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Old 03-13-2014, 03:34 PM   #1
Hookalatch OP
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Suspension- Is Good, Good Enough?

I have about 3,000 miles on my 1984 R80RT based R100S clone http://www.advrider.com/forums/showthread.php?t=879502 . E\
Everything is working quite well and the bike is a real joy to ride. That must mean its time for more modifications! I rarely follow the advice of "if it ain't broke, don't fix it". I would really like to up the compression, change cams, and maybe dual plug. However, I realize the bike is already faster than the handling can handle. Its so much better than before the rebuild, maybe I should just leave it alone. I am sure it can be made better yet but how do you know when good is good enough? I like to corner faster than the average rider. I can ride the bike thru a corner almost as fast as my Wilbers shocked R1200GSA but not with the same degree of confidence.

The rear shocks are Hagons that were replaced during the rebuild. They were a vast improvement over the worn out stockers but I know there are better shocks, its just how much do I want to spend. The spring rate is pretty good. There is about 3/4 of sag (at the axle) when I am on the bike without gear or the bags mounted.

I am more concerned about the forks. I am using the stock R80RT springs which I thought might be about right after removing 40+ pounds of fairing and attachments off the front of the bike. I currently am using about 2 1/2" of the 7.8" of travel as sag. That is about 32% which is higher than usually recommended. However I have yet to bottom out the forks while riding. The forks respond well to small bumps but are really harsh on compression over high speed and larger bumps/holes. They also occasionally make a clanking sound over slow bumps that I believe is topping out. When this happens the forks are usually moving rapidly enough it is tough to determine for sure. I am running 7.5 wt. fork oil.

I have read all the threads I can find about Race Tech Gold Valve Cartridge Emulators. It sounds like they would solve my issues. I could greatly decrease compression damping and use heavier oil to slow rebound. It sounds great but in reviewing the threads it appears many users are less than thrilled with them. The dismantling of parts to make minor adjustments to them, often many times, seems like a bit of a drag too.

The bike already handles far better than the R100GS or R60/6 I have had in the past ever did. Maybe I should just except things the way they are and call it good enough. I wish there had been more happy gold valve users- I would have some on order already. Any opinions welcomed.

Chuck
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Old 03-13-2014, 03:53 PM   #2
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Mmmm, interested to see where this goes.
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Old 03-13-2014, 04:02 PM   #3
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The GV's have one adjustment, pre-load on the spring that is adjusted by tightening the allen bolt, and yes the GV's have to come out to do that.

Once you get them where you want them they work welll.

That being said, the other choice is to change the pre-load on the springs or change the oil weight if you don't go with the valves... changing the oil is more work than adjusting the GV's, changing the pre-load spacer is about the same.


There is no magic bullet here other than trial and error. And once you get the front end dialed in really well you will realize the read end isn't as good/ Then you start the process all over again.
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your bike is suitably dirty. Well done.
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Old 03-13-2014, 04:20 PM   #4
ME 109
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Suspension is overrated.
So many agonise over the finest of adjustments.
The stock suspension from late 70's onwards is perfectly capable.

IMO anyway.
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Old 03-13-2014, 06:30 PM   #5
Hookalatch OP
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Quote:
Originally Posted by ME 109 View Post
Suspension is overrated.
So many agonise over the finest of adjustments.
The stock suspension from late 70's onwards is perfectly capable.

IMO anyway.
Purrfectly capable is going to mean widely variable opinions defining it. But I agree with you about how this bike works now. But I also appreciate how much better suspension can be. I was hoping to see lots of stories about how emulators transformed the front forks. There are people that experienced that but they are greatly outnumbered by those less impressed. The main complaint seems to be very stiff springs and too much compression damping using the recommended/required Race Tech springs and settings.

My stock springs are supposed to be 21.2-21.7" long. A 1885 on R80 or R80RT are 18.6-19.1 long. There is a minimum of about 3" of spacers needed to use these emulators with my forks. I wonder if 1985 R80RT springs would work with the emulators in place. I can find info about spring length but not about spring rates.

Chuck
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Old 03-13-2014, 06:50 PM   #6
supershaft
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I wouldn't raise compression without dual plugging.

3/4 inch? If so, there's a big part of your trouble. You need less preload or a softer spring. You probably want between a 1 1/4 and 1 1/8 in sag. Less than an inch is extreme.

And then you have too much sag in front. Getting your rear end down will cure some of that in itself but you still need to start with a 1/2 inch preload spacer. From there a washer or two will get you about right if a half inch isn't too much. What so many people do wrong is get too stiff springs versus preloading the stock ones.

GV's. The trouble most everyone here has with them is the same trouble they had with the stock setup. They are trying to adjust the spring with oil. WRONG! You adjust the spring with preload. EVEN IF you wanted to jack your forks all up adjusting compression damping instead of spring preload like they should be doing they are STILL trying to adjust that with GV's by changing fork oil weight. The entire point of GV's is that they have an adjustable valve for compression!!!!!!

