Rebuilding Konis is not hard at all, certainly not for an Airhead... but read on, challenging but fun.

A well-stocked seal store can provide a replacement seal (although without the "top hat" part... no problem) and o-ring but there are OEM seals floating around out there. Be sure not to mix up all those thin washers (easy to keep track of if you are moderately organized).

You might just find one of your shocks is dead, pending rebuilding, that is.

Two tricks:

To remove spring, make a spring compressor from a length of redi-rod bent into a tall U and flat piece with a correct hole size in it just a hair bigger than the spring keeper. Check springs on a bathroom scale sitting on your drillpress table, squeeze one inch and check force. Sensible to have 95-140 springs - Progressives are just right although stock are just wrong.

To open, use a BF pipe wrench and heat. No kiddin'. Refill with 5 weight or lighter, not critical. Use teflon tape to reduce friction on height adjuster. Don't be afraid to grind away at springs... if you are sure you
understand the principles.

Koni US importer is friendly (and has many specs on Koni springs, etc) but can't help in any other way.

The nice folks at Koni provided me with the following information. My machine is a 1984 R80RT.

My present shocks are model 7610-1407, Special "D", 8606 - which I think are used by a number of Airhead members. The compresses (pre-loaded spring) is 8.25 inches at its least pre-loaded setting. The Konis require a spring with an ID of at least 1.45 inches.

Koni says that is the incorrect part number for my bike. The part number listed was 7610-1298. The 7610-1407 was used on some Japanese bikes (Yamaha and Suzuki).

The 7610 1407 (really intended for R65, Tom Cutter says) can be used but a bear to get up on centerstand, has the spring rates of 123 lb/in - 213 lb/in with a free length of 235mm (9.25 inches) and has 20mm (.79 inches) of preload.

The 7610 1298 shock used a spring of 106 lb/in. - 235 lb/in. with a free length of 250mm (9.84 inches) and 15mm of preload.

In other words, the 1298 spring starts softer and is far more progressive than the 1407 spring (which sounds good to me) but I'm not sure how this compares to stock. Ideal, I'd say, is Progressive at 95-140, see below.

Koni no longer are making motorcycle shocks. They stopped production a couple of years ago. The last of their inventory went to an Austrailian distributor by the name of Top Performance.

Progressive makes a rear spring which they say is suitable for an 84 R80RT (03-1367B/C) which is 95-140 with a free length of 9.37 and an ID of 1.85 (which seems about right to fit over Konis), for us$73.

Stock length, as noted in Clymer, is 9.88 inches and no rate(s) given. Can somebody fill in this information?

About the amount of oil needed, you gotta leave some air to be compressed when the shaft is in (during compression). But, you don't want the gizmo to come out of the oil on the biggest rebound.

So, and here speaking only of the way Koni is built, the gizmo is in a tube and oil remains in the tube during rebound and only slowly leaks out otherwise. In other words, no danger from too low oil level.

I think I filled like 2/3 full and that seems just fine.

I went with some high class suspension fluid, 3 weight, whatever that means. But was advised to go thicker. Konis tend to be stiff with strong springs and I was intent on changing.

The smart money (except maybe in racing) is springs and shocks that eat roughness (ie, soft) esp for the small stuff but maybe stiffen up for more major stuff. Brake dive is a matter separate from suspension and confuses matters. Dual rate springs from Works are the only feasible fix there.

-Ben Barkow

(Originally posted to the AIrheads list)