Brand-new Scura

[Scud]

A black plate V11! Who'da thunk it?

 

Docc - you've got the California lingo down. FYI to others: When 1960s cars are advertised for sale in California, a "black plate" car generally signifies one that has been continuously registered, and is more "original" than other cars that have had their plates "updated." It's pretty cool that our State government re-released these plates for collectors - and fortuitous timing for Scura-darkeners. Let's see... 20,000 legacy plates times $40 a year extra on the renewal fee... that won't quite balance the California budget, but I'm happy to do my part (because I get a bauble).

 

Meanwhile, supplies arrived in various boxes today. 

 

 

The attentive reader will notice that one of these things may require significant modification to install - or I could put it on the Honda, which has been getting very jealous of all the attention the Scura's been getting.

 

Public Service Announcement 

If you carry a tire repair kit one of two things will happen: 1) you will never need it, or 2) you will be the hero when your buddy (or a stranger) picks up a nail. If you don't carry said kit... well, that's when you start to see the vultures circling overhead. This one fits (with some persuasion) in the tail section. Four CO2 canisters ought to fill a back tire. Five pieces of beef jerky is more than I can eat during a tire repair; it looks rubbery, but it should keep the vultures distracted.

[Scud]

Suspension update: Springs are in spec for me.     Details follow:

 

 

This was an important lesson for me - to get the spring sag adjusted correctly before doing anything else. This conversation has been really helpful - and so were the guys at Kyle Racing. They even sent me the factory spec sheet for the forks (FG8470), which said the recommended stock setting for the fork spring pre-load is 13 (out of 15). Mine was at 0 (no pre-load) when I got it. I previously increased preload by 11 turns and it made a huge difference. So I turned it 2 more and got these measurements:

 

Rear Shock:

• R1-R2 = 10mm. This is sag WITHOUT rider. The target is 5-15mm. (it was previously 14 when the front was set to 0 turns - but now it is exactly mid-range)
• R1-R3 = 32mm. This is sag WITH rider. The target is 30-40mm (previously 30)
• I made no change to the rear spring - but increasing preload on the front by so much appears to have allowed the back to compress appropriately. 

Front Fork:

• F1-F2 = 30mm. This is sag WITHOUT rider. The target is 25-30mm (previously 41)
• F1-F3 = 41mm. This is sag WITH rider. The target is 35-50mm (previously 52)
• Forks now at 13 turns pre-load

 

Fork Position:

Baldini suggested moving the forks up so three rings are showing. GuzziMoto said that decreases rake, potentially decreasing trail and stability for the sake of quick steering and miniscule weight gain to the front.  My forks were already set with a touch over 2 rings showing (not sure what factory spec is).  Maybe I'll play with the fork height a bit later - just to see if I can tell the difference or not.

 

Ride Report:

I took the same loop as after my last adjustment, still really pleased. I can feel the front and back working, it compresses, unweights, and resettles nicely over crests - and it deals competently with all the irregularities of the bumpy-twisties. As for me, I am happy as can be - and feeling much relieved that all four sag specs are within range.

 

FYI on tools - I have not changed the fork oil yet (getting there...) However, I did get the black cap from Kyle racing, which is a very tight fit. Also picked up a fork oil level tool - this looks like the way to do it. In fact, the Ohlins spec sheet does not even list the oil volume - only the oil level (105mm). FWIW the spec sheet also calls for 12 clicks on both compression and rebound.

[docc]

Seems the Öhlins oil level tool might be more sophisticated than the Marzocchi version . . .

[Scud]

That's funny.  I didn't get an Ohlins tool for the oil level, - just a generic one from the local Cycle Gear shop. It looks like you put in a straw (with measurements on it), clamp it at the right depth and use the syringe to draw out everything above that depth. Simple, quick, and precise. 

 

I paid someone to do my dirt bike forks last time - and they're probably ready for another change. So I figure this tool will get some use.

[bikelee]

I want to thank you guys for this treatise on suspension adjustment. I'm gonna use this treatise on my Rossa. I think it handles pretty good now, but i think  I can always make it a little better. Unfortunately it is like 15f degrees here in Upstate NY. Will have to try this stuff in the Spring. Be safe out there. 

 

 

 

Leon (OLD GITT)

[Camn]

Factory spec sheet for the forks (FG8470), which said the recommended stock setting for the fork spring pre-load is 13 (out of 15).

 

 

I have the small supplement booklet “V11 Scura owners manual”, which came with the red "main manual". It is actually only the same “Öhlins” -part, which is also on the later Workshop Manual. This “original Scura manual” also states: “Spring preload 13 turns, i.e. 13 mm.

