Are the studs the 8mm size I’ve seen on eBay I’ve order the same down pipes and the studs look rather rusty, just know they’ll break
I soaked mine for a couple of days. Two front back ones were ok but the ones at the front that are tight were difficult to get a socket on. It unwound the stud and the nuts stayed where they were. I got the ones for 749 999 8 size pack so I can do the rear cylinder if I decide to take that pip off and polish. Although it’s hidden it may look odd against the stainless polished rest
Stainless studs in ally heads will cause corrosion due to galvanic dissimilarity, especially in the exposed horizontal cylinder.
It means the studs will not be easy to remove as they will become seized in the head casting. If you use the correct copper nuts and keep them in good condition (undo them now and again) then they should be fine. Or...use the Ducati OEM studs and nuts? And don’t ride in wet/salty conditions.
Could use Alu-slip (definitely not Copperslip - similar galvanic issues) on the head threads. Use brass nuts or the OEM/other copper-plated steel nuts. Not Copper nuts - not strong enough.
I thought S/S was ok when we fastened Ali equipment to Ali structures S/S fixings were used as specified by the boffins
C’mon fellas, give me a break! I’m a gaffarologist not a metallogist! I have stainless studs and bolts. Guess I need to now get some not copper slip!
Not sure what the OEM “copper” nuts are made of but they are soft as shite so doubt they are steel plated with copper. What would be the point of that?
I am no expert in metallurgy but been using S/S into Ali engines for ages with a bit of molly grease on the Threads without a problems but that’s just. My uninformed opinion
Must admit at times I did wonder , but wouldn’t a simple barrier between the two metals negate the corrosive effects Are we not getting way too technical
See below. The bigger the potential between materials, the worse they will corrode. Materials to the right (Al alloy) will turn to powder while the ones on the left (stainless etc) will just get stuck in the nasty corroded products. You can see that graphite (carbon) to al alloy is a large difference therefore a guarantee of corrosion of the ally. Note that this assumes the presence of an electrolyte (water/salt/shite etc) that will allow the process to occur. Keep it clean and dry and you’ll likely never see a problem but for a horizontal cylinder head on a naked bike it’s going to be exposed to all sorts of shit from the road. Just saying...
No I appreciate what you are saying So the nearer you get to the .8- 1 of Ali the better as far as reaction between the metals is concerned So may as well save a few quid and use mild steel just keep it clean and lubricated
After much advice from others on here this what I got when I replaced the manifold nuts & bolts on mine. I too thought stainless as it won’t corrode but then I’m not a metallurgist. https://www.ebay.co.uk/itm/113941032489
I’m kinda thinking what ever metal you use it will have some sort of reaction Hence the snapping studs, so if you use stainless they could get stuck in the head but are less likely To snap especially with a bit of molybdenum grease applied and the studs aren’t supposed to be removed If that makes sense
That link shows Copper-plated Steel self-locking nuts with steel studs. Perfect. Use Aluslip into the head and a bit of Copperslip on the whole of the exposed stud surfaces to keep corrosion at bay. An unfortunate characteristic of that type of self-locking nut is they have mechanical interaction so you're left with a little bit of prime surface to corrode after the nut has been tightened. A dab of Copperslip on the exposed end of the nut & stud will help against the ravages of corrosion.
