fit bigger front discs to GSX1100f

[garyphiliph]

I am looking to fit bigger front discs to my 1100 Kat and the only ones that seem similar are the first fireblade discs. These look as though they are offset and they also have six holes to fit to the wheel.

has anyone tried to fit these discs?
Is the offset the same as the Kats?
Are the hole centres on the same pitch as the Kat?

I am watching a cheap pair of Blade discs at the moment and wonder whether it is worth bidding on them.

PS I have just bought a pair of GSXR750M calipers to fit to the Kat so bigger discs will be more appropriate.

Feedback will be appreciated.

[Jimmie]

The offset doesn't match.

Check metalgear.com.au for disc size, offset, holes etc.

[garyphiliph]

Thanks Jimmie. I will have a look at that site now

[Vishnuisgod]

I have found that the rc45 (310mm) with a tl 1000 six pot would work, problem is finding the disks.......

If youre willing to machine the posts where the caliper down 1.5 mm i think a CB1300 disk works, its 18.5 mm offset vs 17 regular......what i say is not gospel but maybe it'll help.

cheers
alan



ps is there a 17" wheel swap, I cant seem to "search" any results?

[chemomche]

My brother has VFR discs and cbr900 calipers on his GSX1100ET 1980
the holes do not match so you have to drill new ones
here is a pic

[Vishnuisgod]

Just wondering why he didnt enlarge the holes already present?

1980 too, I am sure the bike felt alot better than stock!

cheers
alan

[chemomche]

Just wondering why he didnt enlarge the holes already present?

because the existing holes were closer to the center, not too small for the bolts

[garyphiliph]

suitable front discs to replace KAT 1100

I had a look at Metalgear.com.au a web site that gives you all the information regarding disc sizes etc. According to this web site the Kats dimensions are as follows:
275mm OD
56mm ID
78mm BHC
6 holes
10.5mm Holes
22mm offset.

The only discs that I can find that come close to this (I am looking for bigger discs) are ones for a Honda CB600F Hornet 1998 - 1999. The dimensions for these discs are:
296mm OD
62mm ID
78mm BHC
6 holes
10.5mm Holes
23mm offset.

The critical dimensions are the BHC, size of the holes and the offset. These discs would fit straight on as the ID is slightly bigger (no problem) and the 1mm offset would be lost to wear and tear on the pads.

Problem is finding a used pair as new ones are expensive.

[Mojoe]

personally, I think you are just wasting a lot of time in an effort to do something that won't give you much better than what you have now. I will bet that when (if) you do it, I could jump on your bike and not see any improvement worth mentioning. you see, the problem is the 1100 forks are soft to start with. improving the grip at the pad will just give you more dive. in other words, the stock calipers and rotors already pretty much do as well as the suspension itself can handle.

so if it was me, I would just look at swapping out the whole front end. you will get your bigger rotors, a bigger wheel to do away with that nightmare 16in tire with limited selection, and a better suspension. doing what you want to do...well, it's kinda like swapping all the rotors for Brimbo's on a neon. it leaves me asking, "what's the point"?

you can't improve the braking without improving the suspension, imho. to make the rotor swap really worth it, you should at least rebuild the fork with progressive springs. but even then, if you are going to go that far, try to find a deal on a whole front end.

[Mogg]

I am with Mojoe on this. Go with progressive springs and maybe a slightly thicker oil, braided brake lines with all new fluid and good quality aftermarket pads, you will see a major improvement while still being stock. If you are after bling, go swap a gsxr 1100 front end over and then make bars and ign switch try and work. After all is said and done, its a great old bike. Just keep it alive and enjoy it. All the stuff I wanted to do to my 1100 is already on my B12 save for the upside down forks. If want more motor, its just a cam swap and jet kit away, lol.
Just my $.02.

[chemomche]

my brother did the disk and caliper swap because his bike has only one cylinder per caliper and the whole brake system is about 30 years old.
He firstly changed the pads, but there was a problem with the brakes- when you hit the brake you can feel the lever pulsation under your fingers and the front end was doing the same. He thought of wrapped disk or problem with the pump and how he has a gsxr600 k1 master cylinder. When the problem did not isappear he decided a disk and caliper swap- now he says he can lift the rear tire in the air if he liked(however, i don`t believe it that)

i agreee with mojoe, too.
how i am swaping the hole front end- hayabusa forks, srad wheel and zx9r 6 pot tokicos
to make my 750 pre even better i will use gixxer 91 frame and 600rr rear swing

[garyphiliph]

Mogg, Mojoe,
thanks for the replies. I agree with both of your comments. I love the bike (fast enough on normal roads for anyone) and I am trying to just improve little bits at a time as money is tight at the moment. I already have Hel stainless steel lines on front and back, a gsxr750 front master cyclinder fitted, a K&N air filter and a pair of MTC race cans on her. I also put her on a dyno and she is putting a 117bhp at the back wheel and a top speed of 155mph (not bad for a 1994 model bike)

I have just fitted the GSXR calipers. Took the bike out for a quick blast and I can already feel the difference. The brakes come on as soon as I touch the lever whereas before I had to squeeze the lever a bit more. My next job is to put heavier oil in the forks and hopefully this will improve the front end even more.