Topic: 1974 CB750 Exhaust Question

[Otto]

Been working on my 1974 CB750. The entire bike seems to be original , right down to the yellow inspection paint markings on the bolts.

Except one thing i noticed tonight.

The mufflers are the same exact length but the headers appear to have been cut shorter on the right side, so that when the mufflers are on the one on the right is 6"shorter than the left side.

This is a 2 into 1 exhaust on each side. i.e. 2 heaers go into a Y on the muffler.

Why would these be different legths? Would they have been that way on purpose or did someone cut them.

If the rest of the bike wasn't so completly original an nice I would not think twice about cutting the longer(left side headers and making the lengths the same. I have another set of headers from a 76 CB750. I held them up to these and they are different lengths, but not enought to make up the 6"or so, + or -... I have another set of mufflers too. The pair is identical.  I even removed the ones from the bike and matched them up with the spares...

Anyone have any insight?   Would have snapped some pix but forgot my camera....

Thanks-

bc

[BobbyR]

If I read your post correctly first off, the stock exhaust would have been a 4 into 4 not a 4 into 2 or any variation. Since it not stock, the PO may have made a repair or a mod to gain clearance for something. One thing is for sure stock exhaust is 4 into 4.   

[Otto]

You are correct. I should have made that more clear. Stock would have been 4-4...

Thanks

bc

[BobbyR]

The only explanation i can think of is that the original exhausts tended to rot out at the weld where the header meets the muffler. I have had that happen to two of them. One I have just had welded. If the mufflers were attached to the original exhaust, the PO may have had to cut back to solid metal.

[754]

Are both 2-1 the same length??? head pipes may have been cut shorter for clerance.. centerstand or sidestand..

[jevfro]

It sounds similar to mine...  The two pipes that slip on the headers are different lengths. I think this is just how some aftermarket mufflers were fit.