Subtle "sticky" feeling in master cylind

[VK]

I just recently finished disassembling, cleaning, then reassembling my master cylinder using the old but cleaned parts.  The result was a dramatic improvement in stopping power.  However, there is a very subtle "sticky" feeling when I squeeze the brake lever softly.  That is, if I very gradually increase the pressure it feels like the piston grabs just slightly, rather than just having a nice smooth buildup of pressure.  If I squeeze firmly this is not at all noticeable and the brakes seem to respond just fine in any case.  I didn't think too much of this until a poster on another thread got me paranoid that I should have replaced the rubber cups in the MC.  Am I worrying about nothing, or is this subtle "stickiness" a sign of pending doom?  If I should overhaul with new parts, is there an reasonably priced source for such parts?  I did  look into a rebuild kit at my local Yamaha dealer but they wanted more than $50 which seemed steep.

VK

[Lucky]

Steep is a relitive term, is your safety worth $50? did you check the bore where the cups ride for build-up or pitting?

[VK]

Lucky,

I certainly agree that $50 would more than pay for itself the very first time it saved my life.  I did look everything over (though not with magnification as  perhaps I should have in retrospect) and all looked fine to my untrained eyes.  Also the bike only has 11k miles on it so had originally thought that all should likely be fine upon cleanup - perhaps another error in judgement.  My problem is that I'm a relative greenhorn when it comes to cycle repair.  I've learned a lot from reading posts on this forum, but I've had little hands on experience.  (I had never disassembled a hydraulic brake of any sort prior to this, for instance.)

VK

[RobTx]

Could it be that since the m/c is fixed, the sticky feeling might be in the caliper?  Maybe you couldn't feel it before when the problem in the m/c was worse.  Just a thought.

[rick_nowak]

and you really wanted to bleed the little bugger again, didn't you.  check the caliper(s).  may be some drag in the pads.  on second thought, first, just check the pads for free movement without opening the system.

[Mike Williams]

VK, take the thing apart again and really give it the once-over. That system can save your life and has to be perfect!  I did an overhaul on my XS650D last year and was going to re-use the MC until close inspection showed it was unsafe.  I was able to buy a "New" Yam MC (without all of the Yam junk on it) from Mike's XS. He has parts for XS650's manufactured by the original jobbers, so everything fits right.  The MC I bought is identical to the MC on my '83 Vision, except it's for a single-disc setup. I paid $65 for a brand-new MC and went the extra $100 for braided stainless/teflon lines.  I now have a two-finger front brake, something the 650 always needed. Mike's XS can supply the larger piston MC for dual-disc setups as well. Check out his website for alot of neat old Yamaha parts.  Mike Williams  ;)

[RobTx]

Mike's XS is the best.  I've bought parts for my wifes 82 Heritage Special there.  Footpeg rubbers are the same as the Visions and only $8 a set.  Find him here: http://www.650motorcycles.com/mikesxs.html
Rob

[VK]

Oops, forgot to post a final update on this thread for the benefit of present and future readers.  While I could have swore that the "stickiness" was coming from the master cylinder, apparently a gunked up caliper was (as others had suggested) the source.  After disassembling, cleaning, and reassembling the caliper the entire braking system now seems to be working as good as new.  

As always, thanks for all of the great advice!  VK

[sdinino]

Mike's XS is the best. ?I've bought parts for my wifes 82 Heritage Special there. ?Footpeg rubbers are the same as the Visions and only $8 a set. ?Find him here: http://www.650motorcycles.com/mikesxs.html
Rob

I'll second that. Even though the footpeg covers have gone up by a buck apiece ($5 each, plus $4 priority shipping) it was still a great deal. Also, they arrived in California from Florida in 2 days - which I think says more about how fast Mike turns his orders around than the USPS.