Wrenching on my R80 G/S, an ongoing therapy

Hey Richard, now this may be a stupid question...but, now that you have the excell rim, you've lost the ability to be tubeless? How's that make you feel? That Harrison is a real beaut!

I didn't want a tubeless rim as I prefer the ease of the tire changes in a tube. This rim should be stronger than the stock GS tube rim, as the AL is of a better grade. The spokes are fricken huge, Woody's super lace three cross. Good turn around time from him, but kind of pricey. I had hoped to get a credit for the RGS rim, but it was bent...damn, just a credit for the spokes. I was charged $20 to disassemble the wheel, should have done it myself!!!!

Look closely at the spoke lacing.

Even though I have the Harrison, I'm messing around w/ a left R1100GS caliper as the mounting hole spacing is the same. Did some measuring of the stock 2 pot Brembo and need to remove 0.158" from the mounting ears of the 4 pot caliper to center it over the rotor. Just need to speak w/ the machinist to see if it can be milled w/o splitting the caliper. I don't want to split it because of the o-rings between the halves. They aren't in the $80 rebuild kit, plus I don't want to rebuild it. I'm not sure i would have bought the Harrison if I had found out before hand that the Brembo was so easy to do. Oh well the Harrison aught to be bitchn'.

I should have the front end on by the weekend, only thing left is finding some fork tube caps from an early R100GS so I can mount the turn signals.

Gonna be a busy weekend , as I'm picking up the work truck tomorrow and have to finish putting the bed together since painting. Painting on a bed liner, wheel well trim and side moldings. Finally the rusty Chevy will look good after 16 years of using it and maybe 16 hand washings!!!.

I can't wait to see this stuff all installed.

The EBC rotor arrived today and was a little pissed that it looked like this.....



Look at the carrier.....it's plain cast and not painted black. So the offending part gets painted w/ the satin black. While the paint was drying I took a road trip on the G/S to pick up the Chevy from the painter. Not very long after returning the front wheel and nacel were pulled off.

removed nacelle pict​

Then the rest off the goodies.

stripped for front forks pict

Once the wiring and handle bars were pulled back the triple tree was put in place. Brake line is pulled up higher than the master cylinder.



The top clamp has a stainless wire across the top to hold the cables back from the nacel, plus the nacel is held in place with the two friction fit nipples.

finished 100GS install pict

This is all for tonite, need to adjust the headset, fill forks, mount rotor and tire. Then the fun part...the mounting and bleeding of the Harrison 6 pot!!!


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For splitting the Brembo, try Home Depot or Orchid Supply if they have them back there...or even NAPA. You can find the correct size O rings there. No one can say officially why BMW (or Brembo) stopped putting the little O rings in the rebuild kit...other than liability.

Just remember to leave the wood block in the caliper, hold it so the brake line is at the highest point, pop it a few times with a rubber mallet or rubber screw driver handle to get the air bubbles started up the line,,,and gently squeeze the brake lever for a few minutes with the handlebar turned full left...MC at the highest point.

You should be a rock solid brake lever in about 5 minutes.

I always bought the rebuild kits from my local Guzzi dealer.... their kits are packaged up in a neat little clear Brembo tray and contain the o-rings... I think they are less than from the BMW dealers as well.

My Guzzi shop is Moto International in Seattle.

Which brings up the question...you get the Brembo rebuild kit from a BMW dealer and the little O ring is NOT included in the clear plastic pack..and yet it is from the Guzzi dealer...interesting.

First thing to do today is to make a longer bracket fro the headlight nacel. The one from the G/S was about 1/2 to short. So one was cut w/ an angle grinder, using the original as a pattern. The original is in my hand, the new one is trial fitted, then painted satin black. It is allowed to dry while the tire is pulled off the Akront G/S rim.

longer nacelle bracket pict​

Changing the tire w/ the Harbor Freight tire changer it's not that much quicker than just changing it on the ground.

HF tire changing pict


With the tire on we're almost there. Sorry for the blurry picture. No Harrison caliper yet.

finish install R100GS forks

The caliper is offered up to the fork leg and brake lines were checked for various line routing. I opted to use a hard line from the caliper around the inside of the fork leg and to a bracket next to the bottom of the gator. Notice the rotor carrier is now black.



Once the lines were routed the caliper was removed and filled w/ a syringe of brake fluid with the bleeder open a the 12 o'clock position. After this was done the caliper was attached to the flexible line, a block of wood inserted between the pads , then bled using the master cylinder.

Caliper was then mounted to the bike and bled again. Fork tubes filled w 10wt, 450cc right and 420 cc.


Harrison 6 Pot pict

Now for the test ride. Nothing to extreme for the brakes as they needed to settle in. Fisrt thing I noticed was the bike leans further over on the side stand, this is because the forks are 1.75" longer from the bottom of the headset to the axle.

Next thing I noticed was the bike had a slight wobble at speeds between 25-45mph...wtf. I'm a little concerned, 1st thoughts are the headset needs to be tightened or to lower the forks 1.75". I didn't do any hard braking during the 1st ride.

I returned home and tightened up the headset till the forks turned w/ a little resistance. Now for the second test ride......still wobbles, but less than before. So the headset was tightened a little again.

As I took off up the driveway the bike was wobbling even more.....then the tire went flat!!!!!! Crap I pinched the tube. The tube was changed and another test ride was wobble free.

