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Author Topic: 82 CB650: Fork oil capacity  (Read 3693 times)
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jacobarber Topic starter
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« on: January 14, 2012, 11:48:33 AM »

Everywhere I've read so far, people are saying the manual (mine is on its way) says to take the forks to the dealer if they need the fork oil changed. The forks are air assisted, so I suppose there was a risk of people getting hurt without letting the air out before removing the caps.

So can anyone definitely tell me how much fork oil (and air pressure) these suckers are supposed to have? I'd really love to get this done before the manual shows up.
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« Reply #1 on: January 14, 2012, 12:22:55 PM »

Hogwash. The manual doesn't say anything like that. Tell those people to give advice only if they actually really know what they're talking about. Besides, the dealer is more likely to screw something up than actually do the work properly.

Step #1: Wait a few days for the manual to get there.
Step #2: Read the manual. Make certain you're using the correct information in the addendums as required.
Step #3: Read the manual again with the motorcycle in front of you.
Step #4: Follow the instructions for the actual work.

This is basically what you'll be doing:

Take the air cap valve cover off the top of the right fork and dump the pressure just like letting air out of a tire. It's not much air if any.
Remove the hose between the forks.
Remove the fork caps on both sides. When you do this, keep your face out of the way. It's no big deal, just don't be putting your eye in line with the piece that has stored energy behind it just like you don't look down the barrel of a gun. Put your hand on top of the plug and keep a little down force as you turn it to keep it from binding with the threads. When the threads finally let go, slowly lift your hand up and the spring pressure is gone. It's not anything horrifically strong, just enough to poke an eye out if you don't put your hand over the thing.
Put a bucket under the drain plug on the forks, remove the bolt and drain the oil. Again, it's not much fluid.
Put the drain plugs back in. (IIRC 3-5 ft-lbs though look it up or I can later)
Add 10.2oz of ATF fluid to each side. (this quantity is for draining, not dry capacity and for the nighthawk, not the standard)
Put the end caps back on. (11-22 ft-lbs)
Reinstall the hose. (Torque to 3-5 ft-lbs and no more)
Pressurize to 10-16 psi. NOTE: This is a small volume system. It's not a giant truck tire. Just a small amount of air volume is all that's needed so don't put the air chuck on there and leave it like you do a tire. I never figured out how to fill it with a bicycle pump without losing all the air. I use my compressor with the hose pressure set to 20psi. (DO NOT do this with a big compressor with an hose pressure in the 100+PSI range or you'll blow the slider seals) A quick tap of the air chuck at 20psi will put the fork pressure at 15psi right then. Every check with an air gauge drops 1psi from the forks. I run at 15-16psi however I also ride in rougher conditions than most riders will so play around with pressure at 10-16psi for what is right for you.
Done.

Total cost: $3ish for ATF fluid if you don't have it.
Total cost at the shop: $50-75/hr for a couple hours plus parts plus whatever they break or screw up or don't actually do.
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jacobarber Topic starter
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« Reply #2 on: January 14, 2012, 03:05:29 PM »

I'm curious why the use of ATF is suggested over actual fork oil. Would something like 10w fork oil be feasible as an alternative?
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« Reply #3 on: January 15, 2012, 02:11:36 PM »

I think the manual calls for the dealer on seal replacement not just a oil change.  havent looked at it in awhile.  A couple have been done on the sohc4 site.  I use 15wt fork oil myself.
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« Reply #4 on: January 15, 2012, 06:42:31 PM »

If compressed air is/or was a concern, remove the air, then remove the valve core.
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« Reply #5 on: January 15, 2012, 07:21:40 PM »

No need to remove the valve core. Just release the air pressure like you would on a tire. After the pressure is released, the only concern is the pressure from the springs.
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« Reply #6 on: January 15, 2012, 07:50:40 PM »

I think the manual calls for the dealer on seal replacement not just a oil change.  havent looked at it in awhile.

The OEM manual shows the procedure to do it yourself in detail.
I have no clue what the aftermarket manuals want you to do.

It's not difficult. The special tool to seat the new seals can be pennyteched with a piece of PVC pipe the correct diameter.
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« Reply #7 on: January 15, 2012, 10:24:21 PM »

New seals are no longer an issue. I grabbed a set of forks off eBay and installed them this weekend. I'm just looking to change the fluid so I can make myself more accountable for the performance of the forks. I've already checked and tested the seals. They are happily leak-free.

I'll be changing the fork fluid next weekend with the proper amount and air pressure. Thanks for the answers
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« Reply #8 on: January 16, 2012, 06:18:06 AM »

O
I think the manual calls for the dealer on seal replacement not just a oil change.  havent looked at it in awhile.

The OEM manual shows the procedure to do it yourself in detail.
I have no clue what the aftermarket manuals want you to do.

It's not difficult. The special tool to seat the new seals can be pennyteched with a piece of PVC pipe the correct diameter.

Obviously a dealer manual wouldn't call to take it to the dealer.  Hap1  The clymer does. Dont know about the haynes dont use it much.
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« Reply #9 on: January 16, 2012, 08:32:22 AM »

Obviously a dealer manual wouldn't call to take it to the dealer.  Hap1

I don't know about that. Have you seen the lack of quality of work coming out of dealers in the last couple decades? And I bet the dealer shops use generic vague wishy washy manuals, not specific vehicle manuals.

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The clymer does. Dont know about the haynes dont use it much.

I wonder if clymers is in cahoots with the dealers. (lightbulb is out, take it to the dealer and we get our cut of your triple digit money) Or just too lazy to write up a simple procedure.

Fork seals. Nothing dangerous, nothing difficult, nothing magical. If it was, the knuckle dragging parts canon boys couldn't do it anyway. If they can do it, you can do it better.
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