Thank you for your kind words and sharing your experiences. I am very grateful to have been a part of your journey and learning to create a wonderful handling FJR!

Thank you for supporting my work with your subscription! Enjoy the content.

There is an Ask Dave video on this very topic! The most common cause is not having a dyno chart and shifting at the right time. If you rev too far past peak power, the bike actually slows down and weights the front tire, then you shift in the meat of the power for the next gear and the front end gets very light. Add in too tight a grip and the head shake materializes instantly.

Great work Rick to make your bike work well of you. Clearly a lot of experimentation, but if you are keeping the bike for several years all that work will give years of great riding.

Thx mate Its only a yamaha r3 but does the Job 1 question for you?? Is 20mm from bottoming out OK and that's with 2 up as well you think it's safe?? Ps: thx for your reply appreciate it

Yes, that sounds fine to me form a safety standing. It takes control of weight transfer as long as the shock is set up equally. As the passenger if they move back and forth a lot when you start to brake and accelerate. If not, spring tension settings are good :)

Hi Dave been watching some of your videos awesome as always but I have 2 questions for you? As I mentioned before I've got the front end set up spot on now after months of playing lol But now I have installed a YSS collar adjuster nitrogen gas rear shock on my (Yamaha R3) Firstly the ome shock was 10 mm free sag (90nm spring) 20 mm rider sag I weight 80kg The Yss shock is 10 mm free sag 100nm, spring 30 mm rider sag Out of the box Feels good but what is a good setting?, as it feels a little to soft and under heavy braking and turning in the front end tends to want to slide on counter steering just a little Also the front end now seems to pogo a touch with the softer rear rider sag I'm thinking turning it back to 25 /27 mm rear sag to free up the front end from pogoing or leave it at 30 mm rear sag and reducing fork oil a little to take out the pogo What's you opionion?, As your the suspension wizard

With that much sag all the weight comes forward on braking hence the sliding. Go to 20mm rider sag and 5mm static sag and see if braking improves - it should.

Most modern sportbike shop manuals (where it is specified) suggest 8,000 miles. My thought on this is quite simple:- if you cruise around most of the time, this is a reasonable number. If you are aggressive, you should consider a lesser number. Why? The beating you are giving the oil in the corners with braking and cornering loads influenced by road conditions and surface. How much do you depend on the front wheel? If it is a lot, would you (like you engine oil if you are aggressive) consider 5-6,000 miles? Fork oil is not very expensive and not a lot is needed.

Dave Williams, editor, replying here. The ZX6R's in this video, kzfaq.info/get/bejne/mNxgqaZ7yZq4cZs.html , are identical, owned by a couple of brothers who both weigh about 240 lbs. One has 5000+ miles on it, the other has 800+. The difference in rebound damping required to make the forks work properly is a testament to how often you need to change fork oil.

Why is it critical to change the oil? I understand the oil thins out over time, but what happens to the internals of the suspension if it gets dirty and is unchanged? Could you just keep progressively adding rebound and compression damping as the fork oil ages?

You could do that but you will have to damp for hot oil only, so cold oil will mean very harsh suspension action as the viscosity range cold to hot increases dramatically with age. Also remember that the metal contaminants from the spring scraping inside with every movement can in some cases create enough debris to block small holes in the compression and rebound pistons.

You can keep adding damping until you run out of adjustment, but the bottom line is thick cold oil through to hot very thin oil and setting the damping for very hot oil - that makes cold oil and cold suspension very, very harsh. If left long enough with some stock pistons you can block holes with packed in metal debris from the spring scraping on the inside of the fork tube.

I always fill the tank and then take settings where they need to go. Another choice is half a tank as we most often ride around with fuel levels at that point as an average.

The book statement is for who, what weight, what pace, what type of roads?????........ the questions go on and on. Thank you for finsing your setting to meet your needs in your part of the world.

Yes, 100% correct. A simple experiment like this can provide an epiphany. It can also show how old your fork oil is via cold to viscosity differences.

Correct - forks do seem very cool to the touch and normally sync with ambient temps. Oil inside can reach 80-100c as per cSt testing and dyno results.

@@catalystreactionsbw Wow, had no idea the temperature differential was that high. I got to meet you a few years ago at Iron Horse Lodge when you came out for the Women's Sportbike Rally... You set up my wife's Street Triple RS for her. Love your videos... I just got my Z900 RS sorted, with a K-Tech shock sprung for my weight, and swapping out the fork oil for Belray 7W. Firmer, while more compliant and the bike tracks much better when wailing on it in the mountains... I am 6'4" and 250lbs in gear. I was on the Tuono V4 when I met you... I also have a 2020 ZX6R I am trying to sort out... The spring rate seems fine, as I can get my 40mm(forks) of rider sag with barely half the preload used up, but having the damping on in one fork isn't enough, so I have been playing with fork oil weights in that one as well. I am now up to Belray 15W(stock is showa brand 10W) and it seems better... I don't know that I will ever get it truly where it needs to be, unless I take the forks off and send them off to be rebuilt to my specs and riding style. Do you offer those kinds of services, or is shipping forks back and forth across the country cost prohibitive?

