Suspension Upgrade in 2 parts

[mcromo44]

Honda ng,
What compression damping adjustment does your Ohlins have?
Is there any, or just rebound adjusment?
The reason I ask is that a 919, even more so a lightly sprung 919, responds well to lots of low speed compression damping re resisting the inherent squat tendency of the 919. I run radically different settings between road and track.
When my Penske was in its original 2 way configuration with hi speed compr and rebound adjustment, I ended up running the hi speed 4/6ths of a turn out from full hard.

[honda ng gingsa]

Oops, i switched my front and rear free sag numbers

Rear 11 mm
Front 29 mm

I seem to be in mid-range (5-15) for the rear but my front number is on the recomended limit (20-30).

[honda ng gingsa]

Originally Posted by mcromo44

Honda ng,
What compression damping adjustment does your Ohlins have?
Is there any, or just rebound adjusment?
The reason I ask is that a 919, even more so a lightly sprung 919, responds well to lots of low speed compression damping re resisting the inherent squat tendency of the 919. I run radically different settings between road and track.
When my Penske was in its original 2 way configuration with hi speed compr and rebound adjustment, I ended up running the hi speed 4/6ths of a turn out from full hard.

Low speed compression, rebound adjustments...haven't touched anything.

[mcromo44]

Originally Posted by honda ng gingsa

Oops, i switched my front and rear free sag numbers

Rear 11 mm
Front 29 mm

I seem to be in mid-range (5-15) for the rear but my front number is on the recomended limit (20-30).

The manual is not written for 919s.

Do NOT run 10 mm free sags on 919s that do not have adjustable shock length, especially on softer springs. (rear chassis height will be too low and swing arm angle gets even worse)
Trust me on this point and save yourself time and grief.
Set the rear free to 5, and see what you get for rider.
Also.
11 mm free and 37 rider does not sound correct for a 1028 # spring on a 919 and someone of your weight. I'd expect at least 40 free.
How many helpers are you using ? 2 ?
Are the exact same measuring points used every time?
How repeatable are your rear measurements ?
All with in a 2-3 mm range ?
What is the difference between your averaged "lift and gently release" and "push down and gently release" numbers ?
Are you doing all the measurements will all of the damping adjusters fully backed out ?

[honda ng gingsa]

Originally Posted by mcromo44

The manual is not written for 919s.

Do NOT run 10 mm free sags on 919s that do not have adjustable shock length, especially on softer springs. (rear chassis height will be too low and swing arm angle gets even worse)
Trust me on this point and save yourself time and grief.
Set the rear free to 5, and see what you get for rider.
Also.
11 mm free and 37 rider does not sound correct for a 1028 # spring on a 919 and someone of your weight. I'd expect at least 40 free.
How many helpers are you using ? 2 ?
Are the exact same measuring points used every time?
How repeatable are your rear measurements ?
All with in a 2-3 mm range ?
What is the difference between your averaged "lift and gently release" and "push down and gently release" numbers ?
Are you doing all the measurements will all of the damping adjusters fully backed out ?

Damping adjusters are where they were as it came outa the box (midway). Didnt realize i shud back them out. I'm gonna redo my numbers more carefully tomorrow with an average of push and release and pull and release and see what I get...damn, I shoulda listened more in algebra! So what's the formula to set 5 mm free sag?

[mcromo44]

Originally Posted by honda ng gingsa

Damping adjusters are where they were as it came outa the box (midway). Didnt realize i shud back them out. I'm gonna redo my numbers more carefully tomorrow with an average of push and release and pull and release and see what I get...damn, I shoulda listened more in algebra! So what's the formula to set 5 mm free sag?

1
Get the rear of the bike off the ground by blocking up the chassis (not the swingarm) so the wheel is hanging with at least a bit of clearance to the ground.
Get your reference length measurement from the two good measuring points you are going to use. You want a vertical line that is fairly close to the centreline of the rear wheel's axle. (I measure on the brake disc side of the bike, and use an edge on the wheel mounting area of the swing arm for the lower point, and a marked position on the undertray inside the pipes for the upper point.
Just make sure whatever points are used are same ones used every time.)
This way it is impossible for the rear not to be fully extended, and no one has to be lifting the rear, so you know the measurement you get is 100% correct.

2
Back out the damper adjusters all the way, but be sure to count the clicks or count the turns as you back out, so you easily return them to the same place.
(suggest that whatever changes you later make are done in terms of referencing your "click count" as being out from full hard. "12 out" for example.)

3
Get the bike of the blocks.
If you have a racestand, you can first do a ballpark Free Sag setup without needing a helper. (you do your own gently released ups and downs and then do your own measurements.)
Whether it is turning the spring collar or using a remote preload adjuster, you either add or reduce the spring preload so the length you measured in 1 above, is 5 mm less.
Half tank of gas is ideal, but don't worry about it being more or less - it's not a lightweight race bike !

