Topic: Honda CB750 HM341 exhaust

[kyle750]

Thanks HondaMan.  Very eye opening to learn that Honda went from an exhaust with no welded internal baffles (only a baffle tube in the end) on the earliest CB750s (Sandcast and K0) and then to 2 welded internal baffle plates in the chamber, then to 3, and Honda kept increasing the baffle plates until reaching a shocking 5 

I will be checking both my existing and newly arrived HM341 pipes by identifying the rows of spot welds (can easily be seen on the inside of the exhaust)  to try to determine the number of internal baffles.

Based on this new-to-me information is it  possible  that high quality reproductions like those made by Yamiya are actually better (many different ways to define better) than Original HM341 Honda pipes?

Late Edit: A quick review of the later Honda production replacement HM341 pipes with extra stamped disclaimer "paragraph pipes" currently for sale on Ebay and you can see many rows of spot welding for the large number of baffle plates.

[kyle750]

Spot welds are easy to see on the inside of the pipes but hard to photograph.  I put together a quick diagram of the spot welds on the newly arrived HM341  pipes.  All 4 pipes follow a similar pattern.  I am guessing that the 6 spot welds around the mounting bracket are not related to internal baffles. I don't know how to interpret this information or how it can be used to determine the internal baffles used on this exhaust system??

[kyle750]

A quick photo of the 2 right side exhaust pipes and spot welds

[PeWe]

Yamiya has sold the early 4-4 with less restrictions.
Called Lotus Root.
Less welds but cost much more.
Deeper tone.

[kyle750]

Yamiya Lotus Root Exhaust and photo of the inside side of the pipes toward the frame. Definitely can see that there is less spot welding therefore less internal baffling and less restrictions

https://yamiya750.com/en/products/m065s-1

[PeWe]

The welded parts inside can be more seen as reinforcements than restrictors?
Here a rear view.
I can take more photos another day. The Lotus Root Pipes are not used today.

[kyle750]

^ ^ ^ WoW ^ ^ ^ The Yamiya Lotus Root look like fantastic build quality. Thanks for the photo.

Another photo of the newly arrived HM341 pipes.  Inside of the pipes had considerable oxidation but polished up nicely