Boxerworks.com

Looking for some details on installing a set in my R90, tips,tricks,pics,links.....thanks

http://www.advrider.com/forums/showthread.php?t=661280

Lots of info there.

Chasbmw also posts here regularly, and he has done it on his 90/6, currently touring in bankrupt Greece.
in fact he posted in another thread just minutes ago.

I have them fitted on my r90/6.

The emulators and springs cost serious money in the UK.

I would not fit them again as to date, I have failed to reach a set up that provides much of an advantages over stock. The ATE forks are really quite sophisticated,more so than the later brembo forks, and I don't think that the emulators work well with the ATEs. In fitting the emulators you in effect heavily modify the fork damper rods, so going back to stock will be expensive.

If I was doing it again I would modify the standard forks by fitting r90/s springs, with the BMW modified damper nozzle, together with 7.5woil. The forks will take some miles to settle in after a rebuild.

If you do go down the emulator route, then use BMW springs, which you will need to reduce in length to get the right initial sag. I found that the RAce tech fork springs as specified for my weight were far too hard. I had no sensible response from tech support at racetech.

Currently sitting by my tent in kephalonia in 35 degree heat, have been riding today in a T shirt, I know that it is naughty, but makes a bit of a change from the full kit we need to wear in northen Europe. The roads can be interesting as are driving standards.

I'm keeping a goodish supply of cash on me, just in case the ATMs stop working! Gas is very expesive €1.70 a litre. I will do a review of my r90 engine soonish, now got 2000 miles on the rebuild.

Tell those Greeks to get back to work. My German friends are really tired of supporting the banks that loaned the money to the Greeks that won't pay it back.

Full retirement at 50. Nonsense.

Turns out that a lot of the QE2 money ended up in the banks of Europe, instead of the USA consumers.

I'm dreaming of a full retirement at 50
Plenty spare time to work on my air heads, air heads friends, time to travel etc

For the fork, genuine, well maintened is not so bad.

Armaguidon13 wrote:I'm dreaming of a full retirement at 50
Plenty spare time to work on my air heads, air heads friends, time to travel etc

For the fork, genuine, well maintened is not so bad.

I had full retirement at 33........ if I wanted, but I love to keep busy, so I only take contract jobs now. Wish I had started with contract jobs out of high school. I have worked about 40% of the time since I was 33.

Talk about thread degradation.

Is the emulator question still relevant? Many times, i can't tell.

I just did an installation of these on my R60/5. I followed the advrider thread, and Chasbmw issues with stiffness before I jumped in.

The problem is NOT with the valves, but with the springs.

If you go by the RaceTech recommendations, you get a spring rate MUCH too stiff (something like 0.8kg/mm) and a spring much too short. Why? Because the racetech system is set up for motorcycles with 5" of travel.

Your airhead has about 8" of travel. Short, stiff springs will limit you to about 5" of travel, and when that travel is used up, you get a mechanical bind (spring coils touching) instead of the hydraulic/bumper cushion. No good.

My solution? I had Sonic Springs wind springs for me of the proper length and rate for the emulators. Instead of the race tech 425mm spring at a .8kg/mm rate, Sonic springs wound me an 0.65kg/mm spring at a length of 485mm. This way, the ride is stiffer (but not ungodly stiff), the bike rides a bit higher in the stroke, and it eats bumps like crazy. Stock springs are about 530 mm long, but if you use an emulator, it consumes about 55 mm of space inside the fork. The shorter spring accounts for the reduction in space available when the emulator is installed.

On my test ride, i was looking for potholes to hit, manhole covers to ride over, and square edge bumps. It was almost like riding my new dirtbike...it really is an improvement. I have my sag set at 25%; i may move it to 30% to see how that works. A bit more sag gives the wheel more distance to travel downward without upsetting the bike when a hole is encountered.

I was a bit freaked out when I first put the springs in and "garage tested" the bike. It seemed REALLY stiff. However, once i rode in the street, the change was phenomenal. A controlled valve stack offers much better damping than a fixed orifice. I am a believer.

I am not affiliated with Sonic Springs. I am just a paying customer who was really happy with the service and the price.

BTW, the "progressive" springs (which are "progressively wound," meaning that the spring RATE increases with increasing spring compression) start at a rate of 0.33kg/mm (which is the rate of the stock BMW fork spring) and increases to 0.66 kg/mm (which is the rate of the HD BMW fork spring available at your dealer).

I could have used the HD bmw springs available from the dealer, but with the emulator, i would have had to shorten the spring, which increases the rate. For about the same money, i had springs wound for my application.

If you actually measure a so called progressive spring you will find very little, if any , change in the rate in the centre 95% of the springs travel.

Ohlins web site has a good write up on this - you will note that they fit straight wound springs on everything the sell.

The critical point with suspension is balance front to rear.

It seems that suspension works best with some pre compression on the spring - Ohlins suggest 18mm + - 2mm , and at the stock 18mm setting the shock they supplied for my GS gave 44/45 mm sag.

It is generally accepted that the front sag should be around 10% more than the rear, and following this gives you around 50 mm sag at the front.

This setting works well on most road bikes, irrespective of the amount of total fork travel available to you, and is OK for reasonable tracks too.

When you get the spring balance correct, front to rear, getting the damping acceptable becomes much easier, and the stock damping is almost acceptable.

Things also work better if the forks are aligned well and a billet top triple makes this much easier for some folks.

Modern full synthetic HVI suspension fluid makes a noticeable improvement to the fork action too.

As do old tech tires {in the correct narrow sizes} which are happy at 10 lbs less pressure than the modern stuff.Not much sense fitting a fat tire 3/4 lbs heavier and then complaining your rebound damping cant cope, when the stock size gives all the grip you need.

Set up properly an old airhead works just fine, and if you dont have the ability to make the stock bits work it isnt going to get any easier with non stock bits.

Roy Gavin wrote:If you actually measure a so called progressive spring you will find very little, if any , change in the rate in the centre 95% of the springs travel.

Ohlins web site has a good write up on this - you will note that they fit straight wound springs on everything the sell.

So, I guess all the Ohlins progressive wound springs available here are something they make to screw up people's suspension?
http://www.moto-services.net/products.php?cat=54&pg=2

Roy Gavin wrote:It seems that suspension works best with some pre compression on the spring - Ohlins suggest 18mm + - 2mm , and at the stock 18mm setting the shock they supplied for my GS gave 44/45 mm sag.

It is generally accepted that the front sag should be around 10% more than the rear, and following this gives you around 50 mm sag at the front.

This setting works well on most road bikes, irrespective of the amount of total fork travel available to you, and is OK for reasonable tracks too.

Those are very high sag numbers. I have never heard of sag numbers that high being recommended for "most street bikes." Sport Rider Magazine's suggestions are: "For street purposes, front sag should generally be between 30 and 35mm, and rear sag between 25 and 30mm." These numbers are much more like what I am used to seeing suggested for the street.
http://www.sportrider.com/tech/146_0006 ... index.html

GS's, depending on year and model, can have quite a bit more travel than "most road bikes," and so would run more sag.