I think changing oil is way easier than adjusting GV's but then again I think adjusting preload is to a lesser extent too. Good luck!
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Old 03-13-2014, 06:52 PM   #7
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Quote:
Originally Posted by ME 109 View Post
Suspension is overrated.
So many agonise over the finest of adjustments.
The stock suspension from late 70's onwards is perfectly capable.

IMO anyway.

I bought an R90s last year and its a horrible ride due to having oversprung Marzzochis on the rear. Front end springs are probably the originals, soft and mushy.
I can see why it got pushed into a shed for 17 years.
Just finished a Koni rebuild for the rear and going to fit HD front springs with stock wt fork oil. Thats what I did for the R90/6 and its a pleasure to ride.

I thought about doing racetech like my track bike ....... but the stock setup is 'capable"
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Old 03-13-2014, 06:55 PM   #8
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Quote:
Originally Posted by ME 109 View Post
Suspension is overrated.
So many agonise over the finest of adjustments.
The stock suspension from late 70's onwards is perfectly capable.

IMO anyway.
I think it's time for us to see some more of your riding ME 109. You seem to manage with your stock set up just fine.
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Old 03-13-2014, 07:26 PM   #9
ME 109
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Quote:
Originally Posted by akabeton View Post
I think it's time for us to see some more of your riding ME 109. You seem to manage with your stock set up just fine.
Got a request? Tight mountain, good dirt, horrid dirt/rock, sand, sports bike fishing ?
Original front springs, no preload.
Ikon rears.
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Old 03-13-2014, 07:44 PM   #10
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Quote:
Originally Posted by ME 109 View Post
Got a request? Tight mountain, good dirt, horrid dirt/rock, sand, sports bike fishing ?
Original front springs, no preload.
Ikon rears.
Yes plz



I thought 32% was a bit much sag for a street bike. Should probably try to get it to less than that, which means bigger spacers, to me, since youre technically over sprung, having lost 40 pounds off the front. I'd try for 25% or so. Maybe roughly two inches of sag for your almost 8 inches of travel.

Befoire going for emulators (I'd honestly go for new forks before emulators, now, theyre just such a troublesome intermediate step) I'd make sure to set up the suspension as best as possible, stock, and see what it really needed, from there.

Also, 3/4 of an inch in the rear is how much, % wise? I would still go for roughly 25%, so it sounds like youre too preloaded in back. If you cant soften it to the right preload, you're over sprung. THe back should have 4-5 inches of travel.. so like Shaft says, you want at least an inch, and more
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Old 03-13-2014, 08:19 PM   #11
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Quote:
Originally Posted by ME 109 View Post
Got a request? Tight mountain, good dirt, horrid dirt/rock, sand, sports bike fishing ?
Original front springs, no preload.
Ikon rears.
You should put 'Original front springs, no preload' underneath all the pics you post of your poor bike's beat up valve covers and crash bars?
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Old 03-13-2014, 09:02 PM   #12
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Quote:
Originally Posted by supershaft View Post
You should put 'Original front springs, no preload' underneath all the pics you post of your poor bike's beat up valve covers and crash bars?
You're forgetting.............my forks are air bag assisted.

I've been thinking of what would look good under your photos.
I can't think of anything!
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Old 03-13-2014, 10:07 PM   #13
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Is good good enough? Sigh...what!?

I've spent good time and money on my /5 forks. They are better than good. But when I ride my Aprilia with Ohlins rear and GP Suspension tuned forks, well, it's a different ball game. Damper rod forks are what they are, and Ikons too. They certainly can be "capable" and I'm not trying to say that any one of you on your stock airhead couldn't smoke me on my Aprilia. Maybe. But for me, the joys of airheads do not lie primarily in their suspension.
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Old 03-14-2014, 12:24 AM   #14
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Quote:
Originally Posted by ME 109 View Post
You're forgetting.............my forks are air bag assisted.

I've been thinking of what would look good under your photos.
I can't think of anything!
My memories (80's) of NSW rural roads are that they are sometimes sealed.
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Old 03-14-2014, 01:53 AM   #15
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The problem with emulators is that they are a one size fits all solution, and have too many permutations in the setup.

Fork oil weight
Fork oil level
Fork spring weight
Fork Spring preload
Emulator spring (3choices)
Emulator spring tension.
No of low speed bleed holes in Emulator (2 or 4)

Too many variables and the base settings provided by Racetech were not correct.

Maxton will provide revised forks with modern internal at a price. For Nortons there is a guy providing decent compression and rebound valuing for Roadholder forks at a reasonable price +_200, maybe we should persuade him to make stuff for airheads. Google Lansdowne engineering.

But for the OP, the late type 2 BMW forks should incorporate all the revisions that BMW made and won't clonking. For once I agree with SS, fit a set of Normal fork springs and set the preload correctly they should work fine.
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