Shimming fork springs

Carlos840

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So, i wanted to change my fork springs and oil.

After a bit of research i have decided to first experiment with different oil weights and trying to shim the stock springs to get proper sag in the front.

It's a lot cheaper, and since i am only 176 lbs i think that i might get away with it as my current sag is not to far from what it should be.

There is one bit of information i cannot find a definitive answer for.

Should i shim on top of the spacer or under the spacer (add a spacer on top of the stock one)?

Thanks

 
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TownsendsFJR1300

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It really won't make a difference but I'd put it at the top so its easier to get at should you decide to replace/remove, etc..


How bout a set of these and really fine tune your front sag? :thumbup:


(Just haven't put them on yet, regular shrader valves from MX style valve stems epoxied into a spare set of fork caps)
 
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Carlos840

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It really won't make a difference but I'd put it at the top so its easier to get at should you decide to replace/remove, etc..


How bout a set of these and really fine tune your front sag? :thumbup:


(Just haven't put them on yet, regular shrader valves from MX style valve stems epoxied into a spare set of fork caps)

Thanks.

I would love a set of these! Problem is i can't seem to find any in Europe.

The only ones i found in the US are those:

04 05 06 07 08 09 YAMAHA FZ6 FAZER CNC BILLET PRELOAD FORK ADJUSTER ADJUSTERS | eBay

And they are to damn expensive and the color combo is pretty nasty!

I find it hard to spend more than a 100$ on something that could be done with 2$ worth of washers!


Regarding washers, the closest to the fork diameter i have found is 40mm (forks are 43mm) is that close enough?

Actually, do you mind measuring the diameter of the threaded part of your caps, so i know the exact inner diameter of the forks.
That would be amazing!
 
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TownsendsFJR1300

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Thanks.

I would love a set of these! Problem is i can't seem to find any in Europe.

The only ones i found in the US are those:

04 05 06 07 08 09 YAMAHA FZ6 FAZER CNC BILLET PRELOAD FORK ADJUSTER ADJUSTERS | eBay

And they are to damn expensive and the color combo is pretty nasty!

I find it hard to spend more than a 100$ on something that could be done with 2$ worth of washers!


Regarding washers, the closest to the fork diameter i have found is 40mm (forks are 43mm) is that close enough?

Actually, do you mind measuring the diameter of the threaded part of your caps, so i know the exact inner diameter of the forks.
That would be amazing!

The ID is 25mm's(the hole in the middle), OD of the threads showing, is 40mm's. Keep it just under 40mm and you'll be good.

Be carefull you don't strip those aliminum threads... :)
 
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Carlos840

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The ID is 25mm's(the hole in the middle), OD of the threads showing, is 40mm's. Keep it just under 40mm and you'll be good.

Be carefull you don't strip those aliminum threads... :)

Damn, i just ordered some 40 mm washers yesterday, i wonder if it will work... might order a few slightly smaller just in case.

Thanks a lot anyway, will have a play and report back. Hope it's a succes!
 

TownsendsFJR1300

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Damn, i just ordered some 40 mm washers yesterday, i wonder if it will work... might order a few slightly smaller just in case.

Thanks a lot anyway, will have a play and report back. Hope it's a succes!

It'll be real close, nothing a good, fine, flat file in a vise can't fix..:thumbup:
 
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Carlos840

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It'll be real close, nothing a god, fine, flat file in a vise can't fix..:thumbup:

yeah, that's what i was thinking...

For some reason i can't find 39mm ones, and can only find 38mm in zinc plated.

The 40mm ones i have are stainless which i think is safer than zinc plated inside a fork, i'll just get my file going and hope for the best! Glad i got 10 now, gives me a few spares in case something goes wrong.

Thanks for your help.
 

TownsendsFJR1300

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yeah, that's what i was thinking...

For some reason i can't find 39mm ones, and can only find 38mm in zinc plated.

The 40mm ones i have are stainless which i think is safer than zinc plated inside a fork, i'll just get my file going and hope for the best! Glad i got 10 now, gives me a few spares in case something goes wrong.

Thanks for your help.

I definitly wouldn't put the zinc ones in there..

If the ones you now have are SS, a file won't trim them. A trip to the bench mounted grinding stone would work fine.. It won't be much, if any, trimming...
 

