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acotrel
Advanced Member
Victoria
2147 Posts |
 Posted - 22 Jul 2003 : 9:40:41 PM
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There was a comment in one of the topics about someone making a front disc for a superbike. I don't want to open old wounds, but there is a guy who some of us know who was involved in a similar project, who has to live with the death of a friend. (The discs exploded off the bike at the end of Conrod Straight).
If you are making brake parts, it is desirable you know something about materials. For example, there are three main types of cast iron - grey cast iron, meehanite which is made by adding calcium silicide to the melt, and there is a nickel bearing cast iron, which can even be used to make gears. The discs on my Yamahas appear to be a high speed steel (low alloy stainless). When you use these different materials they have different friction and strength qualities. The pads used with each type are different.
My advice is to stick to using unmodified production parts.
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Former Member
deleted
92 Posts |
Posted - 24 Jul 2003 : 03:20:01 AM
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| I for one would never use home made discs .it seems like a lot of efort for vrey little .there a lot of discs that can go on the older bikes its just a cace of finding what will fit on what .like the FZR600 full floteres fit on an old 250 lc with no mods .the back disk fits the 125 lc .the R1 discs fit on the 350 YPVS .why make a set just hunt for a moderen replacement .many other parts can bolt on your bikes from moderen bikes like the shoker of an cbr 600 fits a 350 YPVS and the 4 pot caliperes of a FZR400 fits the YP allso .its just a case of looking . |
Thrash to the max you power band crazy fools "two strokes rool" |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 24 Jul 2003 : 9:17:12 PM
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Scott, usually iron discs are cast not forged. The accident I mentioned happened because a person machined up some discs from forklift discs which were supplied to him. When the rider reached the braking area at the end of Conrod Straight, apparently the force applied to the discs by the rivettes, caused the discs to explode off the bike. When the bike passed Mick Hone the rider was climbing off the back, however it was all too late, and he ended up in the car park.
I believe fork lift discs are grey cast iron.
Actually a lot of us knew the guy involved, he was an excellent rider. We also know the guy who machined up the discs. The whole thing was most unfortunate, and there is really no blame. It just tells us to be very careful when working on brakes.
You might also remember Rob Moorhouse died at Skyline on a TZ750 due to brake failure. It should never happen. |
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Former Member
deleted
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27 Posts |
Posted - 25 Jul 2003 : 8:51:55 PM
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| Hi Scott, what is to stop me running RGV discs on my 1000? also I have a photo of a period bike with underslung rear caliper and a shortened gsx1100 swing arm, these are all legal mods I assume? What ignition are you running on your bike? |
Edited by - n/a on 25 Jul 2003 8:54:48 PM |
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Former Member
deleted
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4 Posts |
Posted - 20 Aug 2003 : 7:10:32 PM
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Believe it or not Triumph Bonneville disks will fit onto Triumph Herald hubs and were used on many light race cars FFord etc.But not a good idear to fit them to your road car.
Austin Princess's have 4 pot calipers that fit onto Herald uprights!
ZXR400 front ends have upside down forks ,fit onto ZXR750s and even have the same rim width! But with lighter spokes, maybe not a good idear.
Gray cast iron needs to be 3 times as thick as ssteel to be as strong.
A little knowledge is a dangerous thing. |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 20 Aug 2003 : 7:47:36 PM
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| The lighter spokes thing is a bit funny. Apparently thick spokes break as easily as thin ones. Probably depends on the size of the threaded ends. |
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Former Member
deleted
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4 Posts |
Posted - 21 Aug 2003 : 7:44:51 PM
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I ment this in respect to a modern 3 spoke alumimum wheel.
Yes thin wire spokes are better than thick ones.Thay have much more give so dont fatique as easy.
Its beter to put more thin spokes in a wheel to make it stronger then use thicker ones. |
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matcho mick
Advanced Member
New South Wales
570 Posts |
Posted - 21 Aug 2003 : 11:32:29 PM
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thats comforting,i left the 10g spokes in the front wheel of my 250,addmittedly their buttressed end is 9g,i was thinking they looked a bit fragile?,one less thing to worry about,cheers Mick |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 03 Sep 2003 : 5:03:19 PM
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| It's rumored some historic bikes apparently have RS125 cartridges in the forks. |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 04 Sep 2003 : 9:24:40 PM
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Scott,
Why do the guys with the R1s buy the expensive 'gold valve' kits if the track surface is so smooth? Apparently the valve opens when the forks are compressed, to compensate for more bumps. Just means the wheel is less likely to skip and lose traction - must help!
