Posts
35700
Joined
7/10/2006
Location
Aliso Viejo, CA
US
Fantasy
1215th
Edited Date/Time
2/19/2018 5:28pm
This week's guest in the Vital MX Forum QNA is Jeremy Hoyer.
Jeremy got his start in the parts department at the GEICO Honda team, before moving over to wrench for Jake Weimer and Blake Wharton. At Valli Yamaha he spun wrenches for Nick Wey. Later, at Chaparral Honda, he moved into a Crew Chief/Engine Builder role for Andrew Short. He's also had a stint with American Honda as an Engine Builder for the race team. These days, he works at KYB, on everything from specs for production bikes to being a Suspension Technician for Chad Reed.
Do you have technical questions about KYB suspension? How about the differences in A Kit suspension from different suppliers? Bring your best questions, and he'll be peeking in here this week to answer them. As always, keep it respectful, and ask questions that you would like in a face-to-face meeting.
If you want to see previous Vital MX Forum QNAs, click the Forum QNA tag below the subject line. (Check below to see what it looks like.)
I've always wanted to try A-Kit Suspension, so awhile back I disregarded any sense of fiscal responsibility and bought KYB Factory Kit Suspension for my 17 Honda CRF450 after putting only 10 hours on the stock Showa Suspension. I immediately noticed better handling, increased bottoming resistance and a more confidence inspiring ride. Many on this forum would suggest I wasted my money and could have gotten the same or very close to the same performance re-valving my stock stuff. What's your opinion? Is A-Kit suspension a waste of money for a less than pro rider like me? What's your take on Ti Springs?
In case you have any suggestions for changes, I'm still running the valving and spring rates that it came with from Technical Touch. I'm a 200 lb. Vet Intermediate rider on loamy Texas MX Tracks.
Fork and shock information:
Fork (#17279)
Spring: 4.9 N/mm
Oil level: 365 ml
C: 12
R: 12
Shock (#17278)
Spring: 56 N
LC: 14
HC: 14
R: 14
R (bottom): 14
SAG: 103-105 mm
Thanks for taking the time to do this. What is your take on the KYB Free Piston mod on the stock SSS/AOS forks? If it is something you recommend, would you share any tips on hole size and location?
Thanks again
The Shop
Howdy..Hope All is Well.
DaveO
Also, what in your opinion makes the KYB SSS fork so good? They are very good.
My first inclination is to say that anyone that suggests you wasted money is envious of your shiny Kit suspension, lol. My personal opinion is that Kit suspension wasn't a waste of your money. I believe the Showa components on the current CRF450 are really good for production suspension. Revalving the Showa components would have probably yielded good results, but the nice thing about Kit components are the coatings. Coatings on suspension components make a big difference in performance and feel. Also, the billet lugs that your KYB suspension came with are a nice upgrade over the stock cast axle lugs. If you were to invest the time and money into your production stuff you may be able to rival Kit suspension but the investment would be better spent on a set of complete components in my opinion. I'd rather be riding than waiting for my outers to be coming back from Miyaki (Kashima)!
Ti springs are ok, they provide a different feel/feedback. There are some riders that prefer the feel of the Ti spring, most say that the Ti spring is livelier or more active than steel. I've also heard feedback that Ti is more comfortable than Fe (steel). A lot of suspension tuning is trying to provide a "feel" or "sensation" that the particular rider wants and in some cases the Ti spring accomplishes that. Another obvious advantage is weight, which from a technical standpoint would be the biggest reason to use one. Ti springs were in vogue for a while but seemed to have faded out. I'm sure there are still teams using them for particular reasons.
I think that if you are happy with your current setting there is no reason to go and change it. Suspension settings can be very personal so it's hard to give advice "over the phone" or in this case, computer. Without looking at the spec and getting feedback from you on the positives and negatives it would be hard to suggest anything.
