FZR600 rotors

[kerryg]

Probably a long shot but....

I've got a chance to get hold of some 4-pot calipers at a good price off a 1992 model FZR600, intending to fit them to my 1989 FZR600 (which has 2 pots as standard). Does anyone know whether the 4-pot front calipers on the 1991-onwards FZR600 are a straight bolt-on fit to the 1989/90 (2-pot model)? I'm 90% sure the calipers will bolt straight on (looks like the bolt holes match) but I'm less sure about the rotors (i.e. whether the '91-onwards 4-pots will fit the '89/'90 rotors). Yamaha's parts fiche shows quite different part numbers for the rotors but as we all know that doesn't necessarily tell us much.

If anyone has any info I'll be grateful. Thanks

[F5 Dave]

Quite likely as Yams are tended a bit that way. Do watch the pads don’t clip the rotor rivets, but most likely the 4 pots are thinner pads so you will have more room & might not sweep as much disc, but that’s not a problem. Check that the master cylinders are the same size. Most are 5/8” (cast into mc near the bango just out of sight).

You could ask if anyone has done it on the brotherhood To secret site (well not really)

Don’t tell a WOF person as changing parts is deemed naughty these days thanks to legislation aimed at dorks in toy cars making their vehicles unsafe with dodgy mods.

[riffer]

You could be lucky Kerry. I have just replaced the rotors on my fizzer 750 with those from an XJR1200 1998 model.

Amazing, 9 years later and the parts are absolutely identical, but different numbers...

[FROSTY:Me]

I wouldn't be too worried about getting pinged for different brakes. as long as ya can use standard parts they don;t seem to get too anal

[kerryg]

Quite likely as Yams are tended a bit that way. Do watch the pads don’t clip the rotor rivets, but most likely the 4 pots are thinner pads so you will have more room & might not sweep as much disc, but that’s not a problem. Check that the master cylinders are the same size. Most are 5/8” (cast into mc near the bango just out of sight).

You could ask if anyone has done it on the brotherhood To secret site (well not really)

Don’t tell a WOF person as changing parts is deemed naughty these days thanks to legislation aimed at dorks in toy cars making their vehicles unsafe with dodgy mods.

Thanks Dave. I've decided to chance it so calipers are on their way from the US of A. Master cylinder cylinder wasn't included so here's hoping they'll bolt to my existing m/cyl.

[kerryg]

You could be lucky Kerry. I have just replaced the rotors on my fizzer 750 with those from an XJR1200 1998 model.

Amazing, 9 years later and the parts are absolutely identical, but different numbers...

Hi Celtic, thanks for your input.

[kerryg]

I wouldn't be too worried about getting pinged for different brakes. as long as ya can use standard parts they don;t seem to get too anal

Thanks Frosty. Hope the ZXR project is going well

[F5 Dave]

Good idea to know where you are starting from. Find a similarly braked yam & read the mc size, that way you know whether you are starting with a larger or smaller cylinder. If it is too small the lever travel will be excessive, too big & the lever will feel wooden.

If the lines are replaced with braided it will take some of the sponge out of the system. Early Yamahas (XJs & such) had so much sponge they compensated with the mc size & if you put braided lines on them they felt wooden.

Power wise smaller is better leverage, bigger is not better. This is all relative to the callipers as a leverage ratio. Changnig to a smaller size m/c & compensating with braided lines &/or stiffer callipers will likely bring a power improvement.
Yam callipers also tend to seize up easily, slide the pistons out & clean them up carefully & take the seals out & clean any build up behind them. You will be surprised what is hiding in a set of brake callipers being the lowest part of the system. Just the other day doing a calliper swap I was lazy & didn’t check the calliper & sure enough it was sticky. Yeeuwh it was crappy inside but cleaned up just fine.

If you can pump the pistons out with the brake fluid, though you can take them out with compressed air, but wrap them in rags as they will come out at a million miles an hour. A small wood sash clamp or g clamp (a couple of bucks at the whareyhouse) will help push the pistons back, but make sure they are clean & in straight & don’t use excessive pressure.

As usual bleeding a whole system can take ages & make you think there is a leak. Wrap a rag around each banjo & crack it open as you push the lever & close it before releasing it sometimes speeds the process. Sometimes having the bleed on the callipers open as you push the pistons in helps too.

[geoffm]

I think you will find the bolt spacing is different on the fork legs, unlss you get the matching lowers. FZR400 would be ok.
Check the discks as well - dished or flat. there was difference between the years.
IIRC on the 400, we had to put spacers behind the disk to match the disk width to the calipers. around 5mm (ish). It has been a few years
R6 calipers bolt up to the 4 pot legs accoring to the FZR400 list.
Geoff

[kerryg]

I think you will find the bolt spacing is different on the fork legs, unlss you get the matching lowers. FZR400 would be ok.
Check the discks as well - dished or flat. there was difference between the years.
IIRC on the 400, we had to put spacers behind the disk to match the disk width to the calipers. around 5mm (ish). It has been a few years
R6 calipers bolt up to the 4 pot legs accoring to the FZR400 list.
Geoff

Hey Geoff. Thanks for the info. I hope you're wrong!! I guess if they're not going to fit without spending a heap more mopney and time I won't bother (I'll just flick them thru TradeMe). Actually the two pots now on the bike a not too bad so I'm not going to sweat it...but it would be nice to up-grade if it can be done simply and cheaply

[kerryg]

Good idea to know where you are starting from. Find a similarly braked yam & read the mc size, that way you know whether you are starting with a larger or smaller cylinder. If it is too small the lever travel will be excessive, too big & the lever will feel wooden.

If the lines are replaced with braided it will take some of the sponge out of the system. Early Yamahas (XJs & such) had so much sponge they compensated with the mc size & if you put braided lines on them they felt wooden.

Power wise smaller is better leverage, bigger is not better. This is all relative to the callipers as a leverage ratio. Changnig to a smaller size m/c & compensating with braided lines &/or stiffer callipers will likely bring a power improvement.
Yam callipers also tend to seize up easily, slide the pistons out & clean them up carefully & take the seals out & clean any build up behind them. You will be surprised what is hiding in a set of brake callipers being the lowest part of the system. Just the other day doing a calliper swap I was lazy & didn’t check the calliper & sure enough it was sticky. Yeeuwh it was crappy inside but cleaned up just fine.

If you can pump the pistons out with the brake fluid, though you can take them out with compressed air, but wrap them in rags as they will come out at a million miles an hour. A small wood sash clamp or g clamp (a couple of bucks at the whareyhouse) will help push the pistons back, but make sure they are clean & in straight & don’t use excessive pressure.

As usual bleeding a whole system can take ages & make you think there is a leak. Wrap a rag around each banjo & crack it open as you push the lever & close it before releasing it sometimes speeds the process. Sometimes having the bleed on the callipers open as you push the pistons in helps too.

Hey Dave, thanks very much for the good info