Setting up the Front

[Bruce Reader]

As the title suggests, i'm looking for a good method to mount the forks while making sure everything is well aligned. Apart from measuring each fork from a fixed point does anyone use any other added technique ?

 

Regards

 

Bruce

 

ps. anyone have any instructions on how they service the ohlins fork? Oil type/amount, other things i can do while they are on the

bench

[Guest ratchethack]

Bruce, I applaud your interest in suspension setup!

 

As I've posted many times, I've come around to the understanding in recent years that somewhere less than 10% of riders give this any attention wotsoever. It's a sad, sad thing not to be able to achieve handling that the mfgr's intended, and without basic setup, there ain't much of a prayer of achieving it.

 

I've observed that many simply refuse to read anything "technical" or "procedural" beyond a few short paragraphs. I reckon it's a significant enough deterrent in many cases to kill any interest wotsoever. But such is the nature of the thing, and wotreyagonnadoo?

 

IMHO it's one of those things on the Guzzi that rewards effort in spades -- at relatively low cost in most cases. But zero effort in = zero benefit out.

 

I've posted a bunch of stuff on setup for the Marz 040 USD fork, as well as overall suspension setup. All the principles involved apply to the Ohlins as well as to any other fork.

 

I've found a great deal of value in the suspension setup info at the following 3 sites.

 

http://www.strappe.com/suspension.html

 

http://www.racetech.com/articles/SuspensionAndSprings.htm

 

http://www.peterverdonedesigns.com/oilheight.htm

 

I also opened a fork oil change thread in, "How To" with a procedure that covers some of what's involved, which may be helpful.

 

Many of the guys with Ohlins forks can provide more Ohlins-specific info.

 

Hope this helps.

[Baldini]

You can download Ohlins manual at http://www.ohlins.com >

 

Clik Motorcycles, clik Manuals.

 

There's detailed threads on this site re servicing Ohlins, try search. Or if you have specific question, there's several of us have done it...frequently....

 

KB

[Bruce Reader]

Thanks for the replies guys.

 

I so far have had more appropiate springs installed for my weight- 1.05kg front and 1.1 in rear.

 

I was wondering if a consensus was reached on the correct amount of fluid replacement for the forks ?

 

I seem to remember a conflict between manuals as to fluid amounts/ air spring characteristics etc.

 

cheers

 

Bruce

[docc]

While the experts disagree , the current wisdom is to fill the fork until the is the proper air gap at the top. 100mm is a good starting point.

[Guest ratchethack]

Docc, 100 mm air gap is recommended for the Marz 040 USD fork. IIRC, at least some Ohlins forks have a recommended air gap (or starting point, if you prefer) of considerably greater than this. They also appear to operate on a significantly lower air spring pressure than the Marz 040. My take on this is that this may be due to the fact that the Ohlins have larger-diameter fork tubes using lower-stiction seals, which doesn't add up to tolerance of the higher air spring pressures achieved in the Marz.

[Baldini]

Ohlins spec air gap of 85mm as stock for R&T forks.

 

I run mine around 100mm.

 

When you dismantle forks, do be careful to watch out for small needle assy popping out the top of long thin tube when you pump to purge oil. If you're not careful you could lose it.

 

If you're replacing seals, there are later double lip type which are supposedly improved.

 

KB

[Bruce Reader]

Thanks everyone for the info.

 

Is there a method when attaching the forks to make sure the front is true- or by installing the front wheel and axle make it foolproof ??

 

 

Any ideas on a starting point in regards to dropping the forks with the ohlins for quicker steering ?

 

Are the Ohlins forks the same length as other v11's ?

 

Some people have commented on the Scura being higher at the rear ? Are the ohlins rear shock longer overall than the standard suspension.

 

Is the rear shock servicable by the backyard mechanic ?

 

I have a mark on the forward end of my drive shaft that appears like the rear has topped out allowing a rare contact of driveshaft and swingarm. Any ideas ?

 

Cheers

 

Bruce

 

P.S. Appreciate your time- your expertise/knowledge has enhanced my 5 year (now to be lifelong) love of this marque.

[Guest ratchethack]

Is there a method when attaching the forks to make sure the front is true- or by installing the front wheel and axle make it foolproof ??

by the backyard mechanic ?

