Fork Oil Wight for my 1980 CB750F

[elipeer]

Guy,
I'm building a tracker from my 1980 CB750F, I will install a new Progressive Suspension Springs, what wight oil fork do you think I should use?
I live in NYC and holes are mean… I was thinking of using 15wt modern shock oil.
thanks

 

[gixxerrayfe]

I've just used 15w oil cos it was all I had at the time and it's fine. Our UK roads are terrible!!

 

[Trionda]

What did you end up using?
I am about to use what the book recommends: Automatic transmission fluid, rated at 10W.
I'm going to use synthetic Dex/Merc, because that's what I have, but I'm open to better suggestions.

 

[losttravlyr]

given the choice i would run 15W but if atf is what i had around it would be o.k to. some softer but not that much, if ya dont like it it's easy to change later. either one the fluid fresh and at correct capacity is a maintenance thing and improvement.

 

[gixxerrayfe]

Running 15w for a while and I'm happy. I've braided brake lines and ebc pads. Means I can brake quite hard and the forks don't dive too bad now.

 

[Trionda]

I use 15W Bel-Ray in my daily rider, and it's done a fine job.
With these new, firmer springs though, I don't want to start out with 15W, for fear of making the suspension too tight.
Thanks for your input.

 

[Trionda]

Precisely why I've made the switch to Progressive springs. The stock front end felt as though it would go out beneath me due to the terrific dive I experienced.

 

[losttravlyr]

there is a old trick about putting a washer or two on top of the springs to make them feel firmer.
no substitute for new springs but handy when the bucks are down.

 

[Trionda]

there is a old trick about putting a washer or two on top of the springs to make them feel firmer.
no substitute for new springs but handy when the bucks are down.

Yep; that makes perfect sense. By compressing the springs a little, you pre-load them just a hair, and you also create a slightly firmer unsprung feel.