Exhaust gasket on 4 stroke?

knightscape · Sep 9, 2014

I was just tweaking my Phantom exhaust pipe on my HS 142f and I realized that i don't have a gasket between the block and the pipe. Should I? I don't remeber if one came with the kit that I might have lost with having the pipe on and off while building. There was definitely no gasket on the stock box exhaust when I removed it. I shouldn't really need one since back pressure isn't as important on a 4 stroke as it is on a 2 stroke right? I've found some old threads mentioning gaskets on 4 strokes though so I want to be sure, whaddya say folks?

borntofli · Sep 9, 2014

Its the same gasket as 2 stroke.... I've had to replace mine a few times.....

Going2Hell · Sep 9, 2014

The gasket would not be required as long as you had a good enough fit to keep cold air from seeping in and either cracking the flange or warping a valve.

Otherwise, I did use the gasket from my old Skyhawk 2-stroke as well. I took the heat shield off of the jug and had to use the gasket as a spacer.

maniac57 · Sep 9, 2014

If it's not making a mess, not a problem.
The old saw about cracking a valve has not been an issue since the 40's or so when metallurgy got up to speed.
Mostly the gasket is there for noise and mess.
So if it doesn't bother you as is, it's fine.

racie35 · Sep 9, 2014

You can use the high temp silicone there

The_Aleman · Sep 9, 2014

If you want a nice quality exhaust gasket, look for a heat riser gasket for an old VW Bug with single port engine.

Example: http://www.fcpeuro.com/products/vw-...ng-beetle-karmann-ghia-super-beetle-113251263

GearNut · Sep 10, 2014

The_Aleman said:
If you want a nice quality exhaust gasket, look for a heat riser gasket for an old VW Bug with single port engine.

Example: http://www.fcpeuro.com/products/vw-...ng-beetle-karmann-ghia-super-beetle-113251263

Yup! They are the bee's knees for HS 142's. Waaay better than any kit gasket.

knightscape · Sep 10, 2014

The_Aleman said:
If you want a nice quality exhaust gasket, look for a heat riser gasket for an old VW Bug with single port engine.

Example: http://www.fcpeuro.com/products/vw-...ng-beetle-karmann-ghia-super-beetle-113251263

$.50 huh? I think I can swing that, lol. Thanks guys!

scotto- · Oct 5, 2014

knightscape said:
$.50 huh? I think I can swing that, lol. Thanks guys!

That's cheap for a set of bee's knees! Half a buck.

curtisfox · Oct 6, 2014

racie35 said:
You can use the high temp silicone there

This is what is used on big block chev in my motor home. as the stock gaskets don't last and start leaking after a while. Had to have a new manifold put on this spring on the way to CA and they used the Gold hi-temp silicone..........Curt

KCvale · Oct 6, 2014

borntofli said:
Its the same gasket as 2 stroke.... I've had to replace mine a few times.....

Yep.
A 2-stroke exhaust works dandy on them too.

Msiert · Nov 7, 2014

I had the same question and talk to John at Phantom Bikes and he said they tried a bunch of different gaskets but they all blew out. They ended up using Utra Blk silicone and never had any further problems.

I also used the ultra bulk silicone and after 18 hours it's holding strong with no leaks. I was careful not to over tighten the manifold bolts and have tighten them up a couple of times to where now they are staying snug.

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Exhaust gasket on 4 stroke?

knightscape

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borntofli

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Going2Hell

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maniac57

Old, Fat, and still faster than you

racie35

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The_Aleman

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GearNut

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knightscape

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scotto-

Custom 4-Stroke Bike Builder

curtisfox

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KCvale

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Msiert

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