But… the “Italian thing” is, that if you compare the Guzzi instructions to the original Öhlins FG43 owners manual, there is a critical mistake on the Guzzi manual about the rebound and compression adjustment. Right is: rebound adjustment screw is “B” up at the triple clamp, in the middle of the Öhlins shock. Compression adjustment screw is “C” down at the front wheel shaft level. The Guzzi instructions states the opposite.

[Camn]

My forks were already set with a touch over 2 rings showing (not sure what factory spec is)

Here is the original text of the Scura Öhlins supplement booklet:

“Sliders should come out from the handle hub by about 2 mm, that is up to the first round mark on the very slider".

[Scud]

@Leon: I'm glad this is helpful. Apparently, we love suspension talk; why stop now?  In fact, today we merge our language and suspension settings topics...

 

@Camn: Thanks for those pages. I would like a scan of the whole thing if you don't mind; I'll send you a PM with my e-mail. I attached the Öhlins Front Fork Specification Card, which I also sent to Jaap. He said he will add it to the file-share section next time he does an update.

 

Ohlins fork FG8470_Factory Spec Card.pdf

 

Now that sag is correct, I was curious to see where everything else was set. I have let go of my assumption that my Scura's suspension was untouched and remained at factory settings. Now my assumption is that the PO adjusted everything (and he didn't even ride it more than 200 miles  ).

 

Therefore, my new task is to restore all suspension settings to factory specifications. I further assume that all Öhlins adjusters should be turned clockwise to close - and counter clockwise to open. That is what the manuals say, but I am being extra careful about my assumptions given recent experience.

 

Forks: 

Compression (bottom adjusters) were set at 14 of 20. I set them to 12.

Rebound (top adjusters) were set at 7 of 20. I set them to 12.

I will return the forks height to factory spec (one ring showing) after I do the oil change.

 

Steering Damper:

It was set at 14 of 20. I turned it to 12. (but I don't know the factory spec)

 

Shock:

Compression (adjuster knob on reservoir) was set at 8 of 20. I set it to 12. (but I don't know the factory spec)

Rebound (black ring adjuster by lower shock mount) was set at 40 of 40 (totally open). I set it to 24. (but I don't know the factory spec)

Shock absorber length: I now assume that this has also been adjusted away from spec - so I am hoping to learn the specified length. My guess is that the "lower the front, raise the back" method (that GuzziMoto described) was followed.

 

I think I have now learned every possible adjustment point for the suspension.

 

My assumptions for the damper and shock settings are based on the Swedish concept of "lagom" and the very Swedish-sounding title in one of the Öhlins manuals: "Everything Must Harmonize." Isn't that a great command for a suspension manual? 

 

No test-ride today - rain. I'm not expecting any pity from snow-bound members - in fact, California is still in drought, so the rain is welcome.

 

Skål    

[docc]

 

I think I have now learned every possible adjustment point for the suspension.

 

Oh, wait . . . choose your fork oil not on SAE oil weight, but CentiStokes@(temperature). Good stuff here to keep you (more) busy, by PeterVerdone.

[Baldini]

Scud: Re. "shock absorber length": Do you mean changing sag by adjusting spring  preload? Shock length is fixed, there's no ride height adjustment other than by altering preload. If you now have sag within range you're fine. Reduce/increase sag by more/less preload.

 

Setting sag is basic, first step.

You can alter damping settings to suit yourself.  A good place to start is in the middle of the adjustment range, as you are doing - I wouldn't worry about "factory settings". If you ride the same stretch of road over a few times, & vary damping settings by two or three clicks each time (changing one setting at a time) you'll figure how each adjuster affects bike behaviour. Ohlins adjusters are very effective & after a while you'll be able to notice even very small adjustments. One click makes a difference.

There is a big range of adjustment & the danger is that it can be set way off correct. But once you've figured what everything does, you can tailor damping characteristics to where & how you're riding.

 

I think a Guzzi has too much weight on the back & transferring weight onto the front helps handling in the twisties. As guzzimoto says, raising the forks in the triple clamps drops front, steepens rake & makes for quicker steering. 

I don't know how much each of these factors contributes to the change in handling, I suspect both are amplified by increased weight transfer under braking & into corner entry & through the first part of a corner. It feels easier to hold a line, & reduces the tendency for it to run wide.

It also helps in getting your bodyweight further forward. Being able to hold the line & put weight over the front makes the bike feel more planted in the corner.

This is just how it feels to me. I'm interested how it works but I really don't know the physics of it. I could be confusing different things -  maybe someone else with more understanding can explain.

I don't know about stability in other situations - I have not noticed any increased instability at high speeds, but then I don't tend to do high speeds, I set my bike up for twisty road handling. The Scura is a long, slack bike so it doesn't concern me unduly. But I also think Scura is big, heavy & flexible & if you push it too hard, no amount of suspension twiddling will stop it getting out of shape.

