Please correct me on suspension tuning

Bad-mofo · 03-16-2008, 10:51 PM

I'm not happy with either of my track bikes: R6 and the KTM. Both are at the "baseline" set by other people. I finally decided to tune them both myself as I can tell the difference of a two-click damping change. I've avoided it way too long and it's absolutely not rocket science, wouldn't you agree: adjusting the suspension by feel.

First off, the sag is set correctly on both bikes, but I'm going to recheck it and adjust if necessary. My question is about the trackside tuning.

Today I identified the KTM's problem. First I thought it was a chatter, but now I'm sure the front wheel simply skips over the bumps. Which means too slow rebound. Somehow everyone I've met recommends fast compression and slow rebound. Well, until today as an old friend pointed out the obvious: the wheel needs to rebound quickly to stay on the ground. As far as the compression, the bike needs to dive under brakes for crisp turn-ins. SuMo bikes don't hesitate to turn anyway, but let's talk about roadracing in general.
So? Moderately slow compression (by everyone's personal feel and comfort) and fast rebound? This is my first question.

The second question is how does fork compression affects traction. I understand how it affects the bike geometry and handling, but what about traction. If I crank the compression to the max (slowest) is it gonna be just harsh and uncomfortable, but the tires would still stay in contact with the ground? I tend to think that mostly rebound affects traction.

What else the compression affects? Headshakes? This is my main problem with the R6.

Now after you tuned the forks how do you adjust the shock as both front and rear need to be in balance? Emulate forks setup? Slow compression/fast rebound?

seesm · 03-17-2008, 12:32 AM

I am not sure how to answer this without sounding funny...

You sound like a smart guy but to try to do it by feel... Man go for it but to just get a baseline set up is just that...

A suspension tech can get you worked out faster than you ever could. A good one anyway... Cuz they know what to ask and say to you to ensure your giving them the best info etc etc.

And what you "think" you like or is right may work ok for you but may not be great.

I have ridden LOTS of SM and a bit now of RR but I can tell you riding others bikes there are guys who are faster than me and there bike work like dogmeat.

I rode a fast buddies Yamaha 450 to see what I could to make my 450 better... His blew through the fork stroke when you grabbed a handfull of front brake (dived down like Jack Cousteau)

On top of that it was tall and stiff in the rear...

Mine is sorta SX suspension stiff all the way through and even stiffer at the very bottom... The rear end squats to get traction but not too much but it is a little bit lower in the rear to the front.

RR is a whole other deal I think...

BUt anyway off subject all my bikes are set up my official techs who do this for a living... On my 450 a Ohlins tech and on my 600's Dave Moss and his partner Jim at Catalyst Reaction Suspension. I like my bike.. Could it be better? Yeah maybe... And next time I see Dave we will try some new stuff.. But I would be scared to take my life into my own hands with not "really" knowing what is what... Careful... If your pushing it on unknown stuff you could be a tuck or highside away...

Btw headshake... Do you have a stabilizer on it? if not GPR... A really set up bike will get very little headshake so I set up prior to bolting it on and then get it close and bolt on the stabilizer.

The shock can affect the headshake as well...

testing with Honda on a mx track years ago the forks felt like sh*t and I said to Eric Crippa one of Honda's big dog test guy what was up and he went to teh shock.. I said "Hey no the forks are the issue" He said just try this and darn it wouldn't you know the bike worked even better... On your Ktm what clamp do you have... On my KTm Sm bike I had... the stock 20mm clamp chattered like crazy I put the 12mm off set and it rocked at that point...

Bad-mofo · 03-17-2008, 08:21 AM

The thing is I'm not happy with the "baseline" and after counting the clicks it was right in the middle. I have a steering damper and I cranked it up, but IMO it's a band-aid solution to headshakes. If Dave Moss wasn't in NorCal, I'd go to his shop. he set up a couple of my bikes and they felt great, but I was slow then, so it wouldn't matter. The suspension tech I trust 100% - Dave C. from Chassis Dynamics has retired. Maybe I can try talking to his buddy Charles.

Upon the observation by a friend he said the back on my R6 is too soft: it squats too quickly. He said the same about the front. His bike (set up by Jeff Tigert) is the opposite: hard to push, but rises back very quickly. Both front and rear.

