Help with R6 rear shock and forks that were installed on my FZ6 before I bought it

Gary in NJ

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Back to the shocks!!!
The rear may never work proper without re-valving it as it was never meant to work via direct action. I have a thread on this based on an R1 shock I re-valved which works extremely well.

That said, the damping on the nose is very fixable. Mind you, measuring the static Static SAG will help you know your spring rates and how close they are for you and the bike.
I have many posts on SAG and balancing the the bike. Once dialed, they really are a great bike. I'm 200 w full leathers and boots, the ONE FZ spring works great on the rear of an custom R1 shock. It's all doable...

As others will attest, I'm not here much so include @ user name... and we can get you dialed...

I believe that the Penski shock was not an R6 shock, but is one of the few units (including Fox and Ohlins) that were actually designed or repurposed for the FZ6. Therefore it was designed/valved for a linkless direct fitment. The OP's shock is not an R6 shock.
 

Gary in NJ

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Always start in the middle and then make changes one click at a time. Keep notes on what effect the change had. To me, compression is easiest to set, whereas rebound takes a lot of time to quantify the change.
 

FinalImpact

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So you're saying the rear damping is adjusting and working now?

The front: When you remove the fork cap there is a lock nut to the shaft that must be set to the proper height or it will not control rebound damping. And if set too long, can damage the valve.
In short the damping rod threads to the end is 11.0mm. Loosen the jamb nut just enough to allow the cap to spin off, measure from the end down the threads 11.00mm. Place the nut at 11.25mm. Install the cap and snug the jamb nut.


All of that said, here is what I found works the best on these forks.
They are designed for 5wt oil. Run 5 or 7.5wt, no higher. The fill level is stated to be the fork travel distance of 4.17 in (106mm). This works, but I highly recommend 5.25 to 5.75 in of 7.5 wt.

Pull the forks out and dump out whatever is in there. Split a pint between the two forks dumping, filling, pumping and draining to get the sediment out. Verify the damper rod has the small aluminum adjusting rod inside and that it is not bent. Verify that pushing on the rod gently offers linear resistance. If not, the damper valve may have been damaged.

Whatever you do to one fork, repeat it on the other.

The order here is wrong, but going back to my other post, you need to check the SAG and see if you have the right springs for you and the bike.

Basically you want to know how much of the spring is used to support the bike, and how much the rider takes by sitting on it. So, from suspension fully extended, measure from fixed straight points to say the axles, or for the front, place a zip tie or velcro strap on the stanchion tube and slide it down to the seal. Raise the nose, lower the zip tie to seal, rest the bike on its own weight and carefully pick it back up and measure the distance from the seal to your marker. Bike needs 10 - 12 mm of sag. Now repeat with the rider. Hope for 28 to 32 mm of sag. See if you can adjust the preload to get these numbers.

Damping - You can't understand fully what rebound damping is doing if the compression damping is too high. Back off the compression so that while standing on the bikes pegs and pounce on it, it nearly bottoms out. Mind you this is not safe for spirited riding. ONLY A TESTING.
REBOUND - Your goal is to adjust the rebound so it doesn't pack down once compressed. Meaning, if you hit a series of bumps, under power and the rear sinks/squats more and more never coming up, you know you can control rebound. Adjust the rebound such that on your worst roads, it is active, meaning it hits a bump and time allows it to return to ride height. This is your starting point where you keep track of clicks and go this is my ZERO. Add and subtracted each time you ride until it works for you and bike and you are planted to the road.
COMPRESSION - Now add back compression so that your worst bump in the road does not allow the suspension to bottom forcing the tires to dribble and throw you in the air. Adjust for 90% of worst case condition for where YOU ride. Add or subtract compression damping to preference.

Front Rear Balance - when safe and at speed, pounce on the pegs. Do both ends sink and return at the same rate? If yes, this is your goal. Achieve balance on both ends and you have a stable predictable machine to ride in the corners over uneven terrain.

Look up my posts on suspension tweaking and SAG. You might need new springs to get this right. Also, let us know if the front dampers come back on line after being serviced with fresh fluid. To high a viscosity oil could be your problem if neither adjust works. If only the compression works, the damper rods need adjusted.

