Remove Centre Stand

[George 350]

Try searching for model makers supplies - there are loads of places catering for the back garden shed "steam engine" makers, who will sell you the small amounts of bar/tube/sheet required for this past time so might well be able to supply the tube you need?
As for seamless, if you can only get "normal" tube, most small engineering shops would be happy to run a drill down a tube to make it "seamless" for you. You may have a problem getting the 2mm wall thickness you need though.
If still having difficulty with supply, it may be worth investigating getting the pieces you need turned /bored from solid bar by a local engineering shop?
Hope that this helps.

George.

[EVguru]

Buy a length of 3/4" tube from here;

http://www.chronos.ltd.uk/acatalog/Chro ... e_281.html

Fit a pair of bronze or plastic bushes in the ends.


Job done.

[Steve Brown]

Thanks for the advice chaps. I hope to be able to put a second metal tube in there, like the original arrangement, to help spread the wear out further. I don't imagine I'll be doing mileage like I did in the 70's though, so it may be a bit of overkill-we'll see.

Steve.

[Archie Adv]

This seems to be an old thread that I found very useful. Unfortunately with a bike built in 77 and not been on the road since 83ish my new to me centre stand bold sheared the head of the bold. this necessitated cutting off the LH side of the bolt as it was seized solid. Copious amounts of plus gas and lots of heat failed to move it. Next step was to try drilling but all that has so far achieved is an out of true hole through the remaining bolt to a depth of about 25mm.

After reading this I think the solution will be to chop out the tube and replace it fortunately this was the last item to be removed on a complete strip down to bare frame. So no worries about damaging the paint work as it will be re powder coated before rebuild. whilst I am starting to get my head around the Morini way this as well as the swing arm bolt are poor designs. Maybe if they were service at regular intervals they might have worked but I found the grease journals to be next to useless as the groove is too shallow to convey the thick grease along the shaft to keep it lubricated.

If anyone has any ideas that might be useful before I start chopping up the frame I would be very glad of their advice. Similarly if anyone has a PDF of the manual I would welcome a copy showing these features please.

I will try to update on progress as and when.
Thanks
Archie

[norbert]

Sometimes the problem appears becaus anyone used/forced a bolt with normal metric thread. But the thread in the frame is a special one ("Feingewinde")

[Archie Adv]

Sometimes the problem appears becaus anyone used/forced a bolt with normal metric thread. But the thread in the frame is a special one ("Feingewinde")

Thanks for that Norbert fortunately the thread in the frame is okay! the route cause of the problem is a tight interference fit of the inner tube with water ingress has caused it to sieze with rust. The joys of restoration.
Greusse

[EVguru]

The bolt is not normally a tight fit in the spacer tube, but rust does take up a great deal more volume than the original steel.

Most people aren't patient enough when removing seized fasteners. Soaking in penetrating fluid well in advance is a good start and heat should be applied fast, so you get differential expansion. It's no where near as effective to get things even red hot if it's done slowly. Several heat cycles are sometime required to break the hold of corrosion.

I don't recall the bolt being anything other than an ordinary metric coarse, but even if it's a fine thread, it certainly isn't a 'special'.

I recently stripped down a 1973 Strada frame still running it's original cast Iron swingarm bushes which although worn are still just up to MOT standard. The centre stand came off fine too, but had obviously had it's bolt greased once in a while, which most bikes never do.

There are plenty of other marques of bikes out there that suffer from actual stand failures, so I think you should be able to forgive a design that gives trouble after 30+ years, probably having been neglected for more than half that time.

[norbert]

I struggeld with that theme as well last year. The frame came without that tube. (my café racer will have a main stand a bit modified because there will be no exhaust down there, just for comfort )

k-DSCI0178.JPG (43.05 KiB) Viewed 20202 times

The tube is 14/10. This is a rare size hear, I only found 13,5 and had to drill it to 10 inside.

The thread of the bolt is 10 x 1,25. (the normal metric for 10 mm woulde be 10 x 1,5)

I doubted how long the tube should be Made it al bit longer than the tube of the frame and tightend the stand towards it, and after that contering with the nut.
Whilst the bolt is fixed on the left side of the stand, this must mean, that putting the bike on the stand the bolt shoud also turn. And it does. But looking at Rocinante I noticed that her bolt does not turn (of course I´m not going to touch it, never change a running horse!) But I´m not that sure that I´m smart enough to understand that If the bolt is fixed to the frame/not moving using the stand, that would mean that the bolt turns every time in the thread of the stand I mounted it maybe 13 years ago, of course with grease, but don´t remember even thinking about it at that time. What happens with your bolts when using the main stand?

