Replacing exhaust header gaskets

[nurse]

Managed to get a set of NOS OEM header gaskets.  Having had a close look at the outlets and the top of the headers there seems to be some type of 'black silicon' in places.  I am pretty sure these pipes have not been off since new, but the Haynes Manuel makes no mention of using any sort of exhaust sealant during reassembly. 

Can Anyone shed any light, any thoughts and/advice welcome.

Thanks

[movenon]

I do not know about new but I have had mine off and on 3 times with just the gaskets. No leaks, works great. I can't imagine any sealer up in that area.
As a note I just barely tighten (snug) the nuts. I can replace the nuts but don't want to replace a stud.... Never lost one...
George

[ELIMINATOR]

Regardless of the silicone issue. Soak the nuts / studs in plus gas prior to trying to remove them. I put tissue around them to keep them damp, did this for a week before trying to remove the nuts, adding more plug morning and evening. Even them two nuts refused to budge, I ended up using a cook's blow torch to heat the nuts, they came off then. patience is the key here.

I assume the gaskets are shot?

[nurse]

Regardless of the silicone issue. Soak the nuts / studs in plus gas prior to trying to remove them. I put tissue around them to keep them damp, did this for a week before trying to remove the nuts, adding more plug morning and evening. Even them two nuts refused to budge, I ended up using a cook's blow torch to heat the nuts, they came off then. patience is the key here.

I assume the gaskets are shot?

The nuts came off without too much of a fight.  I shall replace them as they are quite rusty on the outside and arnt pretty to look at.

The old Gaskets look ok but as it's all off they are being replaced anyway.

As a note I just barely tighten (snug) the nuts. I can replace the nuts but don't want to replace a stud.... Never lost one...
George

Thanks for that George I will bear it in mind.

[mz_rider]

When I removed the exhaust on my FJ I replaced the nuts with stainless steel dome nuts. These look good and protect the exposed thread.

I get my stainless here (UK supplier)

http://www.ebay.co.uk/itm/STAINLESS-STEEL-DOME-NUTS-M8-10-Pack-Freepost-/330153219325?pt=UK_Motorcycle_Parts&hash=item4cdeaa54fd

[nurse]

When I removed the exhaust on my FJ I replaced the nuts with stainless steel dome nuts. These look good and protect the exposed thread.

The originals I have just take of are lockiń nuts and are described on the micro fiche as such.  Would domed nuts be prone to vibrating loose? Or did you loctite them on?

[FJmonkey]

Most thread locking chemicals soften with heat. Considering the added heat from the headers, it will likely cook the chemical and it will become something quite different than a thread lock. A Nordlock washer might do the trick, not sure how they perform under that kind of extreme temp cycling.

[fj1289]

How bout a nice and simple lock washer?  Split washer ought to work....

[mz_rider]

I used a plane stainless washer and haven't had any problems with the nuts loosening in 3 years/20k miles. I wouldn't use a thread lock compound in case it gripped too well and caused a stud to shear when I next removed it. You could use an anti-vibration washer to be on the safe side. As I recall the originals were flanged nuts.

[FJmonkey]

I have seen them work loose, Nylock is out of the question due to the heat as well. A locking nut that has been deformed precisely to bind on the threads seems like the best option. Even if it works loose it won't fall off.

[FJ1100mjk]

No loctite needed. Stock nuts, dome nuts, and flange nuts (what I'ved used with success), are fine to use. Use split lock washers if you want, but it maybe overkill. Can't hurt either.

It may help to keep loose (loosen only, don't remove) all of the other exhaust attaching fasteners. The ones on each side where the mufflers are held, and the single one underneath the engine that attaches the exhaust collector box to the frame near the centerstand's pivot. Keep these loose while attaching, snugging up, and tightening the nuts at the engine's exhaust ports. Then go back and re-tighten the attaching hardware that you loosened previously. Keeping the attaching hardware loose while torquing the nuts down, allows the whole exhaust sytem to "float" while it isdrawn up to the engine with the nuts evenly. Then tightening the attaching hardware, locks the whole system in place. It also doesn't hurt to ride the thing a while, then go back over the nuts again after everything has cooled down either. You may find that the nuts are a little loose. Or not.

I have put copper-based antiseize compound on the exhaust studs too, to play it safe.

The above is of hands-on experiences that I've had and done. Haven't had any exhaust clamp nuts loosen up and/or fall off after many thousands of miles.

Probably took longer to type this than it would to put an exhaust system on an FJ too! 

Good luck, and Happy New Years!

[Harvy]

Something to keep in mind....... I've started to strip the '93 I bought as a parts bike. When I trailered it home from Sydney (1000km give or take) a couple of weeks ago, the fork seals leaked so badly that the whole front of the motor got a liberal dousing of fork oil..........just this morning the flange nuts only need cracking with the socket and were then removed by finger......they were that well lubed. Seems whatever fork oil was in there makes a very good rust penetrator.


Harvy

[nurse]

Anyone happen to know off hand the bolt size, are they M8?

[FJ1100mjk]

are they M8?

Yes. M8 X 1.25

Torque: 20 N*m

[carey]

FWIW,

Suzuki GS1100/1150 exhaust gaskets work well on FJ engines.