Why is this a stupid idea? Front brake conversion.

neevo

neevo

Over 1,000 Posts
Looking for a replacement front brake caliper for my 400F and they are pretty hard to come by in working condition. David Silver has them but it will probably run to about £100 all up.

I would love a trailing caliper for looks and was wondering if it's possible to use the mounting points to attach a custom carrier for another style of caliper. There are a few old Ducati Brembos on eBay for about $100.

Would the mounts support a carrier? Why is this a stupid idea?

Would it even be possible to have mounts TIG welded to the fork lowers?
 
No probs, might try some stuff out then. I see a few people running their calipers in the opposite direction too, surely this would apply the same load to the mounting holes? Are there any negative problems with this?
 
I think I remember reading an article that said the caliper and master cylinder have to be compatible. It was a detailed description that had to do with hydraulics. I don't really know much about hydraulics, but I seem to remember is was compared to a gear ratio. Maybe someone knows more than I do.
 
Yeah, a caliper with pistons on both sides will hit the spokes. A small 2-pistons on the outside would work best, like a caliper from a Honda Rebel.
 
Don't most modern calipers only have pistons on 1 side? All my dirtbikes have and a quick scan on eBay looks like there are a few candidates with just the holding tabs for the opposite pad on the inner side of the caliper.

Edit: just looked again and noticed all the double piston calipers fitted to most modern sport bikes. The early 80's CBR's look like good candidates though.
 
CBR F2's seem to fit the bill too. What do you think, is there enough clearance on the back side?

http://bit.ly/Hl2XDf
 
Ah good point re the disc width, didn't even think about that!

Any idea if the F3 calipers would spread 7mm for the 400 front disc? I know they come with a 5mm disc approx.
 
neevo said:
CBR F2's seem to fit the bill too. What do you think, is there enough clearance on the back side?

http://bit.ly/Hl2XDf
Click to expand...
I think they are just plain ugly, if you are going to do i,t look for the little brembos they use on drag racing bikes
 
Oh and by the way, nothing short of dangerous that is, is a stupid idea.
thats how cafe's and choppers and brat were born, people having ideas!
 
Looks like the F3 calipers are barely big enough to fit a 4.5mm disc, that's what the seller on eBay was saying.

Back to the drawing board.
 
Grab a set of SV650 calipers. They are a common two piston sliding caliper design similar to F2/3, EX600, 600 Ninja etc and they are cheap. You do need to match master cylinder and caliper piston sizes and Vintage Brake have a handy dandy chart for that.

Those will fit over a 7mm disk IIRC - JUST - but that would be nuts. Get a modern disk and ave a couple of pounds and get better braking.
 
Get 1997> Suzuki Katana 600/750 calipers. (early ones are 4 piston and pretty deep on the inside)
They are sliding type so you'll have clearance .
F3 calipers are about the same if they are easier to find
Get some 3/8" 6061 plate and bar, make new axle spacers and have plate welded to it (going to need a 'dog leg' at axle end) make sure its long enough for top to mount to original 8mm fork leg lug.
Bolt calipers to plate, lock front wheel real easy, have fun.
I wouldn't use or recommend stainless, too damn heavy
 
Swivel said:
teaser is going down the same path as me,...................................
Click to expand...

Not exactly. That's what I fitted on my GT750 a year or two ago after buying quite a few different calipers and having to re-sell them or scrap them. Thing about SV calipers is that you can get two calipers, brackets hoses and M/C for less than the price of a cheap night out.
 
So maybe the F3 calipers are back on then. I will grab them PJ and get sent over as they are only $30 including postage to FL.

Swivel what do I need to look for in a disc setup? I assume I would go for a disc size that matched the original discs the calipers came off, plus make sure it's got an offset/hole pattern thats the same as the CB disc?

I am assuming a straight fit is not going to happen, so what should I be looking for?
 
Bolt pattern - has to be able to be drilled to match the hub or drill the hub to match the disk
Offset - enough to clear spokes but not so much it hits the fork leg.
Diameter - say 298 or thereabouts
Thickness - 5mm or so is fine. Avoid 7mm old style stainless disks.
Material - modern stainless is OK, ductile iron is even better.
 
Do they come with an offset? Quick look on EBC only showed flat ones.

Edit: thinking flat discs would be better actually because then I can run a spacer which will attach to the hub with the 4 bolt spacing (using 1 hole on the disc maybe) and can be tapped for the other disc holes.

I want future disc swaps to be an off the shelf thing rather than a 1 off fabrication job, just in case I sell it down the track.
 
Will try my best, actually looked at some stock CBR F3 rotors and they have a bit of offset on them already with a 6 hole pattern. Not sure how they would fit on the hub though.
 
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