fork springs

[clive]

For some time I have realised that the front forks on my G3L rigid sit very low (yes that is even before I am sitting astride the bike!). It is only ridden solo and has ally guards front and back. Looking at the limited data I can find fork springs varied in lengths over the years from 10 to 12 3/4 inches. As my bike is a bitsa I really don't know the year of the forks other than they are 1 1/8. I have another bike which has heavy guards, a screen and a 500 engine but the forks sit another 2 inches higher.

So before pulling the forks off to see the length of the springs I had a look at the spare springs I have. I have 2 pairs that are around 12 1/2 inches long but the wire is 0.215 thick. The workshop manual I have found suggests these may be for sidecar use and that the standard ones should be 6G. I believe 6G would be 0.16 diameter, can anyone confirm? None of the springs I have seem to be that thin. Is it possible that the length of the damper rods would limit the length of the springs?

Basically with the potholes around at the moment, and with no suspension at the back I am looking for some more suspension movement at the front. Any thoughts please.

[dave16mct]

6G is 0.192" or 4.877mm. I once measured my '55 G3LS springs which were 12 3/4" long by 5.14mm (1 1/4" stanchions). I've plenty of 1 1/8" type springs so I can measure them tomorrow. I suppose you could always drop in a 2" spacer tube on top of the spring. Plenty of modern bikes adjust the fork height this way. Some use plastic waste pipe. (Edit; that would be on the inside of the stanchion. In our forks it'd be better to use a thick walled alloy tube, or find a longer spring.
Dave.

[Mick D]

Is it possible that the length of the damper rods would limit the length of the springs?

Hi Clive

Yes that's exactly what can happen - with the load off of the front wheel the fork extension is limited by either the bushes contacting each other or the damper topping out - nothing to do with the springs, (see my posts regarding my G15 issue - http://www.jampot.com/forum/viewtopic.php?f=22&t=26977).

If you have incorrect length or rate springs installed the forks will still extend to their designed length if you remove all load from them, (put the bike on the centre stand and raise the front wheel off of the ground).

So, if the forks are the correct length unloaded you will need to investigate the springs - if they are still too short unloaded you'll need to look to your dampers or rods, (it's unlikely to be an issue with the stanchion but not impossible I guess). Of course, if you have an issue with the dampers or stanchions you may still have an associated issue with the springs.

Regards Mick

[clive]

I have just realised from what Mick said that I am comparing a bike with a centre stand and one with a rear stand, and the later obviously still puts weight on the front wheel. I think I will pull the one fork out and check the springs I have, as the front wheel needs to come off for packing under the brake shoe mushroom. Dave it would be helpful to know the diameter of the spring material for the 1 1/8 springs you have. The real issue I have is there seems to be llimited movement when on the road.

[dave16mct]

Here are the results of the North West jury: 12 3/4" x 42mm OD x 4.84mm (0.193")
12 5/8" x 42mm OD x 5.06mm (0.199")
10" x 42mm OD x 5.36mm (0.21")
Obviously the 10" springs are the sidecar but may have used a spacer? I would think the 12 3/4" x 0.193" x 42mm OD are the normal size.
Dave.

[Pharisee]

I replaced the bushes and oil seals in my CS forks recently and noticed that the springs were progressively wound. Are they all like that or just the CS ones?

[dave16mct]

They're all proggressive.
Dave.

[clive]

Here are the results of the North West jury: 12 3/4" x 42mm OD x 4.84mm (0.193")
12 5/8" x 42mm OD x 5.06mm (0.199")
10" x 42mm OD x 5.36mm (0.21")
Obviously the 10" springs are the sidecar but may have used a spacer? I would think the 12 3/4" x 0.193" x 42mm OD are the normal size.
Dave.

well I went back and checked all my spare springs today. I have two sets of 12 3/4 both have a diameter of 0.215" and some shorter ones. Now one of these was given to me by a friend who had some of mine because they were too firm on his trials bike. The others I may have bought when I had a Busmar double adult sidecar or come with forks I had bought, but they definitely seem to be sidecar thickness. So I will wait to see what I have got when I pull the forks out and may well be advertising for some standard road ones. Thanks for the help.

[Stuart Jenkins]

Morning Clive,
The 10" x 0.207 going by the 1953 Army technical handbook, [http://archives.jampot.dk/book/Workshop ... ndards.pdf] are the springs used in the WD g3l bike, and what I had in mine before putting in some 12 3/4" springs. These do noticably raise up the forks, so they ride a bit higher, my original fork spring shrouds are 6 3/4" long so you can see from the photo where they would come to on the slider extention tube (i'm now using rubber gaiters).
Stuart

P.s Spring length info from this book, hope it helps:

[clive]

well an update. The front brake is now working well again with the brake mushrooms having an extra washer each. Whilst the wheel was off I took one of the stanchions off to see what springs I had fitted (not even sure I have had them off before in the 40 years I have owned the bike). Anyway the first spring came out in two parts. They are only 10 inches long anyway. I had a spare 12 inch set of the same thickness. I now have good fork movement but like all fixes on these bikes the extra two inches at the front means the sidestand is now too short!

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