@@SquireSCA I do not service forks or shock as I do not have a shop and travel teaching all the time. You can buy a fork piston kit for the ZX and that will help tremendously. A shock revalve is simple and effective plus a stiffer spring.

@@catalystreactionsbw Fair enough. Traxxion Dynamics is less than an hour from here, so I can probably just pop on over there and see what they offer. Thanks!

Thanks 👍

Correct and with time/heat viscosity changes dynamically

Ride the bike as is and drop the preload and ride again. Focus on the bikes behavior with deceleration and then braking. What happens to you, what happens to the fork travel? Static sag is essential IMHO.

Softer springs for sure via the text book and potentially a smaller preload spacer for the forks. The 5w oil should help a great deal so do that, reassemble and ride. If you are within 25mm of bottom out the springs will work. Then check shock travel used to see where you are on that. Test first before opening your wallet for springs.

Dave Moss Tuning You’re great Dave. I’m subscribing. Next best thing to being able to have you tune my suspension in person. Thanks

exactly

For dirt, 100% yes. For road IMHO, no. kzfaq.info/get/bejne/nb-Fkt1nms61g4U.html

You are completely correct. We think about 1% of road bikes sold get set to the owner and no bike on the showroom floor is set to anyone. I've never owned a steering damper on any of my road or race bikes - I set the bike up correctly and do not need one. The F3800 has vastly superior suspension to the 675 and with that boost in power it is a wonderful motorcycle. I made a video on dialing in the MV to my needs which may be something you would be interested in?

Dave Moss Tuning absolutely going to have to find that video. Thanks for the reply. I love the MV but was worried a little with most of the reviews.

I should do a very comprehensive review on it if there is that much misleading information out there.

kzfaq.info/get/bejne/Zt2AeaZjsKnQiIU.html

Thank you for the time in replies and the link. Starting to watch the full video now.

30-40mm in the forks and 25-35mm in the rear shock are good ranges so you are already there. Set compression in the middle of the range, then go each side of that setting to see what feels better to you. Rebound should be set based on the age fo the oil, so start at 304-% of total range toward the closed end of the range.

Dave Moss Tuning 304-% ? Did you mean 3/4 of total rebound?

Setting rebound is a function of oil age and viscosity change when hot, not speed you ride.

Street is up and settle, dirt is up and settle at least another half stroke

Once you set sag you set rebound and compression. You see how much fork and shock travel you use and then optimize preload to your speed, roads and style. Once done, you can change compression for softer or firmer suspension and then changge rebound periodically to compensate for oil changing viscosity.

What speed are you doing when you get the head shake? Are you accelerating or decelerating? Are your tires at road pressures or lower for dirt? Is your geometry stock?

Dave Moss Tuning Speed about 160km/h and its when I'm accelerating. Sometimes when I'm hitting bumpy sections. The steering feels light in general and there's a fair bit of fork dive on braking which is not to my liking. Tyres are at 2.5bar and suspension was set up between sport and fully loaded. I changed everything to standard this morning and it feels a bit more stable. Thanks for your prompt response!

weight transfer is an issue that you need to resolve first by changing rebound in the forks and shock at the same time. Get the bike to sway back and forth less with acceleration and braking. Then use fork and shock preload for the same purpose.

Correct would be bar input and relax. Incorrect would be constant bar pressure on the inside hand from tip in to post apex. Go 2 clicks either direction to make sure you can feel the difference, 3 if needed. Then hon down your sensitivity.

@@catalystreactionsbw Thanks Dave, Would you prefer to be on the side of maximum feel (slower rebound) over maximum traction (faster rebound) or vice versa?

@@DD-do6gz Slower rebound would be the preferred side for both feel and stability.

@@catalystreactionsbw Thanks again for the replies and your time.

i'd also like to see an answer on that one.

Sorry I missed this somehow! #1 is tire shape and pressure, not balance. If the front or rear is too low on pressure it will create a harmonic where at a certain speed the bar will vibrate and then stop. Is that the case? Rise the pressure to 40/40 cold as a test - did the shake go away? Next is tire shape so run your hand from edge to edge - is the front round and the rear squared off? That will cause the same issue.

Dave Moss Tuning Dave when this happened to me I was accelerating on a highway interchange on fresh well broken in over 200 miles WE tires at 32front/34rear I went hard on the throttle to pass a Mack truck onto the 405s to 110S interchange and went into a lock to lock tank slapper so bad that my tires were perpendicular scuffed to the edge of the tread pattern and my brake reservoir leaked fluid. Bike is stock except your suspension tuning recommendations. I did see the next day in the light that the highway has irregular corrugation that starts and stops at this section. As you said in another video (not to me specifically) I did not pass into the rev limiter in 2nd at 95mph before my shift into 3rd gear. Riders beware crazy shit can happen anywhere, especially on the street!!!

