Topic: Fork oil

[climbingaz]

Rebuilt the forks on my '78 750k yesterday and made a stupid mistake.  Looking at the manual, it called for 7.3 oz of oil but I failed to look at the '78 supplement where it shows only 5.3 oz for my forks.  This, of course, was after I buttoned everything back up and mounted them back on the bike.

So I tried my best to just drain out 2 oz from each fork, but as I'm sure you know, the oil doesn't drain out nice and smoothly when you pull the drain bolt.  I doubt I got it exact.

Should I just go ahead and drain them both completely and refill?  Is the refill process easy without taking the forks completely off the bike again?

Thanks!

[MidnightLamp]

There should be a refill fluid volume for those forks somewhere in the manual. I'm not familiar with those models so I can't quote exactly.

Due to surface tension and viscous effects, a quantity of oil that is reasonably repeatable always stays in the forks themselves. The refill volume is the amount to use when you let the forks naturally drain, as apposed to the rebuild volume, which is the amount to use when all of the oil has been cleaned out.

I use the biggest syringe from the local drugstore (non-needle), which takes 100ml (cc) of fluid at a time. Easy to meter in precise amounts with that!

[nancy]

It was for my bike - which has K7 generation forks. I have drained and refilled mine 3 times. Remove the drain bolts, put plenty of ground cover and a bucket down for spills and pump up and down on the front as you haul in the front brake lever till all the oil seems ejected. Redo the drain bolts up. Undo top retaining cap - carefully, one side at a time - to reduce chances of the bike crashing to ground -  and refill from the top hole. Refit the cover cap. Repeat for second side.
Repeat - don't remove both the caps at same time. Leave one on and work on one fork only.
Top caps are a bugger to refit unless you have sacked springs. Lots of down force on your socket drive - I wear a leather glove - to allow for greater hand force on the tool - otherwise it hurts and won't tighten for me. I just bought new fork springs a while back and went through the exercise again.
regards
Mark

[MCRider]

Rebuilt the forks on my '78 750k yesterday and made a stupid mistake.  Looking at the manual, it called for 7.3 oz of oil but I failed to look at the '78 supplement where it shows only 5.3 oz for my forks.  This, of course, was after I buttoned everything back up and mounted them back on the bike.

So I tried my best to just drain out 2 oz from each fork, but as I'm sure you know, the oil doesn't drain out nice and smoothly when you pull the drain bolt.  I doubt I got it exact.

Should I just go ahead and drain them both completely and refill?  Is the refill process easy without taking the forks completely off the bike again?

Thanks!

Old business: the way to drain a little is to remove teh top cap bolt, and suck it out with a tube, measure what you release from the tube till you've got what you want, then let what's left back into the fork.

New business: You can drain and refill on the bike. Pull the drains and pump the forks. Sounds like you know enough to do this outside where the spray won'yt hurt anything like on a gravel drive. Or have your asst hold a cup up to the drain while you pump, cuz it wioll squirt quite a ways. Let sit overnite, pump some more then refill.
If its new oil to begin with jack up the front, measure the oil level by dropping a rod down the tube, then check the other tube that its the same. Top off accordingly.

All the caveats about properly jacking the front of the bike before removing the cap nuts apply, etc.

[steam-powered man]

there's another spec for oil quantity that is used sometime:  distance from the top of the fork tube to top of oil, with spring out and forks fully collapsed.  done with front end fully assembled, but handlebars need to be moved back to get the springs out.  need to use a suction tube to remove to amount of oil you want, this will result in compressable "air space" above the oil.  you can fine tune your ride this way, depending on your weight/riding style.         

[Duke McDukiedook]

I use a graduated cylinder for mine and I measure the actual level from the top.
Mighty-VACs are good for sucking extra fluid out and bleeding brake lines and slave cylinders.

[stueveone]

http://www.strappe.com/suspension.html

A little over half way down on the page. This is the true tuner way to do it. . .

[2wheels]

From experience it is very important that both forks have the same amount of oil in them.
Handling problems if there not.
So I would not suggest how you do it.  Just be sure you end up with it right.

[drones76]

http://www.strappe.com/suspension.html

A little over half way down on the page. This is the true tuner way to do it. . .

If it is not, that should be on an FAQ page.  Thanks for that link.

[ekpent]

Dammit' I was hoping for a good old fashioned popcorn eatin' oil thread,like what did you use,auto trans-oil etc.   Quess you will just have to re-do it with the proper amount sometime-------but what kind you youzin'   ??    

[Kong]

For whatever its worth on the Harleys I use a turkey baster with some tubing on its end to set the level in the tubes.  Just move the tube on the end of the baster down into the fork tube the proscribed distance (The Harley Shop Manual gives the measurement)  and suck out the excess.  The baster came from the local grocery store, the section where they sell cheap kitchen utensils.

[climbingaz]

As always, you guys never fail to impress me with your knowledge and helpful tips!  THANKS!

At this stage in the game (since I already tried to drain some out), I'll probably just go ahead and completely drain the forks while still mounted on the bike and refill to the proper amount.  At $10/qt for fork oil, I will have only wasted a few dollars.  But I'm certainly not looking forward to getting the huge top bolts back on again.  That was a pain in the azz the first time around...probably won't be any easier while mounted on the bike.  I'll probably take my handlebars off to get more room to work.

Moral of the story....read the manual supplements FIRST before the main service manual. 

[MCRider]

As always, you guys never fail to impress me with your knowledge and helpful tips!  THANKS!

At this stage in the game (since I already tried to drain some out), I'll probably just go ahead and completely drain the forks while still mounted on the bike and refill to the proper amount.  At $10/qt for fork oil, I will have only wasted a few dollars.  But I'm certainly not looking forward to getting the huge top bolts back on again.  That was a pain in the azz the first time around...probably won't be any easier while mounted on the bike.  I'll probably take my handlebars off to get more room to work.

Moral of the story....read the manual supplements FIRST before the main service manual. 

be sure to support the front of the bike before removing even one of the top caps. That will reduce the spring pressure considerably, and avoid the bike crashing to the floor.

As to putting them back on, I use a socket on a speeder wrench, like a brace from a brace and bit. Allows you to push down hard and turn at the same time. Pretty easy then.

http://www.sears.com/shc/s/p_10153_12605_00944271000P

[Kong]

As always, you guys never fail to impress me with your knowledge and helpful tips!  THANKS!

At this stage in the game (since I already tried to drain some out), I'll probably just go ahead and completely drain the forks while still mounted on the bike and refill to the proper amount.  At $10/qt for fork oil, I will have only wasted a few dollars.  But I'm certainly not looking forward to getting the huge top bolts back on again.  That was a pain in the azz the first time around...probably won't be any easier while mounted on the bike.  I'll probably take my handlebars off to get more room to work.

Moral of the story....read the manual supplements FIRST before the main service manual. 

be sure to support the front of the bike before removing even one of the top caps. That will reduce the spring pressure considerably, and avoid the bike crashing to the floor.

As to putting them back on, I use a socket on a speeder wrench, like a brace from a brace and bit. Allows you to push down hard and turn at the same time. Pretty easy then.

http://www.sears.com/shc/s/p_10153_12605_00944271000P

I agree - put a big deep well socket on the nut and the push on the back of the socket with the open palm of your hand while turning it.  Stand on something so you're up above it comfortably and can put some oomph down on the socket;  once you've got half a thread started you're home free.

[george]

I know  I'll get beat up, but easy way to put fork caps back on , Just use your cordless drill with the power turned down to just enough to spin the cap, never been able to cross thread one yet!Don't be afraid, try it!