A moped blog

Mopeds at Dawn is a collection of photos, videos and information on mine, and other peoples classic mopeds.

"Welcome to M.A.D, we hope you enjoy the blog and welcome any feedback. Please don't hesitate to contact us."

Friday, 14 February 2014

Red exhaust gasket maker

Since fitting the simonini exhaust I've had a problem with it leaking. I bought some red high temperature gasket maker and it seems to have done the trick.


  1. i run this pipe on one of my bikes and had the same problem. me personally hate rtv, that being said i have tried to remedy this very problem the same way and had OK results but eventually it blew out and made a mess. here are a couple suggestions that have worked for me.
    1. mix red loctite @ 3 parts and red rtv @ 7 parts. never tried it on that joint of the simoni but it did work great on a stock jug with screw in exhaust
    2. weld it, its what i eventually did and theres no more leaky at all but its a pain to mock up pre weld and install/uninstall. frankly i wouldent do it again it never fit right and is now hacked on to my jawa x30.
    3. heres what i do now when dealing with similar pipes and it works good frankly i wish i just kept doing this instead of welding.
    step 1. get stronger springs by that i mean bigger wire, i got mine at a local car parts store, dont go to autozone go to your local bad ass indie parts place.
    step 2. order a couple stock copper exhaust gaskets from treats. lets see i usually use one but have needed more in certain instances. so what you wanna do is lightly sand the OD of the gasket to fit down into the mating socket that the flange spigot slides into. you want a tight fit so go slow you no you fucked up if when you flip the pipe the gasket falls out, you want it so when installing you have to tap it down with a long socket of similar OD and replacing you have to dig it out with a pick. sometimes if i feel that the id of the gasket is to small leading to a unacceptable obstruction. i sand the id to but remember there hollow and gonna get squished any way.
    step 3. install flange then install pipe with new gasket followed by your new springs you no there strong enough when its close to impossible to install (while your at the parts store pick up a auto drum brake spring tool so worth it) then its just a matter of a couple nice hot heat cycles to anneal the copper gasket sometimes ill idle it and hit the union with a mapp torch to speed up the process but this is not needed and will ruing your clear coat. the key is to let heat up and conform the gasket to the flange and socket effectivly sealing it.
    idk tryit out

    lovethis build bro

  2. Thanks Nick for your mammoth post! I will probably have to re-read it a few times to make sure i understand the process you have explained. I will probably run with the RTV until that gives out as it took me ages to install the pipe. Should i be running a copper crush washer anyway? As i didn't get one with the exhaust so i haven't got one in there. It definitely makes sense to use stronger springs as these where pretty easy to stretch on there so i expect the exhaust pressure may push those pieces apart.
    Thanks again for your very useful comment.