Progressive suspension upgrade

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jigm400

XS400 Enthusiast
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i just installed new progressive fork springs on my XS this morning and let me say WOW:D it made a huge difference on fork bottoming and braking dive. With drewpy"s help on the OE specs i found progressive makes fork springs that will work in the XS400 even though they do not list an application.

the OE fork springs are .4/.575 kg/mm

progressive makes .54/.71 kg/mm (ps11-1115) and .63/.80 kg/mm (ps11-1109)

i installed the .54/.71 because i found a set at work with 10 years of dust on them. just took the bike for a ride and could not make them bottom for the life of me. its huge.:thumbsup::thumbsup:
 
I'm going to order new fork springs in the next couple days and I'm looking for some input. I weigh 220 lbs so I was going to order the heavier 11-1109. Am I on the right track or would that be too stiff? What weight of fork oil would you guys recommend and would you stick with the stock volume? Do you recommend buying them somewhere other than Amazon?
http://www.amazon.com/Progressive-Suspension-Front-Springs-11-1109/dp/B0031BBIP6
 
I stiffened mine up by filling the 20w oil to near the top (as mentioned in the Minton mods) makes it stiffer but great on the twisties.
 
drewpy said:
I stiffened mine up by filling the 20w oil to near the top (as mentioned in the Minton mods) makes it stiffer but great on the twisties.
Click to expand...

Is that Minton's recommended fork oil levels along with the springs I mentioned or without?
 
11-1115 are 22mm for the OD of the spring, the OD of the Forks are 34mm they work great for 150lb rider, as most of our springs are clapped out at this point in time (30 years or so)
 
If you stiffen up the front end, do you need to also stiffen up the rear suspension to balance everything out? Maybe if the fronts stiff but the backs sloppy it wont be all that nice handling?
 
Evan said:
I'm going to order new fork springs in the next couple days and I'm looking for some input. I weigh 220 lbs so I was going to order the heavier 11-1109. Am I on the right track or would that be too stiff? What weight of fork oil would you guys recommend and would you stick with the stock volume? Do you recommend buying them somewhere other than Amazon?
http://www.amazon.com/Progressive-Suspension-Front-Springs-11-1109/dp/B0031BBIP6
Click to expand...

Did you ever install these? Im looking to get the same ones...:thumbsup:
 
last weekend i replaced the seals and springs in my 1980.

was rather easy, except for getting the little round clip out and back in the top of the fork. that took some time and effort (without a vice).

i added 15w fork oil and some generic seals i got at a local shop.

these are the springs i ordered: http://www.amazon.com/gp/product/B000UK7MUG

Progressive Suspension 11-1115

they seem to work and fit really well! i installed them with the tight coils down. seemed to be easier to compress to get the top cap and clip back in.

their website said it makes no difference what direction they go in, but tight coils down may reduce noise somehow.
 
What are these ratings on the springs? I'm a 270 lb Rider (yes I'm trying to lose weight) what springs should I get?
 

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