Goliath has come to play

[Andrew2]

Originally Posted by MIXR

Correct Drone.

I was advised by Laurie at his 'Suspension Smith' shop in Fyshwick (Google him) that it was probably unnecessary to spend AU$1200-1400 on a Wilbers when he could do some magic on my OEM that would work just as well for AU$400. I've just come from his shop, and he offered the following info. It's a mix of metric and imperial data, so read the units as well.

The stock OEM rear shock is a good rebuild candidate if it is in good condition. He cannot do a front OEM shock.

The spring is an Eibach.
It is rated at 1000 lb in that it takes 1000 lb to compress it 1 inch.
Alternately, the compression is 17.9 kilograms per mm. A stock OEM is rated at 13 kilograms per mm.
The inside diameter is 2.23 inches.
The length is 8.0 inches.
He used a 15 mm preload spacer.
The also did a revalve on the OEM to match the damping to the new spring. No details offered.

For the Aussies, I highly recommend you try this before you spend big bucks on Wilbers or Ohlins, even if it's not for sidecar use. He uses a similar build for loaded touring on a solo GS bike, or pillion use.

Hope that helps. Mick.

Mick do you have a photo of the preload spacer.I'm running a 22kg spring in mine and it's still to soft.

Cheers
Andrew

[MIXR]

Hmmm. He said 15 mm but I can only see what looks like this 10 mm spacer at the base above the bottom spring plate. Can't really see what's at the top, so maybe it's up there, or this is it and he gave me a wrong size off the top of head at lunch today. Or this is just the normal base and there's another one up top? Either way, it sure made a difference, but I have nothing to compare it with other than OEM, which was sloppy as a pogo stick in a custard pool.


By the way, thanks for that disassembly video. I couldn't open it at work and had to wait until I was home, but a really good one to view before I tackle the job.

[Bobmws]

Originally Posted by MIXR

My good mate Rob over in WA reminded me that there was a bit of play in the rear wheel when I bought the bike at 42,000 kms. Not an issue for solo work, but possibly a contributing factor to the current fail in sidecar use, and with sidecar loads applied.

I've looked hard at the tyres and the rear (now being replaced) has copped a hiding. The bike is pretty upright (perpendicular to the road), but the tyre has slightly wear to the right of the tread. I do not want to increase the 'lean-out' angle as the chair is already very light.

The bike is still 'steering' left at high speed, so I'm constantly having to input some steering to the right above 90 kph. It's another adjustment I need to make to the toe angle. If I can get the outfit to steer 'neutral' at 105 kph, then there should be no real load on the wheels or bearings. The replacement drive assembly that I'm getting will allow me to continue with testing and set-up work.

I just know it's getting so close to being 'right' for a stock bike. That's what I wanted to achieve. I think SRK must have set it up fairly neutral instead of listing to what I said I wanted. Great in the car park, but crap on the road.

I've seen alot of threads on rear drive failures. Most agree that the initial assembly is to blame, the shimming and clearance are incorrect from the factory. BMW came out with a replacement bearing, but the crucial factor is proper assembly and shimming.

[MIXR]

Figured I would throw in a quick 'Thank you' for all the support, well-wishing, advice and guidance I've been getting. Greatly appreciated team, and makes life easy sometimes when those who have 'Been there - Done that' are happy to offer their views and experience. This is all a bit new to me having come from an R1150R that was utterly reliable (apart form a busted flywheel and slipping clutch ). So .......... Thank you.

Bob - I understand the issues surrounding shimming and preload. I've decided that the old unit will go to my local expert (Mick Owen) for rebuild. He has all the parts on the shelf (isn't that interesting!), has done plenty of these, and the cost is mostly in the parts rather than the labour. I'll pull the unit on the weekend and take it to him next week. Depending on the other internals, it will stay as a spare until the replacement second-hand unit either fails, or until I finish playing with the set-up. I guess it will be good to know I have a spare (also an unhappy thought!).

Cheers, Mick.

[MIXR]

Picked up the used drive unit in Sydney yesterday. Back home late yesterday afternoon, but didn't get started on the job until later in the evening. Got the old one out and new one ready to fit. Had some fun this morning sorting out the 'phasing' of the drive shafts. Pain in the neck when you are doing the job by yourself.

Spent 20 minutes NOT getting the damn unit to mate back up. Surely there couldn't be different sized shafts between the GSA and RT? Pulled both short shafts from the drives for a better look, side by side.

Blooming heck! The GSA has a keyed spline, but the RT doesn't! So I swapped the end shafts over and it all slipped back together! All went pretty well, with just some light use of a scissor jack to help position the drive unit. I didn't drop the rear shock, but did remove the muffler for better light and access.

