Author Topic: 300/341 pipes comparo, watching the repro's (Read 3102 times)

Don R · « **on:** April 27, 2021, 10:27:44 AM »

I got a set of these and don't remember how close to original these detents are. It has been suggested this will limit performance. I was hoping someone had a few original 341's to compare to. links to follow.

https://photos.app.goo.gl/LFqxE7DZEoubjXRr8
https://photos.app.goo.gl/9xULnsdPDfF7hQdh9
https://photos.app.goo.gl/7NXSYa9QC3rgZ1gJ7
https://photos.app.goo.gl/iJreGNz7P48UuDr89

PeWe · « **Reply #1 on:** April 27, 2021, 12:13:28 PM »

Yamiya NOS HM341
(Add to cart Terry!!!

)

Dents ARE deep. Good photos.
https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_142_88&products_id=3905

Other sets.
Italian made hm341?
https://www.mecum.com/lots/LV0118-316305/honda-exhaust-set-cb750-1969-1976/

The dent look rather deep.

If possible to see . NOS HM341
https://www.ebay.com/p/1423862950

New aftermarket "341"?
https://www.ebay.com/itm/72-76-Honda-CB750K-CB750-CB-750-Four-Muffler-Header-Exhaust-Pipe-Set-Trim-HM341-/372974915428?_ul=CN

Don R · « **Reply #2 on:** April 27, 2021, 07:36:48 PM »

Thanks, PeWe I guessed these looked pretty much like oem. I unboxed mine and gave them a good once over. I wonder if these are Italian made? CMSNL and DSS both sell a 341 reproduction and DSS mentions the slight mods needed to install them, sounds like the ones in the auction link.

Don R · « **Reply #3 on:** April 27, 2021, 07:38:14 PM »

Come on Italy, can it be much harder to make no number 300 reproductions?

andy750 · « **Reply #4 on:** April 28, 2021, 03:36:07 AM »

Trying to post pics of the HM341s on the bike but I think the Forum has trouble with uploading pics at the moment....

Don R · « **Reply #5 on:** April 28, 2021, 08:48:04 AM »

This is the one time it's working out having my pics on google photos. Easy to post a link.

MauiK3 · « **Reply #6 on:** April 28, 2021, 08:49:49 AM »

Why 341's over no number exhaust? Wouldn't the no number units perform better? Mine are great, got them from Yamiya.

PeWe · « **Reply #7 on:** April 28, 2021, 10:56:28 AM »

These look like no number pipes!
In stock! Germany. The VAT of 19-20% must be off if shipped outside EU I suppose.

https://www.bikeside.de/4-in-4-exhaust-system-replica-for-all-HONDA-CB-750-Four-SOHC-K0-K6-69-76-MADE-IN-JAPAN

Correct look of the diffuser. No dents on pipes either.
The photos are hopefully up to date with the product.

Kevin D · « **Reply #8 on:** April 28, 2021, 11:44:46 AM »

http://forums.sohc4.net/index.php?action=gallery;sa=view;pic=652
Gallery photos unaffected

These 341’s have been on my bike for 47? years. My original 300’s rusted out pronto, 4-1 headers were very popular and I was fortunate to get these like new pipes. The indent here isn’t nearly as deep what you’re showing and it’s on the right side only. Is your photo showing indents on both sides? Don, If you want a measurement I can put a zip tie around the pipe and check the indent depth.

Don R · « **Reply #9 on:** April 28, 2021, 12:19:51 PM »

Thanks for the pic. I'm OK with these pipes. I'm not wild about the surface rust inside though. I was told someone else was dissatisfied with the indents and decided to share pics of my new pipes like the guitar guys do. "Unboxing day" I'm going to put them on a k0 due to lack of no number repro's right now. Eventually I want to move them to my brothers bought new K4.
I read that traditional mods include drilling the rear baffles with 1/2" holes. I'll begin like they are, to hear if I like them left as is.

Stev-o · « **Reply #10 on:** April 28, 2021, 04:03:02 PM »

Quote from: andy750 on April 28, 2021, 03:36:07 AM

Trying to post pics of the HM341s...

Hey Andy....Glenn repaired the issue, should be good to post now.

andy750 · « **Reply #11 on:** April 28, 2021, 05:50:18 PM »

HM341s on my K4

andy750 · « **Reply #12 on:** April 28, 2021, 05:50:55 PM »

Quote from: Stev-o on April 28, 2021, 04:03:02 PM

Quote from: andy750 on April 28, 2021, 03:36:07 AM
Trying to post pics of the HM341s...

