Fork parts question

I tried a set of the RGM progressive springs, and found that they made a horrible scraping sound as they compressed. The outer dia. is somewhat smaller than the std ones and this seems to allow them to buckle more than the standard ones. I bought a set of A-N standard springs (amazingly cheap actually and am quite happy with them in a set of Lansdowne dampers. I may try the progressives again if I can get around to making some short sections of teflon tubing to act as supports as someone here mentioned in another thread.

By the way, as most of you know by now, John at Landsdowne is not taking any new orders now due to serious health issues.

If any of these aftermarket cartridge solutions could be hidden under the stock chrome top nuts, count me in. My bikes all have a stock appearance and I'd like to keep them that way while hiding any improvements.

I'm afraid that neither of the 2 solutions being discussed here uses the standard chromed steel caps.

Just to follow up, I did hear back from Chris Cosentino and he plans on doing another run of kits soon, but I'm afraid one is outside my budget this time around. So a good conventional fork rebuild is on this winters schedule. Yesterday I talked to Franks and a set of tubes is now $219 plus shipping. I also talked to Race Tech about fork springs. They offer '72 Commando springs in 8 different straight (which I prefer) spring rates for $140 a pair. I have previously found that their over the phone tech support is first rate and they have full fork setup recommendations for my '72.
Bill

Jerry Doe said:

Hello,

I am in the middle of rebuilding my forks for my 1971 750. I have new bushes, seals, fork tube (stanchions) etc. I have been looking at the RGM site and see progressive springs and ally dampers "Improved damping":

http://www.rgmnorton.co.uk/buy/progress ... r_2300.htm
http://www.rgmnorton.co.uk/buy/alloy-fo ... o_2282.htm

I was wondering if anyone else has fitted these and noticed much difference?? I am considering getting these items for my forks.

Cheers-- Jerry

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I installed progressive springs I got from British Cycle a dozen years ago, as the stock springs were very soft for me (I am 6'2", 210lbs) and my semi-aggressive riding style. They made a world of difference and I dont regret the switch in the least - one of the best things I have done.

I need to rebuild my forks as the seals weep, and it is among the next things I need to find the time to do once other life stuff gets out of the way. I have had a set of Lansdowne's on the shelf for about too now, and will get them in with the progressives. If I dont like the combo, I will have to go for some of the Race Tech springs, too.

There are dampner kits and progressive springs and they may help but I'm not familiar with them. To prevent top out with the standard dampners you need to install special sleeves from either RGM or from JSmotorsport. To smooth out the bumps you need to reduce friction more than anything. For that there are the slippery Turkite bushings. You want to be riding on a cushion of oil - not metal scraping against metal. To prevent bottom out you need late model forks or make the modification below. So upgrading your Norton forks its not a bleak prospect at all.

This is what my 71 looks like. I ordered the damper kits from Bill. Not sure what to do with them, but think it should be clear how to fit them when they arrive. Anyway my 71 looks like this:

Jerry Doe said:

This is what my 71 looks like. I ordered the damper kits from Bill. Not sure what to do with them, but think it should be clear how to fit them when they arrive. Anyway my 71 looks like this:

Click to expand...

Yours should be OK. The early ones with the hole drilled below the conical section are the bad ones. That's why I show the photo with an aluminum sleeve covering up the hole below the conical section. A new hole is drilled above the conical section. A hole in the middle of the conical section still works because you still get a hydraulic bump stop when the fork tube closes off the oil when it gets to the largest diameter of the cone.

Using a special sleeve at the top of the fork leg is the best way to avoid top out. I have a split sleeve for this so it stays in place (push fit) It covers the big holes in the fork tubes when the legs extend so you get a hydraulic bump stop. The small holes near the bottom of the fork tubes should also be plugged with small set screws or some other means or you can still get the top out "clunk".