I suspect the old rod dampers don't get anywhere near as good as the new stuff.
Best Regards, |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 06 Sep 2003 : 09:09:36 AM
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I wonder how effective our 'controlling bodies' really are. Both CAMS and MA run 'technical committees',however they seem to miss out sometimes.
In Australia every steel structure, staircase etc has requirements on it for the welding.
Basically a 'qualified weld procedure' must be used, as instructed in an Australian Standard. What this means is doing a couple of test pieces using your standard welding procedure, and getting them tested. You can then use the procedure forever more on that particular type of weld/material etc.
CAMS doesn't require any of this type of control when you weld your roll cage, and I don't think MA says anything about when you weld your bike. Trouble is that when you hit something with the MIG, you don't know whether you'll get penetration.
About time our 'controlling bodies' took control. |
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David
Site Administrator
Australia
999 Posts |
Posted - 06 Sep 2003 : 09:33:55 AM
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How can they?quote:
Originally posted by acotrel
About time our 'controlling bodies' took control.
The people in power at MA need to be changed and people that are in touch with the sport and the community need to be in control, not like what is currently in place.
After all, they currently want to see the decline in Classic, Post Classic and Historic motorcycle racing in Australia as they see no value in it, but what about the Societal Purpose of these controlling bodies? They have a requirement not only for their benefit, but the benefit of Society in general, which is not happening.
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Regards,
David
Webmaster & Owner of Classic Motorcycling Australia
Quote: I thought I wanted a career, turns out I just wanted to be paid. |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 06 Sep 2003 : 10:00:39 PM
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| In every industrial and sporting situation there is what is known as a 'competent authority'. I suggest the accident at Albert Park where the track marshall got killed, proved the 'competent authority' was not CAMS but the Victorian Workcover Authority. Where does that leave MA on safety issues? |
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matcho mick
Advanced Member
New South Wales
570 Posts |
Posted - 07 Sep 2003 : 10:29:21 PM
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i know i'm off the subject/,but 236 lurkers read,20 replied,is that some sort of record David?,Mick
ps i hope "controling body"dosen't get to interferr with scrutineering,it's painfull enough now! |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 08 Sep 2003 : 08:38:20 AM
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| Macho the Controlling body is already involved with scrutineering. All Scrutineers need to be licenced. |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 08 Sep 2003 : 10:16:36 AM
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Matcho, it's correct procedure that the 'controlling body' gets involved in scrutineering, they represent the rider's interests (MA is effectively 'the union'). When the 'competent authority' gets involved is when someone has been killed.
If ever we have the situation where a bike collapses and the riders is wiped out, you can expect Workcover and the Coroner to start looking at scrutineer's competencies.
The health and safety laws have just changed to 'performance based'. These days the law requires risk assessments and controls in just about every industrial situation. It's part of 'duty of care'. If you don't do your risk management the accusation can be that your have exhibited 'gross negligence' - can attract a manslaughter charge.
We haven't experienced this type of trouble yet, however we need to be ahead of the game. Let's hope it never happens in our sport. |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 08 Sep 2003 : 10:22:21 AM
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| If you think a bike has never collapsed in a race - think of Ross Barelli's fatal accident at Bathurst where the discs exploded. And Dennis Neal's accident where the front wheel dropped out as he went over the bump on Mountain Straight also at the same circuit. I wouldn't like to be too close, if these things happened in this day and age! |
Is your machine authentic or merely eligible? |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 08 Sep 2003 : 5:04:19 PM
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| Alan, How would you improve the situation for everybody in a non legalistic manner? What process would you encourage? |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 08 Sep 2003 : 6:26:13 PM
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John, The answer lies in risk control, and to do this it should be based in public documents. For example fuel at circuits should be handled and stored in accordance with AS1940 - Combustible Liquids Code. Circuit safety should be assessed in accordance with an Australian Standard (which could be based on CAMS and MA practice with input from experts). Vehicle safety should be based on Ausralian Standards and I don't necessarily mean the Australian Design Rules. I suggest that anyone designing and building a racer from scratch should be required to have a risk assessment done by an engineer. So there's probably a justified use for log books. It's all a matter of CARE and doing what needs to be done. This business of riders signing to say their bikes 'meets the rules' has got whiskers on it. For one thing you'd probably lose the right to sue the promoter, even where he is partly at fault.
