Swing Arm Bushes

[Kabi]

Hi Colin,

thank you for explaining it
Today i checked the fitting at frame x pin - photo attached.
Tried to fit pin vs. swingarm again and one side of the pin get freely to 1/2 depth of one bushing, then it get stuck. And second bushing is smaller, because in this i'm not able to insert either side of the pin. (hope you understand what meant. It is a little bit hard to explain it in english)
The pin seems to be straight. One small crash i guess, was before i bought Monza (exhaust was a little abraded and driver footrest was misaligned, handlebar lever had lost endball).

So. Not decided what solution to choose. But maybe i'll go with small improving a size of bushing in swingarm. If i will be able to find someone to mesure the straightness of the pin by machine, i'll do that too.

What do you thing?
Thanks a lot

[Duccout]

Hi Kabi,

I don't know, it seems strange. I think that to start with a new pin would be a good idea, possibly this one from Recambio Usado ( if it is the right one).
Swingarm NEW Ducati single cylinder models (Ø 29mm x 200mm)
Swingarm NEW Ducati single cylinder models
NEW Ducati swingarm single cylinder models (Diameter Ø29mm x length 200mm).

Quantity
1
96 items in stock

36.00EUR

And then if it is still tight see if you can get the bushes reamed down, or try the previous suggestion of using a small hone to open the bushes out a small amount. It is possible that the bushes are bent, but it would take a lot of force.

Good luck,

Colin

[Duccout]

Kabi,

Does the pin slide into the frame OK? If it does, then maybe the bushes have small ridges on the surface (burrs) that is stopping the pin going through, so it may be worth trying Jordan's suggestion of a small hone, these can be bought on eBay for less than £10 and may clean up the surface enough to let the pin slide through.

Is your bike Italian or Spanish?


Colin

[Jordan]

If it is decided to ream the bushes, a piloted reamer would help make the holes co-linear.
It must be long enough to reach the other bush.
These were commonly used in the days when cars had king pins for steering swivels.
https://tinyurl.com/y5dfpudj

Another possible method is line boring, using something like this.
https://tinyurl.com/y3nthqf7

[themoudie]

Ahoj Kabi,

K překladu angličtiny do češtiny jsem použil překlad Google.

Souhlasil bych s Jordanem, že otvor obou pouzder musí být kolineární, jinak se otočný čep, i když je to „pravda“, obě strany rovnoběžně, bude v nejlepším případě tlačit při protlačování pouzdry a v nejhorším případě jako vy nález, neprojde křovím.

Jordanova zpráva „Pokud bude rozhodnuto vystružit keře, pilotovaný výstružník by pomohl vytvořit díry kolineární.
Musí být dostatečně dlouhá, aby dosáhla druhého keře.
Ty se běžně používaly v dobách, kdy auta měla čepy pro otočné čepy řízení.
https://tinyurl.com/y5dfpudj

Další možnou metodou je vyvrtávání čar pomocí něčeho takového.
https://tinyurl.com/y3nthqf7 ,,

Doufám, že to pomůže, dobré zdraví, Bill

Hello Kabi,

I have used Google translation to translate the English to Czech.

I would agree with Jordan that the bore of both bushes must be co-linear or else the pivot pin, even if it is 'true', both sides parallel, will bind at best when pushed through the bushes and at worst, as you are finding, will not pass through the bushes.

Jordan's message

If it is decided to ream the bushes, a piloted reamer would help make the holes co-linear.
It must be long enough to reach the other bush.
These were commonly used in the days when cars had king pins for steering swivels.
https://tinyurl.com/y5dfpudj

Another possible method is line boring, using something like this.
https://tinyurl.com/y3nthqf7

I hope this helps, good health, Bill

[Kabi]

Thank you guys for replies
I dont know why i did not this at first - measure the pin and bushing etc
But i took the digital caliper and measured the pin and outer diameter is 28,92 - 29,1 mm(in center) , lenght 200 mm
but the inner diameter in frame and swingarm show 28,7 mm , as frame diameter i guess could be fine, but in swingarm not .

I'm still playing with a small tuning of the pin. Hard to say. Hard to say if is possible that this stuff, like pin or bushing, can get bigger over time, somehow.


To Colin : i believe is Italian.

[Duccout]

Hi Kabi,

The pin is the correct measurement, and the frame clamp can be enlarged by gently tapping a large screwdriver into the gap where the bolt goes through, so that the pin can slide in, but the bushes are obviously too small. Do you have a friendly, small engineering company near where you live, who can look at the swinging arm and pin, and ream the bushes out to get the pin to fit? That would be the best solution.

[Kabi]

Agree with that.
I have to take a look, maybe i’ll find someone outside the city.

I have to thank you for consulting this stuff.
I hope i will post someday finished work with review.

[Duccout]

Kabi,

Another thought: there are oversize pins available, so it is possible that the previous owner fitted one, which would explain why it is too large.

Colin

[Kabi]

aha! That sounds logic. Thank you
Last week i have found a local guy who work with stuff like milling cutter, cnc etc.
First thing he did was to drill by hand tool thru the bushing in swing arm - which was almost ok with drill size 29mm (i guess). But the pin still wont get in freely. He found some bulge(?) on the pin (well, experienced man hands..) so he will improve the pin on milling cutter machine (hope it is correct word in english)

i will inform, when i pickup the parts.