If the

norbert

[EVguru]

Why is there a thread in one side of the stand? If it was designed to simply tighten onto the spacer tube, then a simple hole and nylock nut would have done the job. Having the threaded lug and the locknut means the bolt can be locked in the stand, without the stand lugs being pulled together and crushed against the frame or spacer tube (whichever is the longer on your bike).

As I said earlier in the thread, having the spacer turn in the frame tube doesn't really make sense. Better to have the replaceable bolt wear.

If I was doing a repair, I'd probably put a couple of plastic bushes in the ends of the frame tube. Together with a good dose of water resistant grease, they'll probably be doing their job long after the owner has died.

The bolt should definitely rotate with the stand, otherwise the stand lugs and the bolt thread are being used as bearings. It's a sign of the stand having been neglected (haven't they all!) and the bolt having seized in the spacer tube.

[norbert]

I agree Paul!

But if there is no thread on the other side of the bolt like in the swing/crank (?) It does not really make much sense. You tighten it together till you have the clearence you need, without any distance between, abusing the paintwork. To my point of view there is no big diference if you take a bolt with two nuts or fixing it only to one arm if you dont use any distance in between. The only advantage is that you can conter it corectly on the left side. Or am I totaly wrong

ciao
norbert

[EVguru]

If the bolt were not locked to the stand, there would inevitably be quite a bit of movement and wear of the stand lugs. There is often a fair bit of wear on the bolt head end as it is.

[Archie Adv]

Paul & Norbert,
Gents thanks for taking the time to respond to my wee dilemma!

I visited NLM this morning to get some of the replacement parts I need and also spoke with the mechs in the workshop. Their tried and tested method is lots of plus gas, heat and an air hammer. I have both so will give it a try.

Paul, you are right about the lack of maintenance and of course sitting for 30+ years has not helped. So my criticism is perhaps unwarranted!

Norbert, It appears some had the fine threading in the frame hole along with a locking nut and others didn't have the threaded hole only the lock nut.

It is interesting to note how varied manufacturing could be back in the day that it really did depend on who assembled/built the particular bike and each worker had his own methods rather than process driven like modern manufacture of today where al processes are documented, work instructions are displayed at each work station and the process is followed religiously. Variances of the nature we find on these older machines would not be possible nowadays. I guess it's almost like a fingerprint/DNA to those who were in the game back then and they could tell from these little nuances who built the bike at the factory.

Thanks again and I look forward to more hints and tips.
Have a good weekend whether spannering or riding.

[Archie Adv]

Well it finally came off on Saturday morning but not before I'd made a real pigs ear of it.

I drilled down through the bolt for about 30mm and then realised the drill was skewed and had penetrated the tube sidewall. That left nothing for it but to cut the tubes an clear out the frame holes. I also had to remove the stand stop with the rubber bumper pads but they are easily fixed and re-welded into it's position.

I'm now trying to source the necessary seamless tube profiles at 18mm OD and 14mm OD!! Scarce.! like hens teeth..!! Seemingly even the latest order that NLM received had to be returned to the supplier as they had supplied seemed tubes which don't allow either the inner tube or bolt to travel through the outer tube as a result of the internal seams from rolled welded strip steel.

I've read the alternative suggestions above and whilst they are all logical my thoughts are to use the original remaining piece of tube that I salvaged and once the bolt is removed clean them up and re-weld them back in situ as stubs rather a full cross frame tube. Then use an original sized bolt all the way through. I'm confident this would be more than adequate and would prevent the build up of future corrosion and much easier to service.

Comments invited. Sorry no pics yet

[Archie Adv]

Continuing this thread a little further. Everything was cleaned up ready for new tubes. I obtained the 14mm seamless tube without too much trouble, the 18mm was a compromise.
In the end I bought 18mm rolled welded strip tube and then just eased a drill through the remove the seam. Tubes were cut to 120mm and then dressed back to 118 which is the actual space size between the stand fixing lugs. Tacked in with Mig welder and then the frame was taken for powder coating. Awaiting it's return now!

More anon.