Drilled brake discs.

[johnbirchjar]

Hi guys, I have been browsing through the "Members gallery" and have spotted David Browns "special"and very nice it looks too,I noticed that he has a drilled disc on the back brake,(the front looks highly modified)two questions,could I fit the said disc on my Classic? and will it also fit on the front?(I have been searching for ages for "drilled" front discs)regards,J.B.

[David Brown]

Hi John,The wavy discs on the front are ZX7R to match the forks and were a straight fit. Just be carefull like I wasn't, that when you gently lever the pistons back in the callipers to allow them to fit on to the thicker discs that there isn't corrosion on the pistons which allowed the brakes to go on and not release fully. In the end I had to buy new six pot calipers which cost me about £230.00.The wavy disc on the back was a straight forward replacement for the standard XJ600 item to match the 3 spoke wheel. That's when the problems started. I had fitted the Spondon box section swingingarm and couldn't use the existing caliper bracket. I had a local engineer mill a new caliper bracket and I had to buy a GSXR caliper that had the torque arm mount underneath. I then had to buy a torque arm that I thought would fit, also a GSXR item.Then the master cylinder hose wasn't long enough. When you speak to hose manufacturers they were confused that I was wanting a braided hose for a Yamaha master cylinder to a GSXR caliper on a Norton Rotary!! I emailed a picture in the end.There were times when I wished I hadn't started. When you modify one thing it tends to mean you then have to modify something else. In fact that sounds about right for the story for the whole bike. It is still evolving. Last year I stopped counting after the swinging arm, fork rebuild, wavy discs all round, caliper, 2nd hand wheel, engineering etc came to about £1600. I have made a list of mods for this year funds allowing, despite telling the wife it's finished. David

[David Brown]

Also,I think I still have the original drilled rear disc that I replaced. Depends which picture you were looking at. The front drilled discs may have been the standard ZX7R items. Unlikely to fit a Classic without much modification or why not make a Classis 'special' and stick an upside down front end on it like I did.David

[Richard Negus]

Hi David,Just noticed the Spondon rear fork on your bike photo - looks good !To you list of "Things to do in 2010", please add :-1. connect ejector system2. notify insurance company of 25% performance increaseR.

[johnbirchjar]

Thanks for the info: Dave,sounds awfully complicated,I was rather hoping for a straight swop,but life is never that easy,I think I may have to take the route Alan Stubs took,he just drilled the standard discs for his IP2? anyway,I know of a biker that owns a small enginering firm who may take the job on.I don't think that I will take the "Classic Special" look,I want to retain the old girl as near as pos: to standard,(exept for the Sprint fairing)regards,J.B.

[johnbirchjar]

Richard,am I correct in thinking that Classic & IP2 wheels and brakes are diferent from Commanders,and Dave's wavy rear disc wo'nt fit anyway?J.B.

[rustynuts]

The air cooled bikes have Brembo/Grimeca components and the Commander has Yamaha. If you download the catalogue from EBC brakes, you will find a form to provide them with the appropriate dimensions for them to give you a price for a custom size lightweight disk. Give it a try, I've never been brave enough to see how much one would cost.

[gripper]

If you're looking to loose some weight you've got to look at the silencers first. I hung mine up on the fishing scales, 8Kg each! Of course if you use most after market "cans" the heat will probably eat them, or at least their contents, If you're flush you could look at titanium. I saw an IP2 on ebay a year or so ago with a set of micron cans on.

[David Brown]

Hi all,Thanks to Richard for the advice. Have you got a diagram of how to plumb the ejecter in and what changes need to be made? May be you have a 'how to' list tucked away somewhere other than in your head. I think Richard mentioned Silent Gears in Staffs for the gearbox. Geoff Madden does a lovely job of making race replica silencers or triangular rotor silencers and they look the business and get you noticed. Although that is not always a good thing! They aren't excessively noisey unless you have the unsilenced megaphone that Geoff sometimes puts on his FZR Rotary Streetfighter.Looking forward to meeting up with fellow Rotary Owners sometime this year.David

[Richard Negus]

Have you got a diagram of how to plumb the ejecter in and what changes need to be made? May be you have a 'how to' list tucked away somewhere other than in your head. The rotor cooling part of the conversion isn't too difficult. Remove both carbs / inlet pipes; blank off the l/h hole in the frame and make an adapter for the r/h side and connect to the ejector. The next is a bit more difficult - what carbs to use ? Mk2 Amals or Mikuni or ?? Blank the idle pipe holes in the rotor housing, make new inlet pipes to suit the chosen carbs, and fix the housing butterflies fully open. To lubricate the rotor seals, you'll need to run on petrol/oil mix (100:1) as well as the oil pump for the shaft/bearings/rotor lubrication.I think Richard mentioned Silent Gears in Staffs for the gearbox. Silent Gears have been very silent for some time ; amongst other things, trying to make propeller shafts for Mid-West Engines put them out of business.The Triumph-based IP2/Commander gearbox has the shafts too close together to get big enough gear diameters to handle the torque of a race rotary. I doubt Quaife/Nova/any other could make them unbreakable.R.

[johnbirchjar]

Hi Gripper,I''m not looking to lose weight by drilling the discs,I just think they would look nicer!! (or have we got our wires crossed?)J.B.