Filling Roadholder fork legs with oil

The Commando is the same, isn't it ? According to the book, it's best to lift the front off the ground and let the forks descend as far as possible. You can then trickle in a little at a time.

My solution was a pair of modified top nuts with tubes welded to them. I can now fill each leg and then go away for half an hour while gravity does its job. The nuts need boring right out though, or they seal on top of the springs.

Why not put the oil in before the spring or take the spring out?

dan

Because the spring is on the rod rod under tension to provide preload, I use a syringe but it still needs some time. On forks I have converted to Modern Showa Cartridge inserts the oil used is 5 wt and so thin enough to flow down, that plus the better handling is worth it. 

...because in order to do that, you have to remove the nut from the top of the damper rod which then drops down...it's possible to pull it up again, but you're still faced with compressing the spring and holding the rod up whilst attempting to start the nut...

I remove both top nuts and the wheel, allow the legs to extend as far as they can. have 2 containers with the correct amount of oil and pour in as much as possible in each leg, loosely refit the top nuts (you only need 3 or 4 turns) and compress the forks a couple of times, remove the nuts again and repeat until all the oil is in the forks, then reassemble. You need a slim spanner to loosen the damper rod from the nut, but otherwise nothing special. I don't know how much time you actually save, but you aren't standing about waiting. 

I thought the forks had just been rebuilt.? I add the oil before I fit the spring. I’ve never had any problem tensioning the spring, I’ve had to use one of those magnets on a stick to pull up the rod on a couple of occasions. To be honest the rod should be inspected anyway as it’s prone to rust which then wears the damping cap and so reduces the rebound damping.

But each to his own! 

Dan

I use the method outlined in the American service notes. Purchase a plastic baby's bottle and fill with the correct amount of oil. Then apply the nipple to the exposed springs and squeeze gently. Then rock back and forth slowly while humming quietly. This last instruction won't speed up the process but it will put you in touch with your parenting instinct.

It’s also always a good idea to check the damper rods when doing a rebuild/service they are prone to rusting and consequently wearing the damper caps. I think it’s a bit like the gearbox, condensation can build up in there? 

Dan 

I drill out the damper top to take a PTFE bush and make alloy damper rods to eliminate the rusty damper rod issue and improve the rebound damping. The damper body will still rust so regular inspection is still advised but at least less to rust. 

They don’t rust if you have alloy ones!  .... Just saying!

Dan 

The Commando racers used 170cc as per the Thruxton notes, as this will cover the damper tube on a Commando, the 150cc is lifted from the Short Roadholders and there is a big difference in damper tube length. The damper needs to be covered. Not surprisingly, the forks work a whole better with 170cc of oil installed. 

Place bike on centre stand on a piece of floorboard, remove stanchion top nuts from rods, weigh down back of bike until springs move down the stanchion tubes, top is dead easy. Really don't see the need for anything else.