Topic: A little help with choosing fork oil weight

[Scott S]

 I did a search a week or two ago in preparation for new oil in my CB500 forks.Most of what I came across referred to Progressive springs and handling upgrades, but the consensus was somewhere around 7-10 wt. oil, saying that was close to what ATF fluid is (which is what was often used "back in the day").

 I was all set to try 7 wt. and then came across a recent thread and everyone is talking about heavier oils....12-30 wt.

 I have an early CB500 so the springs and internals are slightly different than most CB550's. I'm 185 lbs. and I'm just looking for nice handling and ride quality. I'm not a knee dragger and I'll most likely never see this bike on the track.

 Suggestions?

[Steve_K]

Here is how I decide on fork oil.  I try 10 wt. in the forks first.  I ride it and see how it feels.  I record oil level with the fork compressed fully. (springs out)   If using old fork springs I may put some spacers(washers) to increase preload.

For me its about how it feels.  This is how I assemble the forks.  No springs in forks.  Oil in forks and record oil level.  Assemble the front end.  The front wheel should go up and down without binding.  Do this by hand  and be sure bike is stable.  The wheel and fender assembly can bind when the fender brace is bent .   The good thing is you can change the oil and preload without removing the forks.

It is a pain to do it this way but it works for me.

Steve

[bwaller]

Scott, I started typing but instead decided to add this http://www.strappe.com/suspension.html. There are similar pieces on the Sonic Spring & Racetech sites. Probably you've seen this but if not give it a read.

Everything considered suspension tuning is probably every bit as important as engine tuning. Even older forks can provide good suspension, it's quite easy and certainly rewarding on the back. 

I use ATF in two bikes and on my racebike use 15W. Thicker oil isn't the answer.

[Scott S]

 Bwaller, I value you're opinion. I'll be doing swimgarm bushings and better shocks at the same time, as well as new tires. I'm sure all of that combined is BOUND to make a difference.

 I think I'll stick with somewhere around 7 wt. to start.