for a ride and at our lunch stop noticed that the wee rubber boot/seal (proper name escapes me) that the brake lever pushes on is cracked and not looking good. is this rubber piece the only thing between the fluid and atmosphere? And if it failed would i lose my front brakes completely? (this was running through my mind the whole way home...)

I also rode a Aprilia tuono that day with brembos and the brakes where amazing. I've bled my standard brakes with braided lines several times now at both the calipers and master cylinder and they still feel mushy and no where near as powerful as the tuonos set up.

Soooo Either way ive now been looking at getting sp1 calipers and a sp1/CBR900 master cylinder to replace the lot. I already have new HEL braided lines to suit the stock rvf brake system. Now would these be able to be used on the sp1 set up? And if i went for a CBR900 M/C what year am i looking for to get the 16mm (5/8ths) bore?

I know someone posted up a list of CBR900 models and their M/C bores but ive searched for ages and just cant find it again!

Thanks!

Went for a ride and at our lunch stop noticed that the wee rubber boot/seal (proper name escapes me) that the brake lever pushes on is cracked and not looking good. is this rubber piece the only thing between the fluid and atmosphere? And if it failed would i lose my front brakes completely? (this was running through my mind the whole way home...)

I believe the rubber boot's purpose is to stop any dirt from entering. Mine is totally perished, and I am not losing fluid.

alexwitham wrote:I believe the rubber boot's purpose is to stop any dirt from entering. Mine is totally perished, and I am not losing fluid.

It's just a dust seal. Handy to have, but mine have always been in various states of decay!

Cheers guys thats put my mind at ease over riding it until i can get hold of some sp1 calipers and suitable M/C

should round to doing mine too, would seem very common for these to perish

Hi, i'd try and rebuild the standard calipers first, and take the seals out and clean the oxide out the seal grooves and put plenty of rubber grease in them when you put them back together. Well worth doing if your brakes aernt upto much, and will only cost you a couple a quid for the grease.
Cheers
Ian

Morespeedvicar wrote:Hi, i'd try and rebuild the standard calipers first, and take the seals out and clean the oxide out the seal grooves and put plenty of rubber grease in them when you put them back together. Well worth doing if your brakes aernt upto much, and will only cost you a couple a quid for the grease.
Cheers
Ian

I guess i should give it another go before i go spending big $$. May as well do it tonight!

Hi, i'd try and rebuild the standard calipers first, and take the seals out and clean the oxide out the seal grooves and put plenty of rubber grease in them when you put them back together. Well worth doing if your brakes aernt upto much, and will only cost you a couple a quid for the grease.

I know a lot of people say SP1 calipers are far better, however I disagree. I fully rebuilt my front calipers, new seals, polished pistons, re-greased, braided lines, new discs and new OEM nissin pads and they are absolutely amazing.

alexwitham wrote:

Hi, i'd try and rebuild the standard calipers first, and take the seals out and clean the oxide out the seal grooves and put plenty of rubber grease in them when you put them back together. Well worth doing if your brakes aernt upto much, and will only cost you a couple a quid for the grease.

I know a lot of people say SP1 calipers are far better, however I disagree. I fully rebuilt my front calipers, new seals, polished pistons, re-greased, braided lines, new discs and new OEM nissin pads and they are absolutely amazing.

the best thing for cleaning/polishing the pistons up is wire wool, I find it cleans them up a treat and won't damage the surface finish.