Hey Andy....Glenn repaired the issue, should be good to post now.

Thanks for letting me know! See above!

PeWe · « **Reply #13 on:** April 29, 2021, 04:26:45 AM »

Strange that they added that dent.
My no numbers have not.

If for brake pedal clearance:
One way to make brake pedal to hit the #4 pipe is when rear brake lever on hub sit wrong.
I know, done that

Maybe possible to mount brake pedal wrong too.

A later pedal will hit pipe. It has not the curved outwards shape as the K bikes.
Done that too.

(I think it was an F pedal I had got.)

Don R · « **Reply #14 on:** April 29, 2021, 03:55:15 PM »

Thanks Andy, that explains it a bit.

itsahonda4 · « **Reply #15 on:** May 02, 2021, 06:40:28 PM »

Im waiting for three sets of no number pipes from WeBike Japan for my sons K0, a set for a my almost- finished K0 and a set for my K1. Yamiya also say they cant advise when these will be available, so I asked the German guys for a price , time will tell......
My K1 Jap-market bike has a mix of 300's and 341's, my sons K0 has a damaged/repaired set of no-numbers and the K0 Ive almost finished didnt have pipes when I bought it .
Pics of K0 attached......
Or if anyone has any repairable no-numbers/300's/341's Id be interested in talking.
Al

itsahonda4 · « **Reply #16 on:** May 02, 2021, 06:41:41 PM »

rolling chassis as bought

itsahonda4 · « **Reply #17 on:** May 02, 2021, 06:42:30 PM »

Don R · « **Reply #18 on:** May 02, 2021, 08:08:07 PM »

Nice comeback on that K0. I think those pipes are made in Indonesia when they have time and right now they are way behind production. Factories all over the world are having supply chain issues due to Covid and shipping container / ship troubles. One ship recently dumped a bunch of them into the ocean in a storm and had to return to port to reload what was left.

itsahonda4 · « **Reply #19 on:** May 03, 2021, 07:07:30 AM »

Yes, as usual with a bought wreck, it was much work, but its looking good finally....
and the engine should be done next week.
I wasnt sure where the replacement pipes were being mfgd, but I knew it was elsewhere. Initially Yamiya lady told me 12 months wait and she had 'hundreds of orders' - maybe Ill get priority for single handedly supporting their company through the pandemic

and WeBike system just doesnt work when you submit a delivery date request.
Al

bluezboy · « **Reply #20 on:** May 03, 2021, 09:22:54 AM »

Man, those are some deep dents, Pandora’s original 341’s are not that deep

Don R · « **Reply #21 on:** May 19, 2021, 04:12:08 PM »

I've been watching Webike, I believe the PMC's are 341 copies and M-Tec are the no number pipes. I notice the price was recently raised on the no number ones even though there aren't any to buy. Nothing on Yamiya yet either.
I'm sure as soon as I bolt 341's to the K0 no number 300's will suddenly become available.

PeWe · « **Reply #22 on:** May 20, 2021, 01:57:25 AM »

You have not checked the link I added earlier if in need of a new 4-4? Look like no numbers.

https://www.bikeside.de/4-in-4-exhaust-system-replica-for-all-HONDA-CB-750-Four-SOHC-K0-K6-69-76-MADE-IN-JAPAN

newday777 · « **Reply #23 on:** May 20, 2021, 11:36:50 AM »

Quote from: PeWe on May 20, 2021, 01:57:25 AM

You have not checked the link I added earlier if in need of a new 4-4? Look like no numbers.
https://www.bikeside.de/4-in-4...SOHC-K0-K6-69-76-MADE-IN-JAPAN

The link no workie......

PeWe · « **Reply #24 on:** May 20, 2021, 11:51:52 AM »

OK, this is another copy of the link when there.
https://www.bikeside.de/4-in-4-exhaust-system-replica-for-all-HONDA-CB-750-Four-SOHC-K0-K6-69-76-MADE-IN-JAPAN

Price with German VAT. I guess off when shipping outside EU.

Hopefully the other systems too
https://www.bikeside.de/navi.php?qs=4+in+4+exhaust+system&search=

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Author Topic: 300/341 pipes comparo, watching the repro's (Read 3102 times)