Confused about exhaust gaskets

Xsolusx · Post by **Xsolusx** » Mon Oct 26, 2015 11:50 pm

I have a Blackjack.

I just took off my cracked Prima exhaust. There was no gasket, just sealant.

I just ordered an NCY exhaust from monsterscooter however it doesn't look like the gasket comes with it.

So do I need the stock round gasket or one of the gaskets shaped like the exhaust flange? or both? I have seen prioes from 99 cents to $10 for the same thing so now Im confused haha.

babblefish · Post by **babblefish** » Tue Oct 27, 2015 12:18 pm

If your engine is anything like my Blur's engine, then the gasket surface on your head should be flat with no recess for a gasket. The exhaust flange should have a recess built into it for a 30.5mm OD ring seal, such as this one found on eBay: http://www.ebay.com/itm/2-GY6-Exhaust-M ... rA&vxp=mtr

You can probably use a "flange" type gasket, but I've never tried it myself so you're on your own there.

Instead of the correct gasket, some lazy people have used a bead of silicone gasket sealant as a (poor) substitute, but this in not a good idea because the exhaust gases are much hotter than the silicone can handle and will burn off leaving you with an exhaust leak.

lovemysan · Post by **lovemysan** » Tue Oct 27, 2015 1:43 pm

I did an ncy pipe on a vino 125 and it came with a stock style gasket ring. My prima came with a flange style and it is reusable. I keep both laying around just in case.

HowHH · Post by **HowHH** » Tue Oct 27, 2015 2:44 pm

I've used both types with my Prima exhaust and currently have a spare of each sitting in my tool cabinet. The pipe has to come off when doing a tire change and I prefer to go with a new gasket (they're cheap!) rather than re-using the old.

Both seem to work OK.

Xsolusx · Post by **Xsolusx** » Tue Oct 27, 2015 3:25 pm

Thanks for the replies! So it seems either will work?

k1dude · Post by **k1dude** » Tue Oct 27, 2015 4:18 pm

My Buddy 125 came with no gasket or sealant. I was surprised to find that out at 6,000 miles when I changed my rear tire. I didn't have a gasket at the time, so I bolted it back on as-is.

I ordered an NCY performance exhaust and it didn't have a gasket. But, by that time I had some spare gaskets on hand. I used one that looks like the flange. It doesn't sound right to me after installation though. It sounds like there's a leak, but I can't find one. I chalked it up to the new sound of the performance pipe.

HowHH · Post by **HowHH** » Wed Oct 28, 2015 2:02 pm

Xsolusx wrote:Thanks for the replies! So it seems either will work?

That would be my experience, at least. The best advice I can give you is as you are tightening down the nuts, to do each nut a little at a time. If you first cinch down one nut while leaving the other nut loose the gasket will not be evenly compressed and may leak.

Xsolusx · Post by **Xsolusx** » Wed Oct 28, 2015 9:57 pm

HowHH wrote:
Xsolusx wrote:Thanks for the replies! So it seems either will work?
That would be my experience, at least. The best advice I can give you is as you are tightening down the nuts, to do each nut a little at a time. If you first cinch down one nut while leaving the other nut loose the gasket will not be evenly compressed and may leak.

Sounds good. I just ordered 5 just in case haha.

babblefish · Post by **babblefish** » Wed Oct 28, 2015 11:47 pm

Just for good measure, I like to put a little bit of anti-seize grease on the threads of the exhaust manifold studs before installing the nuts. Will help prevent corrosion from freezing the nuts onto the studs in the future.