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Hi Carlos. I got your PM. I use washers on both ends of the spring. This ensures the steel spring does not damage any aluminum parts; emulators, fork caps, etc.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2
 

Carlos840

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Hi Carlos. I got your PM. I use washers on both ends of the spring. This ensures the steel spring does not damage any aluminum parts; emulators, fork caps, etc.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

Thanks man, i wasn't sure you got it since for some reason the message did not appear in my outbox...

I'll see how many washers i need and take it from there...
Just wanted to be sure there wasn't a rule to this, there is surprisingly little info on the forum about shimming!
 

TownsendsFJR1300

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Why not just put the spacers just under the top cap, above the long tube spacer (part #18 & 38)?

Its doing the same thing and you won't have ANY CHANCE of a "foreign" object tearing up moving parts?
 

PFD023

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Why don't you just remove the stock spacers and install pvc piping cut to the length you want? PVC is what the folks at Sonic Springs include to be used (and cut to length) in their springs.....many others do as well. I't dirt cheap and can be found at most electrical supply stores.
 

Carlos840

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Why not just put the spacers just under the top cap, above the long tube spacer (part #18 & 38)?

Its doing the same thing and you won't have ANY CHANCE of a "foreign" object tearing up moving parts?

that's what i was going to do... not sure what the advantage of putting them both sides of the spring is, but it sounds like a lot more work!
 

Carlos840

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Why don't you just remove the stock spacers and install pvc piping cut to the length you want? PVC is what the folks at Sonic Springs include to be used (and cut to length) in their springs.....many others do as well. I't dirt cheap and can be found at most electrical supply stores.

Really? PVC pipe doesn't sound like something you would want in your fork!
I'll see how it goes with washers first, i doubt i will need much, according to another thread i saw i might have enough with one or two washers.
 

iSteve

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PVC pipe has long been used in forks by builders and aftermarket spring manufactures. It's cheap, easy to cut and you can get it at any hardware store. If you need to use more then 3 or 4 washers then PVC may be a better choice. But I can't imagine you needing that many washers.
 

Carlos840

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Well, i have two liters of Motul 10w fork oil (i decided to try 10w first rather than jump straight to 15w like some people did), some SS washers to shim, a new steel Renthal 15t front sprocket and a speedohealer!

let the fun begin, i will report back once i do the work.

This whole mod thing is really getting out of control!
 

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yeah, that's what i was thinking...

For some reason i can't find 39mm ones, and can only find 38mm in zinc plated.

The 40mm ones i have are stainless which i think is safer than zinc plated inside a fork, i'll just get my file going and hope for the best! Glad i got 10 now, gives me a few spares in case something goes wrong.

Thanks for your help.

Carlos, do you recall what the OD is for the spacers so they'll fit in the stanchion tube?
We're about to do some work on another Fizzer and I'd like to have some spacers on hand.

Tks in advance!
 

Carlos840

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Carlos, do you recall what the OD is for the spacers so they'll fit in the stanchion tube?
We're about to do some work on another Fizzer and I'd like to have some spacers on hand.

Tks in advance!

I never actually found spacers that worked!

I ended up buying the Racetech springs and set the sag with the new spacer...
 

ozgurakman

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I never actually found spacers that worked!


I ended up buying the Racetech springs and set the sag with the new spacer...

My weight is 74 kgs (163 pounds) but bike has hard side cases and topcase with givi racks.
I tried add shims from pvc hot water pipe, they worked and race sag (which is with rider) is near fine (25 mm.) but free sag was only 0.5 mm so I understood, that oem springs are not enough to stop head diving.

I'll going with racetech, too. Also probably I'll add this adjustable fork caps (I'll ask the seller if adjusters with 10 mm. hex head is available):

$_57.JPG


URL:
Front Fork Cap for Yamaha FZ6N FZ6 2004 2009 Adjustable Fork Bolt | eBay
 
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Marthy

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You need to aim for 10-15mm free sag with a rider sag of around 35mm. 25mm is track stuff... and still.

Free sag too little = spring too soft
Free sag too much = spring too hard

If you want to improve the dive under braking, raise the oil level in thr fork. I will asume that you bottom out the front end... add oil until you're just shy of hitting the bump stop. Figure it out when the spring & oil is out. Using a tyrap has a travel gauge work great.

To give you an idea on my FZ09. I use 0.90kg/mm fork spring. 42mm rider sag with no preload (adjustable om the 09). Free sag is 22mm. Oil level is 130mm instead of 148mm.

That's good for the track by the way... and still comfy on the road.

Rear sag is 35mm.
 
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