Author Topic: Yamiya CB750 exhaust  (Read 1416 times)

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Offline jwurbel

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Yamiya CB750 exhaust
« on: April 19, 2023, 08:01:19 AM »
Purchased the exhaust from DSS  summer of 2022. Examined upon receipt and finish was fine.  Not ready to install until this month.  Fit was terrible and pivot points would not match up.  When I looked at rear of the bike the pipes and weld seams were not aligned to each other or the bike itself.  Additionally the resonators were all drilled and installed off center.

Contacted DSS to discuss concerns. After numerous emails and photo exchanges they refuse to acknowledge anything wrong.  They further indicate that they look identical to their CB 750 KO.  However they offered $45 credit which is unacceptable.

Only my opinion, but I would avoid purchase of this product from DSS.  Possibly direct from Yamiya would avoid the problem.  The set I ended up with had to be seconds although DSS denies this.

I now have an exhaust whose quality is inconsistent with the rest of my restoration.  I am also out $1995 which I probably will not recover. 

I have enclosed photos.  If I am out of line any comments or suggestions will be welcome.

Jim

Offline MauiK3

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Re: Yamiya CB750 exhaust
« Reply #1 on: April 19, 2023, 08:03:03 AM »
First time I've heard such a complaint.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Nurse Julie

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Re: Yamiya CB750 exhaust
« Reply #2 on: April 19, 2023, 11:16:10 AM »
Are these the 300 replicas? We've purchased plenty of sets of the 341's from Silver and CMSNL, that all arrived in Yamiya boxes and they have all been perfect in fit and quality. We're in UK though but it shouldn't make a difference. Did he have seconds of the 300's?, I know he had a big batch of seconds of the 341's.
« Last Edit: April 19, 2023, 11:18:14 AM by Nurse Julie »
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Offline Doobie

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Re: Yamiya CB750 exhaust
« Reply #3 on: April 19, 2023, 11:38:25 AM »
I bought a set from DSS a few months ago without any issues.
You only go around once in life so it might as well be on a motorcycle.

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CB750K2
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Offline Don R

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Re: Yamiya CB750 exhaust
« Reply #4 on: April 19, 2023, 02:20:26 PM »
  Do you think the fault is in the mufflers or the insert baffles? Not that you should have to, but I'd consider slotting the muffler side holes.
« Last Edit: April 19, 2023, 02:22:58 PM by Don R »
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Offline jwurbel

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Re: Yamiya CB750 exhaust
« Reply #5 on: April 19, 2023, 03:46:38 PM »
They are the 300 replicas.

Seems like I’m the only one that has had an issue.

The slot modification is something I considered.  A local machine shop wants $200 to do.  I’m looking at drilling out the muffler holes to give me some “wiggle” room.

Seems a pity to have to do so many modifications for the price paid.

Offline 69cb750

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Re: Yamiya CB750 exhaust
« Reply #6 on: April 19, 2023, 04:25:15 PM »
Quote
Do you think the fault is in the mufflers or the insert baffles? Not that you should have to, but I'd consider slotting the muffler side holes.
Compare baffles, replace if defective.

Offline WideAWAKE

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Re: Yamiya CB750 exhaust
« Reply #7 on: April 19, 2023, 04:26:53 PM »
Have you tried swapping the baffles around.

I know they should be all the same but maybe they may line up better.

You can get new baffles for a few hundred bucks if they are the problem. (I’d be interested in purchasing yours if you wanna recoup a bit of the cost)

I have heard of some people having a hard time getting them on and lined up, but I’ll say getting my original exhaust pipes back on after removing was quite a pain sooo…
« Last Edit: April 19, 2023, 04:32:23 PM by WideAWAKE »

Offline ekpent

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Re: Yamiya CB750 exhaust
« Reply #8 on: April 20, 2023, 05:45:15 AM »
Can you turn the baffle to the other side, line up correctly and drill a new hole and tap for threads ?

