Harley fork oil weight is

[XLFREAK]

type B=5w, typeE=10w, type heavy weight=20w, 07'sporsters models xl883L/xl1200L=12.3oz, all others 11.6oz. factory has 10wt. installed on nightsters and boy is it dirty and rust colored acct. of moisture.

[Stingray]

How do you tell what type oil was installed when the bike was new? I'm going to be changing the front sprins and want to know where to start with the oil weight.

[XLXR]

Good information, but what about Nightster?

Stingray, start with the recommended viscosity if you weigh close to 180 lbs. If you get fork dive, add 1 oz oil to each fork leg. I added two oz's, but I have a Roadster. It all depends on how much you weigh and how you feel the bike is riding. Some guys like the heavy oil, but I rode a 07 Roadster with the heavy oil and the forks were mush compared to mine. If you weigh 140 lbs, you might want to try the 5 w oil.

If you feel the shocks are a little on the stiff side, using 5 w oil in the forks may help a bit because soft forks unload the shocks a bit. Consider 5 w as an experiment, I don't know if any one has done it yet. I tried it and it was too light for me, but I have drilled out the holes in the damper rod.

[XLFREAK]

stock xl1200N comes with 10wt, changed to 15wt with new progressive springs and didn't like the tightness the forks exibited, changed today to 5wt. and only added 11ozs. oil instead of the 12.3ozs. per manual acct. of the larger diameter coil of the springs and added length. It's been raining cats & dogs here in Florida ALL day so was only able to rock back and forth holding the front brake but it seems like a favorable improvement over the overly stiff 15wt., also checked the shims which I cut in half from the 8" stock metal shims which ended up being 3 1/2" long after dressing up the cuts.They extend 1/2" above tubes per spec. sheet...hopefully the ride will be more controlled but absorb small road irregularitys...more info when able to ride...

[XLXR]

When I left Florida for S. California, I thought I would miss it. I don't, it has rained once in almost a year.

Be sure to let me know more details after you test ride.

Trying 5 w fork oil, you are a brave, brave man.

[XLXR]

hoghead - Whittlebeast a spread sheet set up to do all sorts of suspension calculations.

Can you measure out your fork spring so we can figure out what spring rate it is?

We need to know:
1 total spring length in inches
2 Number of free coils, coils that do not touch each other. Since it is a progresse wound spring can you count the number of tightly wound coil and the number of loosely wound coils.
3 the wire diameter, You will need a micrometer for this. My Roadster spring is .180 inch. The Nighster spring is a lot less.
4 the outside diameter of the whole spring. Mine is 1.90 inches.

Thanks

[XLFREAK]

5wt sucks,was getting close to bottoming out when braking,changed to 10wt. and added more shim washers so it is 5/8th above fork tubes instead of 1/2". I have noticed the nightster fork has not got alot of travel...maybe 2" after sitting on bike. Ride report after I change out front M/C from a roadster dually.

[XLXR]

http://xlforum.net/vbportal/forums/s...t=82517&page=4

post 38

Doxbike posted a good description of his experiment with 5 with. With 5 w, it is even more important to add a bit to the oil level correct to prevent bottoming out.