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Discussion Starter #1
The 4 into 4 exhaust that was on my bike was rusted out in three places. I just bought a used Kerker 4 into 1. The guy told me that it came off his 74 CB 750.

I took the 4 pipes off by loosening the collars and sliding the pipe off. On the 4-1, there are mounting brackets welded to the pipe. (The 4-1 does slide over the engine mount as is.)Here is a picture:



My question is: Do I take the eight bolts out of the mounts that are in the engine(sorry I don't know what they are called), then slide the 4 headers in and bolt the thing back on and skip the collars?

OR

Do I slide the 4-1 over what is showing in the picture, use the collars to secure it?

Thanks
Mut
 

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Discussion Starter #2
Oh yeah, you can see the corner of the oil cooler in the picture. I don't really like the look of this thing. I would like to take it off but someone here suggested that I might not want to because it may be on there for a reason. How can I tell if I should keep it?
 

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The mac exhaust has F mounting collars. You remove the spigots from your head (lots of pb blaster and an impact driver) and then get a set of F studs and nuts and then bolt the header to your head. YOu could use regular bolts too but having studs is nice. Don't reuse the screws as they will probably be buggerd when you take them out and if not then you will fuck them up eventually. Basically they are an expensive repair waiting to happen.
 

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Discussion Starter #4
Geeto: I am assuming the engine will need to come out for this operation?

Are most after market exhaust systems going to require removing the spigots?

Thanks
 

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quote:
Geeto: I am assuming the engine will need to come out for this operation?

Are most after market exhaust systems going to require removing the spigots?

Thanks
The engine does not need to come out to remove the exhaust spigots. You only have to pull the engine when you need to do work that involves removing the valve cover.

There are some exhaust systems that are made for the K collars but they are mostly drag/tt pipes and not really performance exhaust. Mac does make K 4 into 1 and 4 into 2 pipes that are muffled too but mac exhausts are only just a marginal exhaust (a lot more sound than fury), most of the high performance stuff uses the F mounting system. Personally I think you are better off with out the spigots but they can be a real bitch to remove because those screws strip if you look at them funny. That kerker exhaust is really nice because the flange is welded to the pipe, allowing you to ditch the F stock collars and shell bearings which tend to rot out and ruin your pipe.

Kerker pipes are one of the best made for a cb750. If you really want a 4 into 1 for the K spigots I will gladly trade you a brand new mac 4 into 1 for a K for that kerker.

BTW jut to be clear on what an impact driver is - it is not an air tool (that is an impact gun), it is a screwdriver that when you hit the back of it with a hammer the front turns a little. It is probably the most useful tool when working on any old machine that uses a philips head screw anywhere.
 

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quote:
It is probably the most useful tool when working on any old machine that uses a philips head screw anywhere.
I just recently found this out. I used to be a skeptic, but now I too am a big fan of the Impact Driver.

****************************************
The best kind of justice is angry mob justice.
 

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Discussion Starter #7
Geeto:

Thanks again. I did think you were talking about an impact gun, that i why i thought the motor had to come out.

I will try the driver.

Once I screw up the spigots that are on there I may take you up on the trade offer. However, If I can get them out, I'd like to try the Kerker.

I'll let you all know how it goes.
 

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Discussion Starter #9
Again, Thanks for the advice, It worked. I bought an impact driver today and used some Freeze Off. With some good tapping the screws backed out easily.

However, I am again confused. I put the new exhaust in place just to see how it looks. I realized that the portion of the exhaust that goes into the engine in longer than the spigots were and that the mounting bracket sit about 3/4 of an inch away from the threads. Is this simply the wrong pipe for the bike or am i missing some part?

As well, I have four new copper exhaust gaskets. I was hoping the old ones would be visible when I took the original pipes off but they were not. Where do the gaskets go?

Finally, look at the last picture. How does the exhaust mounting bracket (at the silencer end) mount to the bike?








 

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The F studs are not flush studs, that means that they have a spot in the center where you can put a wrench on them to install or remove them so right away you are not looking at a flush fit. As visually unappealing as it is, the kerker does get installed with a gap between the head and the flange. Some of the older ones used to come with spacers but I have rarely seen them with spacers installed because they sometimes caused cracking under heat expansion. You can make some out of aluminum but it is better to just install it the way it is and not over tighten it. See the #4 pipe (the one all the way on the right), that flange is bent because it was overtightened. Since you don't have the F studs, I recommend some stainless steel cap head allen screws with a washer to install the exhaust. Make sure you get them long enough to go into the block by more than a couple of threads.

The copper gaskets crush down really thin, really really thin. Spray some carb cleaner in the exhaust port and have a look, might be there just all caked up with soot.

As for the bracket, well the bolt goes through the rear foot peg hole (passenger peg) on the inside of the frame (between the frame and the swingarm). That short little nubby sticking out at the bottom goes up in the 12:00 position.

When installing it you want to just snug the bolts down, then heat cycle the bike (run it for about an hour or so continously, riding not idiling) and then when it has cooled recheck it and retighten.

before you install, I would hit those header flanges with a wire wheel and then give them a coating of black VHT 1500 degree high temp paint (you don't have to do the whole header, just the rust part by the flange). Any rust that is there will only get worse with the accumulation of moisture on initial startup.
 

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quote:
before you install, I would hit those header flanges with a wire wheel and then give them a coating of black VHT 1500 degree high temp paint (you don't have to do the whole header, just the rust part by the flange). Any rust that is there will only get worse with the accumulation of moisture on initial startup.
amen brother! i say do it while it's still this easy.

"Better a cruel truth than a comfortable delusion." -Edward Abbey
 
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