Motorcycle Centre Stand Pivot

[COLIN MARTIN 2Participant @colinmartin2]

I have been lucky enough to be given great advice from the forum in the past, so here’s hoping someone can come up with something this time.

I have posted in the past requesting help with my 50 yr-old Spanish Ducati that has had a hard life. I now have to deal with a centre stand problem. The stand pivots on two shouldered bolts which have dimensions of: 10 mm thread followed by a 12 mm plain shoulder that fits in a corresponding hole in the frame, followed by a 14 mm shoulder that the stand pivots on. This system was used by Ducati for 30 years without any problems except eventual wear on the pivot bolts which are easily replaced. However, my bike has been run with the bolts loose in the frame for a long period, which has enlarged the holes and made them eccentric, with the result that the pivot bolts gradually work their way through the holes and cannot be kept tight.

The only solution that I can come up with is to drill the holes out and thread them and make up threaded steel bushes to screw into the holes to bring them back to standard size. However, the frame is made of high-tensile steel and is hard; would I be able to drill this with a hand drill? Would the eccentricity simply stall the drill bit? Would I be able to thread the hole with a hand tap? Would mild steel be too soft for the bushes?

There is no room to fit anything between the frame and the stand. I did think of bushing the frame holes and threading them to 10 or 12 mm and turning up new bolts without the step, with just a 14 mm shoulder right across  with threaded ends and screwing this into the frame, but apart from the previously mentioned problems, I am not sure that the threaded section would be strong enough and they would be bound to keep working loose. I am not a toolmaker and have rudimentary skills; I have a lathe and pillar drill though. The bike is in running order and I do not wish to completely dismantle it to address the problem!

All ideas will be welcome.

 

Thanks,

 

Colin

[COLIN MARTIN 2]

On 9 October 2026 at 16:00 COLIN MARTIN 2 Said:

However, the frame is made of high-tensile steel and is hard

That is most unlikely.

If you wish to do any machining insitu, with minimal dismantling, a rigid drill bushing/guide will give best chance of success. You can bolt bits of angle iron to the frame at strategic points, tack weld them where they touch, position the drill guide, tack weld it, remove the contraption from the bike (and petrol) and fully weld.

Please have a look at an early episode of Project Binky on YouTube, where they made a reverse suspension jig. The principle is the same.

Pictures of the relevant parts of the bike would be useful to generate ideas.

How thick are the parts you are thinking to thread/tap?

Measure the eccentric holes and 3D print in metal a bush that fits what is on the bike, with a round hole through its centre. Glue it in place with panelbond. Decide on a minimum wall thickness and make a new bolt with reduced OD to suit the ID of the bush.

 

[bernard towersParticipant @bernardtowers37738]

High tensile or just good quality, theres quite a difference. as for your inserts i thought that stainless would be a better option ( all the dirt and water). I have done this on a few BSA centre stands and Harley side stands(big thick lug) so then you can bring it all back to standard. there is no reason why you cannot make your threaded insert from large hex top hat style, then make your stand bolt correspondingly longer to account for the top hat. best of luck..

[COLIN MARTIN 2Participant @colinmartin2]

Thanks for the replies.

I don’t think that any sort of adhesive would hold the bushes in place, as the nut on the end of the thread would be trying to pull the bush out, which is why I thought of threading it. Stainless would definitely be better, but I find it so hard to machine and thread. I will try to organize some pictures but I am not tech-savvy, so would struggle to upload them.

 

The frame where the stand bolts-to consists of a half-inch thick plate either side of it; the stand has two flat plates that fit between these frame plates, so there is no room for any sort of top hat spacer (unless it were sunk into the frame plate)

[Clive FosterParticipant @clivefoster55965]

My fix for a similar issue on the BMW R 75/80/100 series air-cooled flat twins was to re-tap the hole with a first cut (taper) tap using the smallest fine thread that would work regardless of origin. Memory says 9/16 UNF for the BMW but, over 45 years later, may well be wrong. By stopping when the tap hit the sump, before it had gone right through, most of the thread was incomplete and not to full depth so winding the nut in crushed the threads eliminating clearance so things were effectively solid. Loctite for belt and braces.

BMW used a very ordinary bolt with a bobbin for the stand to ride on. The whole set-up was objectively way too weak for the forces involved when the big twin dropped over centre on the stand. I also loctited the bobbin to the lug.

So far as I’m aware all the machines I fixed stayed fixed. Although 10 years later the bloke I sold the first bike I did this to was quite eloquent when complaining about the difficulty in getting things undone to remove the stand.

I imagine something similar could work on your Ducati although, obviously, you will need to use a bolt’n bobbin rather than a shoulder bolt.

Clive

[FulmenParticipant @fulmen]

As DC31k said, it won’t be too hard to machine. Even “high strength” construction steels tap out at 500MPa or so, that’s quite machinable with quality tools. But sure, going at it with a hand held drill and a blunt bit could get ugly…

I can’t really help you anymore without a photo or a sketch of some kind. I’m hopeless at translating text into 3d. Is there a nut on the end or is the bolt screwed into something? is there a head after the 14mm part? Does the bolt rotate in the 12mm hole (originally)?

