Topic: Pipes HM341s quick value question & clarification between stamped numbers

[greenjeans]

Guy down the street has some stock 4 into 4 pipes off a '72 CB750 hanging in his garage.  HM341 is stamped on them.   Look to be in great shape...no scrapes or dents.  All the chrome is there, very little pitting in some areas.  Should clean up very nice.  He's wanting $300.  Does that seem like it's a good price or a bit high.  They really do look nice.  Don't want them to end up on ebay or somebody else's bike when they could look good on mine.

* What's the difference if any between the HM300's & the HM341's  anybody know ?

[honbonduc]

Go get them before he figures out what they're really worth.

[andy750]

I bought a set of HM300s for $300 last year.....Id get them 

**edit - I agree with Rauls comments below - my set was a good price BUT I ended up getting rust pinholes at the end of the pipes (#1 & #4) after 1000 miles or so. Ive been lucky in finding a new NOS #1 pipe for $80 on Ebay....now just need to find a new #4. On the plus side HM341s are supposed to be better quality (though wont sound as good as the HM300s  ).

cheers
Andy

[Raul CB750K1]

I don't think it is a steal, just a fair price. A new set goes for about $800, so paying $300 for a used set that you don't know how much life do they have remaining seems like a good price to me.

[greenjeans]

Thanks guys....think I'll grab 'em

[Raul CB750K1]

I bought a set of HM300s for $300 last year.....Id get them 

**edit - I agree with Rauls comments below - my set was a good price BUT I ended up getting rust pinholes at the end of the pipes (#1 & #4) after 1000 miles or so. Ive been lucky in finding a new NOS #1 pipe for $80 on Ebay....now just need to find a new #4. On the plus side HM341s are supposed to be better quality (though wont sound as good as the HM300s  ).

cheers
Andy

I'm running without the baffles on my HM300 and tell you what, that's an addictive sound. From what I've seen, the HM341 "baffles" doesn't have any muffling material, so it probably goes inside the muffler itself. The bike hesitates a little at low revs, but I've discovered an addiction in cranking the throttle open and listening the pipes thunder!!! I promise, get a ride on the CB750 with HM300 and no baffles and when you return home your stress is gone!!!

[andy750]

You hooligan Raul! 

I ran the bike for a couple of miles missing one baffle and that was enough for me...I prefer throaty exhaust sound as opposed to thunderous roar...I guess Im just more mild-mannered than you Spaniards 

cheers
Andy

[rachet]

I've always preferred a quiet ride over a loud one.  "Sleepers" are much more appealing to me and I would rather not have cops hearing me come from a mile away.  I'm on a quest to get the best performance with the quietest sound possible. 

Don't get me wrong, loud bikes are cool!  Just not for me.

[Jonesy]

The HM 300 pipes were the original exhaust design for the CB750, used for the first few years of production (the earliest few had no numbers stamped on them at all). They are essentially an open megaphone pipe with a small glass-packed diffuser in the end. Remove this diffuser and you are basically running an open pipe.

The HM 341 pipes were the later, quieter version. They had a series of metal baffle plates (earlier ones have 5 baffle plates, the later ones had 7.. count the number of rows of spot welds on the backside) and perforated tubes, similar to an automotive-type exhaust. They quiet the sound more and consequently are more restrictive than HM 300 pipes. The little "diffuser" cap on the end is all you can remove.

There is a post on here from HondaMan about how to drill out part of the baffling in HM 341 pipes to reduce the backpressure yet keep the quieter sound.

[Raul CB750K1]

I've always preferred a quiet ride over a loud one.  "Sleepers" are much more appealing to me and I would rather not have cops hearing me come from a mile away.  I'm on a quest to get the best performance with the quietest sound possible. 

Don't get me wrong, loud bikes are cool!  Just not for me.

I used to think the same way. I have other quiet bikes and that's fine for me, but for some reason, I love the sound of the CB750 with HM300 non-muffled pipes. It is a very different sound of what we are used to know as an "open pipe" referring to the thud of a HD. The racy, high rpm sound of the CB750 makes your blood boil, while the thumping of an HD open pipe causes a different reaction.

I have been using my bike with the mufflers for 4+ years until I removed the pipes in order to clean them. Removed the mufflers for the same reason and decided to give it a go before installing them, as I had never run without them. That was  months ago.

[333]

The numbers reflect what model/year they were originally designed for.  The HM part just stands for Honda Motor.  The 300 and 341 are different years of 750s.  All Honda part numbers have 3 segments.  The first tells what kind of part it is(example 22870= clutch cable)and is 5 digits long.  The second tells what bike(or other Honda machine) the part was originally designed for and is 3 digits.  The last segment tells of changes in manufacturers or redesign of the part,(3 digits) or in the case of a carb jet, the size, which is 4 digits and usually starts with a 0.  Generic hardware has a totally different numbering system

                               Stan