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Ok, Im going to chang my oil to either 15 wt or 20 wt and add a pvc spacer with my stock springs for a temporary solution to the SV's junk forks. Couple of questions though, which oil is good, probably order from dennis kirk, they have bel-ray and PJ1? What weight would you reccomend, I weigh 175 and want a stiffer front end but not too stiff. And finally how many liters do I need, is one liter enough to do both?
 

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I used and always use bel-ray, I put 500ml of 10w in each leg with a 1'' preload spacer, I'm 185/190 you could probably use about 3/4'' spacer. Oh what year is yours? mines an 03
 

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Race tech suggests using Bel-Ray 20W. I just did mine and I have a liter of 20W left over. Was able to do both with one liter. Sell it to you if you want PM me.
 

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1 Liter split between the two forks and your golden. Fork oil is fork oil IMHO. :)


I wonder if you can put some Rotella T full synth in the tubes for increased performance and ride comfort??? ;D
 

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sprint_9 said:
Ok, Im going to chang my oil to either 15 wt or 20 wt and add a pvc spacer with my stock springs for a temporary solution to the SV's junk forks.  Couple of questions though, which oil is good, probably order from dennis kirk, they have bel-ray and PJ1?  What weight would you reccomend, I weigh 175 and want a stiffer front end but not too stiff.  And finally how many liters do I need, is one liter enough to do both?
Use 15w with the stock springs, set at 105mm. Just add enough preload to set your sag correctly. Remember that adding preload isn't making your springs any stiffer, but having the sag set right does have value. Check the Tech Articles section of our website, there's an article there on sag, and changing the preload to set it.
 

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heres a few tips b4 you do it. the fork cap is under pressure and WILL jump out. use something to prevent it from jumping.
 

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Nexus242 said:
Fork oil is fork oil IMHO.   :)
Sadly, not true. A couple of years back someone reported having horrible handling problems after a fork oil "upgrade". Turns out he used some off-brand fork oil (Bardahl or some such oddball stuff). Apparently they figured the oil's viscosity in a way that was substantially different from the norm. The result was that his "20W" fork oil was behaving much more like 5W.

Stick with Bel Ray or similar major brand stuff.

My $0.02

Bill
 

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Has anyone tried reducing the length of the stock, buy cutting off a few inches, as a method of making the spring stiffer, to work with 15w or 20w fork oil?

As I recall the stock spring is about 400 mm and my aftermarket springs are about 340 mm. Had I removed 60 mm from the stock spring, and added a 60 mm spacer, the spring rate would have increased to about the same as my $100 pair of aftermarket springs.
 

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bmetz99 said:
Sadly, not true. A couple of years back someone reported having horrible handling problems after a fork oil "upgrade". Turns out he used some off-brand fork oil (Bardahl or some such oddball stuff). Apparently they figured the oil's viscosity in a way that was substantially different from the norm. The result was that his "20W" fork oil was behaving much more like 5W.

Stick with Bel Ray or similar major brand stuff.

My $0.02

Bill
Well yeah I wouldn't buy any no name crap but all the top brand names are pretty much all the same. I used Bel Ray 15wt in mine but might try 20wt if I change it out this summer.
 

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I used 20wt Bel Ray. I weigh 195 and put in 90 springs from Sonic. Worked for me. I got 2 pints of oil and did not use it all.
 

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inframarginal said:
Has anyone tried reducing the length of the stock, buy cutting off a few inches, as a method of making the spring stiffer, to work with 15w or 20w fork oil?
Yes. A while back someone posted a fromula relating rate to length. I also have it somewhere in one of my engineering texts.

So I cut down my stock springs and was able to custom-tailor their rate to my (ever-increasing) weight.
As I recall the stock spring is about 400 mm and my aftermarket springs are about 340 mm.  Had I removed 60 mm from the stock spring, and added a 60 mm spacer, the spring rate  would have increased to about the same as my $100 pair of aftermarket springs.
Yep.

Bill
 

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inframarginal said:
Has anyone tried reducing the length of the stock, buy cutting off a few inches, as a method of making the spring stiffer, to work with 15w or 20w fork oil?

As I recall the stock spring is about 400 mm and my aftermarket springs are about 340 mm. Had I removed 60 mm from the stock spring, and added a 60 mm spacer, the spring rate would have increased to about the same as my $100 pair of aftermarket springs.
why is this not more popular or done??????????
bill agreed but you didnt give any explanation
 

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There are limits to how short you can make a spring. You have a certain amount of fork travel. You need to ensure that you can compress the spring the amount of the fork travel without binding any of the coils (zero clearance). Measure how many coils you would wind up with after cutting the spring. Add up the gaps between the remaining coils. You have to have more gap than fork travel or you will bind the coils, possibly with very bad effects. Knowing the original spring constant you can figure the new constant (Kx). Cut a new spacer, trim to get the right sag.
 

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Assume the front fork has 127 mm of travel , and the original spring length was 428 mm, and the original spring rate was .65. According to many spring vendors I need (and I purchased .85 springs). .65/.85 is 0.764705882. Thus if we cut the spring down to 327 mm (428 *.7647) the spring rate will increase to .85. Please note that I don't recall the exact amount of travel so I have assumed about 5 inches for the numerical example.

A very important issue is that the cut down spring must be able to compress from 327 mm (unloaded) down to at least 175 mm (327 - 127- 25 mm or so for a fudge factor) without the spring coils touching each other. Then you make longer springs spacers, change to 15w or 20w, and the fork won't dive so badly.

I bought springs from one of the site supporters. They work great. They were only about $100, but guess what .... they were much shorter than the stock springs, which reminded of a engineering class on springs and what not.
 
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