Down under, an idiot and a 400F

hillsy would a 5/8 master cylinder work? That works out to be 15.87mm.

I was reading that you need to take into account the rotor size and the leverage you get from that on the wheel and it's stopping power. I would imagine the CBR F3 wheel is about 17" anyway so shouldn't be too different.

Dime City offers 5/8 MC's which seem a fair bit cheaper than sportbike ones which are mega $$$$.

Trying to work this mc sizing for my bike using this chart:

http://www.vintagebrake.com/mastercylinder.htm

Says 27:1 is ideal for opposing twin calipers. F3 calipers are 25mm x 2 on each side. This apparently is ideally a 14-15mm master cylinder piston.

Have I worked it out correctly?

14mm would give better feel (modulation)
5/8" will move the fluid but won't give as good a feel
You can get used to it, early Yamaha's had terrible brake feel, like squeezing a rock, Kawasaki was exact opposite, lever came almost all the way to bars, felt 'mushy' then locked wheel up (the 70's were a great time for experimenting : )
Either will work
You could also work out total area of all the caliper pistons then divide by area of master cylinder piston

Of course I took the time to do a bit more on the bike today. First up was to strip the forks so that I could give them a good clean, check the internals and fill them with fresh oil.

A trip to the local bike shop for some 5w fork oil and a trip to the local hardware store for a BIG adjustable spanner as my 32mm socket wouldn't fit over the preload adjuster.

Bought a great video a few weeks ago which detailed stripping the forks so I knew exactly what to do, however I've stripped a tonne of dirtbike forks in my time so didn't think it would be a challenge.

All went well, drained some filthy oil and had a crack at compressing the spring by hand. Didn't work!!! So I made a fork spring compressor:



Here it is on the forks with the compressing attachment (a ratchet strap ):





All apart:



Gave them a good scrub as there was plenty of grimy black stuff all over them. They came up really well, they were a bargain for only $240. Only a few scratches on the outer tubes which I can turn to the inside. After cleaning all the internals and polishing the legs with 1200 grit, I put them back together.

Turns out my fork seal driver for my dirtbikes doesn't fit, so I made one out of some water pipe:



And all back together:



On the bike:





It was only 3pm so my attention turned to the exhaust collars PJ made for me, the plan was to gentle polish, not mirror because I'm too lazy for that and can't be arsed with the sanding, but a clean up and mild polish would make them a little more visually appealing.

Before:



Screwed to the bench to make sanding easier:



After some 160, 240, 360, 600, emery and tripoli:

Aint them purdy!!!

Hi Ed,
Neat idea, looks like it worked well
Not sure if you noticed, the axle adapters have different sized ends for the head and nut of axle. (can't remember if I told you already?)
Clearanced for 17mm socket one side and 19mm the other

crazypj said:

Not sure if you noticed, the axle adapters have different sized ends for the head and nut of axle. (can't remember if I told you already?)
Clearanced for 17mm socket one side and 19mm the other

Click to expand...

Yeah I figured that out. I assumed the shallow side was for the nut so a locking pin could be put through.

8)

Not a great day on the tools today, a bunch of effort with little to show for it.

First up the obligatory tidy up:



Thought I would tidy up the front rotor and polish it. Tried to setup the drill press so it would spin it for me, worked ok but not brilliant:



In the end had to grab a round file at go at the hub to get rid of the casting marks. After a polish it turns out my plan had worked ok on the outside of the hub and the spacers, but the inside was still rough





I think I'm going to get someone to whack them on a lathe, remove the centre ridges and then polish both the front and rear hubs for me. Can't be arsed this time on these pieces.

Also bought some 6mm MDF today for mocking up my caliper carriers, turns out I need to push the calipers towards the rear of the bike about 3mm as they are catching the pad clips slightly. Will post pics tomorrow when I redo them.

I probably shouldn't have posted pic of the one I did ;D

crazypj said:

I probably shouldn't have posted pic of the one I did ;D

Click to expand...

No you shouldn't

I'm actually going to get someone to machine the ridges off and then polish both hubs. These are a bit difficult for me and I don't have the patience.

I think you HAD a lot of patience but now you have a lot of parts and want it done ;D

Hahahahahah, not quite at that stage yet PJ thank god. It's just the hubs, really struggle with the contours to get it polished. Was contemplating a Dremel or air version this morning but not sure if I would use it enough considering its a good $150 for the base model here.

neevo said:

Was contemplating a Dremel or air version this morning but not sure if I would use it enough considering its a good $150 for the base model here.

Click to expand...

Ah dont you love justification ;D probably the only thing holding me back from buying that Murcielago

You'll probably need a bigger compressor for air tools?
There must be something similar to Harbor Freight or Northern tool in Oz selling Chinese stuff?
Electric die grinder with a router speed controller works pretty good and has at least 5~6 times the power of a Dremel (probably more)
It would be about $50~$60 here for both

Hint: no point in polishing between the flanges - it's almost impossible to keep polished once the wheel is built. Fins/ridges add something to rigidity, so I'd leave them and just paint between the flanges and polish the outsides. Just another opinion to consider.

I have to agree with Teazer's comment re polishing. Polished surfaces look fantastic but require a huge amount of maintenance to keep that way. If your bike is going to sit in the living room as a display piece (which I suspect it is not!) all well and good. But if you are going to ride it the polish will very quickly become the millstone around your neck! It's hard enough to keep a bike that gets ridden clean let alone polished!

Good valid point about polishing, I've already done mine several months ago though
Rigidity won't be an issue, you would need braces going across the hub on the front to make hub 'stronger', the spoke flanges are not better supported by the ribs
Radial 'fins' are just weight and styling on disc hub.
I wouldn't do the rear hub though, drum brake needs all the surface area it can get plus radial ribs will help keep drum in shape

Thanks gents. I think I'm still going to polish, I clean my KTM polished hubs, it's a bit of a pain but I can get my hand in there. If its too much of a pain I will strip the wheels and look at something else.

Decided I'm not going to remove front ribs, not because of strength but I want them to match the rear hub. So it's just polish all round.

Today's progress. I redid the caliper carriers, pushing the calipers back 3mm as there was slight fouling. These carriers will be made out of 8mm steel plate and then I will use shims/washers to get the right offset. Had a go today using some washers and it looks good. Spun the wheel without pads in the calipers and didn't hear any scraping. Hopefully these are strong enough not to flex:





Clearance at the calipers with the washers to shim:





Phatness on the front end;



Also got a smart recommendation from PJ on how to test the rear tyre width, use my 120 x 18 KTM dirt rim. Glad I did as I didn't realise how tight it was going to be in there. The knobs are 118mm across with not much to spare:













I hate the look, not a tracker bloke as it turns out I hope it looks better with a road tyre on there.

Shouldn't there be something mounting the lower part of the caliper for strength here?