Topic: exhaust wont clamp tight

[cb650 bobber]

My exhaust is leaking pretty bad after reinstalling...anyone have directions aka pics of the exhas on hooking up the exhaust with halfmoon clamps and flanges... Trying to figure out how to hook it up right I dont think it was hooked up right before just got exhaust gaskets.... IT looks like my 4 into one has thinner piece that hooks up to head the original oem ...I think it is a mac and help or suggestions would be awesome. 1980 cb650 c

[cb650 bobber]

ITS SUCKS my manual doesnt show it in chilton....

[martino1972]

did you install the halve moons correctly??? if you look at them the edge on em is out of centre..the longest flange is towards the engine..

[cb650 bobber]

yeah I have the skinny part towards the engine....man I would love a diagram

[Hush]

Sorry no help here, my 4 into 1's are solid so no half moons to fiddle with and my new pipes still on way from Texas.
Can't you weld them?

[cb650 bobber]

it is making me wonder if you are suppose to use the factory mounting system or they made there own...I thought most 4 into 1 used factory exhaust

[NickC]

Did you replace the copper exhaust gaskets?

[CBJoe]

Does the header your using (MAC ??) have built in clamps?  i.e. thin flat clamp instead of the stock finned clamps.

I never could get them to work quite right on my 650 so I cut the crappy flat clamps off and used the stock ones. As for lining up the exhaust collars...

[cb650 bobber]

I just got new exhaust gaskets mine must have been worn away since when I took the old exhaust off there was none there....

[cb650 bobber]

http://www.crc2onlinecatalog.com/exhaust_seals.htm

the guy who I bought them from sent me the corregated aluminum....not sure if the brass is better.

[NickC]

I just got new exhaust gaskets mine must have been worn away since when I took the old exhaust off there was none there....

Take a screwdriver and scrape the surface a little bit, you may see copper. It appeared mine were missing too, but they had just flattened and discolored.

[cb650 bobber]

what the hell do the half moons do are they suppose to push up on the exhaust where it meets the head to seal the exhuast....I am just wondering because the last time I hooked it up I was wondering what the heck the half moons do. they dont reach the whole way up to the exhaust head as I would think they should to put pressure on the exhaust at the head to keep it sealed. It seemed like the stock 4 into 4 had fatter flange on the exhaust then the four into one.

[cb650 bobber]

after looking at it more I think the issue lies in the fact that the exhaust flange that mounts up to the head is to skinny for the half moon clamps to reach to put pressure on....maybe I need to put some shaft collars or something there...has anyone ran into this before.

[cb650 bobber]

I found a pic showing some stuff that comes with a mac exhaust...not sure if it is an adapter that i may be missing.

[cb650 bobber]

maybe i need these instead...I wish I had the spigots they look easier to deal with.

[cb650 bobber]

or maybe I am missing these I think these are clamps...there is just a huge gap between the halfmoons and where the exaust meets the head.

[cb650 bobber]

alright done trying to get an answer....guess I will have to mock something up or keep trying to gun an answer down on the internet.

[Popwood]

I've been dealing with a pipe alignment problem on my 550 and here's what I've been experiencing as it may relate to your leak problem.

Clearly, if the clamps, no matter what style, are to short to press the flange on the end of pipe tight against the gasket and exhaust port, you'll have a leak. It really should not matter that there's some space between the clamps as their work is to apply pressure to the flange so it seats tight to the copper gasket.

If you have not replaced the copper gaskets, you should do so. Each time you slightly reposition the pipe and tighten it down, the soft copper will change shape. I removed a gasket last night and was surprised by how mishapen it had become. I've taken apart and reconnected this one pipe about five times and it has now started to leak. I suspect that it's important to cinch up the pipe going from one side to the other so the relative pressure on the gasket from side to side remains relatively equal. And as I think someone else may have mentioned, be sure the faces of the flange and exhaust port where everything seats together is clean.

Sorry if all this is too obvious.

[cb650 bobber]

the half moons arent even pressing agianst the flange at the exhaust head...that is the space  I am talking about.

[martino1972]

if the space isnt too big,you can try and double up the crush rings,or like i did and roll up some aluminum foil and use that

[strangedaze39]

When I do mine I just first slide the flanges down each headers neck and hold the headers up to where they are ready to bolt in but a inch away from being pressed against the head. I then place the half moons on (you totally need a extra set of hands while doing this) and slowly slide the headers with the half moons on right into the head seating and then take my flanges that are hanging on the lower part of the headers, slide them up over the half moons and bolt them down. Easy as pie if you have a extra set of hands.

[cb650 bobber]

i wish tin foil would work but it is a decent size gap I have to fill...thought somebody would have run into this with another aftermarket header..I thought mine was a mac but not sure

[martino1972]

what i did,is i took a strip of tin foil,and rolled it up tight,like you would a cigarrette,the thickness of the "roll"you determen with how much you roll on it,make it tight,then shape it like a donut.....i had just about a 1/4 inch gap to fill and it works perfect....