Offline Magpie

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Re: Yamiya CB750 exhaust
« Reply #9 on: April 20, 2023, 10:38:00 AM »
I would be a fair bit more than pissed receiving a set of expensive pipes with the baffles incorrectly installed and the seams not lined up. I've ordered and received 3 sets of pipes from DSS which all came in Yamiya boxes. The only thing I ran into was a #$%* of a time lining up the holes for the rear mounting bolt. The instructions that came with them explained how to deal with that so they know the repops are not quite perfect. The need of a soft blow mallet to drive the bolts through the mounts was unexpected.
It's very unfortunate that DSS won't step up to help.
Cliff.

Offline Don R

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Re: Yamiya CB750 exhaust
« Reply #10 on: April 20, 2023, 11:25:57 AM »
 It sucks for sure. I've had 3 1/4 sets and haven't seen that. My 341's from CMSNL weren't as nice as the no no.'s
 
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline BenelliSEI

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Re: Yamiya CB750 exhaust
« Reply #11 on: April 20, 2023, 03:38:44 PM »
I had the same issue as Cliff. On one set, the connector tube just wouldn’t line up at all. Left it alone for a few days and realized the foot peg bracket/ tube (?) had been twisted inward at some point. A very small tweak with a long bar and it all fit much better. They weren’t perfect, but only I noticed.
« Last Edit: April 23, 2023, 05:02:17 AM by BenelliSEI »

Online PeWe

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Re: Yamiya CB750 exhaust
« Reply #12 on: April 21, 2023, 11:54:33 PM »
My Yamiya no numbers (look like HM300)
Have had similar "issues".

It can be a little better if not tighten at front until after tighten at rear.
 I think I have used the rear bilt itself to bend the pipe in a better position or another rod.
Yamiya has also added a short steel tube to mate the pipes when mounting them.

I have not used that procedure.
A friend had to do that to align HM 341 replicas from CMS if I remember correct.
If DSS, same manufacturer I guess.

My No numbers that are a little off on 1-2 side.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline jwurbel

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Re: Yamiya CB750 exhaust
« Reply #13 on: April 23, 2023, 09:07:25 AM »
This is the result of my efforts.  I can live with it, no thanks to DSS.

Appreciate everyone and their comments.

Online PeWe

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Re: Yamiya CB750 exhaust
« Reply #14 on: April 23, 2023, 09:56:44 AM »
Those look good.
No surprise for me if the old Honda pipes were like this.
Tricks and force to make them to align.

I just removed my HM341 from Honda many years ago. I do not recall how they sat. Less visible on HM341 diffusers.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline newday777

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Re: Yamiya CB750 exhaust
« Reply #15 on: April 23, 2023, 01:20:19 PM »
This is the result of my efforts.  I can live with it, no thanks to DSS.

Appreciate everyone and their comments.
That looks better. 
Did you slot the muffler holes yourself?
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline MauiK3

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Re: Yamiya CB750 exhaust
« Reply #16 on: April 23, 2023, 02:23:35 PM »
Odd problem but I suppose after all these years some errors would show up. The manufacturer of these, wherever it is, needs to recheck all the forms and fixtures.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline newday777

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Re: Yamiya CB750 exhaust
« Reply #17 on: May 24, 2023, 07:06:11 PM »
This is the result of my efforts.  I can live with it, no thanks to DSS.

Appreciate everyone and their comments.

So what were your efforts to get them lined up?
(your input as to what you did might help someone else that comes across this thread later using a search on the topic)
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline Don R

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Re: Yamiya CB750 exhaust
« Reply #18 on: May 25, 2023, 12:17:59 PM »
 I noticed Yamiya no longer says expect re-stock in 5/23. Indonesia manufacturing took a few hits with covid, typhoons and volcanos.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline jwurbel

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Re: Yamiya CB750 exhaust
« Reply #19 on: May 25, 2023, 12:55:27 PM »
Took a drill bore and expanded the hole in the direction I wanted to turn them.  Not perfect but close.