respoking 70 S

I got 2 sets of SS spokes (single gauge, not like the original double gauge) and and the front wheel went together just fine. However when I got to the back wheel, with the last set of outer side spokes, I had to force them slightly and bend the spokes to get them into the correct holes on the rim. It did not all go together loose and easily like the front wheel before installing the nuts. With the front wheel, I could put all the spokes in the holes without using the nuts, but on the rear one I had to install the nuts to hold it all together to get the last set of outer spokes in. The outer side spokes all seem to be bent towards the inside of the wheel, it is like the neck on the spokes is too short and there is quite a bend in the spoke, about 3mm after I got the offset correct. I was wondering if this is ok or what is going on. I took the new spokes out and compared them with the old ones and for sure the neck on the longer necked new ones are shorter than the long necked originals. I checked the hub flanges where the spoke holes are and they seem pretty much the same width front and rear. The offset is a bit different, but I didn't like the way I had to force the spokes to get the rear wheel one together. It just didn't go together loose and easy like the front wheel. The old spokes came out loose just like the front one. Why would the rear wheel be different that the front?

I am concerned that this may put some undue stress on the spoke necks. Any ideas? I have contacted the vendor where I got them.

Dave

hi dogt,thats no good it will put too much stress on the spokes dont do it

I didn't think it was a good idea. Here is the old spoke (outer or longer neck) compared to the new one. Time to hassle with the vendor I guess.



Dave

I have just respoked the front wheel on my 750S project, before putting the tyre on I assembled the wheel and backing plate into the forks and found that the rim was slightly off centre in relation to the forks. This is worth checking as it is quite an easy job to recentre it while it is still a bare wheel.

I was careful to measure the offset of the hubs with the hub flanges and also with the hub centers and am sure the offset is just like the original. However for some reason (I think the necks of the new spokes are too short) the rear wheel will not go together without forcing spokes and I am sure that is not a good idea.

Dave
70 S

I generally spoke the front drum brake rims centrally, but for some reason this time that gave me the wrong centreing in the forks, perhaps the backing plate may have been over enthusiastically polished by a previous owner, thus shortening the boss where it buts up against the right fork leg. Regarding your spokes I have had a similar experience with spokes supplied for a BSA that I am rebuilding, the only solution was to get new spokes, I would definitely contact the people who sold you these parts. Also I would not necessarily go on the offset that you found existed on the bike, over years and numerous ownerships things can often get rebuilt or repaired incorrectly. According to various technical books (including Norton Twin restoration, by Roy Bacon) the rear rim should be offset 3/16" to the right. Do you have any photos of your bike? I am always interested to see authentic examples as I am building a replica from a collection of bits that I bought some time back. I am attempting to get it as accurate as possible, it is progressing steadily and I hope to have it on the road in a couple of months.

I bought this bike in April of 72 and the bike was pretty original and had maybe 4K on it. It was in a bit of rough shape, from being stored under a tarp in a back yard. The valve covers have fins on them instead of being smooth, the seat had the Norton logo on the back which I am told is not what a 70S should have and one of the rear hub bolts was missing. I drove it until about 82 or so but it still has only 13K on it. Of course most of the chrome is now rusty.

If you want to see a nice restoration job on a 70S go to http://www.jba.bc.ca/NortonS.htm

I think I have posted some pictures of my bike for you in past posts. You can look up some of those.

I have email off to the vendor to see what we can do. I definitely am not going to use these spokes on the rear, but I wonder why because the front and rear hubs seem so similar.

Got a reply from the vendor, and he said to bend the necks of the spokes so they line up better. Did that and the rear wheel went together just like the front one. He suggested bending them with a soft mallet against the hub, but I made a little jig I could put the spokes in and bend the necks to a smaller angle. It seems to be working just fine so far. I have the rim on with everything finger tight and it is pretty close. Spoking always seems to take me a few days because I cannot concentrate that long on doing it. Guess it is the age. Here is a pic of it finger tight.



Dave
70S

hi dave ,are you using the original rims

Chris,

No, they are replacement chromed UK rims. They appear to be just like the originals but different markings. Got them from Walridge in CAN.

Dave

hi dave, i was just wondering if the hole drillings are the same

Chris,

As near as I can tell, they are exact replicas of the originals without the Dunlop name on them. They may be made by Wassals?? Once you get the spokes set in the hub correctly, they go together easy. There is, however, no hole for the safety lug on the rear. I can drill that out.

I am surprised how easy it is to respoke these wheels once you know what you are doing. Just being finger tight, they are within 2-3mm runout both ways. Same with the offset.

Dave

DogT said:

I can drill that out.

Click to expand...

Do you have to worry about cracking the chrome to do that?

hi dave,thats good i was just wondering if the hole drillings were different and causing the probs you were having,as you put it (no hole for the safety lug)i wouldnt worry about that,its the first thing to get rid of, they were used to stop tyer creep on the rims, which ive never come across,keep an eye on the tube valve, when you fit it vertical it should stay that way, if it starts leaning forward the tyer could be creeping

just to add to my previous post when fitting the knurled nut to to the inner tube valve make sure its screwed up to the dust cap not down to the rim,then if the tyer does creep it wont pull the valve off the tube

I was worried about cracking the chrome plating drilling out for the safety lug. As Chris says maybe I should just forge it. Does anyone have info on the safety lug? I'll do a search on that.

dave
70S