jaan Posted June 9, 2009 Report Share Posted June 9, 2009 (edited) I was going to replace thirty years old front fork springs. The length of the new ones (which were said to be for 348!) were only 47 cm but my original are 50 cm. What's the right length? So whatever it is, I desided to lathe some nylon spacers (30-40 mm) and try with them. Edited June 10, 2009 by Jaan Quote Link to comment Share on other sites More sharing options...
feetupfun Posted June 10, 2009 Report Share Posted June 10, 2009 Jaan the free length of a spring is not particularly important. The spring rate is determined by the other properties of the spring (number of active coils, coil diameter and wire diameter). The free length can change over time. Another thing about 348s is that there was a range of springs used in them so it is no surprise to me that what came out of your forks is different to what someone sold you for your bike. I have three sets of 348 forks and they all had different springs in them when I got them. Without meaning to confuse things further I have found that to get a high enough spring rate for my 348, I have used aftermarket springs made for TY250 twinshock forks. Quote Link to comment Share on other sites More sharing options...
jaan Posted June 10, 2009 Author Report Share Posted June 10, 2009 Thanks once more again! Soon you have teached me to know even a little about my 348. Quote Link to comment Share on other sites More sharing options...
jaan Posted June 10, 2009 Author Report Share Posted June 10, 2009 (edited) I mounted 27x 30 mm spacers and the fork works fine. Have yet try without spacers. I'm not sure about my fork oil, I use modern Bel-Ray High Performance Fork Oil, 10W. What's your experience, opinion, advice? Edited June 10, 2009 by Jaan Quote Link to comment Share on other sites More sharing options...
feetupfun Posted June 10, 2009 Report Share Posted June 10, 2009 Fork oil weight is a personal thing so 10WT might be fine for you and those springs. I use 20WT oil and run the level higher than the standard oil quantity provides (125mm below the top of the tubes with forks bottomed and springs removed) You should set the spring preload to suit whatever springs you fit so that the forks are at about 50% of their travel with you on board and with your weight only the footpegs. Take care not to use so much preload that the springs coils touch before the forks bottom (the more preload you give the springs, the smaller the gaps between the coils) Another thing is that by using solid spring spacers you are effectively reducing the air space inside the forks Quote Link to comment Share on other sites More sharing options...
jaan Posted June 13, 2009 Author Report Share Posted June 13, 2009 Thanks, feetupfun, once again! Quote Link to comment Share on other sites More sharing options...
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