Exhaust question. 1978 cb750k

[Tristan]

I just recently purchased my new to me 78'. It came with a terrible home-made 4-2 exhaust. I bought the MAC 4-1 exhaust to replace it. I thought 8 nuts and 2 bolts for the hangers no problem. The Mac came with pipe joint collars (half moons) but they where not the correct ones. The headers did not make a complete seal once the flanges were bolted down. I thought "no problem" I'll just use the half moons from the old exhaust. Honda Part number 18233-392-000 (stock part) it didn't work. The diameter on stock header (and crap header) are smaller than the MAC header.

Please help. All Exhaust Joint Collars I have found are stock and not for custom exhausts. I see a ton of 78' 750's with this exhaust. How? Any idea?

Thanks
Tristan

 

[jackbeagle]

Umm, those collars are just spacers and don't provide a seal themselves. Sure you put them on in the right direction? When I got a '77 it was all new to me and I put the collars on backwards so of course I had a major exhaust leak. And, yeah the stock spacer collars won't fit on the MAC pipes.

 

[Tristan]

Thanks jackbeagle! So the half moons do not slide under flange? I guess I had it backwards. I'm headed home to try again.

 

[Tristan]

Thanks!

I got it man. I tried 20 different things yesterday so when I tackled it today it was a cinch to remove old exhaust and install the new one. I did it in 45 min start to finish. I can't thank you enough.

Next up is my clutch!

Umm, those collars are just spacers and don't provide a seal themselves. Sure you put them on in the right direction? When I got a '77 it was all new to me and I put the collars on backwards so of course I had a major exhaust leak. And, yeah the stock spacer collars won't fit on the MAC pipes.

 

[jackbeagle]

No problems - it took me awhile to figure it out the first time too.

There's an excellent thread over at the SOHC4 site about getting the alignment correct so you don't break the clutch lifter plate. I highly recommend it when you install your clutch plates.

 

[dirtdigger]

The biggest thing with the lifter plate is to make sure you tighten or loosen the bolts a little at a time. If you tighten one first you will snap an ear off the plate, especially with stronger springs.

 

[junkyardjon]

The biggest thing with the lifter plate is to make sure you tighten or loosen the bolts a little at a time. If you tighten one first you will snap an ear off the plate, especially with stronger springs.

thats the proper way on any bike.

 

[junkyardjon]

what are you doing with your old exhaust? got a pic?

 

[jackbeagle]

http://forums.sohc4.net/index.php?topic=106700.0

Not to get too far off topic for the original posting, but what I was referring to is the alignment of the pressure plate as per the attached Link. I never saw this mentioned in any of the repair manuals so I guess it was dumb luck I didn't break more of them.

But you're right of course that you need to be careful about alternating tightening down the bolts, but I was really careful and still broke off the plate ear.

Just a suggestion...

 

[Tristan]

I have the old exhaust. I'll send you a pic soon. It is an old 4-2 somewhat chrome exhaust.

 

[Tristan]

I have the old exhaust. I'll send you a pic soon. It is an old 4-2 somewhat chrome exhaust.

Here it is on the bike.

 

[Tristan]

New Exhaust on bike.

Here are a couple shots of my work in progress on my daily driver.

 

[fourk]

mine is the same color (77)