Suspension Troubleshooting Guide

[HaulinAshe]

I was attempting to help someone having problems with Gen-I handling and typed this thing up on another forum. Thought it might actually help someone else, so here 'tis...

If you are having difficulty obtaining the handling you desire, there may be something wrong with your suspension. You may find this troubleshooting guide helpful.

1. When's the last time your suspension was serviced, especially the forks? If the fork oil is sludgy and rank, bushings worn and the tubes are sticking, handling immediately goes out the window. If your forks are in good mechanical condition then read on...

2. When's the last time your rear suspension pivot linkages and swingarm bearings were inspected? Any binding from worn seals that rusted some bearings? Anything other than smooth motion in those joints, immediately translates to mismatched geometry and again... handling goes right out the window. If the rear suspension linkages are in good condition then read on...

3. How many miles on your rear shock? If it's a stock Gen-I shock then it was shipped from Yamaha undersprung for nearly every average American male. Once that shock ages and loses even a fraction of its original performance, handling goes out the window. If your Gen-I shock has less than 30,000 miles on it, or you have wisely switched to a Gen-II shock and it has less than 50,000 miles on it, then read on...

4. Now assuming you've made it this far because ALL your suspension components are in great condition, your steering head bearings are well-lubed and tight, you have fresh rubber mounted at the proper PSI... try these BASIC settings:

A. Set the 17mm hex ride height adjusters on the front fork caps (manual calls them preload adjusters-which they are NOT) to three(3) segments visible.

B. Set the Rebound clickers on the forks (black knobs up top) to 12-clicks out (CCW) from fully-closed(CW).

C. Set the Compression clickers on the forks (at the bottom of the fork tubes) to 10-clicks out (CCW) from fully-closed(CW).

D. Set the Rear Shock Rebound to 8-clicks out (CCW) from fully-closed(CW), AS VIEWED FROM THE BOTTOM OF THE SHOCK LOOKING UP.

E. Go ride and evaluate. If you still want significantly better handling than what you just experienced, read on...

5. Find an accurate bathroom scale and weigh yourself. Now weigh the cargo/luggage that you typically load on the bike. If that combined weight exceeds 210 lbs. and you have stock suspension, save up some money. You need some new suspension components to get substantially better handling than what you already have.

If you made it all the way here and still aren't satisfied with the handling, your bathroom scales are lying to you or something remains mechanically wrong with the bike suspension. Go back to #1 and start over.

 

[03HiYoSilver]

Jeff,

Thanks for sharing your words of wisdom...have a great spring season.

 

[3dogs]

A. Set the 17mm hex ride height adjusters on the front fork caps (manual calls them preload adjusters-which they are NOT) to three(3) segments visible.

The 17mm hex IS the rebound adjuster. When turned this hex adjuster compresses the fork spring just like any other preload adjuster. When preload is increased (hex nut turned in--less lines showing) ride height increases. When the preload adjuster is turned out ride height decreases. In general if you weigh more than 195 lbs. the stock fork springs will be too soft and even with the preload adjusted to its highest setting the resulting suspension sag will be too much. Also, you need to adjust the sag (by turning the preload adjuster) based on your weight--not lines showing.

[B. Set the Rebound clickers on the forks (black knobs up top) to 12-clicks out (CCW) from fully-closed(CW).C. Set the Compression clickers on the forks (at the bottom of the fork tubes) to 10-clicks out (CCW) from fully-closed(CW).

12 clicks out for front rebound setting is somewhat meaningless. The viscosity of the fork oil is a significant determining factor in relationship to actual rebound. For example; What is the fork oil viscosity? What brand of oil is used? How many miles has the oil be subject to--2000 miles or 20,000 miles? All of these factors will change the number of clicks of rebound adjustment. I have found in testing numerous FRR's that the stock rebound valving does not restrict the flow of oil enough to get the rebound adjustment in the "ball park" even when it's adjusted with no clicks out. This link How to Adjust Rebound Without Counting Clicks is the correct method to determine/adjust rebound. Compression damping has the same issues with oil viscosity as rebound.

There is a lot of well-intended misinformation regarding suspension adjustments/settings on this and other forums. If you want an education on motorcycle suspension buy this book. Race Tech's Motorcycle Suspension Bible

 

[johnny80s]

The first thing should say fat guys skip to the end. That way we know not to screw with anything and just go out and get a new suspension.

 

[HaulinAshe]

The 17mm hex IS the rebound adjuster. When turned this hex adjuster compresses the fork spring just like any other preload adjuster. When preload is increased (hex nut turned in--less lines showing) ride height increases. When the preload adjuster is turned out ride height decreases. In general if you weigh more than 195 lbs. the stock fork springs will be too soft and even with the preload adjusted to its highest setting the resulting suspension sag will be too much. Also, you need to adjust the sag (by turning the preload adjuster) based on your weight--not lines showing.

I'll agree to disagree, but I'll bend no further. The black knob at the top of the fork is the Rebound damping adjuster.

