New Suspension Time

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Forks built but I’m not happy with them as they have a bit of stiction. I suspect the bottom bushes which were a very snug fit (the wear was mostly in the top bushes prior to replacement and the new top bush/stanchion combination is a perfect sliding fit). I’m busy all weekend so it will be next week before I strip them and have a further look.

Dave
When you have them apart do look at the seals as well. Ludwig is spot on.
 
Original fork seals have too much stiction .
I prefer Ariete 003T seals , but you have to remove some of the outer coating to get them in .
Less stiction , seals better , last longer ..
Ludwig
Which Ariete part number/size do you use?
Cheers
Rob
 
The part number is in Ludwig's post.
Kommando
When I looked them up it appears 003T is a line of seals with different IDs/ODs/thicknesses
I was wondering which specific seal set he bought
Cheers
Rob
 
33mm ID, 48mm OD 11mm deep.

Stanchion is 34.5mm OD, fork leg recess is 47.6mm ish hence the need to file the OD.
 
Thank-you Kommando and Ludwig.
I'm going to try this!
Cheers
Rob
 
Do you have a fork brace? I found that the Hyde fork brace on my Commando when I bought it caused sticktion because it slightly misaligned the forks. This happened regardless of the adjustments present in the brace. I discovered this when I rebuilt the forks/added the Fauth mod shortly after buying the bike in '06. After futzing around with the adjustments to try to eliminate the issue, the only thing that worked was removing the brace. I pitched the brace in a trash can and the forks have been excellent ever since. ;)

No I don't have a fork brace, as I said I suspect the bottom bushes as they were a bit snug. I'm free tomorrow so I'll have a look at what's causing the problem.

Dave
 
Dellis :
Screw you assembled Landsdowne dampers in the new stanchions ( without the sliders )
Then look at the bottom if the damper bodys are perfectly concentric in the stanchions .
If so : fine .
If not : you have a problem that is not easy to correct .

Ludwig,

I take it you are referring to the stanchions being oval? As it happens I did try that as I'd been warned above about oval stanchions and measured the OD and fitted the Lansdowne dampers to check they were concentric which they are.

Dave
 
So the update after the second fork build.

I've stripped and rebuilt the forks and they started out silky smooth, fitted them to the bike, tightened the top nuts, then the spindle, bounced the front up and down a few times then tightened the bottom yoke clamps then the spindle clamp and finally the mudguard fasteners. At this point all is good I've got damping in both directions and no stiction. All is good I think to myself and set off for a test ride and guess what the stiction has returned, it's nowhere near as bad as it was but it's there and needs to be resolved... Any ideas? Is it time to bite the bullet and go for some Turcite bushes?

On the plus side the Falcon shocks are a major improvement over the old Girlings and I am extremely happy with the results. I have also fitted a three phase alternator which has sorted the charging out nicely.

Dave
 
Jack up put stand under front iso mount to get front wheel off ground. Unscrew top nuts on forks and stroke whole front end. Loosen fender, axle one thing at a time till stiction goes away. Misalignment, chrome tubes not straight or round, pocket in bottom of slider not square to bore can make damper rod crooked to bore when bottom bolts tightened. Its gotta be one of these
 
Could be as simple as the mudguard and stays, if you need to pull on a stay to get the bolt to line up then over bend the stay until its natural position is directly over the bolt hole. And bounce the suspension after every step, don't stop after tightening the bottom yoke bolts, carry on after each of the next steps.
 
Jack up put stand under front iso mount to get front wheel off ground. Unscrew top nuts on forks and stroke whole front end. Loosen fender, axle one thing at a time till stiction goes away. Misalignment, chrome tubes not straight or round, pocket in bottom of slider not square to bore can make damper rod crooked to bore when bottom bolts tightened. Its gotta be one of these

Thanks I'll take a look one evening this week.

Dave
 
Could be as simple as the mudguard and stays, if you need to pull on a stay to get the bolt to line up then over bend the stay until its natural position is directly over the bolt hole. And bounce the suspension after every step, don't stop after tightening the bottom yoke bolts, carry on after each of the next steps.

Thanks, stays are a bit of a squeeze, I'll have a look in the week.

Dave
 
What I mean is :
If any of the screw theads involved to hold the damper rod ( top nut inner and outer , stanchion inner , damper rod ..) is only slighty out of square , the damper rod will not sit straight ( parallel ) in the stanchion , resulting in extra friction between the damper tube , damper cap and piston .

Ludwig, thanks for the clarification.

Dave
 
Any one fit Ohlins w/ piggyback reservoirs? I haven't seen any direct fitments listed for the Commando, but I've seen the for Harleys at 12" and 13.25" eye to eye lengths.

JD
 
You may want to have a look at the Fournales oleopneumatic shocks. They are excellent, the price is reasonable (about 600€ a pair). As they are built by company wich does most of its developpement for aerospace, they are extremely well built and reliable. The company started out in the seventies by an aerospace engineer competing in the European Enduro championship who decided that he could apply his expertise to produce better shocks for himself than the ones available at the time. He went out to win the championship as soon as his shocks were on his bike. Their main advantage is weight, they are MUCH lighter than traditional shocks, about 900g - 2lbs per unit if I am correct.
I found out about them by accident: 3 years ago I was on a track weekend in France when one my shocks snapped in two pieces during the first session. I went around the paddock looking for replacement and a friend lent me a pair of Fournales. It was an instant revelation: they were incredibly better than the Hagons I had on the bike, they looked gorgeous in black and polished alloy, they were very easily adjustable while they , most importantly, improved corner exit traction impressively. I ordered a pair immediately and never looked back on my decision.
They have been 100% reliable in the 20000km + since.
 
Right back to my forks; I have now loosened the top nuts, yoke clamps, spindle clamp and mudguard mounts then tightened, with the damping fully wound off for maximum movement, starting with top nuts then re bounce, yoke nuts then re bounce, spindle clamp then re bounce and finally the mudguard stays and please To say at that point no stiction

I’ve now adjusted the damping back up to my starting point of one turn out and all is still well bar a very small amount of stiction which I’m now pretty sure is a bit of drag on the fork seals which with the damping adjusted up is apparent. So I’m now pretty happy and all that remains is a road test which will be at the weekend now due to commitments this evening, Thursday evening and an appointment at my local pub on Friday night.....

Further updates after the run.

Dave
 
So in the end I wasn’t happy with the amount of stiction that remained so I bought a set of turcite bushes from Jim. I’ve had them a few weeks but I’ve not had time to fit them. Anyway I’m off for a few days and with Christmas done I’ve fitted them today.

The result; stiction completely gone, I’m really pleased with the fork action and all that remains is to go for a spin which will be tomorrow now.

Dave
 
I never use a fork brace - with twin discs, you should not need one. I used to push my forks into compression and tie them down while I tightened the yoke bolts and front axle.. But with my current bike, I don't need to do that. The front end is pretty perfect, so I don't get stiction. I've used Koni Shocks for years and they have always been good. However that is not to say that a modern substitute would not be better. I was interested in Dave Moss's videos on suspension and I agree with most of what he says. I have never really thought about sag, but I know it is there. I probably got my bike handling well by accident rather than by design. These days I rarely get the opportunity to ride, however when I do, I find I can safely be more aggressive than I ever was years ago. I regret that I did not race the Seeley earlier.
 
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