In this thread I'm looking primarily for the suspension explained and particularly how to set up the rear as I think I understand how the front works.

What is the clamp? Lower triple clamp, upper triple clamp? Or the brace you put on the old-style (not inverted) forks?

JakeR1 · 03-17-2008, 08:33 AM

Alex, if you're getting nasty headshake, try adding rear compression. I know it sounds weird, but it works.

Apart from that, Dave Moss explains way better than I ever could, most of what I know I learned from him. Check out his tuning page, it might give some more insight.

Feel The Track! - motorcycle suspension tuning, hydraulics optimized

Bad-mofo · 03-17-2008, 08:45 AM

Thanks, Matt. How's your hand? I've read all of Dave's articles and everything else I could find on the Web. The headshake is not nasty, but I've never had at those spots: the apex of the next turn after the Blind Hills (at BW) and the bump on the straightaway between T2 and T3. as far as the Wheelie Bump, I short shift to third there, so I'm fine. And I was running 2:18 - pretty slow.

JakeR1 · 03-17-2008, 12:30 PM

Quote:

Originally Posted by Bad-mofo

Thanks, Matt. How's your hand? I've read all of Dave's articles and everything else I could find on the Web. The headshake is not nasty, but I've never had at those spots: the apex of the next turn after the Blind Hills (at BW) and the bump on the straightaway between T2 and T3. as far as the Wheelie Bump, I short shift to third there, so I'm fine. And I was running 2:18 - pretty slow.

I would add compression in the rear then. It worked great for me.

seesm · 03-17-2008, 09:09 PM

Have you tried getting Daves 2 videos? They offer almost too much info...
Waaay cool...

Jotaro · 03-18-2008, 01:53 AM

Alex, if you're in OC why not go to cyclemall.net? They're partners with Dave Moss as Catalyst Reaction's SoCal base (maybe own by now).

Hit 'em up (Tige) and have your suspension set up by them, so then the next time you're at the track just fiddle around with the rebound damping (so to speak) for fine tuning.

seesm · 03-20-2008, 02:32 AM

Own Catalyst? Come on now that is how rumors get started... Dave owns it... He has brought people in to help out in certain areas and to ensure his vasy customer base is taken care of... He has people doing this that will everyone money and things he can not do on a regular basis... As most fo us knwo he is the track guy to make sure your bike is doing what it is supposed to be doing...

Jotaro · 03-20-2008, 07:51 AM

Quote:

Originally Posted by seesm

Own Catalyst? Come on now that is how rumors get started... Dave owns it... He has brought people in to help out in certain areas and to ensure his vasy customer base is taken care of... He has people doing this that will everyone money and things he can not do on a regular basis... As most fo us knwo he is the track guy to make sure your bike is doing what it is supposed to be doing...

Never meant to start rumors.

SoCalSportbikes - General Sportbike Discussion - Anyone Have: Introduction to suspension with Dave Moss DVD?

03-16-2008, 10:51 PM	#1
Bad-mofo Canyon Carver Join Date: Mar 2005 Location: Aliso Viejo, CA Bikes: 03 R6, 04 R1, 06 450SMR Age: 36 Posts: 549 iTrader: (0) Rep Power: 4 (16)	Please correct me on suspension tuning I'm not happy with either of my track bikes: R6 and the KTM. Both are at the "baseline" set by other people. I finally decided to tune them both myself as I can tell the difference of a two-click damping change. I've avoided it way too long and it's absolutely not rocket science, wouldn't you agree: adjusting the suspension by feel. First off, the sag is set correctly on both bikes, but I'm going to recheck it and adjust if necessary. My question is about the trackside tuning. Today I identified the KTM's problem. First I thought it was a chatter, but now I'm sure the front wheel simply skips over the bumps. Which means too slow rebound. Somehow everyone I've met recommends fast compression and slow rebound. Well, until today as an old friend pointed out the obvious: the wheel needs to rebound quickly to stay on the ground. As far as the compression, the bike needs to dive under brakes for crisp turn-ins. SuMo bikes don't hesitate to turn anyway, but let's talk about roadracing in general. So? Moderately slow compression (by everyone's personal feel and comfort) and fast rebound? This is my first question. The second question is how does fork compression affects traction. I understand how it affects the bike geometry and handling, but what about traction. If I crank the compression to the max (slowest) is it gonna be just harsh and uncomfortable, but the tires would still stay in contact with the ground? I tend to think that mostly rebound affects traction. What else the compression affects? Headshakes? This is my main problem with the R6. Now after you tuned the forks how do you adjust the shock as both front and rear need to be in balance? Emulate forks setup? Slow compression/fast rebound?

