Quick question re: fork oil

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My shop manual calls for 4.6 oz of 30 weight oil per leg.
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I used 10 weight in my ‘77 and also put an extra oz. in each leg.
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So do I need to run out and get 30 w?
Thanks Bob
 
You're a brave man Bob..... asking a "oil" question. :whistle:
 
That's hard to say. Fork development and technology wasn't very far along back in the early '70's. Many bikes called for plain old motor oil but that may be because dedicated fork oil was hard to come by back then. You may have to do some experimenting. The 10wt. called for in the later forks is probably too light, but maybe a 20wt. might be better than a 30. Hopefully 2M will see this and chime in. He's had his XS1 like forever and has probably tried all sorts of oils and weights in his forks.
 
Thanks , yeah I’ll hold off a bit, I can still put the front end together and add the oil later.
 
Well, there you go. What you don't use in the forks you can run in the motor, lol. No mention of amounts though. More that stock is good on the later forks but I don't know about the early ones. You have to be careful when doing this because too much will blow the seals, lol. Been there, done that, years ago on a Beemer I was hanging a sidecar off of. To stiffen the forks up, I put heavier oil, and more of it, in the forks. They were stiffer alright, but after a couple big bumps, one of the fork seals popped right out of the leg, lol.
 
In that pic with the Frappuccino bottle (the 9.5 oz. size), you can see where I've marked a 250cc line, in case anyone else wanted to copy, mark-up their own cheapo measuring bottle. That's about an ounce, 25cc, over stock. Strictly for XS1/XS1B forks...
 
If I'm doing fork oil I will always put in thicker grade oil. This stiffens up the front end and makes the bike handle and brake much better under having braking and turning. If the manual calls for 4.7oz put in about 5.5oz.

I use the heaviest maxim oil 30w.
 
I've never bought specified "fork oil". Non-detergent oil is still available at some farm stores for hydraulic use, same stuff as that oil in the "fork oil" bottle. This is what I use in my compressor too. The plain stuff without the fancy expensive bottle is getting harder to find, but it's still out there in 10, 15, 20 and 30 weights. That "anti-foaming" on the bottle means Non-detergent.

Scott
 
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