GL
 

FinalImpact

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To help turn in, loosen the stanchion clamps and raise the tubes up above the triple 6mm. The end of an Allen wrench works good for measuring both sides. Start there. I found 12 and 10 to be to squirrely at speed, 6 to be best.
 

Tom24GR

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I will get started getting the supplies and checking sag which I can do now. How much free and static sag should the rear have approximately?

Also wanted to say thanks for your help.
 

FinalImpact

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I will get started getting the supplies and checking sag which I can do now. How much free and static sag should the rear have approximately?

Also wanted to say thanks for your help.

It's in the post above...

Bike needs 10 - 12 mm of sag. Now repeat with the rider. Hope for 28 to 32 mm of sag. See if you can adjust the preload to get these numbers.

- think of it this way, at 38mm you've already used up more than a 1/3 of the travel on the nose, so I prefer the 28 to 32mm...
 

Gary in NJ

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Its the same front and rear. The FZ6 has 5.1 inches (130mm) of travel. Without you on the bike the suspension should sag 10-15mm under its own weight. Then with you on the bike, wearing typical riding gear, there should be a total of around 30-40mm of sag. You are able to adjust these figures by adjusting the pre-load on the springs.
 
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FinalImpact

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Its the same front and rear. The FZ6 has 5.1 inches (130mm) of travel. Without you on the bike the suspension should sag 10-15mm under its own weight. Then with you on the bike, wearing typical riding gear, there should be a total of around 30-40mm of sag. You are able to adjust these figures by adjusting the pre-load on the springs.

The early R6 has less travel than the Fizzer. Pretty sure its 4.6 or 4.2". Hence, making the spec tighter. I've these forks on here since 2012, 8 years. They work well when set properly and both front and rear are dialed in...
 

Tom24GR

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Hey guys. I have been unable to get to the suspension because I ended up having to replace the ignition cylinder, gas cap and seat lock. But after going for a ride yesterday I noticed something new and wanted to see if its related to my suspension. Under hard acceleration in a straight line, I feel this vibration/rattling in the handlebars. This is not engine vibration. It happens during acceleration only).

Could this be because the forks are low on oil and not damping right or is this something more along the lines of a wheel bearing or steering head bearing? To put it in perspective the bike has 23,000 miles.

P.S. Im pretty sure its not rough pavement underneath me because if that was the case I think would feel weird regardless of acceleration or deceleration. Lemme know if that is true or not. Thanks again.
 

Gary in NJ

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It could be any of the problems you mentioned.

If the fork seals are shot and you are low on oil, that has to be addressed. Before you go correcting problems that may or may not exist, fix the known problem. With that one problem resolved you can then see if the vibration still exists.

My thought...a wheel bearing cares little about cruising or accelerating. When a bearing is shot it makes noise and vibrates all the time. The head bearing would bind if it was shot...however, if the upper nut was loose...things would vibrate especially under acceleration. You might want to get the bike on its center stand and pull the forks forward and push them after (violently shake them) to see if there is any play. Shake them from the upper stanchions. If you shake the bike from the fork lowers you may feel movement from worn bushings. This is very likely if the bike has been ridden with blown seals.
 

Tom24GR

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I'm definitely going to get to the fork oil and seals within the next week. If I shake the forks back and forth and they move then we are talking about bushings where the fork mounts to the wheel? The forks don't visibly appear to be leaking but we came to that conclusion previously because of their lack of damping/ adjusters not working.
 

Gary in NJ

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The forks could have lost oil years ago. Those R6 forks should provide good damping (resistance) and the "clickers" should effect the amount of damping. Since you are getting little daming, you probably have blown seals. You wont know until you get things apart. Each fork leg should have around 16 oz of fluid. If you get less than say 14oz, then you have blown seals. Oil doesn't evaporate...it had to go somewhere. If you have blown seals...you'll probably get 10oz or less.
 

Tom24GR

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Hey guys, I ordered my springs and the new oil and was wondering what you all thought about ordering something like this. They are new compression and rebound adjusters for the forks. I figure since some of them aren't clicking and I'm already going to have them apart maybe I should add these. From what the page says its for the OEM forks.

 
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