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General Category => General Discussion => Topic started by: Yukonica on April 21, 2015, 05:23:57 AM

Title: rear brake cylinder V7s ~ does it require a return spring?
Post by: Yukonica on April 21, 2015, 05:23:57 AM
Finally got around to installing a set of Sato rear-sets I bought from Todd last fall. Installation was straight forward. I set the brake pushrod to roughly the same amount of play as the stock unit (checked before I pulled it off).
When I press the pedal down; the rear brake works but the piston in the cylinder doesn't push back hard enough to disengage the brake.
Brake light stays on, there's drag on the wheel, and I need to 'toe up' the pedal.
The factory pedal uses a return spring. The Sato website has two images of the set-up with no return spring.
I suppose cobbling a spring onto a top shelf part isn't the end of the earth (maybe a bit irritating) but if the slave should have return pressure then perhaps i've set to much play in the linkage?

Suggestions?
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: lucky phil on April 21, 2015, 07:36:03 AM
It shouldnt really need a seperate return spring. check your adjustment and linkages for binding and if thats all good try giving the rear brake a good bleed and exercise.
Rear brakes can bind up and drag due to low useage and contaminated fluid. May be this is the case with yours and the extra factory return spring helps disguise this.
Race bikes sometimes use an additional rear brake return spring due to riders accidently riding the brake while racing, but the std m/cylinder internal return spring is generally all thats required.

Ciao     
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: Yukonica on April 21, 2015, 08:56:10 AM
Thanks Phil. It'll come apart tonight
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: Orange Guzzi on April 21, 2015, 12:37:36 PM
 My opinion and there are lots of them here, I would put a return spring on the brake lever with a stop.  I would not depend on the tiny little spring in the brake cylinder or balance around the lever pivot point as a means to release my brakes.  It may not be a DOT requirement as some here like to use as a standard, but it is a personal safety concern for me.  Plus hitting bumps on the road is enough to move the rear brake lever up and down.  Applying the brakes, the brake light and causing drag on the pads.   
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: Yukonica on April 21, 2015, 09:14:05 PM
Sage advice Orange Guzzi.
Please have a peak at the SATO website images for the V7 rearsets. http://www.satoracing.com/rearsets_motoguzziV7.htm
Any advice on where to mount the spring would be cool. Springs weren't designed into this plan.
Even though I agree they are probably the best application, I'll accept suggestions before hooking a monstrosity to the toe of the lever....
Cheers.
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: RinkRat II on April 21, 2015, 09:31:51 PM
 Stupid question for ya, is there an internal spring in the pedal that has disengaged?. Pull off the lever see what's inside. ~;

    Paul :BEER:
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: Orange Guzzi on April 21, 2015, 09:34:27 PM
Put a spring on the back side of the pivot point that pulls down or in front that pulls up. Go to your local hardware store and pick something out that will will work.  You should only need a very light pull spring. 
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: RinkRat II on April 21, 2015, 09:51:26 PM
 After looking at their website I found this..http://www.satoracing.com/brakereturnspring.htm (http://www.satoracing.com/brakereturnspring.htm)  Hope it solves the problem.

    Paul :BEER:
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: kirkemon on April 21, 2015, 10:40:58 PM
After looking at their website I found this..http://www.satoracing.com/brakereturnspring.htm (http://www.satoracing.com/brakereturnspring.htm)  Hope it solves the problem.

    Paul :BEER:
Well that does say for use with specified sets. I noticed in the picture of the V7 set up, the master cylinder looks to be horizontal and in the picture with their return spring the master cylinder seems to be vertical.
I also noticed an email address and a phone number - maybe you could contact them and inquire, if you haven't already.
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: lucky phil on April 22, 2015, 02:19:28 AM
Plus hitting bumps on the road is enough to move the rear brake lever up and down.  Applying the brakes, the brake light and causing drag on the pads.   

Oh dear, overthought this one I fear.
Ciao
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: kirkemon on April 28, 2015, 01:57:47 PM
Yukonica,
How did you eventually solve this? Did you add a spring?
Thanks
Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: Yukonica on April 28, 2015, 04:24:13 PM
Yukonica,
How did you eventually solve this? Did you add a spring?
Thanks

When taking the whole rearset frame off the bike I noticed the cylinder spring was pushing the rod back so I decided alignment with the cylinder was the problem.
I added a couple washers between the lever and the frame then applied red loctite before tightiening the retainer bolt down. I torqued it in until the spring quit working and backed the screw out 1/4 turn.
I think the real solution will be to add a spacer at the top where the ball joint holds the push rod and a second spacer at the point of lever and rearset frame contact.


Title: Re: rear brake cylinder V7s ~ does it require a return spring?
Post by: kirkemon on April 28, 2015, 05:52:58 PM
Thanks. I'm taking note of this as I think I would like the Sato sets if I ever get a V7 ::)