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I would like to know the correct thread size for the bolt that mounts the muffler to the frame. Is it the same as the foot pegs? I have seen this quoted as 7/16-20, but that seems like too fine a thread.

I am also looking for a PDF file of the parts manual for a 1966 Mark 3, so a narrow case bike. Any leads on this would be much appreciated.

I am relatively new to the list. Have been into vintage Ducatis for a long time. I am near completion on a restoration of a 1966 Mark 3 and am about half way through on a 1965 version of the same bike.

Thanks in advance for the help.

Ken

Hi Ken,

I've never seen an inch series (either Unified or British) thread on a Ducati, I think it's M11 x 1.0 pitch. I'm sure it's the same as the footpeg thread though. The hexagon is 18 across flats and about 6 high with a domed face.

Cheers,

Stewart D

As odd as it seems, the footrest thread is indeed inch sized.
A factory drawing states it is 7/16 x 20 pitch.

It used to be that many seatbelt mounting bolts were this size. They were also often with a thin head.

Hi Ken,

According to my copy of the parts book for the 250 Diana, the part number is 0170.03.330. Which, according to Andy Nienhagen, is 7/16" x 18 TPI.

(Note that 18 TPI is standard for BSF. 20 TPI = AF (UNC).

Not sure if this helps or confuses; but ...

Craig

Source: http://www.desmo.net/pr_liste.htm

Ventodue wrote: According to my copy of the parts book for the 250 Diana, the part number is 0170.03.330.

And here's 4 (why 4? ) of them for sale on eBay. (Buy the lot, and sell three of them on ? At least you'll know how to advertise them correctly ... )

http://www.ebay.co.uk/itm/DUCATI-BEVEL- ... 540879c933

Thanks everyone for the input. I ordered the four from Ebay. I only need two, so If anyone is in a similar boat and is looking for one, Let me know.

Ken

i had some footrests made folding and non folding . the thread used is 7/16 X 20 UNF

sold about 7 or 800 so far and never had a complaint about not fitting

Eldert

Jordan wrote:As odd as it seems, the footrest thread is indeed inch sized.
A factory drawing states it is 7/16 x 20 pitch.

Jordan,
I'm most amazed at that - I measured the bolt in the photo so I could I could sell it, in the ad I just put down M11 x 1.25 pitch thread. This was about a year ago when I was having a big cleanout.

7/16" ( x 25.4)= 11.1125mm

20 T.P.I. (25.4/20) = 1.27mm Pitch

My eyes aren't good enough to tell the difference of 0.02mm so apologies for the misleading post.

Craig,

I think they have made a mistake on that list - 18 T.P.I. (25.4/18) = 1.4111 - When I measured mine I used pitch gauges and though I missed the difference between the threads 1.27 pitch and the 1.25 pitch gauge that I used, there is no way I would have missed the difference between a 1.4111 pitch and a 1.25 or 1.5 pitch gauge.

Maybe Ducati just bought a cheap job lot of seat belt bolts for the silencers. It's certainly makes things a bit easier for anyone wanting to make a new bolt/footpeg/replace frame bosses - the taps and dies would be pretty easily available.

Cheers,

Stewart D

Eldert wrote:i had some footrests made folding and non folding . the thread used is 7/16 X 20 UNF. sold about 7 or 800 so far and never had a complaint about not fitting

Thanks Eldert.

(Do you want to tell Andy, or shall I? )

Craig

Just wanted to follow up and say I received the bolts spotted by Ventodue (thank you) and installed them this evening. Perfect fit and are indeed 7/16 - 20. Who knows why, but thanks for all the help.

Ken