Are you limited to DIY? A skilled welder might be able to fill in the hole so you can restore it properly. And how worn is the hole? What’s the minimum size you would need to open the hole to, and will this weaken the part in any way?

[bernard towersParticipant @bernardtowers37738]

Colin, what grade of stst are you using?  try 303 or 304 much easier to machine and plenty strong enough for your job.

[peak4Participant @peak4]

Trying to read between the lines without seeing a photo here.

I think we have a stepped bolt, with the stand pivoting on the 14mm section, a 12mm section going through a hole in the frame, followed by a washer and a 10mm nut.

You say the hole through the frame is worn eccentric; does that mean elongated, oval, cam shaped or what?
If there is enough metal left surrounding the odd shaped hole, how about making a replacement bolt with a 14mm + section to suit the stand, followed by a 13mm+ section, which you can then file and fit exactly to the odd shaped hole, then add a nyloc nut as normal.

Uploading a photo is relatively easy from a computer;

Take photo and store somewhere obvious
Start your reply, add some relevant text
Line space
Top right hand icon of the little mountain; hover cursor over it and it says “Insert Image”

A new popup should appear when you click on it, saying “Upload Image” drag drop tap or click

Do one of those, say dragging in the photo off your desktop, and the image should appear in the post just like the screenshots above.
So long as the photo isn’t huge, the forum will resize it to suit, and/or, you can click on one of the image corner boxes to enlarge or shrink it.

Bill
p.s. Mine’s, a 1977 900GTS

[COLIN MARTIN 2Participant @colinmartin2]

Thank you all.

Bill, you have it exactly right, and the centre stand bolt is identical to those fitted to your 900GTS. When I first discovered this problem a couple of years ago, my solution was to do what you suggest and turn up new bolts with a larger shoulder, but what has happened is that the bolts have gradually worked their way into the holes and keep coming loose. The holes are elongated and after thinking about it, this problem may be harder to fix than I first thought. To get enough metal in a sleeve I am going to have to enlarge the holes quite a bit, and this is going to bring into play keeping the hole centres accurate.

[mgnbukParticipant @mgnbuk]

My fix for a similar issue on the BMW R 75/80/100 series air-cooled flat twins was to re-tap the hole

What era of airhead were these Clive ?

I have had a number of “post ’81” light flywheel airheads and there is no tapped hole for the centre stand on those – just a countersunk hole in the frame lug for a countersunk socket head bolt that secures the stand pivot bobbins, with a locking nut on the other side.

I only used OEM screws here as the loads are high. The last bike I rebuilt ( an ’84 R100RT) had had stainless bolts substituted by the PO – they bent and worked loose, eventually wearing the countersunk holes in the frame. Had to build up the damaged area with weld and re-profile with a Dremel before having the frame powder coated – same with the stand. New OEM bobbins, screws & nuts fitted on re-assembly were still OK 5 years later when I sold it.

Access to the socket head of the countersunk screw was compromised by the exhaust pipes & I added a cut down Alllen key to the factory toolkit to allow for regular checks of tightness of the screws.

My Wife’s ’86 registered (’84 built) R65LS still has the OEM screws, bobbins and centre stand fitted as it approaches 100k miles, so while the system as fitted isn’t great it does work long-term if maintained.

Nigel B.

[MacolmParticipant @macolm]

One way to repair a difficult access stripped thread is to obtain a suitable diameter large socket head Allen grub screw, then bore and thread from the other end leaving enough of the Allen hex accessible through the new threaded hole. It can then be screwed in, leaving the new thread in place.

Unbrako and similar quality large grub screws can usually be drilled and threaded to provide a better thread than the original. It does depend on luck to find a suitable size. The hex usually seems harder than the rest of the screw, but should not need machined. Another possibility is to make a similar dual threaded sleeve, leaving a short length of the bore a smaller size to file out square, usually to suit a quarter inch socket extension. You just need the corners – it does not have to be a full square.

 

[Clive FosterParticipant @clivefoster55965]

Colin

Ultimately you are fighting an inadequate design. Given the sharp increase in loading as the bike drops over onto the centre stand at the end of the lift the only long term satisfactory solution is going to be an interference fit thread with zero clearance.

Or at least what i was told by someone experienced in such stressing problems. He reckoned you can’t get enough tension into a normal bolt to stop the peak stresses almost overcoming the tightening induced tension so the actual effective tightening torque is momentarily quite small. Hence the bolt can slowly loosen over many cycles as the movement of the stand tries to twist things.

Interference fit bolts, theoretically, have zero clearance in the thread so are much more resistant to this sort of thing. Hence my use of a taper tap as a crude simulation on the BMW separate bobbin system. Its possible that using keyed bobbin that cannot try to rotate under stand movement loading might overcome the loosening tendency. Certainly the anally retentive BMW types who regularly lubricated the pivot, there is whole although I defy anyone to find it with things fitted to the machine, seemed not to suffer the problem. Or at least didn’t admit to it! The ignore it, seized solid, brigade just let it work on the threads until everything was totally clapped.