At KYB we don't use the term "A-kit", it is more of a colloquial term used to describe particular suspension components. I believe that is a term made popular by Showa. At KYB we have Production, KIT, and Works. There are varying degrees to those levels of components. As it pertains to Kit suspension there is generally Enzo Racing Kit and Technical Touch Kit. Technical Touch Kit is usually ID'd by the billet aluminum lugs in your photo. Enzo Racing Kit is usually spec'd with a hard anodized cast aluminum lug. Technical Touch shocks usually come with the Integral Adjuster and Enzo Racing usually use Ross' own proprietary High Speed Adjuster. Most of the componentry between the two companies are the same, each just use slightly different parts to make them their own.
As it pertains to work, I prefer bench stuff. I really enjoyed my time as a mechanic but it is a tough job, it's not for everyone. Being a race mechanic is a big commitment and I got to a point where I didn't want to spend so much time on the road. Transitioning to a "in-house" job allowed me to reclaim some of that personal time back. I really enjoyed engine building so that was what I started to move towards. Bench work is nice because I like to work on something that you can lay out right in front of you. I still enjoy bike work very much. I have a few bikes myself and work on them regularly. I tend to enjoy bike work when it is something cool, like a restoration or something along those lines. So bike work for me now is generally a hobby activity.
I did have formal training. I went to MMI and did the Motorcycle Specialist coursework and FAST, which is Factory Authorized Suzuki Training. Prior to MMI, I worked at a motorcycle shop as a mechanic. I went to MMI with some encouragement from the shop I worked for. Mainly I was looking for a raise and we had an agreement that if I went to MMI they would rehire me upon graduation at a better rate of pay. I went on from there to work in a Honda dealership. I like to think I have good mechanical aptitude....my family owns an automotive repair business so I've been around motor vehicles all my life. I didn't grow up in the moto-mecca of Southern California so I didn't know anyone to get me "in" somewhere. I worked at the Nationals for a privateer (Jeff Northrop) and was approached by a guy named Dave Chase and he asked if I wanted a job at Pro Circuit, that's how I got started. I worked as the Amateur Support Technician at PC for 2 years before going to FC. So, maybe there was a little right place/right time but I'd like to think Dave saw that I really wanted to be a race mechanic and be good at it and he gave me a chance.
Good question. I believe the Free Piston Mod is worthwhile and do recommend it. For those who may not know, the modification is simple- drill a hole in the Free Piston for AOS (spring fork). The reason we do this is to relieve any pressure that may build up in the Free Piston Assembly. Pressure can come from the area above the piston, like when someone doesn't bleed their forks or it can come from oil passing into the piston. The hole in the piston allows this pressure somewhere to escape instead of being trapped in the piston body. This mod will save you from buying new pistons if they break (they aren't cheap). It's only something I recommend if you have your forks apart, like for a service. I don't think it's necessary to tear the forks apart just to do this. Regular bleeding is usually sufficient to keep the pistons in good condition.
I locate the hole in the center of the piston. It is personal preference if it is one or two holes. I do one big hole as opposed to two smaller ones. The hole I drill is roughly 6 mm. I use a Uni-Bit because I can mark my bit with a Sharpie to the size I want and the Uni-Bit cuts into the plastic really easily.
All is well.
Chad has been keeping me busy...
Nice to hear from you, hope things are good.
It is hard to make recommendation over a computer but maybe some questions can get you going in a direction....What is shock spring preload? What is sag number? I'm more interested to know how much preload is on the 56N spring. What is rebound (clevis) adjuster set at? Does the shock feel soft, getting deep in stroke? Or does it feel tall/stiff? Where does it feel nervous (what kind of obstacle/condition)?