Bruce, there's right ways and many more wrong ways to assemble a fork. The right way ensures that the fork tubes and stanchions are perfectly parallel and there's no internal tension in the fork through its full stroke. The wrong way results in a fork that's not true, "twisted", or "pre-loaded" with unwanted internal stresses. It's pretty easy to get it wrong if you don't follow the correct assembly procedure. A twisted or otherwise non-parallel, or incorrectly "pre-loaded" fork will have a tendency to bind and give poor performance.

 

The following is for a Marz fork, but all the principles apply to every other fork. I've been doing this on my Guzzi for years, as well as many dirt bikes for many decades, including the one I'm riding now, and a Pal's new dirt bike just last weekend after his "maiden" traumatic -- yet nonetheless spectacular -- unplanned "mishap".

 

With dual disk brakes, this is a little easier. With fork loosely assembled, before tightening anything, using a straightedge running through the wheel laid across the top of the disks and resting against the fork tubes (I've always kept an arrow shaft in my shop for this purpose), you can sight from above the fork from the riding position along the top triple clamp to ensure the top triple is parallel with the straightedge. By tugging on the bars with the wheel clamped between your knees, you can coax it into "true".

 

The proper tightening sequence is: Lower triple clamp pinch-bolts first, Upper triple clamp pinch-bolts next, spindle pinch bolts last. Bouncing the fork after properly torquing the spindle nut, but before doing up the spindle pinch bolts will naturally "set" the spindle in the right place so the fork won't bind.

 

As you do the first steps, keep an eye on alignment via the straightedge. With everything snugged-up properly, you can then snug up the fender fasteners.

I have a mark on the forward end of my drive shaft that appears like the rear has topped out allowing a rare contact of driveshaft and swingarm. Any ideas ?

Bruce, there's no way the driveshaft can contact any part of the swingarm while underway at suspension top-out or bottom-out unless a U-joint has let go or unless the torque arm has got loose. I can't be certain of wot you're looking at, but it sounds like something a PO or mechanic has done whilst removing or attaching the wheel or bevel drive.

 

When removing the rear wheel, one common faux pas for the uninitiated (as mentioned in previous posts) is to withdraw the spindle fully before separating the rear wheel from the bevel box. If the wheel has been left unsupported, this allows the full weight of the ~40 lb. wheel and bevel drive to drop down sharply, placing horrendous leverage on the forward end of the driveshaft and forward U-joint, risking damage to the trunnion bearings. This would tend to leave a horrific witness mark on the driveshaft where it contacted the bottom of the driveshaft tunnel in the swingarm. Maybe this is wot you're looking at? If the mark in qustion appears to be a "one time" thing, this should be apparent, and the above might be my assumption, since it seems to be a fairly common thing. Withdrawing the spindle by only about 7-8" allows the bevel drive to remain "hung" on the spindle while the wheel is safely separated from the bevel drive and removed. The bevel drive can then be safely removed after unbolting the torque arm.

 

Hope this helps.

[dlaing]

Is there a method when attaching the forks to make sure the front is true- or by installing the front wheel and axle make it foolproof ??

 

 

I have a mark on the forward end of my drive shaft that appears like the rear has topped out allowing a rare contact of driveshaft and swingarm. Any ideas ?

I think Ratchet covered those questions very well.

My only problem with the method he suggested for the fork seating is that it is not completely foolproof.

Keeping the bikes weight centered is critical, so you don't want to follow the instructions by putting it on the sidestand.

Having an assistant tighten the axle pinch bolts as you keep it centered with your weight on it, well help achieve perfection.

 

Any ideas on a starting point in regards to dropping the forks with the ohlins for quicker steering ?

Not sure what the stock height is for the Scura, but I would try lowering the triples a quarter inch.

Make sure your front wheel/fender has adequate clearance.

 

Are the Ohlins forks the same length as other v11's ?

I replaced the stock Marzocchi fork with Ohlins from a Cafe Sport.

The Ohlins are considerably longer, probably and inch or two. Enough longer that I can mount my convertibars on top of the triples, if I drop the front end enough....

 

Some people have commented on the Scura being higher at the rear ? Are the ohlins rear shock longer overall than the standard suspension.

