400 sandpaper for master br. cyl.?

[DreamV4]

Which # do you use? I mean inside, were piston is.

 

[PATMAX]

Soda blasting !

 

[02GF74]

I would use 800, maybe go as low as 600 and sand in a circular motion, not in and out.

The above assumed that the wet n dry grading system here in UK is same as where you are.

 

[DreamV4]

Lever is not getting hard, I 'll have to sand cylinder with higher number tomorrow. Hopefully some air bubble with go up overnight.

 

[02GF74]

And the braking system has been bled so you are certain there is no air in the system?

Although I have never needed to do it, have you tried reverse bleeding (queue Fire-medic to explain)?

Is a new seal fitted to the piston in the master and in the correct orientation?

Note sanding the bore enlarges it so reduces the sealing efficiency, you would need to measure the diameter of the bore but I'm guessing the amounts 400, 600 grade paper is removing is not significant but depends on how much sanding is done.

 

[DreamV4]

Seals looked good.
I cleaned at least 20 master cyl. before.
I bled calipers, no bubbles.
Yesterday I leaned bike to the left (it was straight to work on master cyl.) to get rid of possible air in cyl./hose joint.
To diagnose bad seals/cyl. I am going to use some bolts and washers to plug m.cyl.
After that I will sand it again with 800/1000 sand paper. Universal master cyl. are cheap, but I don't want to wait 3-5 days for delivery and I need to make sure it is a problem.

 

[MaxMidnight]

... and I need to make sure it is a problem.

If it isn't now I suspect it will be after being attacked by sand paper.

 

[DreamV4]

Aftermarket m. cyl. is installed, can it have too small piston for 2 big br. calipers?? I guess it should be pumped hard anyway maybe in 2-3 pumps.

 

[DreamV4]

2 pieces of radiator hose, 2 cents and vise-grips. I clamped lower end of br. hose. Problem is NOT m. cyl.!!!!! There should be air somewhere.
2nd test: clamped 2 hoses to calipers, hard lever

 

[Pighuntingpuppy]

Aftermarket master cylinder is wrong. My 1982 Virago hit a transmission slick and fell on its side. Slid into a car and bent the forks. So, I took a set of forks from a 1982 Yamaha Seca and installed them on the Virago. The Virago was a base 750 with a single disc brake in the front. The Seca was a dual disc set up with anti-dive forks. Try as I might, I could not get a "pedal" on the brake. I went through a gallon of fluid trying to get something. Finally gave in and got the Seca master cylinder. MUCH bigger reservoir and bore to move fluid for all those brakes and anti-dive. I think you have the wrong size master cylinder.

 

[DreamV4]

thanks.
Right now:
one caliper has clamped hose, (m. cyl. works only on one caliper.) but lever is not hard.
Found this about Harleys:
5/8" bore for single caliper early F & R and most 77-83 dual disc front
9/16" bore for later front single caliper 84 up
11/16" bore for later dual disc dressers like FLHR
3/4" bore for early dual disc dressers like 80-83 FLT

Ebay has lots of 14 and 16mm cylinders. If mine is 14, that is the problem.

 

[DreamV4]

I measured 12mm, which can be m.cyl. from a Chinese scooter!!!!
Thanks!!!! Ordered 16mm piston cylinder.

 

[Screwloose]

If it isn't now I suspect it will be after being attacked by sand paper.

I use fine wire wool for that type of job.

 

[DreamV4]

I disconnected left caliper and closed it with vise-grips. Taped vise-grips to left fork, brake started working and I rode my bike first time!!!

 

[one2dmax]

5/8" bore is stock Vmax and works the stock 2 piston, and later 4 pistons just fine. It also works the 6 piston sumitomo's well

 

[Fire-medic]

I disconnected left caliper and closed it with vise-grips. Taped vise-grips to left fork, brake started working and I rode my bike first time!!!

If your Vise-Grips fall-off, you have no brakes?

I'm gonna take-out a life insurance policy on you, because I will soon collect.

The Darwin Awards (2006) - IMDb

 

[DreamV4]

If your Vise-Grips fall-off, you have no brakes?

I'm gonna take-out a life insurance policy on you, because I will soon collect.

The Darwin Awards (2006) - IMDb

Thanks for your concern!
I wanted to ride my bike first time to check gears, speed was around 30 mph, rode 2 miles or so around block (no cars) I believed It was not likely vise-grips would open. I usually use both brakes.

 

[DreamV4]

Reporting to Firemedic! It is delivered!!!!!!!

 

[Woody]

Will you work on my bike ? I'm interested in the visegrip mod.

 

[DreamV4]

Will you work on my bike ? I'm interested in the visegrip mod.

Sure! How many brake calipers do you want to clamp? I will not do it to your ex girlfriend's bike!