At Winton the responsibilty to exclude oil spilling sh*t heaps is recognised, but you can't look everywhere for faults which might cause an accident.
I suggest mods to brake components, frame geometry, front forks, should be certified by someone who is competent. Trouble is, how many professional engineers in Australia have the expertise?
I know a couple of people who don't like doing scrutineering, because they might become accountable. And it's a bit unfair to expect a scrutineer to find cracks in anything, identify weak materials or even bodgy welds. |
Is your machine authentic or merely eligible? |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 08 Sep 2003 : 6:28:06 PM
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| Incidently, when Ayrton Senna died, they found the steering column had broken at a weld. Wonder who shortened the thing, and whether they used the MIG? |
Is your machine authentic or merely eligible? |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 12 Sep 2003 : 1:50:48 PM
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| is this a Carrie site or do we deal with motorcycles |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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David
Site Administrator
Australia
999 Posts |
Posted - 12 Sep 2003 : 2:19:38 PM
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Who knows anymore there John.quote:
Originally posted by john
is this a Carrie site or do we deal with motorcycles
Not many seem to be chatting on this site anymore as I know there are people and they are at sites trying to discredit this site so I have been told.
Maybe that is why I went from 350 visitors a day to 200 visitors a day. But I am still getting over 200 a day which is good. It seems that some organisations are trying to kill off Classic/Post Classic and Historic motorcycle racing and that is why there is the decline.
Some of these just refuse to help, why others only talk about one aspect of the sport and attack others that talk about anything else to do with the sport.
So any chatter here is good at the moment. It is more than some sites are getting.
Still it is silly to build your own part with-out the strees testing of that part. And there are other parts that should not be done, i.e.: disc brakes. To save $50.00 (under at least $1M anyway) is not worth putting your life at risk. 
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Regards,
David
Webmaster & Owner of Classic Motorcycling Australia
Quote: I thought I wanted a career, turns out I just wanted to be paid. |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 12 Sep 2003 : 3:05:57 PM
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| I am one who has make a part that broke with the effect it broke my own neck. I still make bits but I get advise, feedback and use competent people for critical applications nowadays. I think sometimes our self belief over rides caution. |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 12 Sep 2003 : 4:58:19 PM
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| Bob Martin made his discs from RenualtDiscs he machined down. I asked him about it recently |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 12 Sep 2003 : 7:22:16 PM
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Sorry about mentioning the tin tanks on our precious site, however I'd point out that we race on car circuits and what happens with CAMS and the promoters indirectly affects motorcycle racers. If the car guys start sticking armco everywhere, we'd want to have something to say about it, same with sand traps.
The welding thing directly affects motorcyclists. Fortunately we've got guys like Bob Martin making most of the frames for historic bikes. |
Is your machine authentic or merely eligible? |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 12 Sep 2003 : 7:28:25 PM
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| Incidently, ross Barelli's disc weren't a cost cutting exercise. The discs on the RG500 were chrome plated aluminium, and subject to the chrome spalling. A relative commisioned someone to make the cast iron discs to overcome the problem, and in theory cast iron discs give better friction. The theory was great, its just that the tensile strength of grey cast iron varies from 12 TSI to about 18 TSI where mild steel is usually 35 TSI,(sorry I don't work in MPa). Rosco was just bl**dy unlucky, however I think the incident could have been avoided. |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 19 Sep 2003 : 8:10:34 PM
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The RG500 I referred to was a Mk1 production GP bike, not a converted street bike. I believe it was one of those the boys had at Laverton. Blakey beat Ago with one. ( It didn't get much press here, however I beieve it was big news in Italy.)
I think you'll find they all had metallized aluminium discs. |
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