tlthehun
knight in dented armor
Daren "manimal" PMed me about my suspension setup.
Here's my reply:
Daren.
You were missed last weekend. Bring the kid(s) next time, I'm sure between everyone they will be well cared for.
I'll hopefully have a more complete answer for you about NSR50R suspension at the next race but here's what I know at this moment:
My NSR came from the factory with the fork setup totally wrong. The fork oil level was way too low, causing the front to bottom and the tire to slide.
I changed fork oil with Redline Medium synthetic and set the oil level to factory spec of 106 mm. If you were to bring me your fork legs we could make the change in less than 30 minutes for the less than $10.
Aside from the fork, I raced all of last year with completely stock suspension at standard settings.
This year, I felt more pressure to stay upright than to win races but I do want to win so I've added focus to getting the bike to work as well as possible so that I can keep a safety margin.
Before the first race, I identified the point at which the forks are bottomed with a zip tie and added another zip tie to indicate the travel that I'm using. I was very surprised to find that I was using all of the travel even in the rain. Not good. Knowing that, I kept adding spring preload that seemed to make it work better and better. If you change the oil, you should at the same time do the zip tie thing with your fork.
The problem with adding spring preload is that it wants to make the fork topout and/or the fork extend too forcefully at the top of the travel and bounce the front wheel off the ground. I was having that problem with the counterclockwise layout with the almost 180 degree turn 1 (when we have the short start in front of the smaller bleachers) when transitioning from hard left to hard right.
For Race 2, I installed the optional stiffer springs from Honda/HRC and custom mixed oil for an exactly 50% increase in viscosity with standard spec oil level of 106 mm and standard preload. With the standard preload, I found that the bike didn't want to turn so I reduced the preload to zero and added a 1/2 turn of compression damping to the shock to keep the rear end up and kept that setting the entire weekend.
Prior to Race 3, I decided to change the oil in the shock and to take advantage of my relationship with Aftershocks to have the shock dynoed, in case Phil Douglas could see something obvious that could be improved.
A box similar to Pandora's has been opened.
According to Phil and his $30,000 dyno, the stock NSR shock has a major fundamental problem. After a high speed shock compression movement, pressure builds inside the shock and there is zero rebound damping for the first bit of rebound travel, then the rebound damping suddenly kicks in.
What the tire contact patch feels is load from cornering, load from the shock extending then unload from the shock rebound suddenly kicking in. If the shock was perfect, the tire would get loaded to exactly the cornering force and stay there.
Now that I know, it's clear to me that I've been riding around a problem.
Kinda pointless to do it with a stock NSR shock because we know the problem that it has but I wholeheartedly recommend that anyone who races a motorcycle have his shock dynoed just to see where they're at. It'll be the amongst the best $25 you've ever spent.
Phil's very confident that the stock NSR50R shock can be fixed but he couldn't do anything in time for Race 3. We changed the oil from 5 weight to 2 1/2 weight and, using the dyno, identified a combination of adjuster settings that would make the shock behave as close to normally as possible.
Race 3's layout is normally my favorite. Essentially missing practice on Saturday (had 5 laps) and changing my shock settings completely messed with my confidence. After a couple of sessions I've alway been able to hold the throttle wide open from the exit of the right turn after the bus stop through the sweeper but Sunday, I didn't complete one lap without backing out of the throttle. It wasn't that the shock was working horribly, it's that the math had changed from knowing that setup A means wide open through the sweeper to I'm not so sure. In light of my crashing problems last year, I didn't want to take chance in front of Matt and the world and I don't actually like crashing.
Between the shock, fork and no practice, I changed one setting or another before every race on Sunday. By the mains, I had pretty much refocused on attention to my riding rather than deciding whether the suspension change was an improvement or a hinderence.
The lesson for now is if the bike's not doing something wrong enough to clearly identify and solve, leave it alone, especially on race day.
Hopefully before next race, I will spend a Monday testing suspension and chassis setup hopefully with an Aftershocks tuned shock. I'll know a lot more then.
For now, all NSRs should change the oil in the fork and set the oil level. Just about maxing out the compression damping to 1/16 of a turn out and 1/2 to 1 turn on the rebound gives it the best looking damping curve. Increasing the compression helped the rebound damping kick in earlier, increasing the rebound makes the initial compression damping stiffer.
My NSR momentarily is setup as follows:
fork springs: HRC 0.55 kg/mm
fork oil: Redline mixed to 45.6 cSt @ 40 degrees centigrade
fork oil level: 106 mm
fork height: 9 mm
fork preload: 1 1/2 turns
shock spring: stock 18.5 kg/mm
shock oil: Redline ExtraLight 9.8 cSt
shock spring length: 102 mm
shock pressure: 160 psi
Tom
Here's my reply:
Daren.