So my 1st impressions of the Harrison 6 pot caliper are that it is plenty strong even though I haven't grabbed a hand full of brake. Just two fingers and not grabbing very hard. This is with the stock 12 mm master cylinder. Travel for the brake lever is not excessive and doesn't bottom out on my fingers. I think I'm gonna like the 6 pot caliper



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Looks Good

I can't believe you're not getting any "squish" with your 12mm M/C. I've got the 4 pot right now, and my 12 is very soft. Bled it about 4 days ago with a vacuum pump, and rubber banded the lever overnite to catch any stray bubbles. Alright, we'll have to thumb wrestle next time I see you, I think I might make some money off you.

Oh, by the way....looks sweet!!!!

While bleeding it seemed like I was going to have some trouble getting the air out, but when I was going to give up and go for a ride anyway the lever came up. Lever feel isn't rock hard, and does travel some before getting firm. Yeah it has some squish to it. You'll have to try it (anyone else that wants to can too)at Tellico Plains. I'll probably bleed it again to see if it firms up some more, but I can live with it.

I never had much luck w/ vacuum pumps, never did make it any bigger......oh not that pump.....but seriously, had a mity vac bleeding by hand works as well especially to get the pressure up. You might push fluid through the system just right after the MC. I did that with a syringe at the hard line just before the caliper, pushing the bubbles out. Also tapped the caliper with a rubber hammer to dislodge bubbles. This didn't get to many out.

If you haven't bled the traditional way (w/o vacuum pump), then do. Sometimes I'll pull the MC cap and pull the lever slowly and can see bubbles comming up in the MC, but be careful if you pull to quickly brake fluid will shoot out.

OH yeah and make sure the bleeder is at the highest point!

Note- the master cylinder was recently rebuilt.

I haven't seen anything posted about your DR front end? When ya going to write something?

BTW- I'm not even going to try the Brembo 4 pot which is being machined, probably sell it. I may have the machinist do a few calipers if I find some at a good price, then sell some here. Anyone interested???

not too much to say just yet. I can't ride it too much right now as I still have the original ST rear shock on it. Lot of cut and fabricate on my end. Well, a lot for me. I was thinking it was pretty plug and play, wrong. No one that I know of(beside AW and he doesn't count since he went back to BMW) has put the DR front on an ST. The bummer is my new fancy sidestand is now too short. But that will be rectified.

Overall, I think I'll be happy.

Put the HPN tank on to get ready for the Knobbies Rally in NC. Guess what, the stock springs are WEAK! Race tech .85 kg/mm ones ordered.

I hope I don't bottom out to much this weekend!

The Harrison 6 pot works great. Front tire really digs in on pavement, but right now it dives like a SOB. Not sure about the 12mm MC. It's adequate, but after a couple of brakes the lever gets closer to my fingers. Still locks up though. I will probably bleed the brakes again and see if that helps.

How much pre-load are you running on the RaceTech?

The forks have the OEM springs right now. I think they are rated at .47 kg/mm according to the Race tech info.

I wont get the Race tech springs for about a week.

The GS front end felt good on pavement with the stock little G/S tank, but the extra 6 gallons.......not so good. I still haven't pushed the bike on pavement yet and haven't even seen dirt yet. Taking a long ride to NC this weekend, but won't be pushing it any until it's got about 5 gallons left.

I will be ridding some off road, but expect to bottom out w/ the OEM springs.

For the lower instrument cluster nacelle mount, you needed to order the one for the 1988 R100GS. It's an inch longer than the G/S version.

The brake lever should be firm..you've still got a bubble in there.

Why not try a heavier fork oil till the springs arrive? That may help the dive a bit.

Ive got 10w oil in there now. At $5/ pint I think I'll just suffer. It was easier to make a bracket than order one and wait, but I don't think it was that expensive.

Lever isn't to bad when I just pull it, but after a few stops it feels a little squishy.

BTW- thanks for the parts.

well, it certainly looks great to me!
you'll get it sorted out.

Sorry, pre-load on the emulators...

I'm at 1.25 turns on the emulators. Feels pretty good.


Just got back from Moganton NC, about 100 miles off road. I was running w/ about 5 gallons of gas, on gravel roads, mostly smooth, with a small section of washboards. Comparing this fork to the G/S, well no comparison. Definitely more solid. I don't know enough about how a front end should feel to offer much criticism off road, but I'm pleased with it. I was concerned about the stock GS springs, but when only filled with about 5 gallons it seemed good to me.

THE MOST NOTICEABLE DIFFERENCE WAS ON PAVEMENT, with a full tank of gas, 11.5 gallons ,camping gear and tools, there was NO wobbling from the bike, well not completely true, at about 85mph, passing a truck, there was a little bounciness. This is probably related to the front wheel not being balanced.

On pavement I now have confidence in the front end when hitting bumps in mid curve. It feels very planted and predictable unlike the G/S front end, which had it's own ideas when cornering.

While just getting off a gravel road and feeling good to get on pavement a group (three) of us caught a BMW car on the Blue Ridge Parkway, for a while he was making a decent pace, but after a little bit he must have gotten sick of having use on his tail....too bad. He picked up the pace and still couldn't shake us. The bike felt GOOD on pavement, first time I've felt confident with pushing the bike in the twisties!



Note- the G/S front had, a billet upper triple, plus a lower hooped brace and it was still wild as hell when cornering. Felt like it was getting ready to break loose when hitting bumps mid curve. Down right dangerous.

The Harrison, needs some attention, as the firmness on the lever isn't what it should be, possibly a bubble. Need to look into it more.