Hello everyone
I had the bike (85 RT) up on the centre stand, trying to clean the speedo sensor connections. Got it working again, but noticed the back wheel
doesn't exactly freewheel in neutral. I'm not sure what I was expecting, sort of push bike wheel ease to turn, but it slides against the discs.
I haven't had any heating problems at all but it seems to be tight, the wheel doesn't spin, it stops quickly.
I think I saw something about rear brake piston take up adjustment but just wanted to know what is normal.
Anything from you Gurus please.
Cheers RT.

Hi there, there is no adjustment, if the pads are touching the disc that hard, even if there is no noticeable heating, you are waisting pads and disc. You need to check the wole system and probably overhaul it. Non retracting pistons can be due caliper and or master cilinder failure. Search the forum on the subject there is a lot on it.
Best regards.
JAP

Tks JAPUENTES
I replaced the pads a while ago but didn't overhaul the system, a must do job
next.
It has been too warm to stop riding and do all these small jobs but winter is coming here soon. Tks for reply my friend
Regards RT.

RT, I'd be interested in what you find as mine also doesn't spin as well as I thought it would.

The disc doesn't get hot and I would say it's warmish.

maybe just clean up the holding pins ....in the caliper ...i would think that the pads would tend to hold one way or another if movement is inhibited by all the crud that accumilates there ...

Good point Charlie, I'll take the pads out and give everything a good clean before I start splitting calipers etc.

A few other things to take account of which may help to solve this problem -
Assuming all is well with the master cylinder, and fluid can return to the reservoir as normal, the pistons rely on the deformation across the section of the piston seal to provide the return "spring" action. In effect this is only minimal, like probably 0.002" per piston (for this fixed caliper design).
If the pads are binding on the pins it's possible that they may be heard to rattle slightly, though not always, due to clearance between the steel backs and the pistons.
It may be that there is some corrosion (salt-like appearance) on the outsdie of the pistons causing them to bind slightly in the bore(s). If this is suspected to be the cause of binding, eject the pistons with air pressure (careful) and carefully clean up with steel wool and CRC. Thoroughly degrease before assembly, when parts must only be lugricated with brake fluid.
At the end of the day the pads never entirely clear the disc, they will always lightly touch/rub/slide, call it what you like, but there will be the slightest resistence to turning, though not a distinct bind.
Hope this helps rather than confuses, Dennis.

aye ..dennis... that sounds like the go to me ...

just because i have had my bevel drive off a couple of times recently.
i was able to excersize (the pads and) pistons with just a (clean) screwdriver (10mm blade) applied between the pads with a twisting motion , amazingly they retracted verry easily.
this tecnique could be a good indicator .

as we have seen before in other threads... go carefully when rebleeding/pumping the fluid ..i suspect that the piston in the master cylinder will be prone to bore corrosion over all those years of small amounts of movement and will probably rip the piston rubbers to death if excersized outside its normal range of movement .

In stead of pushing the piston OUT Why not pushing the piston IN, cleanup the edge of the bore (where the corrosion appears) then push the piston out for a full cleanup.

My problem is that I have rebuilt the master recently, renewed the small O ring seal but not the ones around the piston. I must say it doesn't bother me except that I thought it would roll more freely.Cleaning the pins sounds like a good idea. Raining today so I might be able to escape the housework nazi and creep into the shed.
RT

RT wrote:Raining today so I might be able to escape the housework nazi and creep into the shed. RT

I guess she didn't see what you posted!

The thing is I'm trying to get financial approval for a higher screen. Somewhere there will be a payback, so had to help with the grocery shopping.
Now the sun is out, Eva is off to the doktors in an hour, I see an escape opportunity for a ride.
These are the days when something big goes wrong miles from home.

RT wrote:The thing is I'm trying to get financial approval for a higher screen. Somewhere there will be a payback, so had to help with the grocery shopping.
Now the sun is out, Eva is off to the doktors in an hour, I see an escape opportunity for a ride.
These are the days when something big goes wrong miles from home.

ouch rt .....know what you mean ....enjoy brother !!!!

Well made it back, 200 klm and the disc is only just warm ( was hilly and steep) so I think it is ok. Now I have the old intermittent oil leak from clutch push rod rubber, have to find that thread again as I bought a new one last time this happened then it stopped.
RT

RT if you were to spin the back wheel with the pads out you would see that it wont spin much anyway as the wheel is turning the pinion drive and the output shaft in the gearbox all slowing things down pretty fast. your observation of the temp of the disc does ensure that things are all an good. for the screen I used to have a old screen that I attached on stilts (blocks of black plastic really with a hole drilled through it) that set the old screen about 2inches off the new screen and plumbed into my height worked great till I was turning left in a through lane and the bloke from out of town thought he had to stop for the imaginary traffic neither screen survived so bought a 600mm high one it didnt let air in like the bitser did so was alittle noisier. pity this time round i might just go set myself up with a vented one similar to the bitser I started with. frames on the bench and the rest of it covers my shed.(so many parts so little room) Keith

Tks K75cster
I'm more comfortable now after lots more miles.
My bike has what's called a Comfort Screen I think but it is very windy up to 90ks, I tried to fit an 86 RS tall screen but it seems to be the wrong shape and won't fit on. I'm confused but should start another thread for that.
I better check where Abermain is, new to me.
Cheers RT

RT I'm up here in the old coal fields out from Maitland. I think it would be good to start another line on the screen and how it effects our helmets It would be one of the key ingredients in a good ride Cheers Keith

Oh yes, Putty road in winter without a screen. I had a flat tyre one night, got snowed on and almost froze before my wife bought the trusty Holden ute up to pick me up. Since then carry one of everything (including fire utensils). I might get up there sometime this year.
RT

Yes my end of the putty is great for removing any flat spots on your tyres they all end up nice and rounded, just like a bought one Keith