The Ohlins shock is about 1cm longer than the Sachs shock. This translates into it being roughly 2cm higher in the rear, if the sag is set the same. The Ohlins also has 1cm more travel, so if you don't add a lot of preload the Ohlins can be just as low as the Sachs.

But since you want nimble handling, you probably want to keep the ride height up high in the rear. But make sure you have at least a couple millimeters of sag. I set my Penske to about 5mm bike only sag, which gives me a nice ride height. YMMV

 

Is the rear shock servicable by the backyard mechanic ?

I don't know. My Penske is supposed to be user serviceable, and serviced frequently <_ but i don have access to nitrogen so know how can service it. something figure out any tips would be appreciated src="%7B___base_url___%7D/uploads/emoticons/default_anigrin.gif" alt=":grin:">

[Guest ratchethack]

I think Ratchet covered those questions very well.

My only problem with the method he suggested for the fork seating is that it is not completely foolproof.

Keeping the bikes weight centered is critical, so you don't want to follow the instructions by putting it on the sidestand.

Uh, thanks, Dave. However,

 

Completely foolproof?!

 

Dave, I don't know where you saw any instructions to put the bike on the sidestand to true the fork. Not from me.

 

Per his posts, Bruce has his fork apart. Starting with the fork fork "loosely assembled, before tightening anything", as I've described, it would literally be impossible to have the bike on the sidestand. Seems to me if someone doesn't know enough to have the bike on a shop stand with the front wheel off the floor while assembling the fork, it'd be highly unlikely they'd have ever got the fork apart in the first place.

Having an assistant tighten the axle pinch bolts as you keep it centered with your weight on it, well help achieve perfection.

There is absolutely no need whatsoever, nor have I ever seen, nor heard of any procedure that would recommend having someone tighten axle pinch bolts with someone sitting on the bike as an aid to aligning a fork.

 

The Guzzi stand allows bouncing the fork with the bike vertical and front wheel on the floor after torquing the spindle nut prior to tightening the spindle pinch bolts, just as I've described above.

[antonio carroccio]

All that crazy theory about fork setting up!!!

I decide to go myself to the Dutch guru at Assen with the bike and with this guy try to get the best setting for my Ohlins on the bike.

[dlaing]

Uh, thanks, Dave. However,

 

Completely foolproof?!

 

Dave, I don't know where you saw any instructions to put the bike on the sidestand to true the fork. Not from me.

 

Per his posts, Bruce has his fork apart. Starting with the fork fork "loosely assembled, before tightening anything", as I've described, it would literally be impossible to have the bike on the sidestand. Seems to me if someone doesn't know enough to have the bike on a shop stand with the front wheel off the floor while assembling the fork, it'd be highly unlikely they'd have ever got the fork off in the first place.

 

There is absolutely no need whatsoever, nor have I ever seen, nor heard of any procedure that would recommend having someone tighten axle pinch bolts with someone sitting on the bike as an aid to aligning a fork.

 

The Guzzi stand allows bouncing the fork with the bike vertical and front wheel on the floor after torquing the spindle nut prior to tightening the spindle pinch bolts, just as I've described above.

What are you talking about?

Why could you not have the bike on the sidestand before fully tightening up the pinch bolts. I have managed this literally impossible feat many times!!! You are obviously misunderstanding me, or maybe I am misunderstanding you. The pinch bolts are the pairs of bolts at the bottom of the forks that clamp the axle, right?

If you tighten them up when sitting on the side stand, you are looking for trouble.

Some of us fools don't have Guzzi stands and are going to be dropping the bike off of the 2x4s that were holding it up during the front tire change, and then we are going to have to make sure the front is tightened up properly to ensure good alignment. To keep it foolproof, I thought my instructions were a fine addendum to your otherwise fine instructions. Capice?

[luhbo]

...

With dual disk brakes, this is a little easier. With fork loosely assembled, before tightening anything, using a straightedge running through the wheel laid across the top of the disks and resting against the fork tubes (I've always kept an arrow shaft in my shop for this purpose), you can sight from above the fork from the riding position along the top triple clamp to ensure the top triple is parallel with the straightedge. By tugging on the bars with the wheel clamped between your knees, you can coax it into "true".

....

 

Thanks for that

 

Hubert

[Guest ratchethack]

What are you talking about?

. . .[unfathomable]. . . Capice?

[. . . sigh . . .]