03-17-2008, 12:32 AM	#2
seesm Canyon Carver Join Date: Jan 2007 Location: Auburn, California Bikes: (2) 2007 R6's, lots of minibikes and a Bobcat ready to work... Posts: 833 iTrader: (1) Rep Power: 2 (13)	I am not sure how to answer this without sounding funny... You sound like a smart guy but to try to do it by feel... Man go for it but to just get a baseline set up is just that... A suspension tech can get you worked out faster than you ever could. A good one anyway... Cuz they know what to ask and say to you to ensure your giving them the best info etc etc. And what you "think" you like or is right may work ok for you but may not be great. I have ridden LOTS of SM and a bit now of RR but I can tell you riding others bikes there are guys who are faster than me and there bike work like dogmeat. I rode a fast buddies Yamaha 450 to see what I could to make my 450 better... His blew through the fork stroke when you grabbed a handfull of front brake (dived down like Jack Cousteau) On top of that it was tall and stiff in the rear... Mine is sorta SX suspension stiff all the way through and even stiffer at the very bottom... The rear end squats to get traction but not too much but it is a little bit lower in the rear to the front. RR is a whole other deal I think... BUt anyway off subject all my bikes are set up my official techs who do this for a living... On my 450 a Ohlins tech and on my 600's Dave Moss and his partner Jim at Catalyst Reaction Suspension. I like my bike.. Could it be better? Yeah maybe... And next time I see Dave we will try some new stuff.. But I would be scared to take my life into my own hands with not "really" knowing what is what... Careful... If your pushing it on unknown stuff you could be a tuck or highside away... Btw headshake... Do you have a stabilizer on it? if not GPR... A really set up bike will get very little headshake so I set up prior to bolting it on and then get it close and bolt on the stabilizer. The shock can affect the headshake as well... testing with Honda on a mx track years ago the forks felt like sh*t and I said to Eric Crippa one of Honda's big dog test guy what was up and he went to teh shock.. I said "Hey no the forks are the issue" He said just try this and darn it wouldn't you know the bike worked even better... On your Ktm what clamp do you have... On my KTm Sm bike I had... the stock 20mm clamp chattered like crazy I put the 12mm off set and it rocked at that point... __________________ MotoElite.com / Snap Dragon Photos / Fast50s.com / Slide Motorsports / Advanced Metal Finishing & Powder Coating / greateryamaha.com / Bell Helmet / leovinceusa.com / Gpr Stabilizer / Mike Wymer Perf. / Kevin Greene /Oury Grip / www.sportbikeswest.com / Catalyst Reaction Susp / Elka Shocks / Race Tech / Inhouse Susp / two2cool / Works Connection / motionpro.com / Tech Spec / SupermotoUSA / e-racings.com / axialvideo.com / bickleracing.com / Got Moto Parts

03-17-2008, 08:33 AM	#4
JakeR1 Club Racer Join Date: Mar 2006 Location: SD Bikes: '99 R1 "The Disintegrator" '07 R1, '04 R6 "Slow" Age: 25 Posts: 2,517 iTrader: (1) Rep Power: 5 (62)	Alex, if you're getting nasty headshake, try adding rear compression. I know it sounds weird, but it works. Apart from that, Dave Moss explains way better than I ever could, most of what I know I learned from him. Check out his tuning page, it might give some more insight. Feel The Track! - motorcycle suspension tuning, hydraulics optimized __________________ Just call me Matt... www.msf-usa.org

03-17-2008, 08:45 AM	#5
Bad-mofo Canyon Carver Join Date: Mar 2005 Location: Aliso Viejo, CA Bikes: 03 R6, 04 R1, 06 450SMR Age: 36 Posts: 549 iTrader: (0) Rep Power: 4 (16)	Thanks, Matt. How's your hand? I've read all of Dave's articles and everything else I could find on the Web. The headshake is not nasty, but I've never had at those spots: the apex of the next turn after the Blind Hills (at BW) and the bump on the straightaway between T2 and T3. as far as the Wheelie Bump, I short shift to third there, so I'm fine. And I was running 2:18 - pretty slow. Last edited by Bad-mofo : 03-17-2008 at 08:47 AM.