Dave Moss Tuning my tire pressure is set at factory recommendations 36/42. I will try your recommendation and see if it helps and will definitely take a look at the tires shape.

Sounds like there is a geometry issue with very sudden weight transfer to the back of the bike taking weight immediately off the front tire. Testing is obviously dangerous, but it would be worth adding a lot of compression as well as taking away a lot of compression to see which direction is needed to eliminate it.

Great connection between preload and rebound and that also relates to fork position so it sounds ike fork geometry is your next experiment with 2mm increments. Rebound control is indeed about topping out but the older the oil the narrower the window of control due to massive viscosity differences between cold and hot oil.

@@catalystreactionsbw that's great advice thank you! The fork oil is due to be changed out, for sure! Is there ant particular brand or manufacturer that is better then others? I need a oil that is capable to withstand 130mph+ on fairly smooth course, for 100miles at a time-? I use motul MotoV in the engine, I am happy to service more frequently to achieve optimum performance! Thanks again-

@@freelancerider100 Motul or Maxima are my go to choices. Bel Ray or Motorex if those are not available.

@@freelancerider100 Brands I use are Motul and Maxima, BelRay and Motorex.

Experimentation is something will all do most of the time to make something better. Great idea and I'm sure you have thought of the variables of suspension unloaded with high speed bumps and fully loaded in regards to pressure and velocity of oil and where to set you blow off limit to or work around. Personally I have not taken apart the Suzuki forks, but like all pressure systems, the principles are the same.

Thanks for your quick reply. Indeed, I've tried gathering as much information as possible. as well as considering the different variables.Initially I swapped the original springs with Sonic ones, as well as decreasing the oil viscosity. And, although the (unadjustable) rebound damping decreases of course, I haven't had any issues because of that. In general, my fork action has improved, except for the high speed damping, which still suffers from the old damper rod design.A successful modification of the PDF units, rather than using emulators, has several advantages - I save the money, I won't have to modify the forks as such - and, it's more fun and satisfactory to successfully modify what's already at hand (I think you'll agree on that one). As you probably know, many eighties Suzuki's had these PDF units, replacing the previous anti-dive units - and nearly as many owners weren't completely satisfied with their behaviour. So, perhaps others can benefit from the lessons I learn from this project.I'll keep you informed, if you have any interest on the matter. c",)

Roy - the showroom settings are actually not far off in regards to general street riding. Sag will be changed if you get close to bottom out (mark it please) and that is a 5mm fixture at the base of the fork. Once preload is set correctly, try compression working in from factory setting .75 of a turn.

Dave I will give that a try .. I've fitted a rear ttx and I just think I've knocked the full bike out.. I have the back end set up and it feels good but it seems out of balance and while iam on the gas on corners at local track iam now fighting with the bike...iam going to knock the rear back to the base settings for my weight and then do what you said with the front.. I have an r6 with rear ttx and 30mm nix forks and it rides like it's on rails but I just can't seem to dial this in Dave... i have a full day at track next week so will try what you said and I will get back to you..pitty iam in Scotland or I'd be bringing it to you but your just a bit to far away...lol..big thanks Dave..Roy

Roy - if this gets a little complicated we can use Skype. I charge $50 for 30 minutes and that might give you the best ROI and test plan for the track day.

brilliant Dave...take care..your the man...,😂...

I will be home at Christmas time as normal to visit family. We had a sold out event in Telford last year sponsored by SSR suspension so we will do that same again, somewhere around December 20th.

Thanks Dave. I'll keep an eye out. Cheers!

Correct - the App was discontinued on both platforms as for 6 months we had literally zero users.

Bummer. Ok thank you

There were literally zero users for 2 years so it was taken down. All the content was moved into the www.davemosstuning.com website.

Sorry to hear that and surprised. Thank you for replying. Keep up the great work, loving the videos. Stay safe.

@@laurencelagden So were we. I created a massive dedicated tire wear section for road and track among 4 other categories - perhaps it was just a few years too soon? Stay safe too!

weight, ability, climate and type of use - alll variables

Help in regards to service, oil viscosity, oil volume or... ??

@@catalystreactionsbw i want to service it and I can't find any manual to see how is inside the valves because its old and its two different forks.left is compression and right is rebound

@@kostasxtz are you simply doing a fork oil change? If so, you can use the upside down "dump and run" video. If you are trying to do a revalve, that requires specialty tools to take the cartridge apart.

@@catalystreactionsbw and it's not upside down fork's

@kostasxtz The service manual will have the break down of parts, but not the internal structure of pistons and shim stacks. Single function forks have been around for decades so this is common engineering. You will need a lot of specialty tools if you want to take the cartridges and valving apart.

Thank you for your comment. Please create the story board text that needed to happen for this video to have the correct information.