Topic: K3 Exhaust Baffles

[BoCoJohn]

I'm starting to look for a used set of stock pipes for my 1973 CB750.  I understand Honda may have changed baffles in the HM 341 pipes from year to year.  Does anyone know how I can identify the correct pipes for my K3 ?

Thanks for the help,

John

[ekpent]

Look for pipes that are stamped HM341,anything from 1972-1976 will work, basically all the same. Unlike the earlier HM300 which actually has a real baffle pipe the HM341 has just a diffuser cap at the end of the muffler,good for keeping out a mouse,and most of the baffling in that pipe is done with multiple internal chambers. Get some HM300's if you want to "wake" it up a little.

[BoCoJohn]

Thanks for the info.  I thought Honda detuned the 1975 and 1976 HM341 pipes to compensate for the change in carb jetting....and other detune mods

[ekpent]

I am not aware of that. If they were very different seems they would have changed the part numbers to reflect it.Same muffler part numbers for 73 and 76.If Hondaman notices this thread maybe he could shed some light on that theory for us,but I think they are all the same and the detuning was more in the carbs and engine.They were going for better gas mileage and a little better low end torque for all the people who were loading them down with fairings and bags for touring in pre Goldwing days.

[BoCoJohn]

Thanks Okpent,

I called a couple guys at Honda.  They said the same thing you did i.e. 1972-1976 all HM 341 are the same.  Just wanted to make sure before I dropped $1K for new pipes if I can't find a set of reasonable used ones.

[ekpent]

I see my local Honda dealer can still get the OEM pipes for around $240.00 each but the downside is you get severely nickle and dimed on all the very overpriced bits like the diffuser caps,rubber bits and clamps,bolts etc------