XR400 fork springs feedback

[GreenPeace]

As promised, some feedback on XR400 2000 fork springs.
I love them.

I installed them on Friday & did a race on Saturday.
The biggest advantage is in tight corners. No more nose dive and you can hit the corners. You can sit on the tank without problems. Great handling.

The 0.4kg/mm ( 2000+ ) is perfect. The 0.38kg/mm ( - 1999 ) would be to soft for me. My weight is 170lb.

The only problem is the bike is out of balance again. With the stock 0.35 spring 470mm and preload of 40mm ( 110mm spacer ) the balance was better, but handling horrible. With the 20mm preload ( 90mm spacer ) I bought the bike with, the bike was out of balance.

With the XR400 springs I set the preload on 10mm ( 10mm spacer )
I know Canyn wants to go to 6mm but then my bikes balance will be worse. I think of going to 20mm to get the balance better, but then the pebbles will become stones.

The alternative is to install air nipples and regulate the pressure. I read a thread about that once.
Those who did that mod, can you please inform me on the findings.

I doubt the info of the XR400 2000 that are 0.4kg/mm. They feel more to 0.38 to me. Honda SA could not give me that information.
Is there anyone that got that info from a reliable source?
The lenght of these springs are 536mm brand new.

I hope this sums up & ends the confusion about the on-going stories of the XR400 springs.

If I didnt mention it before. I love the XR400 springs!!!!!!

 

[Matt90GT]

Go to RaceTechs website as they have the spring rates measured:

2000 xr4: .400 kg/mm

1999 xr4: .382 kg/mm

 

[canyncarvr]

Robcolo has a pressure system on his bike...complete with attached gauge if I recall correctly.

re: Out of balance

As determined by? If I understand correctly maybe the balance issue comes from something like a 95mm sag on the rear? Change it to 100, then. Or..what's your free sag now?

Ongoing 'confusion' over XR springs? You're evidently referring to someone else? ;)

Glad to hear you like 'em!! Seeing as you changed from original equipment though, most anything would have been an improvement.

BTW..I'm running 2mm preload. That and 5 clicks out (from 8) completely changed the kdx's personality....for the better!

 

[kevin c.]

I read on the FRP site that the .38 springs were recommended for a rider from 140 to 200 lbs but I have read two treads lately that 180lbs riders were getting .40, I have just ordered springs last week that are .38 and I am 185lbs,, did I get the wrong ones? Bike is a 03 220.

 

[GreenPeace]

The rear sag is 100mm, didnt measured the free sag yet.

Kevin, sorry but you are on your own....
Braahp had the 0.4 and changed to.38 and prefer the latter. If I remember correctly he weighs over 200.
I weigh 170 and love the 0.4 but never tried the 0.38. If I compare the 0.35 to the 0.4 I will not go down to 0.38.

Sorry, not much of help are we?
Please let us know when you installed them.
I think you are on your own now.....

 

[canyncarvr]

Try race-tech's site for their suggestion on rate for your setup. I'll bet you $$ to dogturds that your query in their system comes back with something over .40.

OK..I couldn't stand it. Did it myself. Racetech says .43s!

Point is not that racetech is always right and FRP isn't. It's that different vendors/suppliers have different ideas of what works. In the end, it's your point of view that matters. If 'X' suits you, and some hotrod tuner says you must use 'Y' it's usually the former that will work best, not the latter.

There's always an opportunity to learn something new. In the above, you may indeed find that 'Y' really is a better choice if you could handle it.

Doesn't seem quite right to run .38s for a 14+stone rider.

BTW, racetech says their spring set length for the kdx is 543mm! AND a 130mm oil level! FRP doesn't like that idea, either (springs longer than oem 470s).

 

[kevin c.]

OK Guys, my .38s came on ups today so I will try them anyway,( good thing springs aren't too expensive.) any one know what size the stock ones are on
a 03 220? Thanks Kevin

 

[Braahp]

There are many variables involved. For instance my .38 springs are stiffer throughtout stroke with 20mm preload than .40 springs with 10mm preload.

 

[canyncarvr]

kevin:

Yes, I do.

http://www.buykawasaki.com

or:


http://www.racetech.com

and a spring search will tell you.

 

[GreenPeace]

Braahp, you made an interesting comment.
I plotted 2 graphs with distance travelled (mm) against load (kg).
It is true that the .38 with 20mm preload is stiffer than .4 with 10mm preload.
But only until 180mm of front fork travel. That is where the two graphs meet. From there on the .4 is stiffer. The total travel of the fork is 290mm.
Interesting though.
I am very suprised that there is so little difference between the two graphs.
Did I ever mentioned how I enjoy this forum?

Cheers