What the heck forks do I have on this thing?

Something here isn't right. I've been reading around and nothing matches up.

I have a 1982 XJ650RJ Seca. I am rebuilding the forks (along with about everything else) But they're definitely not stock.

First off, they have air valves in the top, which sounds like it was the norm for the Maxim bikes, with the air assist, but the Seca isn't supposed to have those. Okay, so it seems like at some point a previous owner replaced the shocks with some Maxim units.

EXCEPT: The Maxim shocks supposedly had short springs with spacer tubes in them, and mine do not. They have no spacers at all, and the springs appear to be progressively wound (not sure if the factory springs were like that on any of the XJ650s)

Anyway, here are a couple pictures. The first is the caps with the air valves (it had a connector hose with a single valve, I presume that's just an upgrade to balance pressure in both forks) Second is a picture of the actual springs that were in the bikes. Are those factory? Are those aftermarket upgrades already? I'm thinking of buying new springs but if I don't need to, I'd rather spend the money on other things!

 

so I'm not sure if these are Maxim forks with upgraded springs, or SECA forks that have been retrofitted for air-assist.

If they're upgraded forks, should there be a space in there that the previous owner just left out, and maybe that's causing them to sag because they don't have enough preload?

Something seems not right.

 

Seca 750's have air, FWIW. But they also have anti-dive, which would be pretty obvious.

 

Mostly I'm curious about the springs. Do those look like stock Seca springs? Should I put in a spacer? Should I just upgrade them to some Progressives? ARE those Progressives?

 

The only thing the magazines could find to gripe about (just a little) on the 650R was the suspension, justifiably. Very softly sprung from the factory. The 650R definitely didn't have air assist. They are probably from a 750, but I don't know how to tell.

Not 100% sure, but I don't think those are stock springs. (since the only one's I've seen are from a 650R)

If those are aftermarket springs from Progressive, then yes, there should be a spacer, not sure of length since we don't know exactly what forks you have.

Causes of sagging:
Worn springs
Incorrect weight/level of fork oil
bad air valves (in the case of the air assist, like yours)
Missing spacer with aftermarket springs

Yeah, it's usually an un-informed PO that isn't right.

 

The caps (not the fittings) look like the 82 650 Maxim while the springs look pretty normal to me (meaning I don't recognize them as unusal). You have a different set of forks for sure, show us some pics of the brakes/calipers... there are differences between the years.

 

Is there any different in the length of the actual forks between the maxim and Seca? What I'm thinking might be the case is that they're Maxim forks with Seca springs in them.

I went ahead and ordered a set of Progressive fork springs. I figure I'd just make the right length spacer and put them back together as-is. Since the new springs are plenty stuff the air-assist I'm sure will be unecessary and largely useless, so I just plan on capping off the fittings and basically turning them back into non-air-assist forks.

 

From the axle position on the forks and the harp of the brake calipers I can say with some confidence you have a set of 82 650 RJ Seca forks. The air caps are not normal however, they were only on the Maxim. Looks to me like you got a mish-mash of 82 parts.

 

Those are your Seca's forks, somebody added air caps is all. You've got Seca brakes there; the Maxim had a single caliper that attached to the fork differently.

The original springs were progressively wound, yes; but those don't look quite like factory springs either.

For the 650 Seca, the stock front fork spring "Free Length" spec is 540.5mm, or 21.28" (in other words, measure the springs.)

For the 650 Maxim, the spring free length is 606mm, or 23.86"

 

they're 21 3/16ths or 21.1875. A little shorter than the factory spec, but I imagine that's fairly normal after decades of use.

 

Then they probably are the original springs, sacked out a bit. Good that you ordered replacements; the Progressive suspension springs are MUCH better than even low-mileage stock; I have the ability to compare them side-by-side right now and the difference is noticeable.

 

I hear nothing but rave reviews!

I also really want to get a set of progressive rears, but I can't afford those quite yet. Fortunately those are pretty easy to swap out!

Thanks for the help, guys. I got the new oil seals back in and the forks are back together. Just waiting for my new tapered roller steering head bearings to arrive then I'll get the front end back together and just put the new springs in while everything's on the bike. Then it's on to wiring and electrical, air box, and rear fender.

At that point I should have cleared up a bunch of space in the shop so I can get back to tearing the engine apart to replace 1st gear and the shift cam!

 

The above stuff is right, stock Seca springs are progressively wound (with the tighter coils at the top)

They still benefit from some pre-load spacers though - about 1" or so. I used coins (7 x 2p pieces per leg). The tops take a bit of pushing down, but it's worth it.

Nige