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Suspension and other settings, for a light weight rider


howie333

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2017 FJ-09

I've been riding this bike since new with 12+K mikes. I would go thru front tires prematurely, always scalloping (cupping front tire) and bike could not handle any type of aggresive cornering, and could feel it in it's handling overall. ( I do live in the mountains of Tennessee). It occured to me the problem has always been in it's suspension settings. I had it set for soft ride and to help keep it low in the rear and always felt tall in the front. I'm 5'9" tall, and could just barely flat foot it. I just replaced the front tire, lowered the air pressure a few pounds from spec, and firmed up both front and rear compression and also set up rebound dampening. the bike handled better than it had, but i think it could be better and more precise. Today a friend and I tried to set up both front and rear spring compression and rebound dampening according to basic suspension tutorals, and general specs for my weight. According the Dave Moss and other video's i've studied, there should be approx. 30-35% total suspension sag front and rear for general street riding. I measure 150mm total fork travel, made deduction for actual fork travel and deducted the 137mm, made 13mm mak on fork tube, w/ tiewrap on fork tube, I measured 72mm left w/ fully loosened adjusters. would'nt my sag only be 46% ? I would need only 55mm left to get a 35% sag. I weigh 165 lbs. and cannot get baseline settings with this stock suspension. with the adjusters all turned fully looseened, I still cant get enough weight to compress the suspension to a 30-35% sag with my weight. I'm closer to barely get 20.5-23% sag. With this setting the bike handled badly. Does this mean I need a softer shock and front fork springs ? to handle better, i'd be barely @ 15-20% sag  w/ adjusters full loose!

 

Thank You...

Howie....

Edited by howie333
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I'm interested in the response, as your specs track alongside mine. My tires have never cupped, and my handling is better than you describe yours, yet I don't have the same comfort in the corners like I do on my other bikes. Just following... 

’70 Yamaha 125 Enduro; ’75 Honda CB360T; ’81 Yamaha XS650SH; ’82 Honda GL650 Silver Wing Interstate; ’82 Suzuki GS650L; ’87 Yamaha Virago 535; ’87 Yamaha FJ1200; ’96 Honda ST1100; ’99 Yamaha V-Star Classic; ’00 Suzuki SV650; ’07 BMW K1200GT; ’12 Suzuki DR200; ’15 Yamaha FJ-09.  Bold = current

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39 minutes ago, howie333 said:

Today a friend and I tried to set up both front and rear spring compression and rebound dampening according to basic suspension tutorals, and general specs for my weight. According the Dave Moss and other video's i've studied, there should be approx. 30-35% total suspension sag front and rear for general street riding. I weigh 165 lbs. and cannot get baseline settings with this stock suspension. with the adjusters all turned fully looseened, I still cant get enough weight to compress the suspension to a 30-35% sag with my weight. I'm closer to barely get 20.5-23% sag. With this setting the bike handled badly. Does this mean I need a softer shock and front fork springs ? to handle better, i'd be barely @ 15-20% sag  w/ adjusters full loose!

Yes, setting sag to determine if you have the proper spring rate should be done first before adjusting the compression and rebound damping. 

If you call any reputable suspension shop they should be able to give you guidance on proper springs for your weight.

***2015 Candy Red FJ-09***

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...so that we're talking the same numbers... 30% of your total wheel travel (130mm per spec. for the rear) is 39mm. What is the free length?

Edited by piotrek

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50 minutes ago, piotrek said:

...so that we're talking the same numbers... 30% of your total wheel travel (130mm per spec. for the rear) is 39mm. What is the free length?

The free length (stretched out)rear shock measured from 2 points(axle to fender point) was 590mm, static @ 583mm, and 550mm w/rider weight. So thats a 30-33mm rear sag. Is that right ?

 

50 minutes ago, piotrek said:

...so that we're talking the same numbers... 30% of your total wheel travel (130mm per spec. for the rear) is 39mm. What is the free length?

 

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55 minutes ago, howie333 said:

The free length (stretched out)rear shock measured from 2 points(axle to fender point) was 590mm, static @ 583mm, and 550mm w/rider weight.

You are at 40mm, so about where you need to be for 30% rider sag. Static at 7mm ia also about right.

I don't recall the front suspension travel spec, but do same calc for that. Edit... 137mm, so ~40mm front and rear should do... then tweak your rebound damping.

Edited by piotrek

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You don't mention if you're measuring rider sag or static sag. Both are relevant for checking correct spring weight. But the 30ish% measurement is a rider 'on' measurement. Though you must know this I guess if you've watched some vids? As a very rough guide, push cable tie to top, get on bike and gently lift her vertical, then get off. The tie should be in vicinity of 100mm up from the bottom (ish).

And, ok, I'll be the first; the rear shock isn't worth the material it's made of. Forks aren't actually too bad for stockers. But if you're very light, you might want to get lighter springs?