Chad is currently running Technical Touch KYB Kit Forks with a KYB Works Shock. If you may have listened to some of Chad's interviews we got a really late start with the bike. This is the first time KYB has been used on a Husqvarna for SX so our data with the bike was non-existent. I think Chad had only ridden a couple hours prior to A1. Our time together with the bike has been almost exclusively limited to Raceday. We have been using our 28 minutes of practice/qualifying to do the brunt of our testing. Chad has been riding back home between races and we have been shipping suspension back and forth during the week trying new settings based on his feedback. All the while he has been working on rehabilitating his ankle. We have been showing up to Raceday with the best setting from the week and tweaking it over the course of the day. We were able to get a day of testing in Southern CA between Oakland and San Diego and we were able to make some really good improvements. San Diego was the first race we used the KYB Works shock, so we only had one day on it prior to Raceday (see Pit Bits), we had been using a KYB Kit shock at previous rounds. Everyone involved is working really hard to progress as quickly as possible, it's not ideal but we are making progress. The hardest part is lack of data with the motorcycle, we just haven't accumulated enough time to know all its nuances. We get a better picture of what the bike needs each week and we make adjustments accordingly, trying to push the settings forward.
I believe air forks were a phase that the motorcycle industry went through. I think that manufacturers were looking for something that had performance with weight reduction and they found that with the air fork. Air forks have some positives to them such as bottoming resistance and hold-up. I think that PSF1 was a solid fork that performed really well given the air forks that were available to race teams and the market at the time. PSF1 is a low pressure air system and in a lot of ways resembles a spring fork and that makes it familiar. Currently though, it seems that the field is split and more guys are transitioning back to spring forks. I'm not sure that anyone outright preferred the air fork over the spring forks, it was just that the air fork was the "thing" to have. I do believe however that teams have learned a lot from the air fork and that will be used to produce the next generation of forks.
At KYB we refer to the spring fork as AOS, the SSS is just Yamaha nomenclature/branding for the AOS fork. ML likes to confuse everybody further by saying AOSS, which is a different but similar spring fork from 2005. I think there are a few reasons they are good, but the biggest reason is the fork has been evolving every year since its introduction in 2006. Yamaha never jumped on the air fork band wagon and I think that definitely plays a big part in the praise the fork gets, they refine it year after year. By continuing to produce the AOS fork while developing other systems in parallel KYB is able to learn from the other systems and apply that data to refine or evolve the AOS.
Pit Row
You answered GuyB's question on the diferent flavour of kit forks and in return you identify them as production, kit and works. You explained the differences in kit and production so what makes a works fork a works fork as opposed to kit?
Cheers for your time,
Bryce
ok this is the picture of my preload i can't make a measure now because i can't remove the spring but with this preload i have 103 mm sag. rebound click are 11 out. It feel tall and it kicki on some jumps landing and also when i jump from a wave to another .it feel nervous on rough fast straight . I ride 80% on rough hard pack.Now with mousse traction is better and this help to calm it.
Here in the States we don't have any interaction with Gas Gas. I believe the development for them is done by Technical Touch. I looked up their product line and it looks as if the GP editions are using a Production AOS fork spec'd with DLC on the Inner Tubes. The shock looks to be Kashima coated, I wasn't able to see if they were using DLC on the shock shaft. The GP spec looks very nice for Production stuff. The non-GP spec bikes are running a standard Production AOS with a hard chrome Inner Tube. The shock looks as if it maintains the Kashima coating. The Forks would be 48mm AOS and the shock would be 50mm RCU across the Enduro line. Overall the bikes look to be outfitted very nicely. I'd like to ride one!
My suggestion would be to send them to Enzo Racing and let them revalve them for you. Unfortunately I don't have any tips that are going to be magic with those forks. What bike are they on, Honda or Suzuki?
Will we ever see DLC on Yamaha's production bikes? I understand that Kawi does it, yet no other manufacturer that I am aware of, aside from TM, have done so. Is the price difference radically different, or is it a matter of engineering?
Thanks for the Q&A!
Do you have much involvement in the race development side of the engines.
Post a reply to: Vital MX Forum QNA: Jeremy Hoyer