Hitchcocks Forum

My 2008 Classic 500 has the older "push-in" type exhaust pipe - do I need to use any exhaust paste when refitting it into the cyl head, please?

Sorry if this has been covered before - but I can't seem to see any threads about it - and I'm a NEWBY !!!

Mike

Hello, YAMAHA 1}-------------- My, that's a brave "handle" you have there !! (only joshing a little). I'm surprised you haven't found a recent thread re}--- Classic 500 exhaust pipe sealing... it's a popular request. The general consensus tends to favour the bathroom silicone sealant that comes in a tube(From most DiY shops, B & Q etc.). Make sure the exhaust port in the head is clean with no carbon deposits---firmly smear the silicone onto the surface and in the far end recess. Also put some onto the pipe end that fits into the head. Push the pipe fully into the head noting that a bead of excess may form on the pipe.....Fitting one of those finned pipe clamps and butting it up against the head also helps to seal the exhaust gasses (plus it looks "period" as well.)....Either let it go off over night OR start the engine, let it run on idle for 10 mins to help cure----whichever is appropriate....Water or spittle helps it "tool" easier as well.

Do NOT use paste, it is a b'stard to get the pipe out next time & being a cement has to be chipped off to clean up the port and pipe......silicone sealant is the way forward

Yes, ordinary bathroom sealer. Sounds daft but it does work.

Agreed - I use normal silicone sealer. Occasionally I have to redo it but not to often (once a year before the MOT.)

First off , dont use anything only if it leaks

Hi NEDDY,--------yes, quite so !!----------no need to "fix" something that doesn't need it in the first place....it's so tempting just to have a little dabble, isn't it ??

Thanks very much, guys, for the fast replies - and for not calling me a "numpty" for not finding the answer before posting!!
Seems like silicone is the answer, then - it's definately leaking at the head, so guess I do need to seal it.

I think I have some "always stays white" super-dooper bath sealer left over - so it should always look freshly applied!!!

Maybe you won't mind another question?
I would like to remove the complete PAV system, as our hosts tell me most owners DO remove it without any drawbacks.
I do have a blanking cap for the exhaust pipe - but what about the breather box and carb connection - guess this will need blanking off - but how? Also, how is the crankcase then vented if the PAV system is removed - maybe somewhere there is a "This is how you do it" article to guide me? Should I bother - or leave it as it is?

I seem to be falling in love with my quirky little 500 Bullet Military - the only thing really anoying me at the mo is the decompressor valve is leaking a mess around it, so obviously leaking, and effecting the compression - but a new one is on its way from our Hosts. If this doesn't improve the compression, then the head will need to come off to regrind the valves - I read somewhere you should be able to stand on the kickstart on the compression stroke - my cat may be able to - but I can't!!

Thanks, guys,

Mike

I used a self tapper on the carb to fill in where the metal pipe came out. Was extremely careful not to let bits drop into the carb! I did this years ago and it's all fine. Hope that's helpful, Chris.

Hello again --------------- Your breather could make use of our hosts BREATHER MOD.on page 38 of the current cat.Part No.}--- 90060 OR 90061......... The air filter could be changed to the Tea-Caddy type (see page 13, part No.}-- 90009).... This, along with the PAV removal, will release much useful space in your tool boxes.