4
Now have your two helpers handy.
Do not use front or back brake to hold the bike ,have the bike in neutral.
Fine tune your Free sag and get it to 5 mm.
Then measure the resultant Rider Sag. I have gone back to my 1000 # spring notes and found 5 mm Free / 34 mm Rider and I'm only a few pounds heavier than you. Do not go with less than 5 mm of Free Sag in an effort to get less Rider Sag, otherwise you're rear travel top out will be too stiff and have no compliance.
5
Return your damping adjusters to their original settings.
6
Lucky you re having low speed compression adjustment. That will be your friend at the track and you will be making it firmer from mid point and never softer. Watch out on rebound, just right is perfect, less firm is OK, BUT too much is very bad and can get you into serious trouble from "packing".

7
IF you want to run a soft top out style Free Sag of 10 mm or so, you need an adjustable length shock so you can get the lost chassis height and swingarm angle back AND you need a stiffer spring, absolute minimum 1100 # and 1200 # better. All this in terms of emphasis on track time.
8
I have done one man Free Sag setup with a race stand and the front wheel blocked up to keep the bike level. I have done two man Rider setup, again with the race stand and the front wheel blocked up to keep the bike level. The results are not bad, and for sure get you in the zone, but proper 3 man work does give more accurate results. The Free Sag one man set up actually works quite well.

[hornet641]

Hi guys I'm a newbie here & took delivery of an '07 Hornet 900 yesterday. Went out for about 15 miles before getting the bike up on the table to swap the bars for the ultra lows that came off my previous CB 13. The Ohlins shock from Kyle went in after the bars were finished. Went out this afternoon & as expected just these two mods have made a massive difference. I would be interested to know the length of spacer tube should be used with 1kg fork springs. I understand this preloads the spring. I am 200lb kitted for riding. Thanks guys

[rmb]

Originally Posted by hornet641

Hi guys I'm a newbie here & took delivery of an '07 Hornet 900 yesterday. Went out for about 15 miles before getting the bike up on the table to swap the bars for the ultra lows that came off my previous CB 13. The Ohlins shock from Kyle went in after the bars were finished. Went out this afternoon & as expected just these two mods have made a massive difference. I would be interested to know the length of spacer tube should be used with 1kg fork springs. I understand this preloads the spring. I am 200lb kitted for riding. Thanks guys

My opinion. but I think 1kg springs will be too much. I'm 240 w/gear and just installed .925's and am thinking of going to .90's. As for spacer length, oal of OEM springs and spacers should = oal of aftermarket springs and spacers. Disclaimer: I'm no suspension pro but from everything I've read this is true.

[zaq123]

Originally Posted by rmb

My opinion. but I think 1kg springs will be too much. I'm 240 w/gear and just installed .925's and am thinking of going to .90's. As for spacer length, oal of OEM springs and spacers should = oal of aftermarket springs and spacers. Disclaimer: I'm no suspension pro but from everything I've read this is true.

what he said. You can make them longer to get the initial preload but you need to know what your sag #s are with said springs before experimenting with it. Obviously you don't know as your springs are not installed yet so I would just follow what rmb said above.

[mcromo44]

Originally Posted by hornet641

Hi guys I'm a newbie here & took delivery of an '07 Hornet 900 yesterday. Went out for about 15 miles before getting the bike up on the table to swap the bars for the ultra lows that came off my previous CB 13. The Ohlins shock from Kyle went in after the bars were finished. Went out this afternoon & as expected just these two mods have made a massive difference. I would be interested to know the length of spacer tube should be used with 1kg fork springs. I understand this preloads the spring. I am 200lb kitted for riding. Thanks guys

1.0s are way too stiff unless you want a buckboard ride.
Even more so in terms of the rear spring rate I'll bet you have, likely a 1028 # /inch
You are only 10 # more than I am.
I am running 0.925s with 14 mm of internal preload and my setup is track oriented.
0.90s to 0.925 max.
I would not use more than 15 mm of internal preload.
How did you pick 1.0s for your 919 ?
Simple spring tables or on line calculators are not adequate alone.
One factor in 919 front spring selection is the severe stiction.
Overly stiff springs + Stiction = Excessively harsh front end that lacks compliance and has uncomfortable road manners.

[hornet641]

Thanks fellas kind of what I expected. Threw 1kg out there to see what would come back. Can't fault your reasoning so I'll start with .90 linear springs & see how it feels. I have a mega suspension guy near me with WSB & TT teams on his long list of experience so we'll have the shim stack apart & do our best to cure some of the much talked about stiction. This bike's a keeper so this is to get me through til next season as I'm heading towards MDtoney's impressive RC51 front end. I'll experiment with fork oil grades & air gaps also. Thanks again.

[mcromo44]

Originally Posted by hornet641

Thanks fellas kind of what I expected. Threw 1kg out there to see what would come back. Can't fault your reasoning so I'll start with .90 linear springs & see how it feels. I have a mega suspension guy near me with WSB & TT teams on his long list of experience so we'll have the shim stack apart & do our best to cure some of the much talked about stiction. This bike's a keeper so this is to get me through til next season as I'm heading towards MDtoney's impressive RC51 front end. I'll experiment with fork oil grades & air gaps also. Thanks again.

I am very sure that the stiction problem is heavily due to the fork seals.
Simply put, they are too good.
They are 100,000 km + fork seals, and rickard is proof of this.
Original oil from day one, original seals, forks are bone dry, which is too dry in terms of reduced stiction.
Be sure to put suitable grease between the upper and lower lips when you assemble.
The bushings are also a factor to a certain degree, but I see the seals as being the major issue.