KX Riders

Maintenance & Technical => KX500 Original => Topic started by: S38B38 on October 08, 2017, 05:11:52 AM

Title: Best expansion pipe o-rings?
Post by: S38B38 on October 08, 2017, 05:11:52 AM

The brown viton ones that came with my Cometic HG set were too large and would not fit without getting sliced on the exhaust port, the FMF ones seem to last only a couple months before totally degrading...OEM?

Title: Re: Best expansion pipe o-rings?
Post by: big green on October 08, 2017, 05:23:03 AM

I have used both OEM and FMF with good success.

Title: Re: Best expansion pipe o-rings?
Post by: sandblaster on October 08, 2017, 07:26:47 AM

I use the Cometic or OEM.
A little lube goes a long ways...

Title: Re: Best expansion pipe o-rings?
Post by: Foxx4Beaver on October 08, 2017, 08:49:01 AM

I only use OEM.

Title: Re: Best expansion pipe o-rings?
Post by: 1901306708 on October 27, 2017, 12:59:00 PM

i got tired of buying orings and just use high temp silicone.

you can drill a 3/16 hole in the header pipe and it wont make a lick of difference on a dyno.

Title: Re: Best expansion pipe o-rings?
Post by: Foxx4Beaver on October 27, 2017, 01:21:35 PM

The O-rings don't just act as a means to seal up the connection...they also help prevent rapid wear and tear on the inside of the exhaust flange on the cylinder.

I use Loctite 5920 along with the O-rings...it's pretty brutal stuff, but I've had red RTV start leaking a few times over the years.
(https://scontent.fbos1-1.fna.fbcdn.net/v/t1.0-9/22851697_299257647226512_4111325086377792322_n.jpg?oh=3d42f84e8f654cc266154bc9bb9a54e0&oe=5A78C3DE)

Title: Re: Best expansion pipe o-rings?
Post by: 68Fastback on October 27, 2017, 01:51:25 PM

I use OEM with Red RTV and a new crush washer and change as needed.

Title: Re: Best expansion pipe o-rings?
Post by: Hawkeye58 on October 31, 2017, 06:23:10 AM

I have found great results from a farm and Ranch type hardware store here in Vegas, with the o rings sold there. If you are fortunate to have a store such as this near by they have lots of different diameters and thicknesses. I matched up the FMF ones and bingo! .35 cents a piece. Those along with your favorite RTV and you are golden.
I am curious as to the longest any of us riders have gotten a set to last?

Title: Re: Best expansion pipe o-rings?
Post by: Foxx4Beaver on October 31, 2017, 07:58:45 AM

Quote from: Hawkeye58 on October 31, 2017, 06:23:10 AM

I am curious as to the longest any of us riders have gotten a set to last?

I'll replace mine once a year, even if they don't appear bad.
 

Title: Re: Best expansion pipe o-rings?
Post by: Hawkeye58 on November 20, 2017, 05:40:59 AM

I am at a month now after a new FMF Pipe install.

Title: Re: Best expansion pipe o-rings?
Post by: Heniz on November 20, 2017, 09:20:04 AM

try using Viton orings. They have a better temperature rating compated to EPDM or Nitrile. Most standard orings are Nitrile.