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Post by StewRoss on Feb 16, 2007 1:26:07 GMT -5
Hi again Benetta, It's fun playing with these bikes. As Gary said I'm modifying one at the moment that should hopefully handle very well when it's finished. So far I have fitted '99 R6 front forks in Franks triple clamps (...standard offset) and I am getting Wilbers shocks for the rear. I am still deciding what length swing arm to put on the bike and what length rear shocks...lots of variables. The lighter the wheels, brakes etc. the better... The frame will be strengthened above the swing arm pivot on both sides by tubing; at the end of the oil tank on the top tube and on both sides of the area behind the head stem. I'll fill these areas in with steel plate (...neatly of course ;D), and also perhaps in a few other small areas. The swing arm and longer rear shocks will serve to increase the head angle a bit and I'll fit a steering damper to it so that it won't throw me off...  ...across under the front fairing mount... All of the suspension will have rebound and compression adjustment and the forks and swing arm will be a lot stiffer than standard. Wizz954 here is sorting out the standard forks and using aftermarket rear shocks for racing and he is a good source from his experience without going overboard as I am  If you use the standard swing arm then perhaps look at IKON shocks or similar and they have 3 way adjustable damping as well. There are various fork springs around including IKON so you won't run out of choice there either. Gold valves etc, etc... It all depends on how much you want to change and what expense you are prepared to go to. In the end 17' wheels allow a better tyre selection however I am sticking to 18" for my own reasons. Have fun...in my mind this is what these are all about! SR  |
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Post by Retread on Feb 16, 2007 11:06:11 GMT -5
Thanks for the info, has anyone tried leading axle forks to reduce the trail for quicker steering? I think this might work quite well.
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Post by Retread on Feb 16, 2007 11:15:16 GMT -5
Works Performance makes adjustable height shocks you know - but when all is tried it is very hard to decrease the 27.5" rake. Are there any vintage racers in this forum that have proven modifications? I hate to do alot of what others are doing and end up with a cool looking bike but really having no improvement in how it works. How wide of a rim and tire can you go with the stock swing arm? I should post a picture of my $27.50 bike. Maybe in a couple of days.
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Post by StewRoss on Feb 18, 2007 1:40:33 GMT -5
Hi, Try Wizz954... SR |
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Post by Retread on Feb 21, 2007 13:18:55 GMT -5
I don't know how to post a link but try this site that has an article on SR500 racing mods - www.eurospares.com. Maybe some one can create a link for me. |
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Post by Retread on Feb 21, 2007 19:36:07 GMT -5
Well, HEY!!! I discovered the SR500 Cafe racer link to the Yahoo web site. WOW!! I didn't know people were taking these bikes to such extremes. I guess every one has an idea on what is "done right". I shall have to figure out what is "done right" for me. I took a before photo of my project bike today also. It will be posted soon. The link I mentioned above is on the Yahoo site and by now I am thinking it is nothing new to this site.
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Post by wizz954 on Feb 27, 2007 8:54:16 GMT -5
Hi Retread,
I've sent a detailed reply to your PM.
In essence, I prefer to get things working optimally before swapping parts and changing geometry. You'll be surprised how much you can improve things on stock parts.
On the front forks, use Racetech Gold Valve emulators to get better compression damping control. Use 20W or 30W fork oil to get the best rebound damping and then adjust the compression damping using the spring preload adjuster on the emulator.
Use a stiffer spring to avoid excessive dive under braking and allow you to speed up steering by dropping the forks through the yokes by 10mm.
Front wheel - try changing to 18" instead of 19" to quicken steering and give greater tyre choice
Rear ride height - increase shock length to 330m from 315mm
Swingarm bearings and pivot pin - check and most likely replace as they tend to rust and seize almost solid.
Riding position - change it from sit up and beg to the racer crouch. You will need clipons and rearsets to shift more weight over the front.
Wheels and braking - the stock wheels are very heavy and adding a second disc is not advisable as the weight of the disc and the extra caliper will make decent spring control impossible. I'm still running stock wheels, but using a Brembo caliper with an adapter plate and this is as good as a twin disc setup of that Era without the weight.
The setup I have just described is all that is required to set the fastest lap in class in the 1 hour endurance race at Wakefield Park, on a motor that is producing only 40hp at the rear wheel. The suspension is much more important than the engine and it doesn't take much to get it right.
There are other improvements I will be trying this year and when I think I have reached the end of the development path, that's when I will try other parts. At the moment I think there's still a lot more potential from the stock setup with fine tuning.
Reference:
Ikon fork spring - part number 500-181 which I think is good for the road but too soft for racing. Depends on your weight too.
Ikon rear shocks - Koni Dial-a-ride equivalent 7610-1418 with suitable spring for your weight
These are all cheap parts and work perfectly well. You can go to Ohlins rear shocks but they will be worth more than the bike!
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Post by marlon on Mar 13, 2007 13:07:58 GMT -5
Sorry to hijack the thread, but i'm going to be looking at some rear shocks sometime soon. I'm tossing up between Ikon's and Ohlins. To be honest, I don't know much about bike suspension at all, and as such am completely open to ideas.
No track work on my bike, a fair bit of stuff on the twisties - typical Australian roads with plenty of mid corner potholes, bumps and wildlife. However the bike is used for commuting day to day at work. Eventually I might be carrying a pillion for short distances...
Koni's or Ohlins? I know Ohlins are drastically more expensive, but in my circumstance, are they worth it?
Cheers in advance...
Marlon
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Post by StewRoss on Mar 14, 2007 1:12:31 GMT -5
Hi Marlon, If you have a styling reason, plenty of spare cash or just love Ohlins shocks then go for it...otherwise...although the Ohlins are the better shock, the Ikons are not too bad either. They have adjustable damping and spring pre-load and if you get them from the factory (in Albury) you can get them to asist you with spring selection etc. They also make an alloy-bodied shock as well... There are many other shocks as well like Hagons etc. but probably Ikons are the best value for money...and they're made here. SR |
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Post by marlon on Mar 14, 2007 11:01:48 GMT -5
Thanks Stew... I don't really have a styling reason (and a mate of mine said that Ohlins are a quick way of letting people know you're bike is worthy of flogging) I've got no prior conception of Ohlins, but my Dad, who used to be heavily into bikes swears by them.
Then again, you've managed to fire up a bit of patriotism in my and I'll probably go for the Ikons. Australian made, and from what I've read are very good value for money - $540 or so for ones with adjustable dampening.
Reckon I can stick them on myself?
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Post by StewRoss on Mar 15, 2007 0:59:01 GMT -5
Hi Marlon, Easy, a five minute job...change them one at a time of course. Do it on the centre stand and away you go. Make sure you tighten up the cap nuts of course! You'll notice an improvement straight away. I am fitting Wilbers to my new cafe racer. SR |
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Post by aero on Mar 30, 2007 23:38:43 GMT -5
Reference the mods to the area around the head stock: Don't waste your time adding metal here. Tube is highly resistant to twisting loads, the bigger the diamater the more load it can resist. This is one area were the SR frame is extremely strong form standard, due to the large diameter of the back bone spine. You could even make the frame weaker by introducing extra welded seams.
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...across under the front fairing mount...
