It could be that I just have too much time on my hands and I’m finding problems that don’t exist, but . . . I think my fork springs are tired. I suspect they are the original springs, and as it is a 1974 bike, that would make them 47 years old!
With the bike off the stand, if I hold the front brake on, I have just under 30mm of travel, which seems low to me. Also, if I put the bike on its main stand and take the weight off the front wheel, I can measure 120mm between the top of the dust cap on the slider and the bottom of the lower yoke. Then, if I take the bike off the stand, this gap drops to 90mm. So I am losing 30mm without me sitting on it.
Does anyone know how much travel there should be in the forks of an old 850T ?
No idea as to what the figures should be, but my 1978 Spada felt similar. The bike didn’t seem to have much movement left in the forks when I was sitting on it and occasionally would bottom out when I hit a pot hole. I remember doing that at about 90 on the M1 and it gave the whole bike a right jolt.
I fitted some slightly stronger secondhand lower springs that someone was selling from a cafe racer project he was building. The springs in mine and thos I bought are in 2 parts and I had to use the original shorter softer spring to get the length right. I guess I could have added a spacer in each leg, but went for the easy option. The result was a massive improvement.
Thanks Don. I’ll take the springs out and measure them. That might indicate whether they need to be replaced.
The replacements I got were made from a slightly thicker guage wire to make them a bit stronger. It was probably half a mill extra or so, but it did help. I seem to recall I did the job without removing the chrome stanchions, just dropped the lowers off by undoing the allen bolts up from the bottom and releasing the dampers from the top.
Leaving the dampers in the yokes sounds like a neat tip. I’ll report back when I get the springs out and measure them.
Today I finally got around to replacing my fork springs ( a long story but basically I have too many bikes ). I got new springs from Gutsibits. Removed the old springs, leaving the stanchions in place as per the tip from Don, and compared the lengths. The new springs were only a little longer than the old ones BUT, they were much stiffer.
After fitting them I now have about 2cm more fork leg showing between the bottom of the lower yoke and the top of the sliders.
Needless to say, the ride and handling are much improved. Should have done it months ago.
Good result. When I changed mine, I found the new (to me) springs were made of a slightly thicker guage wire It certainly lifted the front end and copes with pot holes better now.