Author Topic: Fork springs  (Read 518 times)

Offline rustywheels

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Fork springs
« on: March 03, 2021, 05:30:20 PM »
My front forks feel as if the springs are a little on the worn side, and looking for any recommendations.  I've used Hagon on my other bikes, but they don't supply a replacement set, and nor does Mr Silver.  Spookily there isn't much chatter around replacing springs on the forum, so am I in the minority?  Is it just a case of an oil change to a heavier weight like 20w?  I don't experience excessive dive (probably because I'm not going that fast!!), but can be a bit crashy on bumps.

Thanks for any advice
1977 Honda CB400F
1978 Yamaha XT500
1989 Mazda MX5

Offline oapcb400

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Re: Fork springs
« Reply #1 on: March 03, 2021, 07:09:00 PM »
if you go to www.brooksuspension, they list upgraded fork springs made by wirth for the cb400.   £130 post free

Offline TrickyMicky

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Re: Fork springs
« Reply #2 on: March 03, 2021, 07:31:52 PM »
Before spending good money on new springs, and going through the hassle of fitting them etc., I would be tempted to drain the old oil out, and refill with the correct amount of new. I've always used auto transmission fluid and been happy with that.
   If you are not getting too much dive on braking then the springs cannot be too bad. Quite often the 'crashing about' on bumpy roads could well be a lack of rebound damping which is what the oil is there to control. Be lucky. Michael.

Online K2-K6

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Re: Fork springs
« Reply #3 on: March 03, 2021, 08:26:10 PM »
I'd initially change the oil too. 

ATF is fine and not expensive,  but feel that a dedicated fork oil holds advantage and makes the fork action smoother.  Over about 10 viscosity usually makes them quite harsh.

Preference for me is Motul fork oil in 7.5 grade but they do others too.

Offline philward

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Re: Fork springs
« Reply #4 on: March 04, 2021, 10:25:00 AM »
I agree with the above comments - I fitted progressive springs as an upgrade to my 750k2 but to be honest, couldn't notice much difference in normal riding (I don't go scratching the pegs anymore!). Although the oil was nearly new, I changed the grade to a recommendation on the forum and that produced a big improvement (can't remember the grade  now)
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline rustywheels

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Re: Fork springs
« Reply #5 on: March 04, 2021, 01:02:04 PM »
Thanks all.  I'll change the oil and see how that gets on.  Always good to save the £
1977 Honda CB400F
1978 Yamaha XT500
1989 Mazda MX5

 

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