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5 hours ago, howie333 said:

2017 FJ-09

 I measure 150mm total fork travel, made deduction for actual fork travel and deducted the 137mm, made 13mm mak on fork tube, w/ tiewrap on fork tube, I measured 72mm left w/ fully loosened adjusters. would'nt my sag only be 46% ? I would need only 55mm left to get a 35% sag.

Sounds like you're trying to have 33% left. You want 33% used, 66% left unused at a standstill. So, around 100mm. It seems you need to wind preload in to increase the 72mm dimension.

Though I am a little unclear on your measuring system..

 

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Also make sure your forks aren’t binding. 
loosen the pinch bolt at the bottom of the fork tube, compress the front end several times, and then retorque it to 13-15 ft lbs. 

(I’ve seen bound forks cause a bad sag measurement and poor handling in the front.)

-skip

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Whats aggressive cornering? With your current setup, Im guessing you are getting alot of nose dive when hard on the brakes and wants to run wide out of corners when hard on the gas.

Without any real description of what the motorcycle is doing, it really hard to know where the issue is.

With your current setup , your motorcycle is out of balance. The issue is not the forks but how soft you have the shock. For real aggressive riding, both the front and rear need to be setup properly. Currently it is not. 


If ya need a lower motorcycle, do it the right way,  get lowering links and not use suspension settings. 
 

Soft and hard are incorrect terms for dampening suspension settings. The proper terms is fast and slow.

The way you have the shock set up allows for fast dampening. Nose dive can be a result of too fast rebound dampening. Fast rebound damening on the shock will alllow for the back to raise really fast under hard braking giving a sense of excessive nose dive. 
 

Running wide out of corners when hard on the gas is too fast compression damening and/or not enough preload. The rear squats down, changing the steering geometry which causes the motorcycle to want to run wide. 

Get the shock set up properly.

For me, aggresive cornering requires hard braking going into turns and hard on the gas out of turns.

 

 

 

Edited by duckie
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18 hours ago, skipperT said:

...loosen the pinch bolt at the bottom of the fork tube, compress the front end several times, and then retorque it to 13-15 ft lbs.

I think the manual calls for 17 lb-ft. 😬

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There’s not much difference between your 17 and my 15. 

Not sure that you’re doing your set up or measuring correctly. 

The front has 130mm of travel, I’m 163lb and aim for 40mm of rider sag. To do this properly it’s a lot better with three people, you on bike, second person to hold bike upright and third person doing the measurement. I usually do it with my daughter who takes measurements as I can usually balance the bike for 4 or 5 seconds with feet on foot pegs while she measures. 

The front stock suspension is absolutely crap, way under damped and has progressive springs that introduce way too much sag and dive.

Ive installed 0.9kg/mm single rate springs with Racetech gold valves and custom shim stacks. Only way to get rid of sag. 

For your stock front end I would adjust spring compression to the maximum, with rebound 3/4 to 1 turn from full hard. 

The rear has the correct spring rate for my weight, but the spring is too long. So you will never get correct rider sag. All you can do is spring preload to minimum and play with the rebound to suit. 

The rear shock also suffers from non existing damping so it will never give a good ride no matter what you do  

The lack of rear rider sag will constantly be launching you off the seat as you exit bumps, giving it more rebound will help a bit, but also makes ride harsher  

Only way to fix early Tracers suspension is by throwing it all in the bin  

Stock set up makes front dive too much under brakes and uneven squat with rear under heavy cornering which makes bike turn in fast but without control, as you accelerate out front comes up too much which makes bike run wide on exit  

A corner full of ripples will see the bike run wider and wider, so you cut throttle which introduces dive and lack of suspension compliance, front tyre starts to hop over ripples and makes things worse.

If your bike hasn’t been flashed, it probably also has a choppy throttle and too much engine braking which magnifies all these problems.

Good news is that if you address all these problems properly, you’ll end up with a great bike.

 

 

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Well; Thank you for the informative replies. I plan on reviewing what I measured and do again w/ a front wheel stand, and a Slacker measuring device I saw Dave Moss use which allows you to do all measurements yourself w/o anyone to help and can take my time to do a better job. Hopefully this suspension is salvagable and adjustable. How often should I be changing fork oil, manual states use Yamaha fork oil, but doesn't state what weight for climate and how I ride. I'm @ about 12.5 K miles now. I dout I'd have to rebuild them yet, just change oil maybe.

 

Thanks for replies..  

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FWIW, the reason I suggested thinking in terms of fast and slow v hard and soft is because what the dampening settings are really doing is controlling the speed at which the wheel will move up and down when a bump or hole is hit. Soft=fast, Hard=slow. With the compression set to soft, you can compress the forks or shock faster than when set to hard. But soft and hard terms do not reflect what is actually happening with wheel movement.
 

Do you think all the racers use the same suspension setting? 
 

Or do they set up the motorcycle to suit their riding style and track?

Static settings get ya in the ball park. The real magic is in the fine tuning of the settings under dynamic conditions. Meaning how you ride and the roads you ride on.

The is a reason for electronic ride control…….not one set of settings works for all roads. 
 

For a motorcycle to handle its best, the front and rear need to work in harmony. 
 

I need a ride…….

 

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