New fork springs.

[Eddie Munster]

I am ordering progressive Rate springs for my 1989 1100 kat. Is this any easy job to replace and refill the forks. I have done it before on an old GS but it as been a long time.Anything to look out for. Thanks

[cintidude04]

One thing to look out for.... don't use progressive springs.
Talk to Tmod about getting RaceTech springs for your weight.

[DClark]

I found a big enough improvement just by swapping out the stock fluid and keeping stock springs.
I used Redline oil fork oil, medium grade.
I empty out the oil by remove the fork, draining the fluid into a measuring cup, then adding the same quantity of fluid through the drain hole.

[Snowhere]

Just a cautionary tale. Years ago, I went to a beemer rally on my kat with a beemer friend. So some unknown reason, I decided to swap out the fork oil with lighter weight oil while we at the rally. We rode around with out bags and our camping gear and I had no problems. The problem started when I loaded up for the 4 hour ride home. With the weight of my camping gear and my saddle bags on the tail end, I became a wheelying machine! Only, I did not have to do anything other then hit a bump in the road! The first time it happened, it happened to be in a turn and I lost my steering! I got her down and with some caution, I found that any good bump would send my front wheel up. We endded up strapping my saddle bags and pack onto my friends R1100 and limped home. With out the gear on the back end, I could keep her grounded for the most part. Still, larger hits at highway speeds would send my front end up. After I got home, I drained out the lighter weight oil and went back to the stock weight.

As far as measuring, I have one of those cups that dirt bike riders use for oil. It has graduations so I just measure out the proper amount and then just pour it into the fork. Takes the guess work out of how much oil should be in there.

[cintidude04]

Why would you put lighter weight fork oil in anyways?

[JayBell]

I am ordering progressive Rate springs for my 1989 1100 kat. Is this any easy job to replace and refill the forks. I have done it before on an old GS but it as been a long time.Anything to look out for. Thanks

as Cinti said, just get Racetechs non progressive... they are about $110 a set, and all ya do is unscrew the fork caps, take out the old ones, drop the new in, and cut the spacer tubes the right length for the desired preload.

[Snowhere]

Why would you put lighter weight fork oil in anyways?

Yea, I know....... But back then I was a teenager that did not know better and some one convinced me to do it....... Hindsight is always 20-20.......... I think the oil was 5 points lighter, I was definitely surprised at how much difference it made..............

[Royson]

Why no progressives?

I posted a few days ago that I disassembled the forks on my 1990 1100 and ordered a set of progressive springs. No one said a word about progressives being undesirable. So I have to ask, why are progressives a bad choice for the 1100 Kat?

Guess I should have dug into the suspension threads first?

[arsenic]

why are progressives a bad choice for the 1100 Kat?

It's not just the 1100 Kat, and it's not that they are worse than stock. They just aren't as good as RaceTech springs. So, if you're gonna go all out and replace the fork springs, you may as well get RaceTech springs.

[Royson]

Racetech

Ok, after digging into the Racetech website, I am convinced these guys know their stuff. Problem is, they offer so many improvements, that I am tempted to go with emulators, rear shock spring changes, and the cool suspension tools they sell etc. Like the site says "Call for specific recommendations".

Though I agree that redoing my suspension via Racetech would be the "Best" way to go, it may not make sense in my case at this time. Since I bought the Kat not running I've not actually ridden it yet, so I don't know what handling upgrades would be desirable. I have four other motorcycles, all running stock suspension, and until recently, I never felt dissatisfied with suspension handling. My newest bike is a 2003 Kaw ZRX, once I got some saddle time on the Rex, I noticed that my three older bikes had crappy suspension by comparison. I am a fairly conservative rider so until now, didn't feel any need for suspension upgrades. Complicating the picture is the possibility that I might do a fork/wheel swap on the Kat in the future, so upgrades to the stock forks would be misspent.

Guess I'll stick with the stock springs for now till I have a chance to ride the Kat and evaluate what kind of suspension/wheel changes I might want to make, if any.

