Fork questions

I have some confusions with forks ( the motorcycle part), if my seals seem good, should I still replace them, I dont remember any leaking when I had it, but I never rode it and never put real stress on it. I also have no idea how much fork oil to put in a cb360 ( Is there an online manual?). I got 30w oil for a stiffer ride, and better around the corners but I dont know if u mix it or what. Thanks again DTT members

The manual specifies that ATF should be used to fill the forks with each fork taking between 160cc and 165cc. If the seals are fine and you're not wanting to adjust the ride at all, leave it be. If you are wanting to adjust the ride, you'll want new seals.

Sonreir said:

The manual specifies that ATF should be used to fill the forks with each fork taking between 160cc and 165cc. If the seals are fine and you're not wanting to adjust the ride at all, leave it be. If you are wanting to adjust the ride, you'll want new seals.

Click to expand...

I been trying to get the manual, taking forever, but what do u mean by adjust? like lowering it? Like I said I have a confussion with forks. Thanks for the help

Ride height is largely controlled by the length of the spring + any spacers (which would be aftermarket) and in some cases the forks themselves are longer or shorter. It is, of course, possible to just clamp the forks a bit lower, but this always looks ghetto in my opinion.

For stiffness the spring, again, has the most to do with this. The thicker the spring, the stiffer the ride. Also, less coils means a stiffer ride. So it's possible to increase the stiffness without lowering the height by cutting a couple of coils and adding a spacer so that the uncompressed length is about the same.

Changing to a thicker oil will increase the stiffness to a bit, but mostly it increases the damping affect by preventing the spring from compressing and decompressing too quickly. Basically, it makes it less bouncy. Going too thick on the oil may lock the forks, so go easy.

Oh ok, than I think just doing thicker oil is good enough, and I am just going to clamp them lower, I think it looks cool, but to each his own, actually didnt like it at first. I guess I will check for leaks, and if not I will pass on changing them out. Thanks again, now to polishing my forks and putting my fork gaiters on

Sonreir said:

The manual specifies that ATF should be used to fill the forks with each fork taking between 160cc and 165cc. If the seals are fine and you're not wanting to adjust the ride at all, leave it be. If you are wanting to adjust the ride, you'll want new seals.

Click to expand...

All correctm except for the ATF part. ATF wont hurt your forks, but theres a reason they make fork specific oil now.

The manual is awesome, just downloaded it and wish I did a long time ago, should help me a lot.

You're getting some good tips from Sonny, I will add if you are just draining the forks and filling them back up it's recommended to use around 140cc, and if your doing a full tear down you'll be in the 160cc range.


I'm also in the fork stage, looking to stiffen my CB360 forks since im dropping them through the top triple.
But it seems as I may be able to physically shorten them as well (without having to cut and re-thread that long damper rod).


Ive been bothering PJ about this for the last few hours so, i'll post whatever I can come up with on here.


But these are my internals for the CL/CB360.





From what my brain can comprehend, PJ mentioned using some PVC, about 1.5" - 2" , to be placed right above the lower rebound spring. Then cut an inch off of the main spring, and fit a 1" spacer right above it, then button her up.


That should be the stiffening procedure...
But as for actual LOWERING, without sliding the forks through the top triple; im still trying to comprehend it.


As for for oil, WITH stiffer springs you can use a 20w+ weight fluid, otherwise you'll get hydro. lockup.
For stock, I wouldn't go past 15w. Just some regular Fork Fuild should be just fine. You can get away with motoroil aswell.

Chime in brothers! I feel like im a bit wrong...

This is very good information, and very important, because I dont want lockup. So basically I need to cut and space my springs to use the stiffer oil to have better handling, looks like I am redoing my forks. ;D Thanks guys i will stay tune to your posts

The spacer you put under the return spring / damper rod will shorten the fork.

The reason you cut the main spring is so you can get the fork cap back on (because the spring effectively be longer by the amount of spacer you put underneath the return spring).

And removing coils from a spring makes the spring stiffer - which is good because you will have less travel in the fork now and it will bottom out easier.

The bottom of the fork tube has an internal lip.
it 'catches' on the piston at top of damper rod.
if you fit a spacer, in effect it shortens the damper rod by moving the tube down (really preventing it from fully extending)
You have to shorten fork spring if forks don't use spacers stock.
Shorten spring about half the amount of damper rod spacer, then add spacers to top of fork spring to get ride you want.
Probably a good idea to try springs without any additional spacer first, then add if needed (you will find a major change
You wont need 20wt oil, compression damping is only about 20%~30% of rebound damping, using thick oil to control compression means rebound will be almost solid so forks will go down, but take a while to come back to normal level
I vary rarely use anything above 10~12 wt, particularly if your not modifying damper holes or fitting emulators

That makes perfect sense, I think I will just mix the 30wt and some ATF but it wont be a solution, and seperate, soo i dont know if that would be a problem

Go to Wal-Mart and ind the cheapest 10w/30 full synthetic engine oil.
You'll be real surprised how well it works

Alright will do, seems like you know your stuff pretty well. Thanks again PJ

SO today I am going to get around and get my forks done, or I would hope. So just making sure, I just need to take the fork springs out and cut them half of what the spacers are and then put the fork springs in and the spacers on top, fill wil 10 30, and compress and screw on the top fork bolt. is this right? I am trying to get motivation this morning, I looked out the window and noticed my car was leaking powersteering fluid........aggggain, old cars...

When you do fork oil, leave top spring out, compress fork leg, put some oil in and work for up and down a few times to get all the air out of the bottom half, then top up to about 5.5" from top, no spring, fork compressed.
I rarely measure fork oil quantity as the level is way more important.
You have a long Allen key to remove through bolt holding things together?
It's best to loosen it before you take top nut off (drain the oil though)

Will a allen socket and extensions work? I loosen the bolt on the bottom, but I have no idea how it comes out so I stop messing with it. Thanks and I got some electrical PVC pipe to use as spacers today

That's the way to do it. 8)
You may need to compress fork (hod it in a vice by the solid bottom piece and not where the tube slides)
You have to take bolt all the way out to separate fork and add spacer under damper rod piston.
It's real simple when you have it apart

Ohh ok sorry that makes total sense. I cant wait until I can stop asking questions and start answering peoples. I made the spacers, a little below 2'' but both equal. I will put up pics when I am done. Thanks again

Well it seems that the allen socket cant reach because its too fat, so I am going to have to make a tool. It will be easy just dont know what size that bolt is and dont want to cut up a bunch of allen keys. thanks guys, IDk if I am doing something wrong, because it shouldn't take this long haha. ???