Does exhaust flange sit in gasket recess?

[Nismosis]

This might be a silly question but… Is the exhaust flange at the barrel end supposed to compress the exhaust gasket and sit inside the circular recess in the barrel?

Or is it supposed to compress the gasket and sit flush with the outside of the barrel flange?

I’m sorry if I’m not explaining it very well but last night I took my Micron exhaust off so I could change the gearbox oil. When I came to re-fit the exhaust I put a new gasket in the barrel flange recess with a blob of silicon just to hold it in place, I then fitted the exhaust and tightened up the nuts on the exhaust studs and you could see the exhaust flange compressing the gasket until it came flush with the barrel flange. I thought that the exhaust flange was supposed to fit inside the circular recess that the gasket sits in but the outside diameter of the exhaust flange is larger than the inside diameter of the gasket recess in the barrel. This makes me think that the exhaust flange is only supposed to tighten flush against the barrel flange and the circular recess is purely for the gasket?

Is this right??

I compared the old gasket to a new one and it was compressed to about half the thickness of a new one.

Anyway, the exhaust doesn’t leak and the gearbox now has lovely new Motul Transoil 10W 30 splashing round it.. The old oil I drained was a very dark grey and I drained it into a tin with a pair of my wifes tights (she doesn’t know I raided her sock draw yet!) stretched over to top to catch any swarf. I noticed only a small amount of tiny metal fragments, I would say about the same as a half a turn on a pepper grinder.

Is this normal??

I’m not sure when the gearbox oil was last changed and it’s the first time I’ve changed it since I bought it (probably done 200 miles since I’ve owned it).

Cheers

Gary

[Nismosis]

I've done a quick sketch showing what I mean....

This is how it currently is as fitted to the bike



But should it be like this?



Cheers

Gary

[raven13]

im sure its the first one.
dont think ive ever had one were the exhaust flange sits inside the exhaust gasket recess

[Nismosis]

Ok Raven, that sounds good to me. I thought I was going mad as I really thought the exhaust collar (I called it flange) sat in the recess and compressed the gasket. It makes sense now because the collar on the standard exhaust has an even bigger diameter than the micron. Both are too big for the recess where the gasket sits.

All good, thanks mate

Regards

Gary

[LC_BOTT]

Sorry can't remember which model it was from, but there was an aluminium spacer/thick washer that sat behind the gasket that took up the 'slack' very rare to see now, and not sure if this was only for the early non tie-bar models? thought there should be a gasket between barrel and exhaust flange (not as in your pic)

here you go, (just found this) assuming its an LC not YPVS?

rd350lc.net/pageEXHAUST.htm

[museumman]

There is always a tiny bit of movement as you mate up the flange to the gasket and start doing up the nuts. Ive often tried to see if there is a correct positioning, but it just seems to find its way and seat.

Nice drawings btw

[Nismosis]

Cheers, not totally accurate but I tried to go the point across with the drawings. Exhaust back on now and gearbox oil changed with Motul Transoil 10w 30. The bike is off for a dyno run on Friday to tweak fuelling and get her running as good as can be with current set up. Only £40 for the dyno, will let you know the results.

Cheers

Gary

[museumman]

For info exhaust flange is 49.5mm OD and you can see the mark it's left on this original barrel.
It looks like any movement during fitting won't obscure the exhaust port.