[Tmod]

Ok, after digging into the Racetech website, I am convinced these guys know their stuff. Problem is, they offer so many improvements, that I am tempted to go with emulators, rear shock spring changes, and the cool suspension tools they sell etc. Like the site says "Call for specific recommendations".

Though I agree that redoing my suspension via Racetech would be the "Best" way to go, it may not make sense in my case at this time. Since I bought the Kat not running I've not actually ridden it yet, so I don't know what handling upgrades would be desirable. I have four other motorcycles, all running stock suspension, and until recently, I never felt dissatisfied with suspension handling. My newest bike is a 2003 Kaw ZRX, once I got some saddle time on the Rex, I noticed that my three older bikes had crappy suspension by comparison. I am a fairly conservative rider so until now, didn't feel any need for suspension upgrades. Complicating the picture is the possibility that I might do a fork/wheel swap on the Kat in the future, so upgrades to the stock forks would be misspent.

Guess I'll stick with the stock springs for now till I have a chance to ride the Kat and evaluate what kind of suspension/wheel changes I might want to make, if any.

The best you've ridden is the best you know, Until you have ridden something better you would probably be happy with the stock suspension.

With that said you have a 1990 1100 according to the post and that has a cartridge inside a conventional fork so emulators are out of the question. Racetech does not show anything for that year but I have come up with the spring numbers you would need.

The issue with progressive springs is that they change rate throughout the travel, They are soft at the beginning and stiffer at the end. One of the issues with that is you valve for a set spring rate and if it is changing all the time where do you set the valving at? With Linear springs they remain the same rate throughout the travel and offer the same rate from top to bottom.

Maybe some of those that have had suspension work done will chime in and give you some idea of why what they thought was good enough wasn't after a suspension upgrade.

Tmod

[mammut89]

I got my suspension modified by tmod, I can say that what I had before was almost dangerous.

[Kreylyn]

I got my suspension modified by tmod, I can say that what I had before was almost dangerous.

What Mo said... and I only have a rear shock on my main bike. But the Wife's has the full monty (front and rear) and ... well... I think she's considering letting me put up that bike storage garage sooner than later so she can lock it up from me.

Krey

[Badfaerie]

As a new and non-aggressive rider I didn't feel suspension was a needed expense. I mean, the Kat is just a big heavy tank anyway right? Finally Kreylyn talked me into going with Tmod's suspension method to lower my bike, something that was important to me, and at the same time we had him adjust the suspension for me.

There are no words for how much better the bike is. It is no longer a big heavy tank once it is moving. I am a better rider just because of the suspension being correct. I am a safer rider because of the suspension being right. The best money I have ever spent on a bike was getting the suspension right. It is the #1 upgrade that makes the biggest difference.

Suspension isn't just about comfort, it's also about making sure your tires have good contact with the road and your bike acting and reacting in a predictable manor. It affects your acceleration and your braking and your handling during acceleration and braking. As a new rider or a casual rider who's instincts aren't honed by riding on the edge all of the time, I feel suspension is even MORE important. I increases your margin of error and gives you the best possible chance of coming out ok when things go terribly wrong.

I know I'm preaching, but I'm just that much of a convert. You and I may not need a $5k Ohlins set up, but having a good set up specific to us individually is worth way more than we'll ever pay for it.

[Royson]

Good Advice

Thank you guys! I absolutely agree about the desirability of good suspension tuning. I read "Sportbike Suspension Tuning" by Andrew Trevitt a few months ago, some serious information in there and a little overwhelming for a guy who has been riding for 36 years without so much as adjusting the preload on rear shocks. I have convinced myself that this is not really a DIY project for someone with my limited knowledge. Thing is, I disassembled the forks to replace the seals, and thought I was killing two birds with one stone by putting progressives in while I had them apart. I'm glad to get this advice before I unpack the progressive springs I ordered.

I have developed a much stronger interest in suspension tuning now, thanks to the difference between my 2003 bike and the older ones. Once I get the Kat on the road I will get some serious hands on help from Tmod.

I really appreciate the guidance. Will report my progress.