exhaust stud choice???

Moderator: Moderators

Post Reply
User avatar
Miles
zxr400 oc member
zxr400 oc member
Posts: 453
Joined: Wed Apr 30, 2008 11:00 pm
My Bike: ZXR 400 L3
Location: Bangor, Northern Ireland

exhaust stud choice???

Post by Miles » Sun Jan 22, 2012 9:40 pm

Hello folks, in the middle of my rebuild and wondering if anyone has changed the studs to stainless steel bolts. I understand you shouldnt do it to load bearing bolts such as discs etc but is it ok to change the exhaust studs to stainless?

User avatar
gavinfdavies
zxr400 oc member
zxr400 oc member
Posts: 358
Joined: Wed Jun 23, 2010 10:56 pm
My Bike: gpz500s d5, zxr400 L5
Location: Peterborough
Contact:

Re: exhaust stud choice???

Post by gavinfdavies » Sat Mar 03, 2012 3:00 pm

The problem here is all about corrosion. If a steel stud corrodes with the ally head (dis-similiar metals), they will seize solid. This though is not a problem since the stud stay where it is and the nut comes off it (the nut also being steel shouldn't react with the steel stud).

If you use steel bolts however, then when they seize to the head, you'll a) round the heads off b) shear the heads off d) shear the bolt off, leaving the base in the head, or e) strip the threads in the head.
Any of these are a real pain in the butt, and can junk your head.

You might be able to get away with it if a) you use really good high-temp anti-seize compound (contact an aerospace supplier to the really good toad), and are careful when torquing them, or b) you rarely use the bike (ie trackdays, race meets), and are happy to remove and grease the bolts on a regular basis to prevent corrosion building up.

You could try good quality thread inserts, like helicoils or the solid alternative. I think MM posted something on here about them. But do you really want to risk junking you head?



FYI,
I'm planning on using very good quality stainless bolts myself, along with high-temp anti-seize, when I rebuild my zxr cafe racer. But it's going to be naked, and be having an under seat radiator and oil cooler, so I can check the bolts very easily. Not so easy on a fair bike!

oldman
I do 700 miles a week in all weathers including snow, that's roughly 35,000 miles a year, and some weekend warrior biker has the nerve to get out of his Audi at work to tell me to I was riding far too fast in the wet (over taking at 50... fast eh?).

cargo
zxr400 oc member
zxr400 oc member
Posts: 3339
Joined: Sat Jan 08, 2005 10:33 am
My Bike: tomos moped
Location: Carrickfergus Northern Ireland

Re: exhaust stud choice???

Post by cargo » Sat Mar 03, 2012 3:07 pm

why not just just stainless studs ?

Along with stainless nuts and a sexy wee stainless washer if need be

Post Reply