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Fork Spring / oil

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Paulreade:
Hi guys, working through a process of elimination to remove a hop or bob out of my k6 front forks. I will attempt to ensure wheels are true and steering head tight in due course. I will then probably try a thicker oil first before replacing springs.
Q: if I remove the springs - is there a way of checking if they actually need replacing or is it just worth doing due to the age of the bike ?
Q: David silver do not stock any longer - I have located progressive springs that may be available via Hagon - is this the best outlet ?
Q: I believe I have 10w oil in there at present, might it be worth draining and trying a slightly thicker oil before a spring change to say 15w or even 20w. I'm only around 11-12 stone so I don't want to stiffen it too much as I believe some of the thicker oils are needed for a heavier load ?
Any advice welcome
Regards
Paul

K2-K6:
Making the assumption that you're not talking about wheel balance which would be consistent and regular as speed increased?
Then, my interpretation of "bobbing" is too much damping in the fork.  This effectively gives a hydraulic locking effect when asked to move at a certain linear rate.

The feeling is that the front of the bike is bounced upward a small amount rather than the suspension moving to accommodate the road irregularities.

To try and see a different effect,  I'd put in 5w oil to make sure the fork will move quickly enough and prevent it trying to move the vehicle mass upwards.  In other words, getting the fork to respond within the range you are operating it with your total all up weight.

I'd not initially consider the fork springs unless there is a very clear measurable sag in static suspension setting. 

At what pressure are you running the front tire? This older and larger setup don't normally need excessive pressure as they are more supported than modern 17 inch rims with small sidewalls and lighter carcass construction. The tire is an undamped spring which will easily introduce bounce into the overall setup if out of pressure range.
Your low body weight would allow you to use lower than spec,  perhaps 2 psi drop to make a difference.  Quick and easy to try.

hairygit:
Alternatively, Honda recommended "Premium quality A.T.F" (Automatic Transmission Fluid) which is fairly thin, but has always worked fine for me, plus ATF contains an addative to swell the oil seals and reduce risk of leakage.

Green1:
You check the springs by measuring there length. I can't remember it of the top of my head but I should imagine there fine unless the bikes done a lot of work.
My gold bike has around 23000 on the clock and there like new. When I got my green bike it had around 80000 miles and they were on there limit. I replaced them with Hyperpro progressive springs and it made a massive difference. The bike was far more stable at speed or mid corner.
I think they supplied 10w with the springs and I recently changed it to ATF fluid and it feels exactly the same.
I only weigh 10 stone if I make a pig of myself and have 28psi in the front tyre.

Well described Nigel I get that happen occasionally but only on rippled roads at certain speeds so I just go faster.
Mick

Underdog1:
Off the top of my head you want the spring length to be over 18.5 inches. Not sure where I’ve got that from though!

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