I just drained the oil and pulled the front springs from my 78 special. The springs that were installed appear to be progressive springs (probably not stock?). They were installed with the end where the coils are closer together at the top. I thought the end with the closer coils when down. Which is correct?
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
Front Shocks Question
- Thread starter NP2650
- Start date
Tighter wound coils do go up, that way they displace less oil and don't raise the level as much. Stock springs were progressive and pretty nice, but usually too soft by now (due to age and sagging). But you can add short preload spacers to fix them (about 3/4"). This is a cheap way to avoid the cost of new aftermarket springs.
IAW the Factory Service Manual, the stock springs free length specification is 610mm or 24in. If they measure shorter, they're sacked. I replaced mine when they came up short. I had over 60,000 miles on them. I don't know a good reason why you shouldn't shim them if that's what you choose to do. YMMV
What service manual? I have the XS 650 SF/2F OWNER'S MANUAL in front of me. It reads "recommended oil: Yamaha Fork Oil 10 Wt or equivalent". That said, I think the bike predates fork oil, so an earlier manual may be calling for 20 Wt engine oil? 10 Wt fork oil is the way to go, IMHO.
Hmm.....I think the spring free length @ 482mm is right (seen misprints though), but the 10wt is what the fork wants nowadays (6 - 6.5 oz too). The 3/4" spacer is a good mod too.
Last edited:
I think that must be a misprint because all the 35mm forks from '78 on called for 10 wt. in all the manuals I've seen. Yes, Yamaha did spec 20 wt. for the '77 forks, but that was the 1st year for the 35mm forks, and I think they realized that oil was too thick so reduced the viscosity for all the 35mm forks after that.
These are the fork specs I have. Springs aren't 610mm long but rather 482 (or about 470 for the '77 forks). I know that's right because of the fork work I have done over the last few years .....
And yes, these forks work much better with a little more than the stock amount of oil in them. I use 6.5 to 7 ounces, then suck off the excess to bring the levels 6" from the tops of the tubes, springs removed and forks fully compressed. I also do something called the "Minton Mods" to the damper rods. I think it helps and makes the forks a bit more compliant and responsive, and it's basically a free mod.
These are the fork specs I have. Springs aren't 610mm long but rather 482 (or about 470 for the '77 forks). I know that's right because of the fork work I have done over the last few years .....
And yes, these forks work much better with a little more than the stock amount of oil in them. I use 6.5 to 7 ounces, then suck off the excess to bring the levels 6" from the tops of the tubes, springs removed and forks fully compressed. I also do something called the "Minton Mods" to the damper rods. I think it helps and makes the forks a bit more compliant and responsive, and it's basically a free mod.
I’m going to check when I get home. I have loose springs handy. FSM may have another misprint. Mine is for the XS650SJ.
My XS650SJ factory manual has plenty of erroneous information. On page 5-14 it states fork length as 610mm and 24in. That's hardly a misprint. It's just wrong. In chapter 7, fork spring length is stated as 482mm. The springs I have lying around match the 482mm spec.Hmm.....I think the spring free length @ 482mm is right (seen misprints though), but the 10wt is what the fork wants nowadays (6 - 6.5 oz too). The 3/4" spacer is a good mod too.
Clymer makes no mention of the free spring length.
