Topic: Fork oil - maybe I'm making this harder than it is.

[gregimotis]

'76 CB750 f1


Allright, searches and the FAQ's make it sound like all I need do to change my fork oil is drain one fork at a time, unscrew the top bolt (keep pressure so the spring doesn't pop up) and refill.

Thing is that my manual specifically says not to remove the top bolt without first releasing the fork from the triple tree mount.  Now the manual also assumes I'm doing a complete teardown, so maybe this doesn't apply... but now I have 'The Fear'.


Can anyone be kind enough to rule on this for me?

[petercb750]

I have changed the fork oil in both our 750 and 400 and done it the way you were going to do it with no problems or ill effects. I drained both forks at the same time by removing drain bolts and pumping the forks up and down, with a couple of tins that managed to not catch most of the oil, because it squirted out past them  , and then replaced drain bolts, removed top caps and refilled according to specs.
Hope that helps.

[gregimotis]

Thanks.  I couldn't believe it was harder than that, but then I'm just the sort of person to not read the instructions really mess a thing up good.

[StevieMac]

I'd suggest that you take the weight off the front end before you pull the fork cap(s).

Also, the clamping force of the top triple clamp around the top of the fork can make it tougher to remove the cap in my experience, so I would loosen that bolt first.

[DrMark]

This may help...Manual says to only loosen the top triple tree bolts. It allows the top nut to be loosened easier and replaced without having pressure form the triple tree clamp bolts. Hope this makes sense?

[BobbyR]

Well I have two chips in my tank from the throttle cables when I removed the two fork caps at the same time. It seems one spring will hold the front end up. Jacking it up would be better, but you cant pump out the oil that way. No fear my brother, just use common sense.     

[Rocking-M]

Just curious but is there a better performance oil for the forks?  Maybe aid in the handling a bit?
I know that valving and oil weights can be change on Koni shocks, for instance,  to change handling characteristics.
Just wondering if anyone has experimented with the forks on our old Honda's.

[nickjtc]

   with a couple of tins that managed to not catch most of the oil, because it squirted out past them  ,

The oil will squirt 2 or 3 feet so take the appropriate steps to catch it! I'm still finding vestiges of old fork oil under the work bench...

[eldar]

You should see the oil squirt when you pull off both caps with the bike jacked in the front, then removed the 2 bolts and drop the front end! Mini firehose!

I have one thing to ask. When was the last time your fork seals were replaced? If it has been a while, maybe you should just removed the forks and clean things out and replace those. Just a suggestion.

[ofreen]

Well I have two chips in my tank from the throttle cables when I removed the two fork caps at the same time.      

Draping a thick towel over the tank whenever doing any work in the vicinity of the tank saves a lot of grief.

[dusterdude]

Just curious but is there a better performance oil for the forks?  Maybe aid in the handling a bit?
I know that valving and oil weights can be change on Koni shocks, for instance,  to change handling characteristics.
Just wondering if anyone has experimented with the forks on our old Honda's.

there is something to this idea,you can change the rate of up and down movement and the spring "rate" so to speak,you change the oil viscosity and/or amount of oil,which does what i do not know.

[nickjtc]

Just curious but is there a better performance oil for the forks?  Maybe aid in the handling a bit?
I know that valving and oil weights can be change on Koni shocks, for instance,  to change handling characteristics.
Just wondering if anyone has experimented with the forks on our old Honda's.

Has anyone tried the 'pre-load' thing where you slip a length of appropriately sized ABS tube over the top of the springs?

[StevieMac]

Has anyone tried the 'pre-load' thing where you slip a length of appropriately sized ABS tube over the top of the springs?

Not on my SOHCs but yes.  It can make a really big difference in how the bike handles.  As I recall, somewhere between 25 and 30mm of sag is optimal but I can't remember for sure.  It's been a while since I was up on all that stuff.  I should check the sag on my 500 one day though to see where it's at.  Sounds like a good winter project (one of many....)

[BobbyR]

I pre loaded my spings with 2 washers, that is the most I can fit in there. I personally use ATF as per the manual, but I may try some SAE 30 and see if that helps or hurts.

[eldar]

I think 30 weight oil would be too heavy.  the honda fork oil is 7 weight and you can get 10 weight I think.

[Hockers Choppers]

The haynes manual says 10w30 for all cb750's. It this right?

[Dave K]

When I change fork oil only I remove the front wheel and fender. That way I can place a jack under the engine to secure the bike and then pump each for tube by itself. Many times I will add fresh oil and simply pump it out again just to flush the forks clean. I find it a good time to just remove the tank and use a socket on an extension to remove the fork cap nuts. I dent or scratch in a tank is a terrible thing to have happen. Besides, how long does it take to remove two gas lines and the rear strap to remove the tank? It isn't worth the potential damage to me. Another reason I remove the front fender. If drop a wrench on that soft metal?