Brakes and Disc Spacing

[Evilchicken0]

Righto, I splashed a bit of cash a while back and bought some Dymags off Das Bay. They're orginally for a CBR400 so it's a bit of a punt.
Soooo, I go hold of a pair of CBR discs and had a little measure up (accross the forks). The FZR is 131mm the Dymags 133mm which is only 1.5mm per side. Now I could have the caliper / fork mating surface machined the 1.5 (on the caliper) or fit some blue spots on spacers (ugly). After that I need some different bearings to fit the smaller dia FZR spindle (if anybody knows the FZR bearing code I'd be grateful).

But ... can the 1.5mm be taken up (safely) by the brake pistons ???

Then I need some spacers and a different speedo

[4StrokePete]

Hi Evil, My book tells me front wheel bearing for 3TJ RR is 6203, 17x40x12 , Pretty sure RR and SP front wheel bearings are different. I have tried mounting calipers that were not centered, didn't work for me.
Cheers Pete

[Evilchicken0]

Ta for that 17mm internal.
Yes I guess I knew the caliper thing wasn't wise but I guess you gotta ask.

Fingers double crossed for the rear wheel

[Martinh]

I may be totally missing something here evil but surely if you've machined the caliper/fork leg down 1.5 mm to make the disc line up surely the brakes will be centred that being the whole objective? Maybe i've misunderstood.

If i were you i would have the hub machined down, it doesnt really make a difference but i would prefer to not have to faff around with spacers if i wanted to return to standard. If it were a normal wheel the machining shouldnt cost more than 20 quid. As its a magnesium wheel you may have to pay a little more to cover the risk of burning the engineers workshop down if the magnesium catches!

cheers martin

[Evilchicken0]

I guess your right I just thought it would be easier to do the caliper mating surface rather than mount up a wheel.

[Hogdigerdy Dog]

the bearing part number (yamaha) is 933062031000 the actual bearing number is B6203DU but you'll be better off going to someone like ashley bearings with the bearing number and only have to pay about 1/4 of the yam prise

[Evilchicken0]

Cool - but it's a Dymag wheel so the bearing is different

[oollit]

Have you checked for bearing availability EC?

Does the Dymag rims take the same sized bearing as the stock CBR rims?

I did a quick check (nothing on the telly = bored) and the CBR(29) bearings are 20x42x12, the FZR bearings are 17x40x12, so you will need a 17x42x12 by my calculations. I googled it and couldn't find any wheel bearings in that size.

I did see that some of the older Dymags run 40mm outside diameter bearings, so if your wheel takes 40mm bearings then the FZR bearings should slot straight in.

[Evilchicken0]

Dymag use sealed bearings so there are no seals.
Of course I didn't check their bearing availability - It's posh wheels on e-bay innit ... buy first fit later

[oollit]

Thats the spirit, worry about the small details afterwards.

Even if they can't fit, just hang them on the living room wall with a clock in the middle of the rim, although the Mrs to be might have something to say about that.

I recently bought a Formula 27 kit car chassis because it was cheap, had no idea if any of the parts I needed to finish it off were available until after it was bought and paid for and sitting on the workshop floor. Turns out parts are still available, but I ain't going to use them, I'll make my own.