Which latter recollection makes me wonder if reversing the pivot system with a bearing bush in the frame lug and a “fixed” pin screwed through the stand into the bush might work. Especially if you could figure some way of stopping the pin trying to unscrew from the stand. First find a spare stand to experiment with I guess.

The actual bearing loadings probably aren’t that high. My rotary engined Norton has simple nylon bushes between the stand and cross pin they run on which are reported not to wear significantly. Memory says around 5/8″ bore by 3/4″ long. Mine certainly haven’t over an estimated 5,000 stand operations.

Clive

[COLIN MARTIN 2]

On COLIN MARTIN 2 Said:

Thank you all.

Bill, you have it exactly right, and the centre stand bolt is identical to those fitted to your 900GTS. When I first discovered this problem a couple of years ago, my solution was to do what you suggest and turn up new bolts with a larger shoulder, but what has happened is that the bolts have gradually worked their way into the holes and keep coming loose. The holes are elongated and after thinking about it, this problem may be harder to fix than I first thought. To get enough metal in a sleeve I am going to have to enlarge the holes quite a bit, and this is going to bring into play keeping the hole centres accurate.

Just been out to check mine, which fortuitously is on the bench in the garage; it’s a half length bench, so the whole back end is in fresh air with the frame supported by the stand.
Unfortunately I can’t take it off the stand at the moment to examine it closely, partly because the engine is in bits awaiting re-assembly, but that’s a long story.
By the looks of it, what I did 20 years ago, was to make new stainless bolts, but was able rely on the shoulder to clamp it up on the frame; even with a photo I can’t see exactly what I did.

The bolt’s outer shoulder will be as tight a fit as I could get in the frame, but the inner ends seem threaded at 12mm (possibly fine), so I’m not quite sure what’s going on there, maybe in my case the centre stand holes were worn.
On the right hand side, it may be that the whole bolt assembly is free to rotate, but on the left side, it’s certainly fixed, as it holds a bracket for a home brewed brake light switch.

Edit, thinking about the photos now, I might have dispensed with the 12-10mm shoulder, and uses 2x12mm nuts, so I could adjust the tightening clearance, rather than relying on one nut and a fixed stop.

How about making up a new bolt, with a shoulder to fit your elongated hole in the frame.
Dispense with the 12mm section and go straight for 10mm, which will leave a bit of space in the stand’s hole.

That space can be made up with a stainless top hat bush, where the brim acts as a separating/thrust washer between the frame and the centre stand.
There is then a plain washer and locknuts inboard, trapping the top hat bush tightly against the frame, whilst providing a pivoting bush for the centre stand.

Bill

[COLIN MARTIN 2Participant @colinmartin2]

Hi Bill,

 

Thank you for the suggestion. I will check tomorrow whether it will work, but I doubt that there is room for a top hat spacer to fit in either side of the centre stand, although there is a small amount of side-to-side clearance. I may have to see if I can sink the top hat spacer into the frame plates slightly, but I don’t know how I will do that; possibly the spacer could have a steep taper next to the stand hole and I could countersink the stand pivot hole slightly to accommodate it.

[COLIN MARTIN 2]

On COLIN MARTIN 2 Said:

Hi Bill,

 

Thank you for the suggestion. I will check tomorrow whether it will work, but I doubt that there is room for a top hat spacer to fit in either side of the centre stand, although there is a small amount of side-to-side clearance. I may have to see if I can sink the top hat spacer into the frame plates slightly, but I don’t know how I will do that; possibly the spacer could have a steep taper next to the stand hole and I could countersink the stand pivot hole slightly to accommodate it.

On the 900GTS, the centre stand is tubular, with a pair of fish plates welded onto the top, so it would be easy squash them together a bit with some threaded rod or a large vice.
The stand fits inside the frame, so that would make clearance.

Bill

[COLIN MARTIN 2Participant @colinmartin2]

Right, I have begun! I have turned-up a top hat spacer that fits tightly in the frame and a bush that the stand pivots on, and have a bolt going through the assembly which is bolted to the frame (on one side). I have called it a day now but hopefully I can turn up the other side pieces tomorrow. I still have to squash the stand plates together, but interestingly, one side is actually bent outwards, so I will need to devise a way of easing that side back in to give me clearance, and then cut the bolts to the correct length, and then see if it all works! It would be nice if it does.

 

Thank you to everyone who offered suggestions; this has kept me awake at night trying to work out the best way of dealing with it.

 

Cheers,

 

Colin

[COLIN MARTIN 2Participant @colinmartin2]

All done! And it appears to be working fine; the rear wheel sits about half an inch higher off the ground now that the pivots are not flexing up and down. I don’t know how durable the repair will be – I would have preferred the top-hat spacers to be of a larger diameter, but it would have entailed a lot of turning and I am not sure how much wear would take place on them, as the stand is free to move slightly from side-to-side. Still, it is only a hobby bike and I only do about a thousand miles a year on it, so hopefully it will see me out!

Thank you to everybody who contributed.

 

Cheers,

 

Colin

[Author]

Posts