Fork Oil Grade

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Any oil labeled as fork oil will work; I do suggest starting with a 15w to break-in the new parts. If you have selected springs that give the correct laden sag than you can try different weight oil until you get the damping that suits your riding style.

Best.
 
The last few bikes I've had were Japanese, and I used ATF.
Where I needed another grade, I preferred Kenny Roberts fork oil, mixing them to get say 12.5 grade etc.
 
Staytite said:
Hi Bernhard

what did/do you use in you Commando forks and do you like it?

Thanks
Click to expand...

That's kinda like asking if you like ketchup or mayonnaise with your fries.
I like oil in my forks. Unless you are racing, who cares
 
Staytite said:
Which fork oil make and grade do you use and do you like it ?
Click to expand...

Try Motorex 15w, if you must have a brand name, for break-in the new parts it really doesn't matter what brand you use. And it will continue to not matter if you change it regularly; unlike most Norton owners that still have the factory installed oil and ride on happy as a clam. If someone asks them about it they'll say, the forks don't leak (the sorry seals won't pass tar). and they'll ad, it handles like a sport bike...

After a 200 miles, or so, you'll get a good sense of if the damping suits your riding style. If your Norton feels vague at the speed/roads you ride on go to a 20w, the feel WILL change; 20w is, probably, the most used. Without adjustments for compression and/or rebound damping fork oil weight has an effect on both. The OE Roadholder forks were hot stuff up until sometime in the mid 70s; compared to a modern cartridge fork they just don't offer the bandwidth. Got it?

Best.
 
RoadScholar said:
Try Motorex 15w, if you must have a brand name, for break-in the new parts it really doesn't matter what brand you use. And it will continue to not matter if you change it regularly; unlike most Norton owners that still have the factory installed oil and ride on happy as a clam. If someone asks them about it they'll say, the forks don't leak (the sorry seals won't pass tar). and they'll ad, it handles like a sport bike...

After a 200 miles, or so, you'll get a good sense of if the damping suits your riding style. If your Norton feels vague at the speed/roads you ride on go to a 20w, the feel WILL change; 20w is, probably, the most used. Without adjustments for compression and/or rebound damping fork oil weight has an effect on both. The OE Roadholder forks were hot stuff up until sometime in the mid 70s; compared to a modern cartridge fork they just don't offer the bandwidth. Got it?

Best.
Click to expand...
FYi I was not as happy as a clam on my first ride with the infamous Roadholders.
I knew nothing about forks then, and only slighty more now.
Then, surprise, surprise, it turns out that Norton had got it wrong and had been drilling the holes in the WRONG place inside those forks, hence thousands of Norton owners are riding around with a fault that, including me, don't know about!!!!!
Someone else is offering a "fix it " solution that costs $$$ ! WTF!
 
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Bernhard said:
FYi I was not as happy as a clam on my first ride with the infamous Roadholders.
I knew nothing about forks then, and only slighty more now.
Then, surprise, surprise, it turns out that Norton had got it wrong and had been drilling the holes in the WRONG place inside those forks, hence thousands of Norton owners are riding around with a fault that, including me, don't know about!!!!!
Someone else is offering a "fix it " solution that costs $$$ ! WTF!
Click to expand...
I think you're a bit wrong there.
Yes - the roadholders do have a damping fault - will top-out too easily.
But there is extensive information on how to fix the problem yourself - our own @dynodave has published info on this - I believe called the"covenant conversion".
So- yes - you can always pay someone else to fix any problem you have - or, get off your butt.
 
PPi
robs ss said:
I think you're a bit wrong there.
Yes - the roadholders do have a damping fault - will top-out too easily.
But there is extensive information on how to fix the problem yourself - our own @dynodave has published info on this - I believe called the"covenant conversion".
So- yes - you can always pay someone else to fix any problem you have - or, get off your butt.
Click to expand...
Pity you do not aim your remarks to the primary offenders of this complaint!!!!
Sad :-(
 
Bernhard said:
FYi I was not as happy as a clam on my first ride with the infamous Roadholders.
I knew nothing about forks then, and only slighty more now.
Then, surprise, surprise, it turns out that Norton had got it wrong and had been drilling the holes in the WRONG place inside those forks, hence thousands of Norton owners are riding around with a fault that, including me, don't know about!!!!!
Someone else is offering a "fix it " solution that costs $$$ ! WTF!
Click to expand...

