Exhaust Manifold Bolts

[Fowlersrs]

I am tempted by the idea of changing the exhaust manifold system on my gsxr 750 from the mild steel that's on there to stainless.

The one thing that makes me hesitant is how easy the bolts will come out.

I take it there gonna be Alan key bolts which is no prob as I have a good quality set of keys I use for work.

However what I don't want to do is sheer one of these fuckers off. How tight are they gonna be? Would it help to warm the metal before attempting to undo them?

[P.]

Plusgas, soak them in it overnight.
Repeat for the rest of the week.

For best results use a blowtorch too

[Islander]

As Paddy said, soak them in plus gas or other penetrating oil beforehand. If they're socket head bolts then you could use a 1/2" drive allen key on an impact driver to shock them loose. Good quality keys that fit well are paramount here and clean the crud out of the socket heads before you attempt to remove them so that the key can fit properly.

Having said that, I've just replaced the header gaskets on my Hornet and all the fasteners bar one came off fairly easily. The one that was stuck got additional overnight penetrating oil and came off the next day after a whack or two. It's not always the hellish job it's made out to be.

[Robby]

It would be unusual to have the exhaust manifold bolted on, usually the manifold sits onto studs and is held down with nuts.

The studs are doing up tight and sit in fairly soft alloy, so you want to be using all of the thread. This is tricky with a bolt, unless it's exactly the right length. Too long and it will hit the back of the hole before clamping down. Too short and you aren't using enough of the thread, so you risk stripping the thread in the soft alloy head.

I always use mild steel studs and brass nuts. The mild steel studs will rust a bit, but if they snap you have a chance of drilling them out. Drilling stainless is far more difficult. The brass nuts are soft enough that the thread on the nut will fail before the stud snaps, so if you get stuck removing the nuts you an keep spinning them until they pull off the stud, then clean up the studs with a die once the exhaust manifold is removed.

Stainless is pretty, but it snaps with less warning and is an utter bastard to drill.

[Vincent]

I like to replace the usual rusty nuts with deep domed ones.
____________________
Space Is Deep

[J.M.]

Also use the loosen and tighten technique if they're being a pain.

That's where you loosen it a fraction, then tighten it back up. Keep repeating and very gradually increasing the amount that you loosen or tighten it each time. It helps to crack the rust and reduce the chances of snapped bolts.

I've removed the downpipes on 2 bikes now and they were both a nightmare. I snapped one stud/bolt on each bike.
____________________
2004 R1 & 2018 XSR900

[Blau Zedong]

Try Plusgas, try heating etc but in my experience they'll either come out or they'll snap off. Cest'la vie. Although depending on talent level and accesability you can drill and helicoil them in situ.

See page 2 of this thread for biblical exhaust fail

https://www.bikechatforums.com/viewtopic.php?t=266673
____________________
18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth