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Old 06-08-2015, 02:00 AM   #1
Voltaire OP
Bored Of The Rings
 
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Joined: Jun 2011
Location: Auckland,New Zealand
Oddometer: 1,717
Airhead Suspension

I put emulators and .80/kg/mm springs into my race bike a few years back.
RT swapped out the .80 for .90's earlier in the year and supplied some S36 Ohlins.
Seems to work ok.

My R90s said to me that it needed the front sorted so I thought I'd used the .80kg/mm springs and get another set of emulators.

I had a spare set of damper rods, so drilled out the compression holes and cut off the top, made up some PVC spacers etc.
added 20wt oil and filled to 150mm from top and refitted springs and a pvc preload spacer.

it was getting late so just took it for a ride.
Steering shook a bit at low speed and ride seemed to follow the bumps.
Measured up the sag and only about 25mm.
Total travel under brakes is about 80mm

The more you read about emulators the more you find out.... drill the emulator out, don't drill it, 10wt,20 wt, 1kg/mm....165kg/mm... more oil, less oil...and so on.

I fitted the blue springs and next step is to reduce the preload and try the silver emulator spring that is the lowest.
I suspect the spring rate is too high but the Racetech sites says it the one...
Lots of variables. Worst case I can just put it back the way it was and live with long travel soft mushiness.
BMW springs I gather are about .33kg/mm
Tried the bathroom scales on some and came out with about .5
Anyone else played with suspension with any success.
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Old 06-08-2015, 02:52 AM   #2
innathyzit
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Joined: Dec 2008
Location: Nelson NZ
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My front end needs work, but refuse to change the forks. Soaks up small bumps beautifully, and is good on the road, but big hits off road are puckering. Played with oil viscosities, 5wt then 10wt . 10 wt works better.

Rear is good/awesome now with the Ohlins.

Has anyone had any experience with these?
http://www2.munichmotorcycles.com.au...ath=505_17_221
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Old 06-08-2015, 04:32 AM   #3
warewolf
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Location: Nelson, New Zealand
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Quote:
Originally Posted by Voltaire View Post
Anyone else played with suspension with any success.
Heaps; but perhaps I'll just mention some stuff that is likely relevant. I put Ohlins springs and RaceTech emulators in my Triumph Trophy Super III; that took a bit of sorting. I used the lighter of the two poppet valve springs, mucked around with too little preload trying to get them to handle square-edged bumps, and then Dr Robert said they'd released a lighter spring...et voila! Much, much better and with normal preload on them.

However Dr Robert pointed out that there was no way even a well sorted road bike - which mine was - was ever going to soak up big hits like my KTM, so maybe I was expecting the impossible. Got a pretty good result in the end though.

Another thing he mentioned was that there should be a really good fit between the emulator and the top of the damper rod, to avoid blow-by. To that end, he uses the next size up and bores out the damper rod to match.

Norm Cobb reckoned that sports-tourers like the Trophy will wear out the fork internals (bushings, seals etc) in 20,000 km, so if you want the front end to be top-notch you have to replace all that fairly regularly.
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Old 06-08-2015, 01:43 PM   #4
Voltaire OP
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Cheers Colin, I noticed the silver springs in the packet ( afterwards) as last set only had red and blue.
I see what RT means by good fit as otherwise you will get blowby of the fork oil.
There are pages and pages of this on the SV650 forum.....

I measured the stock BMW springs using a length of threaded rod and bathroom scales and found rate to be .5kg/mm
I double checked using the kitchen scales and came close to that.
They are on the soft side.
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Old 06-08-2015, 10:27 PM   #5
warewolf
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The Trophy had something like .4 & .75 dual rate springs. I had issues with the softer portion coil-binding with a jolt, usually while tipping in... puckering! The Ohlins were .9s, the lightest they made. Beautifully firm though. Supported the front end properly on bumps and under brakes.
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Old 06-08-2015, 11:05 PM   #6
Box'a'bits
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The stock GS springs are 0.48kg/mm.
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Old 06-09-2015, 02:54 PM   #7
Oscar
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I put a YSS on the back of my R80 and the front end needs sorting but I want it to look stock.
What sort of emulators do you guys use?
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Old 06-09-2015, 09:07 PM   #8
Voltaire OP
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Location: Auckland,New Zealand
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Quote:
Originally Posted by Oscar View Post
I put a YSS on the back of my R80 and the front end needs sorting but I want it to look stock.
What sort of emulators do you guys use?
Ractech ones.
Last night i stripped it all down again, did some measurements, the spring wire is 4.5mm on both the Ractech and the BMW springs I had on the shelf ( suspect HD)
Did a comparison of both using the bathroom scales and a length of threaded rod with a nut. pushed down 10kgs and measured the diff.
Chopped 3 coils off the BMW springs, thus making them harder.
Same length as ractech ones + 75mm spacer.
Replaced the medium Emulator spring with the silver one on lowest setting.
Reassembled, increased sag, total stroke with brake on increased 20mm.
Took for test ride and better than before.
Only 999999999999 other possible combinations to try
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Noobs guide to racing.
http://www.advrider.com/forums/showthread.php?t=790873
Saigon to Hanoi two up on a Honda 150
http://advrider.com/forums/showthrea...1009571&page=2
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Old 06-11-2015, 12:34 PM   #9
Voltaire OP
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Joined: Jun 2011
Location: Auckland,New Zealand
Oddometer: 1,717
rode to work today, 10 mins on the motorway and bit of urban.
I hunted out the bumps and quite good.
Its firm like the R90 I put the HD springs in, but without the harshness over bumps.
Try it out on some back roads over the next few weeks and see how it goes.
At the end of the day its a 40 year old bike.
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Link to Classic BMW Racer Project.
Noobs guide to racing.
http://www.advrider.com/forums/showthread.php?t=790873
Saigon to Hanoi two up on a Honda 150
http://advrider.com/forums/showthrea...1009571&page=2
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