"Preload" is the term for compression pre-applied to the fork spring that effectively "shortens" the spring from its Free Length during assembly. The length of the spacer tube(collar) is what sets the actual spring preload. The adjuster raises and lowers the ride height independently of the spring pre-load through nearly ALL of its travel (with the exception of the uppermost limits). It's deceiving and you must study the FJR fork cap carefully to see what's really taking place. Preload certainly helps define ride height, but in the FJR fork specifically, the hex adjuster is an additional way to adjust ride height without changing the actual spring preload. (Again, with the exception of the uppermost limits of adjuster travel.)

12 clicks out for front rebound setting is somewhat meaningless. The viscosity of the fork oil is a significant determining factor in relationship to actual rebound. For example; What is the fork oil viscosity? What brand of oil is used? How many miles has the oil be subject to--2000 miles or 20,000 miles? All of these factors will change the number of clicks of rebound adjustment. I have found in testing numerous FRR's that the stock rebound valving does not restrict the flow of oil enough to get the rebound adjustment in the "ball park" even when it's adjusted with no clicks out. This link How to Adjust Rebound Without Counting Clicks is the correct method to determine/adjust rebound. Compression damping has the same issues with oil viscosity as rebound.

There is a lot of well-intended misinformation regarding suspension adjustments/settings on this and other forums. If you want an education on motorcycle suspension buy this book. Race Tech's Motorcycle Suspension Bible

Admittedly, there is some information missing from this thread that had been previously discussed in the original post that I copied from. It was never my intent to make this "guide" a published work of technical wisdom, worthy of printed publication. Absolutely, go purchase something if you really want/need to get into the details. But somewhere near the very top of my list is a section about making sure your forks are serviced and sound. I'll dangerously assume that people understand that means fresh fluid with the proper viscosity etc.

I'll leave it to the forum readers and users of my suspension work to determine if this is nothing more than well-intended misinformation. I see no substantial reason to change a darn thing.

 

[rogdeb]

Good info Jeff, thanks for sharing with us all.

 

[Niehart]

:assassin:

 

[RadioHowie]

So Jeff, whatyersayin' is, since I'm somewhere between 270 and 280 lbs, I drive an '04 Gen I with the original suspension -- now at 60,000 miles -- attempting to get ANYTHING out of my stock suspension is pretty much a waste of time? My only alternative is to drop a couple of grand into forks and shock?

DAMN! Missus Howie ain't gonna like this! It's gonna cut into her "casino" fund.

(p.s.: I'm serious about the "age" and originality of my suspension)

 

[DailyCommuter]

I love suspension threads.

Take a look at this one- especially the 3rd post in the thread.

https://www.fjrforum.com/forum/index.php?showtopic=117110

 

[TriggerT]

Damn, #1 I am glad I upgraded to an after-market rear shock, and #2 I am glad I am trying to lose a few pounds. I could only carry 5 pounds worth of crap as it is right now.

 

[LAF]

Thanks for the information once again. It is a confusing subject for some of us to grasp and your explanation makes it a little easier to understand.

I know I was wondered if my settings from Traxxion were right and due to the different oil level recommended by them, 1.1 Omni Springs, and 10W oil. I used what they said and it is very close to what you advocate for starting points on OEM. Not identical but close and that tells me your recommend settings are very good.

I think the point is you need to be in the range of recommended rider weight to achieve the best results. Or do as I did and buy new springs and service your front forks. I am 215 or so with full gear on, 190 or so in street cloths. So reading that the stock springs are optimal for 175 pound rider I knew I had to get some springs to handle my weight without going to the outside limits of OEM springs. I think this is a big issue and you advocate the upkeep of forks and oil in your posts and also recommend springs for your weight.

Information is here and all you have to do is find a starting point and ride it. Make one adjustment at a time and ride it. With the base settings it makes it relative easy to change and experiment a bit and if you FUBAR, go back to your original settings and try again.

I thank you for your time in 'splaining things and as always you can walk a horse to water, but you cant force them to drink.

 

[3dogs]

I'll agree to disagree, but I'll bend no further. The black knob at the top of the fork is the Rebound damping adjuster.

You're correct, brain-fart, I ment "preload" when refering to the 17mm hex.

 

[jwhite518]

The only problem I have with this is recommending a generic preload setting for everybody. I weigh 260 on a good day, and my preload settings are different from yours. The best way to set preload is by making some measurements. I won't go into details on how to do it, that stuff is easily available on many suspension websites. What I will say is that the recommended 'rider sag' for front and rear on a street bike is 30mm.

On my bike with aftermarket suspension front and rear, I get 36mm on the 2nd line of the front forks, which was odd because it was in the 20's with zero lines showing (all the way in.) That leads me to believe that it's counterintuitive. Screwing the adjuster in makes the sag go down, screwing it out makes it go up.

Anyway, I'm running 30mm sag in the rear, 36 in the front, and I like it so far. I may try dialing in the front to get it closer to 30, see what happens.