03-17-2008, 09:09 PM	#7
seesm Canyon Carver Join Date: Jan 2007 Location: Auburn, California Bikes: (2) 2007 R6's, lots of minibikes and a Bobcat ready to work... Posts: 833 iTrader: (1) Rep Power: 2 (13)	Have you tried getting Daves 2 videos? They offer almost too much info... Waaay cool... __________________ MotoElite.com / Snap Dragon Photos / Fast50s.com / Slide Motorsports / Advanced Metal Finishing & Powder Coating / greateryamaha.com / Bell Helmet / leovinceusa.com / Gpr Stabilizer / Mike Wymer Perf. / Kevin Greene /Oury Grip / www.sportbikeswest.com / Catalyst Reaction Susp / Elka Shocks / Race Tech / Inhouse Susp / two2cool / Works Connection / motionpro.com / Tech Spec / SupermotoUSA / e-racings.com / axialvideo.com / bickleracing.com / Got Moto Parts

03-17-2008, 08:21 AM	#3
Bad-mofo Canyon Carver Join Date: Mar 2005 Location: Aliso Viejo, CA Bikes: 03 R6, 04 R1, 06 450SMR Age: 36 Posts: 549 iTrader: (0) Rep Power: 4 (16)	The thing is I'm not happy with the "baseline" and after counting the clicks it was right in the middle. I have a steering damper and I cranked it up, but IMO it's a band-aid solution to headshakes. If Dave Moss wasn't in NorCal, I'd go to his shop. he set up a couple of my bikes and they felt great, but I was slow then, so it wouldn't matter. The suspension tech I trust 100% - Dave C. from Chassis Dynamics has retired. Maybe I can try talking to his buddy Charles. Upon the observation by a friend he said the back on my R6 is too soft: it squats too quickly. He said the same about the front. His bike (set up by Jeff Tigert) is the opposite: hard to push, but rises back very quickly. Both front and rear. In this thread I'm looking primarily for the suspension explained and particularly how to set up the rear as I think I understand how the front works. What is the clamp? Lower triple clamp, upper triple clamp? Or the brace you put on the old-style (not inverted) forks?

03-18-2008, 01:53 AM	#8
Jotaro Newbie Join Date: Jun 2006 Location: Irvine, CA Posts: 39 iTrader: (0) Rep Power: 0 (10)	Alex, if you're in OC why not go to cyclemall.net? They're partners with Dave Moss as Catalyst Reaction's SoCal base (maybe own by now). Hit 'em up (Tige) and have your suspension set up by them, so then the next time you're at the track just fiddle around with the rebound damping (so to speak) for fine tuning.

03-20-2008, 02:32 AM	#9
seesm Canyon Carver Join Date: Jan 2007 Location: Auburn, California Bikes: (2) 2007 R6's, lots of minibikes and a Bobcat ready to work... Posts: 833 iTrader: (1) Rep Power: 2 (13)	Own Catalyst? Come on now that is how rumors get started... Dave owns it... He has brought people in to help out in certain areas and to ensure his vasy customer base is taken care of... He has people doing this that will everyone money and things he can not do on a regular basis... As most fo us knwo he is the track guy to make sure your bike is doing what it is supposed to be doing... __________________ MotoElite.com / Snap Dragon Photos / Fast50s.com / Slide Motorsports / Advanced Metal Finishing & Powder Coating / greateryamaha.com / Bell Helmet / leovinceusa.com / Gpr Stabilizer / Mike Wymer Perf. / Kevin Greene /Oury Grip / www.sportbikeswest.com / Catalyst Reaction Susp / Elka Shocks / Race Tech / Inhouse Susp / two2cool / Works Connection / motionpro.com / Tech Spec / SupermotoUSA / e-racings.com / axialvideo.com / bickleracing.com / Got Moto Parts

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