You were missed last weekend. Bring the kid(s) next time, I'm sure between everyone they will be well cared for.
I'll hopefully have a more complete answer for you about NSR50R suspension at the next race but here's what I know at this moment:
My NSR came from the factory with the fork setup totally wrong. The fork oil level was way too low, causing the front to bottom and the tire to slide.
I changed fork oil with Redline Medium synthetic and set the oil level to factory spec of 106 mm. If you were to bring me your fork legs we could make the change in less than 30 minutes for the less than $10.
Aside from the fork, I raced all of last year with completely stock suspension at standard settings.
This year, I felt more pressure to stay upright than to win races but I do want to win so I've added focus to getting the bike to work as well as possible so that I can keep a safety margin.
Before the first race, I identified the point at which the forks are bottomed with a zip tie and added another zip tie to indicate the travel that I'm using. I was very surprised to find that I was using all of the travel even in the rain. Not good. Knowing that, I kept adding spring preload that seemed to make it work better and better. If you change the oil, you should at the same time do the zip tie thing with your fork.
The problem with adding spring preload is that it wants to make the fork topout and/or the fork extend too forcefully at the top of the travel and bounce the front wheel off the ground. I was having that problem with the counterclockwise layout with the almost 180 degree turn 1 (when we have the short start in front of the smaller bleachers) when transitioning from hard left to hard right.
For Race 2, I installed the optional stiffer springs from Honda/HRC and custom mixed oil for an exactly 50% increase in viscosity with standard spec oil level of 106 mm and standard preload. With the standard preload, I found that the bike didn't want to turn so I reduced the preload to zero and added a 1/2 turn of compression damping to the shock to keep the rear end up and kept that setting the entire weekend.
Prior to Race 3, I decided to change the oil in the shock and to take advantage of my relationship with Aftershocks to have the shock dynoed, in case Phil Douglas could see something obvious that could be improved.
A box similar to Pandora's has been opened.
According to Phil and his $30,000 dyno, the stock NSR shock has a major fundamental problem. After a high speed shock compression movement, pressure builds inside the shock and there is zero rebound damping for the first bit of rebound travel, then the rebound damping suddenly kicks in.
What the tire contact patch feels is load from cornering, load from the shock extending then unload from the shock rebound suddenly kicking in. If the shock was perfect, the tire would get loaded to exactly the cornering force and stay there.
Now that I know, it's clear to me that I've been riding around a problem.
Kinda pointless to do it with a stock NSR shock because we know the problem that it has but I wholeheartedly recommend that anyone who races a motorcycle have his shock dynoed just to see where they're at. It'll be the amongst the best $25 you've ever spent.
Phil's very confident that the stock NSR50R shock can be fixed but he couldn't do anything in time for Race 3. We changed the oil from 5 weight to 2 1/2 weight and, using the dyno, identified a combination of adjuster settings that would make the shock behave as close to normally as possible.
Race 3's layout is normally my favorite. Essentially missing practice on Saturday (had 5 laps) and changing my shock settings completely messed with my confidence. After a couple of sessions I've alway been able to hold the throttle wide open from the exit of the right turn after the bus stop through the sweeper but Sunday, I didn't complete one lap without backing out of the throttle. It wasn't that the shock was working horribly, it's that the math had changed from knowing that setup A means wide open through the sweeper to I'm not so sure. In light of my crashing problems last year, I didn't want to take chance in front of Matt and the world and I don't actually like crashing.
Between the shock, fork and no practice, I changed one setting or another before every race on Sunday. By the mains, I had pretty much refocused on attention to my riding rather than deciding whether the suspension change was an improvement or a hinderence.
The lesson for now is if the bike's not doing something wrong enough to clearly identify and solve, leave it alone, especially on race day.
Hopefully before next race, I will spend a Monday testing suspension and chassis setup hopefully with an Aftershocks tuned shock. I'll know a lot more then.
For now, all NSRs should change the oil in the fork and set the oil level. Just about maxing out the compression damping to 1/16 of a turn out and 1/2 to 1 turn on the rebound gives it the best looking damping curve. Increasing the compression helped the rebound damping kick in earlier, increasing the rebound makes the initial compression damping stiffer.
My NSR momentarily is setup as follows:
fork springs: HRC 0.55 kg/mm
fork oil: Redline mixed to 45.6 cSt @ 40 degrees centigrade
fork oil level: 106 mm
fork height: 9 mm
fork preload: 1 1/2 turns
shock spring: stock 18.5 kg/mm
shock oil: Redline ExtraLight 9.8 cSt
shock spring length: 102 mm
shock pressure: 160 psi
Tom
Last edited:
And tbh, I am too old (40 & older club 
) to prove myself to anyone, only to myself........I can do it! 