Cylinder head stud spacing

[Ducrider52]

OK I have a couple of questions regarding my 1980 900 SD Darmah.
When I bought the bike it was fitted with 36mm Mikuni carbs and what looks like home made inlet manifolds both with different stud spacings. When I reinstalled the stock 32mm Dellortos and inlet manifolds I got with the bike I discovered that the front (horizontal) head had inlet stud spacing of 58mm with a manifold to suit and the rear (vertical) head has 53mm stud spacing with manifold to suit. I have a spare set of heads from supposedly the same year and model of bike and both heads have 53mm stud spacing.
My questions are:
- which head/ stud spacing is correct for the 1980 Darmah?
- If the 58mm inlet stud head is not from a Darmah what is it off of?
Any help much appreciated
Reg

[desodero]

go to ebay australia in ducati bevel and veiw inlet maniflods for sale
this will give you some info

[Ducrider52]

Thanks Desodero. The ad your talking about was what got me thinking, I already bought one new one at 58mm stud spacing that doesn't fit the rear head. The parts manual for the Darmah shows the samr part number for both front and rear manifolds but my rear is 53 mm stud spacing.
Reg

[BevHevSteve]

should be 58mm

I got a 77 900SS awhile ago with the same thing.....

I bet someone ruined a head and the replacement was the different one... oops!

[Craig in France]

Hi Reg

Darmahs up to engine no. 903025 had 52mm stud spacing. Thereafter, 58mm.

So, depending on your engine number (registration dates don't tell you much), more than likely someone's swapped the earlier head for a later one.

HTH

Craig in UK/France

[Ducrider52]

Steve, Craig
Thanks a lot for your information. That clarified thigs for me and was about what I figured. The guy I bought from did similar with the pistons one is 86.4 the other 86.6 and both look like new???
My engine # is 904492 so by Craigs info it should have 58mm inlet stud spacings. Problem is I have 4 good heads but three are 53 mm spacings so I will probably use two of those if I can find manifolds for them.
Reg