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paul d

Can not get full tavel from my FZ 07 forks

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paul d

Hi guys this is my first post, not good with computers, bare with me.  I can only get 3 and 1/4 inches travel from my forks, checked with a zip tie.I changed fork oil to 400cc 15wt as yamaha shop manual called for. Oil level was about a half inch high, it helped the nose dive, travel remained the same. Later removed 10cc each leg helped compliance and comfort on harsh jolting roads.Tried 10mm shorter preload spacer,helped alittle, only increased sag 4mm to total of 20.mm Later took another 10cc of oil out of each leg, helped the ride- softer, no change in sag or travel.I have heard the top out spring, and the oil flow stopper at the bottom of the damper rod, use up some of the forks claimed 5.1 inches of travel. Anybody know if this is true? I would think getting the forks full claimed travel with decent damping would give the best ride on the harsh jolting road surfaces I spend a lot of time on.I weigh 185 with gear, and use stock fork springs. I talked with Rich at Sonic, he said Ive got the right springs. I want to get Cogent DDC's, but want to get my travel and sag problems straitened out first. I would appreciate anybodies thoughts or help with this.  Thanks Guys.

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YZEtc

The Service Manual specifies 403 cc of 10 weight oil (not 15 weight, which is heavier and would tend toward more harshness over sharp bumps), with the goal being an oil level of 162mm.

I'd correct that, first, before you go any further with your experimentation. 

Make sure all of the trapped air is purged from the fork leg before you measure the oil level, with the spring removed and fork bottomed while measuring.

 

Personally, for a Stone-Aged damper rod-type fork, I feel the FZ-07 fork ain't too bad at all.

I've owned street bikes with forks that felt much worse over sharp bumps, like my 2007 SV650K7.

Terrible on anything but smooth pavement.

 

I doubt you'll make a habit of using 100% of the fork travel for typical street riding without doing some serious front braking or slamming over huge pot holes.

If the fork did bottom during your typical morning commute, it would likely be way too soft.

 

On my SV650K7, Race Tech Cartridge Emulators did the trick for that bike.

 

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blackout
On 10/13/2017 at 9:49 PM, paul d said:

Hi guys this is my first post, not good with computers, bare with me.  I can only get 3 and 1/4 inches travel from my forks, checked with a zip tie.I changed fork oil to 400cc 15wt as yamaha shop manual called for. Oil level was about a half inch high, it helped the nose dive, travel remained the same. Later removed 10cc each leg helped compliance and comfort on harsh jolting roads.Tried 10mm shorter preload spacer,helped alittle, only increased sag 4mm to total of 20.mm Later took another 10cc of oil out of each leg, helped the ride- softer, no change in sag or travel.I have heard the top out spring, and the oil flow stopper at the bottom of the damper rod, use up some of the forks claimed 5.1 inches of travel. Anybody know if this is true? I would think getting the forks full claimed travel with decent damping would give the best ride on the harsh jolting road surfaces I spend a lot of time on.I weigh 185 with gear, and use stock fork springs. I talked with Rich at Sonic, he said Ive got the right springs. I want to get Cogent DDC's, but want to get my travel and sag problems straitened out first. I would appreciate anybodies thoughts or help with this.  Thanks Guys.

Yes, 20mm of sag is not enough for street riding.  I would pull the stock springs and have a shop check the actual spring rate.  Or check your self, if you can figure something out using a scale and a ruler to measure pounds required to compress one inch.  Then order softer springs.

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gregjet

The forks definitely should get pretty much the total advertised travel. That's drop and compression travel.

THE most likely you are getting limited travel is hydraulic lock. If you get blown seal you will know for sure...however BEFORE that happens...

Did you completely disassemble you forks and fill from clean? If not the chance is that was still oil in the forks.

The safest way to fill forks is distance down fron the top of the tube with the forks fully compressed, unless you have done it that way and then measured how much that was.

Empty them and ensure all oil is out. Then fill and pump to ensure the oil is all where it should be. 120mm from the bottom of the cap threads on full compression ,no spring should be close. BUT fully extended will have some drop travel fluid around the top out spring.

Unless you are very light, the stock spring are VERY soft. If you have 20mm sag ( with or without rider?) , you probably have too much preload. This shouldn't limit you travel unless you are getting spring bind ( unlikely, as the springs have a LOT of extra travel to coil bind).

My advice for what it's worth...clean em out and start agiin

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mcbrien

MCN says sag should be 25% of total travel. I weigh 185lbs and the stock springs are perfect for me with a sag of 1 5/16.

I read a post saying to use an oil with a viscosity around 45cst@40 . Agip 10wt is on the money. My forks are great now.

Air gap should be162mm (6.4in) no springs fully compressed.

You want 1 5/16 sag on rear also.

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pattonme

In the case of Yamaha and this bike at least, the factory does not count top-out spring compressed into travel numbers. I think Honda does though. If you pull your forks apart the damper rod should be sticking out ~130mm out the bottom. Oil lock takes away about 20mm which doesn't mean you don't have that 20, it just means things get stiff in a hurry. 

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