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Discussion Starter · #1 ·
I'm replacing seals on my friends '98 750. Should I just go with the service manual as far as oil weight and level? Is there an improvement with a 10 weight oil?
This is a street bike that is also used for trackdays.
Thanks. Mike
 

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The 5w should be fine if the springs are the correct ones for his wieght...

John
 

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Discussion Starter · #3 ·
Good question.

What is the rate of the stock springs in a '98?
 

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the service limit on the front springs is 9.9 in.

the oil type is #10
 

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Originally posted by spongebob:
the service limit on the front springs is 9.9 in.

the oil type is #10
<font size="2" face="Verdana, Arial">Yea the zuk #10 is a 5w fork oil... I asked about that when I first did my forks... I tried 10w when I had stock springs and it helped a bit... but it is much more nice with the correct spring and oil..


Springs are rated at .801 kg/mm per RachTech...

John
 

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wot the fook is "rated"???
in my post(above) the 9.9in. is the overall lenght...this would be how "short" the spring can get before it needs to be replace!!
 

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Discussion Starter · #7 ·
So the stock springs are .80 kg/mm according to Race Tech. I understand that.

"I tried 10w when I had stock springs and it helped a bit... but it is much more nice with the correct spring and oil.."
This I don't quite understand.

I've got 5w Honda and 10w Silkolene to pick from.
At .80 kg/mm, the springs are too soft for my portly, 185lb friend. I should get some .95 springs. More spring means more damping. Maybe I'll use the 10w.

Mike
 

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No more spring does not meen more damping...

THE SPRING HOLDS THE WIEGHT UP AND THE DAMPING CONTROLS THE SPEED THE FORK COMPRESSES AND EXTENDS.

So with that in mind... You should not have to change the oil when you change the springs. I used a thicker oil with my stock spring to help make up for the fact that the spring were to soft. This made the compression a bit more stiff... Witht he correct spring, the oil would stay the same no matter what spring you have in it.

John
 

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Discussion Starter · #9 ·
"More spring means more damping."

That was a statement.

Let's say you had the correct damping force and the correct spring rate. If you increase your spring rate alone you will need to increase your rebound damping rate to control the spring.
Heavier fork oil will affect rebound damping but not compression. A different air gap (oil height) measurment will alter compression.
Agree?
Mike

[ 08-12-2002, 03:22 PM: Message edited by: Minnesota51 ]
 

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No I dont agree.. The rebound should not have to be adjusted if you have the correct spring becuase the wieght from the rider and the bike would control the extra spring...

Also the oil does control the compression as well... The thing that the oil level does is control the botom out of the forks...

Now yes you would need to change the oil (or the valves) if you over sprung or under sprung the bike... but lets say that you spring the bike for a rider that is 150 and you set the valves. then you spring the bike for a 200 lbs rider. The people riding the bike are the correct wieght for the springs, the change to the valve would be very minimum... The extra wieght of the rider will slow the rebound as long as the tire is in contact with the ground.

If you were to lift the bike then yes the rebound would be faster, but since the spring has to fight the wieght of the rider as well as the valves... it shouldnt be that different.. I have done this a lot..

John
 
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