All seemed to go ok. I know I'll be pulling this again, so I used medium strength loctite instead of the serious stuff. There is another view on this, and I followed someone else's lead and just marked the bolts as a tell-tale. I can't see 160 NM conming undone, but will keep a close eye on it.

I need a mate to drop in to sit on the bike and preload the suspension for the lower arm torque. Decided not to use a strap to winch the bike down. It can wait while the loctite cures. Not even sure how critical this is, but since it's my first run at this job I'll do it right and torque the arm.

The 'new' drive unit has no lugs for the GSA rear splash guard, and has an ABS sensor and lead fitted for the RT. I've kept that on and just strapped the lead out of the way. Saves wrecking a good item that may eventually get sold on to someone else with ABS.

Anyway, some boring pics of the job in progress below. Nothing special. Really pleased I did it myself. Old drive will go for a rebuild this week, subject to what the damage is like inside. I might just cart it around as a spare. I need weight in the sidecar anyway!

Also took the opportunity to adjust the toe in one more turn (out a turn at the back arm). I hope that's enough to bring the high speed cruise steer problem back to neutral.

Cheers all, Mick.

[Andrew2]

Originally Posted by MIXR

Hmmm. He said 15 mm but I can only see what looks like this 10 mm spacer at the base above the bottom spring plate. Can't really see what's at the top, so maybe it's up there, or this is it and he gave me a wrong size off the top of head at lunch today. Or this is just the normal base and there's another one up top? Either way, it sure made a difference, but I have nothing to compare it with other than OEM, which was sloppy as a pogo stick in a custard pool.


By the way, thanks for that disassembly video. I couldn't open it at work and had to wait until I was home, but a really good one to view before I tackle the job.

I definately don't have that on mine.

[MIXR]

The second-hand drive seems to be fine. Did a run to Sydney and back on the weekend (600 kms) and had a shorter 100 km run the previous day. No play evident, and oil seems fine. Maybe the purchase of an unknown history rear drive will work out ok after all. The original should be back this week, with a bag of shrapnel!

I've continued to make adjustments to the lean angle, trying to get that 'neutral' steering at 100+ kph. It's still steering slightly towards the chair (left). It's very close now, but I'll probably load the thing up with the gear I'm taking to Nambucca Heads in a couple of weeks and see what effect that has on the steering. Toe angle seems to be pretty good, so I'll leave that alone. I know the load will drop the rear, which seems to ease the steering effort required as it changes the overall balance of the rig. The whole thing seems to be very sensitive to cross-winds and road camber. I guess that's what a leading link would address.

Heck of a learning curve, but I think I can honestly say that I'm starting to get a very good understanding of sidecar dynamics out of this exercise. Heaven only knows what SRK were thinking when they put this thing together.

I'm still not convinced the GSA is a good tug for sidecar use. It seems to be too tall and has too high a weight bias for anything other than highways and sweepers. The tight and twisty stuff is definitely not where it shines. But, It is a lot of fun when it's in the groove!

Attracts too much attention though. Everybody wants to say hello and have a chat.

[Clancy]

Mick, I've only come back to reading this thread after not taking much notice for a while I know they are different models, and you probably finished and got all the bases covered by now, but take notice of the wear in the uni joints next time you pull it apart. Mine let go at the front uni a while back and did a fair amount of damage to the swing arm as well as the shaft itself.






That's the inside of the housing (Sorry for the picture quality). I obtained a complete new diff and have modified that, replaced all the bearings, all the pivots, and replaced the aluminium cone with a steel one. Enlarging the diff to carry a bit more oil and adding some cooling fins can't do any harm either. I now carry a spare tailshaft too. Currently doing the same things to another diff so there's a spare on the shelf

[MIXR]

Nice one Clancy! I actually had a real good look at the Unis on both drives while they were pulled down. They are fragile little things aren't they?

Both had a tiny bit of 'notchiness', but I had no choice other than to re-use the GSA shaft as it had the matching keyed spline. It was fine when fitted. Very smooth at all angles under rotation.

I am very weary of the loads that this thing suffers in the tight stuff. It scares me now! As a result, I've decided to ease up a lot with my riding and just smell the flowers (and dead roos and wombats) in the tight stuff, and hope that it holds together a bit longer than you would otherwise expect.

My Nambucca ride mid-Feb will be a huge test. It's a nominated 1200 km ride there, and 800 to get back home. 2000 kms in two and a half days. If it's going to fail, that will be when.

If I have to go to your trouble, I'll sell the thing. I need a reliable long-distance machine or it just won't be worth hanging on to it. Plus, there is a limit to how many $ I can pour into this beast.

Nice photos though. You have been far more patient with yours than I would be with mine. Cheers, Mick.

[pops]

You Mean like this Clancy.