 

Tyres also have a huge effect on handling. Different profiles have big effect on steering.

 

To qualify everything I say - I only know what I learnt messing with my bikes over the years - Scura is the first time I ever had fancy suspension on a bike - previously I'd never heard of "sag": I just thought the forks & shock where there to hold the bike off the ground. There are far more qualified people here to explain it all, & point out where I'm wrong. This is just stuff I've figured out that works for me, we all ride different & maybe others will have different preferences.

 

Good luck. KB

[Scud]

@Docc -

 

Wow, there's always another level. I think I'll stick with the oil I already bought. You are right that oil type and oil level (aka air gap), are other adjustments, along with tire size, shape, tread, pressure, total weight of rider(s) and gear, etc... not to mention road conditions and highly subjective opinions about what constitutes "better" handling for various purposes (touring, sport-riding, commuting).  Throw in some confusing language and inconsistent use of terms and it's no wonder that the suspension topics go on forever.............. 

 

@Baldini -

 

I'm following in your footsteps with the Scura. It's also my first time having such a nice suspension on a street bike (I actually felt a bit obligated to learn how to use it properly).

 

Re factory settings - my intent is not to set them and leave them there, rather, it is first to ride it "as designed" and use that as the base-point for my adjustments. The PO clearly made a lot of adjustments. So far, putting them back to spec has resulted in improvements for me. I think there will be a hex-wrench in my jacket pocket for a while... so I can adjust the compression and rebound settings on the forks (the shock adjustments can be done without tools).

 

Re shock length - the attached page from the manual shows what I was talking about. However, the Scura does not appear to have an "adjustable end eye/bracket." If it did (I am speculating and trying use my new vocabulary words in sentences) it would appear to increase rake (same as lowering the forks in the triple clamp) without decreasing trail (because rear is lengthened, rather than front shortened). Anyway, there's the difference between theory (reading books) and practice (turning wrenches); I can imagine adjusting the shock length while reading the book, but when I looked again (just now) there was no nut to turn.

 

 

Re riding style - during a spirited romp through the twisties, I do tend to get forward on the seat and put more weight on the bars - I also generally use light brake pressure on the front through the corners (a trick I learned on my old BMW boxer that has served me well). I don't go "fast" either, but 90mph is frequently just going with the flow of traffic on the freeways. Sometimes I go slow and enjoy and enjoy the scenery.

 

Thanks again (to everyone) for sharing your experience. Between the manuals (as corrected) and what I've learned here, I'm about ready to claim that I am a suspension-tuning amateur - that's good enough for me.

[Baldini]

Scud, no the Scura doesn't have the adjustable lower eye. It's fixed length.

 

This stuff confuses me ...hopefully someone will correct me if I'm wrong...but my understanding is:

Dropping the nose or lifting the rear is going to increase rake & reduce trail, however you do it. It's not a product of lengthening the bike, it's the angles it presents to the ground that gives these specs. If you draw a line through the steerer tube to a point on the ground, & a line vertically thru the front wheel spindle to another point on the ground, the distance between the two points is trail. If you lift the rear or drop the front of the bike, you will bring the first point back toward the second, increasing rake & reducing trail.

 

[Scud]

Oh - looks like I didn't use my new words correctly.

 

I can't see the picture you uploaded, but a quick web search turned up this:

 

http://www.sportrider.com/art-science-fun-geometry

 

Executive summary:

• Rake = angle of the fork. Decreased rake = more vertical. Increased rake = more horizontal (think of a chopper)
• Trail cannot be directly measured on the bike. It is the distance on the ground between two points: 1) drawn from the steering head to the ground, and 2) drawn from axle center to ground. It's the amount of distance that the contact patch of the tire "trails" the input from the steering head.

I think this is what you said - but I'm saying it again in a different way to make sure I get it.

[Baldini]

Yeh, pretty much.

It's more easily understood in a drawing - dunno why you can't see the pic I put up: - just put "rake & trail" into google images search, there'll be loads.

[Zooter]

Scud, no the Scura doesn't have the adjustable lower eye. It's fixed length.

 

This stuff confuses me ...hopefully someone will correct me if I'm wrong...but my understanding is:

Dropping the nose or lifting the rear is going to increase rake & reduce trail, however you do it. It's not a product of lengthening the bike, it's the angles it presents to the ground that gives these specs. If you draw a line through the steerer tube to a point on the ground, & a line vertically thru the front wheel spindle to another point on the ground, the distance between the two points is trail. If you lift the rear or drop the front of the bike, you will bring the first point back toward the second, increasing rake & reducing trail.

 

http://www.totalmotorcycle.com/pics/rakeandtail.gif

if you leave out the forum image tag around the gif URL it will display as a blue http link that everyone can use manually. For some reason this forum auto window popup thing won't work even with popup killer turned off.