Shocks - Koni / Ikon spring selection
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
NOTE: Koni / Ikon rear shocks were NOT used originally. However, they are a common replacement shock that performs very well.
I extracted this information from Mike Tiberio on the Yahoo! Loopframe_Guzzi news group. In Mike's own words:
Got a set of long Le Mans 1000 konis off ebay, but was not happy with the soft spring. Had to run the preload up one notch to prevent bottoming, which ruined the ride. Had MG Cycle order a #204 spring from australia. $110 later, the eldo rides like it should. Floats over small bumps, and doesn't buck over the big bumps. The spring is now working the progressive part of the rate properly. just my $0.02 to add to the collective knowledge base...
Question posed by Gregory Bender: Do you know what the original spring rate was? Or rather, how did you know to go with #204 springs versus another number?
Are you asking how did I know what direction to go on the spring rate? I doubt that's what your asking, but its an easy answer. 1) the spring that comes on a Le Mans would by design be softer than one usually fitted to a heavier touring machine, so I guessed I had to go stiffer. 2) The spring from the Le Mans 1000 was the softest IKON/KONI made for the longer 7610-1429 shock. Since I was able to identify that my ride suffered due to bottoming, and not non-compliance, I knew I had to go stiffer, and it was the only alternative spring anyway.
How did I know not to got 2 steps higher to the #217 spring? I didn't, and might yet if I felt I had to. Sometimes (as you well know) you have to gamble with $110. I don't wager on sports or cards, so wagering on something I could sell on eBay is no biggie...
Note the springs numbers are not rates. They make no sense:
- #230 is at 84-146 pounds/inch progressive
- #204 is at 100-185
- #217 is at 123-218
Whats even loopier (no pun) about the koni/ikon springs and shocks is the short shocks (stock for short swing arm guzzis like loops) numbered 7610-1297 have 255 mm long springs, the longer shocks have 235 mm springs???
So if I want to have alternative springs for my Vert which runs the standard 7610-1297 shock, I can't use the ones for the 7610-1429!!!
One last note on the shock geometry between loops and early tontis. Both have short swing arms, that are the same length from swing arm pivot to rear axle. Yet I noticed a decided difference on how each rode on the same KONI recommended shock. The only shock geometry difference that I can see is the upper shock mount on the loop looks to be further back than on the tonti. This would make the loop ride stiffer that the tonti given the same shock. That's what I saw, and that's why the 1297 that I originally bought for my loop is on the vert where it works fine, and not on the back of the loop where it beat the sh*t out of me. I do have a firm solo saddle, so all mysuspensionis in the shocks. Last point, I think the two bikes are about the same in weight, the vert has all the hydraulic stuff, but a lighter frame and fenders. If the loop is heavier, it should have ridden better on the stiff shocks, it didn't, and I doubt being lighter than the vert is why it rode stiffer...