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Author Topic: CB700SC exhaust help  (Read 1672 times)

Offline Scoobe700sc

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CB700SC exhaust help
« on: January 22, 2016, 09:53:20 PM »
I'm looking to replace the stock exhaust on my 85 CB700SC, and I've got a few questions regarding fitment and some advice hopefully.

1. All the exhausts I can find say they're for the later NH 750, not the CB700SC. Would something like a Vance and Hines for a NH 750 fit my bike?
2. I like the sound of the Vance and Hines and I am looking into them specifically.  The only problem is all of them have the chrome finish. I know they did at least make that model in black. Do they still sell them in black or would I need to have a chrome finished exhaust powder coated?
3. Would I need a rejet to run the Vance and Hines?
4. Anything else I should know exhaust related? I've only had the bike a few months and i'm in no way an expert.


This is the Vance and Hines in black


Offline brittles

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Re: CB700SC exhaust help
« Reply #1 on: January 23, 2016, 12:36:36 PM »
The late model 750 exhaust will fit, but the rear mounting point won't. You'd need to fab something.

A rejet would be recommended.

Offline jimmycorp

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Re: CB700SC exhaust help
« Reply #2 on: January 26, 2016, 06:56:53 AM »
I recently purchased that same V&H exhaust (silver, used) for my 700S.

The stock exhaust bolts are the ungodliest of any bolts I have ever encountered in my lifetime.

They do not work with the V&H as they taper from pencil this to Qtip thin.

Upon attempts to remove  them (8bolts) they've all sheared at the taper point.

Its taken me 4 weeks to remove 7 of the 8 bolts.

Below are the methods used:

1) heat (2000° butane torch) & vice grip. --> no result.

2) socket type stud extractors:
a) Straight teeth: worked for 2 bolts straight away  using smallest size extractor.
B) offset teeth: --> zero grip due to the small tapered edge.

Upon using the smallest size, the bolts snapped ; again at the taper point.

3) impact screwdrivers: I notched the studs with a dremel, then went to town. Zero result.

4)Drilling:

Snapped the following drill bits:

2 titanium tipped ( after much pressure and virtually zero progress)

2 Cobalt hardened steel left handed drill bits.

Success drilling holes for extractors.

End result properly sized extractors could not grip the inside of the bolt properly for extraction.

I had to drill larger bikes and use bigger extractors.

I am still working on one screw . I am basically drilling it out slowly as it kines up with the frame and the angle is slightly off center.

In order to have clearance and make progress I had to put the bike in my harbor freight 1500lb motorcycle jack, remove the cables and forks/wheel for clearance.

All of the above efforts were in conjunction with heavy doses of ATF/Acetone mix as a penetrating fluid, since it works better than anything commercially sold (wd40, pb blaster,etc)

Moral of the story? Really think about the possible headaches.

If you decide to move forward, just use left handed Cobalt bits and drill/ extract them out.

 The culprit:



Offline brittles

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Re: CB700SC exhaust help
« Reply #3 on: January 26, 2016, 02:26:04 PM »
I've never had to remove the exhaust studs for an aftermarket exhaust.

Offline ariwhiteboy

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Re: CB700SC exhaust help
« Reply #4 on: January 26, 2016, 04:27:57 PM »
Me either, but the Irwin bolt grip extractors have always allowed me to remove broken studs pretty easily, to include NH 750 exhaust ones.
What is good Phaedrus...

Offline jimmycorp

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Re: CB700SC exhaust help
« Reply #5 on: January 26, 2016, 05:42:33 PM »
I've changed the exhausts on my '06 ninja 650, '85 ninja 1000, '88 xt600, '03 ninja 250 and '93 dr650.

Never had to remove bolts on any of those bikes.

However the bolts were not tapered and did not have the unthreaded middle section as the  Honda.

That is why they needed to be removed , and replaced with a standard threaded exhaust stud (no taper).

It was damn near impossible to get the new nuts to grip into the stock bolts .

I used Irwin bolt extractors, however it snapped all bolts at or near the taper point, except that one in the picture.

As the smallest size barely fit. It slid off the stud, even after cleaning the  grime off it.

Then when it did grip, even center punching the broken piece kut if the extractor for was a bust.

Must be a 700s thing, this is by far the most annoying of my 6 bikes to work on.

Like I said, project from hell. Every time I touch this bike.

She's like my crazy ex girlfriend. Nice to look at and fun to ride, but a headache in between.