Hi Mick . Quote (The whole thing seems to be very sensitive to cross-winds and road camber. I guess that's what a leading link would address.)
Don't bet on it that l link forks will fix this. I have a l link on our setup now and to tell the truth I should have stayed with the stock setup with the trail reducer .I convinced myself that i needed a l link
Then again it might just be how our sidecar is set up?

Quote (I'm still not convinced the GSA is a good tug for sidecar use. It seems to be too tall and has too high a weight bias for anything other than highways and sweepers. The tight and twisty stuff is definitely not where it shines. But, It is a lot of fun when it's in the groove!).

We have been very happy with ours so far Mick .

Cheers Ian

[Clancy]

Originally Posted by MIXR

Nice one Clancy! I actually had a real good look at the Unis on both drives while they were pulled down. They are fragile little things aren't they?

Both had a tiny bit of 'notchiness', but I had no choice other than to re-use the GSA shaft as it had the matching keyed spline. It was fine when fitted. Very smooth at all angles under rotation.

I am very weary of the loads that this thing suffers in the tight stuff. It scares me now! As a result, I've decided to ease up a lot with my riding and just smell the flowers (and dead roos and wombats) in the tight stuff, and hope that it holds together a bit longer than you would otherwise expect.

My Nambucca ride mid-Feb will be a huge test. It's a nominated 1200 km ride there, and 800 to get back home. 2000 kms in two and a half days. If it's going to fail, that will be when.

If I have to go to your trouble, I'll sell the thing. I need a reliable long-distance machine or it just won't be worth hanging on to it. Plus, there is a limit to how many $ I can pour into this beast.

Nice photos though. You have been far more patient with yours than I would be with mine. Cheers, Mick.

It's more the lateral loads we put on the bloody things mate. Then we load them up with all manner of stuff and I don't really think you can get around the problems. All you can do is build everything so that it lasts longer.
It's not really very much in $$ terms, but you can spend a huge amount of time playing aound. I have to admit I've lost a bit of confidence in mine, but I'll give it another try and hope I've covered all the bases.

[Clancy]

Originally Posted by pops

You Mean like this Clancy.





Hi Mick . Quote (The whole thing seems to be very sensitive to cross-winds and road camber. I guess that's what a leading link would address.)
Don't bet on it that l link forks will fix this. I have a l link on our setup now and to tell the truth I should have stayed with the stock setup with the trail reducer .I convinced myself that i needed a l link
Then again it might just be how our sidecar is set up?

Quote (I'm still not convinced the GSA is a good tug for sidecar use. It seems to be too tall and has too high a weight bias for anything other than highways and sweepers. The tight and twisty stuff is definitely not where it shines. But, It is a lot of fun when it's in the groove!).

We have been very happy with ours so far Mick .

Cheers Ian

Bloody hell Ian. Those pictures look familiar Bloody scary when it happens too. Couldn't believe the noise

[MIXR]

NOW you tell me all this stuff? Thanks Ian. Maybe I should have purchased the drive shaft and tube when I got the second-hand rear drive?

Yeah, my prior research indicated that the drive-line was 'fragile'. That's why I went with a smallish chair and don't overload the bike. I carry enough gear, but nothing excessive. In fact, I'm now carrying so much stuff FOR THE SIDECAR that I'm not sure it was such a great idea.

But ------------------- I did hope that the lighter setup would avoid some of these issues.

I'll get this Nambucca run done and then maybe I'll propose a meet-up somewhere for Aus GS'rs (If I still have a working machine). Or has that been done? Maybe we are too far spread?

[pops]

Originally Posted by MIXR

NOW you tell me all this stuff? Thanks Ian. Maybe I should have purchased the drive shaft and tube when I got the second-hand rear drive?

Yeah, my prior research indicated that the drive-line was 'fragile'. That's why I went with a smallish chair and don't overload the bike. I carry enough gear, but nothing excessive. In fact, I'm now carrying so much stuff FOR THE SIDECAR that I'm not sure it was such a great idea.

But ------------------- I did hope that the lioghter setup would avoid some of these issues.

I'll get this Nambucca run done and then maybe I'll propose a meet-up somewhere for Aus GS'rs (If I still have a working machine). Or has that been done? Maybe we are too far spread?

Hi Mick. In all fairness the tail shaft did go a few days after the sidecar wheel broke .The bike got a real hammering when the sidecar wheel broke .The rear wheel was up of the road 3 or 4 times and then slaming back down before we could stop .And then the tail shaft did let go just as I landed after hitting a grid to fast A few days later.

On our last big ride of 3 weeks and 8000km, around 80%dirt . The sidecar with trailer was 850kg with out us on it .
No problems with the bike on the ride ,except a fuse blew.



They are tough .

Cheers Ian

[MIXR]

One look at that photo explains it all. You wouldn't have broken anything if you'd lightened up by cutting your toothbrush handles in half!

Cheers mate. Mick.