CB200 exhaust header question

[Saru]

There's a gap between the head and the exhaust flange. Is this normal?

This is on the right side with exhaust removed.

Looks like there is a crushed copper washer, not sure if it should be more like a donut, and less flat? Looks pretty pressed into place. Not sure how I would remove it. Many thanks, have learned o ton from you guys.

 

[ancientdad]

Completely normal to have a gap between the flange and the head, in fact if you didn't have a gap I'd be concerned about the ability of the studs and nuts to push the exhaust far enough into the head to crush the gasket and provide proper tension to seal them. Remember, the flange (Honda calls it the exhaust pipe joint) pushes on the split, 2 piece collars (Honda calls them joint collars) which push the pipe into the port and against the gasket. If the flange was pressed up tight against the head it would not be able to apply further pressure to do its job properly. As for the gasket stuck in the port, just take a flat screwdriver and dig under it and pry it out, unless you go crazy you won't do any damage.

 

[Saru]

Sweet thank you sir, that makes sense. Thank you for your nomenclature, it's good to know what all these parts are called. So for sure replace the gasket, correct?

 

[ancientdad]

Absolutely, they're cheap enough and now is the time while the pipes are off.

You look to have an oil leak somewhere in the top end, oil is burned onto the head and exhaust studs.

 

[Saru]

Yes I saw that ad well, I think/hope that it's coming from the tachometer cable.

 

[ancientdad]

Have you ever replaced a tach drive seal? It's not difficult but can seem a little tricky if you've never done it before. Once the cable is removed, you basically just pull the shaft out and the seal comes with it. Since it's a worm gear drive, the shaft will want to turn a slight bit.

 

[Saru]

Never replaced by me, yes I'll order one at the same time I get the gaskets. Seems like that is the only leak so far.

 

[Renegade]

After you pry out that old gasket, make sure there isn't another gasket underneath it. After 40+ years of heat and oil building up in there the old gasket starts to look like it's just part of the head and it's not unheard of for people to not realize there is a gasket there and put another one on top of it. I found two gaskets on mine when I pulled off the headers for the first time (almost didn't notice the second one, though -- it was caked on there nice and tight).

 

[Saru]

Thanks Stefan, will do. Yes it's crusty in there. Should be fun.

 

[Richard Pitman]

Have you ever replaced a tach drive seal? It's not difficult but can seem a little tricky if you've never done it before. Once the cable is removed, you basically just pull the shaft out and the seal comes with it. Since it's a worm gear drive, the shaft will want to turn a slight bit.

CB175 parts but same as CB200. Watch out for the little washer at the far end, easy to misplace this when refitting the assembly. Use an appropriate sized socket as a drift to press the seal home.