Topic: front fork maintenence

[hymodyne]

evening,

I've drained and refilled my front forks with oil. do I need to compress them before I tighten the fork caps?

hym

[frostypuck]

huh? I think if you compress them at this point, you'll end up with un-filled front forks. If they are still on the bike, I find it's easiest to jack the front wheel off the ground while pushing down on the cap and turning it on by hand to get it started on the threads.
Good luck,
Chris in Boston

[Jonesy]

Once you get the fork caps on a few turns, gently work the forks up and down a few times to get the air out of the lower portions of the valving in the forks. Then, tighten the caps, and take her for a spin!

[rob]

Has anyone here ever done maintenance on the air-assist forks that are seen on models such as the '81 CB650 Custom?  The Clymer manual for that bike says that the air-assist fork type shouldn't be done by a home mechanic, and should be taken into a shop (however, the Clymer manual also says that about the front brake caliper, which was a piece of cake to take apart and fix).

I have looked on the web and this forum, but I can't seem to find any info on the air assist forks?  Anyone have any recommendations on whether or not it is easy to change the seals in these for a home mechanic?

Thanks,

Rob

[dpen]

A handy little tip from when we rode? (worked on) British bikes.
Nip everything up (axle, triple tree etc) but don't tighten them completely. Push the bike forward two or three times & hit the front brake. This helps to align everything. Tighten it all up & you're off.

[bryanj]

Air forks are just same as oil forks you just gotta be way mor critical about marks/pits on the legs and super careful about removing/replacing seals----Oh yeh and let the air out first usless you want to find out what an oil bath really is!

[cb750_chris]

Air forks are nice.  They are basically regular old forks with air fittings on the caps.  You can get kits to put between the fittings and have the air balance itself.  I think that is a waist of time and money though. 

If you have air fittings get yourself a progressive susspension pump.  It's a small syringe type pump with a 0 to 30 psi. guage on it.  It also reads kg/cm^3.

When you get it you'll think what did I just spend my money on?  When you use it and realize how accurate and easy it is to get exactly the right ammount of low volume low preasure air in both forks you'll wish you always had one. 

I found mine after a couple of weeks of searching e-bay for I think $15.00. and now have 13 psi. of air in both forks.  My manual recomended 11 psi. but I found that 13 gave me the rebound I was looking for. 

[mgilvary]

I think I'll piggyback onto this thread...

I have a '75 550 and I'm a little concerned about the front suspension. I put in new seals and oil, and recently installed some new, pretty stiff rear shocks to replace my terrible old originals. The rears seem to work pretty well, but they also seem to amplify the deficiencies of the forks.

I've been riding a particularly jagged stretch of road up in the mountains that has been really cracked up from the winter rains here in LA. When I hit that stretch, my front end bounces so severely that I have to slow down from 50-60mph to 35-45mph -- and I'm talking on the straightaways. And even then, if feels iffy. The rear end, I should point out, is rock steady. I never hit that stretch of road when I was using the old rear shocks, but on other bumpy roads, I think the squishy rears would absorb a lot of the front-end bouncing, resulting in the bike teeter-tottering back and forth, which, oddly enough, is less scary than the front end bouncing up and down while the rear remains in place.

My riding mates, who are all on modern bikes, say the road is bad for them as well, but they leave me in the dust nonetheless. I know my old girl will never take that road as well as my buddy's CBR, but, because I like to remain on my bike, and I like for my bike to remain on the road, I am trying to figure out how to improve my front suspension.

So far, the only feasible option I see is to buy some new springs from Progressive and drop those in. Has anyone used those and have an opinion about them? Anybody have any other ideas?

[kyre]

yes get the progressive springs. you'll notice a difference right away. also make sure your headset is tightened and there is no play in the bearings/frontend

[rob]

Thanks for the reply on the air forks. 

On the top of the fork, there is a little chrome twist on cap covering the air inputs.  I am having a heck of a time getting it off.  Is there a trick, or a tool that is required to get these off?  I have carefully tried to use vice grips, but I have only succeeded in stripping some chrome and dinging things up.

Thanks,

Rob

[cb650]

Some one might have cross threaded it.  Should come off like a tire cap.




                                Terry

[rob]

Hey everyone,

I am tyring to replace the oil in my '81 CB650C air-oil forks.  Attached is an image of them.  How do you get the oil in?  On forks without the air, there is a large bolt at the top of the fork you can loosten, then fill with oil.  On these forks, it is just a black plastic cap for the air nozzle. 

Thanks,

Rob

[kmmoran]

Those look just like the ones on my 82 CB650SC, so I'll say that like mine, that whole black piece with the threaded holes for the air hose on the top of the fork is the bolt you are looking for.  If you use an adjustable wrench on them, you can pad the jaws with a shop rag to keep the black paint pretty.  Once you have those off, you will see the top of the spring - make sure the forks are not compressed, or it will launch the black top cap further than you'll want to look for it. 

Kevin

[rob]

ok, i've given that a shot, but I can't get a good enough grip on the fork tube, and it just spins around.  Does this need to be mounted in the tripple clamp?

Thanks,

Rob

[TwoTired]

ok, i've given that a shot, but I can't get a good enough grip on the fork tube, and it just spins around. Does this need to be mounted in the tripple clamp?

That should work.  Or, you might try a strap wrench on the tubes.

[rob]

Ok.. another question.  Do I need to loosten the allen bolt at the bottom of the fork leg?  The one underneath..

Thanks,

Rob

[TwoTired]

Not, if your just changing oil.  At, least you don't on the CB350,400,500,550, and 750.  I never worked on the CB650, though.

[mgilvary]

yes get the progressive springs. you'll notice a difference right away.

Installed the Progressive springs on Friday. Rode the canyons to Malibu on Saturday. Remarkable handling improvement over the ancient stock springs. I should've bought them the day I bought the bike.