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Author Topic: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??  (Read 1725 times)

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Offline markb

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Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« on: March 11, 2008, 11:22:36 AM »
I've got a decent set of HM341 pipes that I'd like to run on my K0 until I can afford to buy a set of new HM300's.  Anyone know if the K0 diffusers will fit the 341 pipes??  What differences are there in the pipes?
Thanks,
Mark
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Offline JLeather

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #1 on: March 11, 2008, 11:46:45 AM »
Nope, the HM300 diffusers are larger (and so is the opening in the end of the pipe).  That's why they sound so cool.  The HM341s are a smaller diffuser and are quieter.
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Offline 736cc

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #2 on: March 11, 2008, 11:48:58 AM »
  If you are very brave and like to hop things-up, remove the 341 caps, get a loooong 3/8" drill bit and drill a bunch of holes inside the pipes. Leave the caps off or hacksaw them to open-up the tiny outlet. They will sound and breath like 300 pipes. And you will be officially a hack.
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Offline markb

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #3 on: March 11, 2008, 06:36:09 PM »
What if I run the 341's without the diffusers, would they breath about the same as the 300's with diffusers.  I'm wanting to run standard plugs and carb setup until I can get the real thing.
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Offline Jonesy

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #4 on: March 11, 2008, 06:46:49 PM »
Removing the diffusers from HM341's might improve the sound a little, but the HEm341's have baffling welded in place inside. The HM300's were open expansion chambers with glass-packed tips- quite a difference in construction (and performance!).
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Offline Terry in Australia

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #5 on: March 11, 2008, 07:07:22 PM »
I love my HM300's...............  ;D
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Offline cafe750

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #6 on: March 11, 2008, 07:09:46 PM »
Quote from: markb on March 11, 2008, 06:36:09 PM
What if I run the 341's without the diffusers, would they breath about the same as the 300's with diffusers.  I'm wanting to run standard plugs and carb setup until I can get the real thing.

You can run the 341's without diffusers, and its loud, with a sound similar to the 300's, but much "tinnier". The 300's that I have replaced my diffuser-less 341's with, perform better, and have a much "tighter" sound, and thats with the 300's diffuser in. I too Love my HM300's... ;D . Hope this helps a bit...
« Last Edit: March 12, 2008, 05:39:19 AM by cafe750 »
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Offline andy750

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #7 on: March 12, 2008, 05:25:45 AM »
Quote from: Terry in Australia on March 11, 2008, 07:07:22 PM
I love my HM300's...............  ;D

+1  (and I also have HM341s - completely different sound)

I just replaced the baffles on the HM300s (well 2 of them at least) and wow what a difference in sound! Is this normal? Do new baffles really make that much difference? Should I replace the other 2!? Sounds much throatier now, love it! Of course I did change the pipes from the CB750K4 to the K2 but didnt think this should affect the sound......

good luck in getting the HM300s....

Cheers
Andy
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Offline 736cc

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #8 on: March 12, 2008, 08:24:21 AM »
  Remove the HM300 baffles and hacksaw-off the inboard-ends and chuck the cloth while you're at it. Replace the baffles (diffusers). Now we're making the perfect tone, something between HM300 w/ and w/o baffles.
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Offline Jonesy

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #9 on: March 12, 2008, 06:33:13 PM »
I just installed brand-new HM-300's on my 750... Now I REALLY have spring fever!!!
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Offline markb

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #10 on: March 12, 2008, 07:24:00 PM »
Thanks for all the great replies.  Looks like I might have to bite the bullet and by the 300's.  It's the right thing to do.
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Offline Jonesy

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #11 on: March 13, 2008, 03:07:04 PM »
Quote from: 736cc on March 12, 2008, 08:24:21 AM
  Remove the HM300 baffles and hacksaw-off the inboard-ends and chuck the cloth while you're at it. Replace the baffles (diffusers). Now we're making the perfect tone, something between HM300 w/ and w/o baffles.

I finally got to take mine for a very brief and chilly ride today, and I see what you mean. The 341's sound "tinny" as someone described, while the 300's sound sort of "nasal" (best word I can describe it with). I might try your approach...
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Offline andy750

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #12 on: March 13, 2008, 03:23:06 PM »
Quote from: Jonesy on March 13, 2008, 03:07:04 PM
Quote from: 736cc on March 12, 2008, 08:24:21 AM
  Remove the HM300 baffles and hacksaw-off the inboard-ends and chuck the cloth while you're at it. Replace the baffles (diffusers). Now we're making the perfect tone, something between HM300 w/ and w/o baffles.

I finally got to take mine for a very brief and chilly ride today, and I see what you mean. The 341's sound "tinny" as someone described, while the 300's sound sort of "nasal" (best word I can describe it with). I might try your approach...

Agree Jonesy! Im going to try and get some video of the HM300s this weekend.....and post it on here...my HM341/K4 bike is not re-assembled yet so comparison for me at least will have to wait.

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Offline andy750

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Re: Will diffusers from HM300 pipes fit in HM341 pipes (CB750)??
« Reply #13 on: March 15, 2008, 01:00:14 PM »
Here is a movie I took yesterday after riding home...little bit of camchain noise that needs to be adjusted but you get the idea with the pipes when throttle is turned...sorry i was doing to myself so filming/throttle is a bit off....upper 2 baffles are new....

http://s141.photobucket.com/albums/r58/andy750/?action=view&current=P1090240.flv


cheers
Andy
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3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350
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