Offline brittles

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Re: CB700SC exhaust help
« Reply #6 on: January 27, 2016, 07:59:29 AM »
Here's the late model 750 Kerker on my 700S.....







Offline jimmycorp

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Re: CB700SC exhaust help
« Reply #7 on: January 27, 2016, 08:26:04 AM »
Nice. Like I said I have 6 bikes, the only in that ever gives me sh*+is the nighthawk.

Needless to say I'll never buy a other Honda.

Offline Scoobe700sc

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Re: CB700SC exhaust help
« Reply #8 on: March 08, 2016, 05:38:23 PM »
So I have a few new ideas that may or may not work.

1. Remove the baffles from the stock exhaust and drill holes, replace baffles.
2. Cut off the stock mufflers and have a new universal exhaust welded on.

Honestly I am mainly looking for a nice sound. Do these ideas sound at the possible for my goal? or are they pretty stupid ideas?

Offline jimmycorp

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Re: CB700SC exhaust help
« Reply #9 on: March 10, 2016, 06:24:28 AM »
So I have a few new ideas that may or may not work.

1. Remove the baffles from the stock exhaust and drill holes, replace baffles.
2. Cut off the stock mufflers and have a new universal exhaust welded on.

Honestly I am mainly looking for a nice sound. Do these ideas sound at the possible for my goal? or are they pretty stupid ideas?
Don't screw with the stock exhaust, you may want to go back to it at some point.

If you want a cheap nice sound, get a couple of cherry bomb or universal glass packs.

Get a universal fit/reducer kit from dime city cycles and use exhaust clamps. Do not weld.

Don't forget to rejet.

I put a cherry bomb exhaust on my 06 ninja 650, (8inch length 2 inch inlet/outlet) it was cheap $20 and sounds fantastic.

Only slight weight savings compared to stock though.

I realize a car exhaust on a bike is unorthodox , but I needed a cheap muffler to ride around on while I fixed up the bike to sell.

Good luck!

Offline AHenry014

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Re: CB700SC exhaust help
« Reply #10 on: March 10, 2016, 01:03:27 PM »
my parts bikes exhausts aren't in the best shape externally.  I have to check the condition on them, but would be happy to sell a pair of baffles to you if youd like to give the drilling a shot.  PM me if interested. 
-Alex

Offline Scoobe700sc

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Re: CB700SC exhaust help
« Reply #11 on: March 19, 2016, 04:27:30 PM »
If I was going to go with a muffler from dime city, do I need to cut off my stock mufflers or do they slide off?

Offline mollusc

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Re: CB700SC exhaust help
« Reply #12 on: March 19, 2016, 05:35:27 PM »
The 700S exhaust system doesn't disassemble, except to split in half at the crossover box.  The rest of it is welded together so you'll have to cut the pipes to remove the mufflers.
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Offline Dindindin

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Re: CB700SC exhaust help
« Reply #13 on: February 13, 2017, 06:58:29 AM »
Adding a 4 into 1 system to my nighthawk instead of two 2into 1's. I bought the whole stainless system for 30pounds....50 dollars ....used but in good clean condition. Anyone else done this? And did it give any problems?

Offline jimmycorp

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Re: CB700SC exhaust help
« Reply #14 on: February 13, 2017, 07:07:42 AM »
Adding a 4 into 1 system to my nighthawk instead of two 2into 1's. I bought the whole stainless system for 30pounds....50 dollars ....used but in good clean condition. Anyone else done this? And did it give any problems?
I did this last year, Vance & Hines 4-1, you must rejet, all bikes are so different and location/altitude are also factors.

Make sure you check the oil drain plug clearance, mine was blocked by the v&h exhaust.

I had to heat it with a blow torch and shape it so it would clear.

Be super careful with the stock exhaust bolts and studs; they're made of cheese and will easily snap (happened to me).

And make sure you use new exhaust gaskets.

Also consider putting a rubber stopper on the center stand, otherwise it will just clank on the frame.



The bike revs much better with a free flowing exhaust.

Good luck.

Offline Wahrsuul

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Re: CB700SC exhaust help
« Reply #15 on: February 14, 2017, 06:02:06 AM »
just an FYI, the late model NH750 exhaust will fit the 700 - the pipes line up at the head, and the bolts under the engine line up as well.  The only issue is the hangers on the mufflers themselves.  I don't recall right off which way the hangers are off (forward or back), but you'd need to either fab a bracket or move the mounting tabs.  Or cut off the mufflers entirely and go with universal cans of some sort.

 

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