The problem is that holes in the bottom of the damper body are too low which will allow the forks to bottom out. You have some choices for implementing a fix, possibly more, but in my experience sealing the existing holes and drilling new holes higher up will permit a hydraulic lock that bleeds off around the damper rod piston; the Covenant Conversion is very effective and very inexpensive.

www.rgmnorton.co.uk

COVENANT FORK DAMPER CONVERSION KIT (IMPROVES DAMPING)

www.rgmnorton.co.uk

RGM also has new damper bodies with the higher bleed hole. Before I discovered that my wallet had greater depth I would purchase all new fork internals from RGM (damper body, damper rod, piston, cap for damper body, lower stanchion bushing, upper "high Hat" slider bushing, and the seals-3 per side). The forks behaved well, but they are still, barely, post Jurassic as you have noticed.

Landsdown and Consentino internals give you external control of compression and rebound damping, but are uber expensive. There is a post on this forum about Olins inserts. Pick your poison.

Best.
 
Staytite said:
Hi Olympus

I believe from your posts you recently fully rebuilt a Commando.

Which fork oil (make and grade please) did you use and do you like it?

Thanks

Just read your thread on the roll pin for the petrol tank cap. Very interesting as I’ve
to do that shortly and remember it being a big worry.
Click to expand...
I have to say after extensive fork rebuild & bushing the damper caps, tightening clearance in the damper valves, brazing up1/4" holes on the damper tubes and drilling a smaller holes higher up the tubes, extended top bushes etc i was hoping for much better front damping using 20wt oil..... over the winter I'll be changing for 5 wt. oil or ATF to improve the complete lack of damping
 
olympus said:
I have to say after extensive fork rebuild & bushing the damper caps, tightening clearance in the damper valves, brazing up1/4" holes on the damper tubes and drilling a smaller holes higher up the tubes, extended top bushes etc i was hoping for much better front damping using 20wt oil..... over the winter I'll be changing for 5 wt. oil or ATF to improve the complete lack of damping
Click to expand...
Confused! How does a lighter grade increase damping? Not contradicting - just wondering. BTW, I'm big so I run SAE 30. When smaller and could get it, I used SAE 20 in both cases, plain old oil.
 
olympus said:
I have to say after extensive fork rebuild & bushing the damper caps, tightening clearance in the damper valves, brazing up1/4" holes on the damper tubes and drilling a smaller holes higher up the tubes, extended top bushes etc i was hoping for much better front damping using 20wt oil..... over the winter I'll be changing for 5 wt. oil or ATF to improve the complete lack of damping
Click to expand...
Get a set of Lansdowne dampers. Easy as to dial in.
 
gortnipper said:
Get a set of Lansdowne dampers. Easy as to dial in.
Click to expand...
I have Lansdowne dampers. Had to try several weights of oil to dial it in. Every brand of oil is different with their
weight scheme. Don't believe anything. I tried the following weights: 7.5, 10, 15, 20. I settled on 15.
Your brand may differ. There is no universal fork oil weight scheme.
 
lazyeye6 said:
I have Lansdowne dampers. Had to try several weights of oil to dial it in. Every brand of oil is different with their
weight scheme. Don't believe anything. I tried the following weights: 7.5, 10, 15, 20. I settled on 15.
Your brand may differ. There is no universal fork oil weight scheme.
Click to expand...
Maybe I got lucky. At first, I used Castrol 10wt, because that is what I had on hand prior to rebuilding my forks. It proved much to soft.

So, in looking at the table that has been referenced from Peter Verdone I created an xls that I could sort by Recalculated Viscosity Index (VI) and
VT.

The Castrol ended up in the about halfway up the scale for VI and about 80th percentile for VT. From this I gather that it is simply too thin.

So, I looked for an oil that was ~80th percentile for VI and VT and was locally available. So, I settled on the Bel Ray 10wt HVI

With this, I have to set minimal damping on the Lansdownes, maybe just slightly too minimal. But, it works well and I dont notice that much a difference between the beginning and the end of a ride.
 
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gortnipper said:
Get a set of Lansdowne dampers. Easy as to dial in.
Click to expand...
The crux of the problem is that i have next to no damping under normal riding conditions unless you hit pot holes, and i believe with tightening everything up in the forks a 20wt oil is now to heavy so i may try a 5wt oil or use ATF
 
Staytite said:
Exactly as you say. It's only that I am about to fill some new forks that I started to over think it.

I went out yesterday on my working Commando when the sky was blue, but it was very cold. While
thinking about how my forks were operating it hailed hard then a partridge walked into the road and
stopped. Sh*t !

Should I go left or right of it ? Sh*t !

I was saved by a souped up 1 series BWM with black windows and fat alloys who came past me with
his (her?) 4 exhausts blazing like I was stood still. He/she hit the partridge and I passed through a shower
of feathers. Must have made a nasty mess of the front of his car.

But I lived to tell the tale and go back to contemplating grades of fork oil.
Click to expand...
I like olive oil for Partridge…..
 
I decided to use Castrol 15W Fork oil and am happy with the fork action for
my old codger style of riding on the local roads which traffic conditions rarely
allow for much over 70 mph.
 
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