Author Topic: Exhaust options for a CB650 (Read 15818 times)

jwhazel · « **on:** December 19, 2006, 08:49:45 PM »

Well hello all. I've been on the board for a few days now looking through threads and finding info on my newly acquired 1980 CB650. I would have posted something in the introductions forums, but I'm really not that interesting. I've been using forums for 6-7 years now and know the etiquette behind using the search button so you won't see me post much other than to ask the occasional odd question or help someone else.

So anyways, my situation is that the gentleman who owned the bike for a whole month before me apparently thought that it would sound cool to cut the ends off of the mufflers (stock 4 into 2's) and just gut them

. I have to say that I don't particularly care for the sound of "open baffle" cans, nor do my neighbors nor do the cops down the street, so I'm faced with finding replacements. Until a few hours ago, I thought that the cans were just bolt-on's to the collector making this a fairly straight forward job. After removing a footpeg and a guard, It appears that the can is welded directly onto the outer header and then just clamped onto the inner one meaning that the exhaust is one whole piece (well, two if you count both sides). So now I'm left wondering what to do? Used decent exhaust seem to be few and far apart on ebay. A brand new aftermarket one cost more than I paid for the bike.

My big question: Does anybody know the possibility of using a cb650c slip-on on my current headers? I found a nice price on a new set but for the life of me can't tell if they would fit on my headers with minimal modding. From what I gather in my searches, the cb650c had 4 into 4 pipes. But detailed pics and dimensions of the stock custom pipes are something I have not been able to find in my search. I can post pictures of the slip-ons in question if it would help.

Does anybody have any other good ideas? The headers that are on my bike now seem to be in really great condition. A little pitting, but no rust, no dents, no major discoloration, and still pretty shiny looking. I hate to throw out the baby with the bathwater in order to fix the noise issue. Any help is greatly appreciated.

pae · « **Reply #1 on:** December 20, 2006, 12:19:10 AM »

One of my pipes (LH) was rusted right through a few inches behind the welded joint when I got my project, so I've been looking to re-do that whilst keeping the standard headers. I've just picked up some Dunstall silencers which I'm going to clamp on. I'm going to cut off the silencer just ahead of the weld and slip on and clamp the new silencers on. details are here ... http://www.sohc4.us/forums/index.php?topic=16559.0;topicseen

I'll be looking for a rotten RH pipe to cut up, as that one is in good condition - I don't wnat to cut up a good one. As you say they're not easy to find.

See my website (in signature) for full story.

regards, Phil

jwhazel · « **Reply #2 on:** December 20, 2006, 09:47:18 AM »

Thanks for the reply Pae. I looked at your thread before posting and it looked rather enticing. However I'm afraid you got pretty lucky on your find, a set of Dunstall's will run me a little over 100 usd. What I've found is a set of NOS Mac's for the cb650c at a fraction of that price. For the life of me, I can't figure out if these would match up to regular cb650 headers or not. Every pic I've been able to find of the cb custom's headers has already been modified with a new pipe. They're so cheap though I'm wondering if I should just throw up a hail mary and try it.

DammitDan · « **Reply #3 on:** December 21, 2006, 01:52:35 PM »

I have a set of MAC 4-1 headers and can on my bike now, and while they work, they're poor quality. There's a reason you're paying a fraction of the price. The chrome is starting to come off in places on the can, and the flat black painted headers somehow started blueing and started rusting after just a month.

So remember, you get what you pay for.

cb650 · « **Reply #4 on:** December 21, 2006, 03:49:24 PM »

I have a macthat has 30k on it and still looks good except for operator FU's.

Terry

jwhazel · « **Reply #5 on:** December 21, 2006, 04:40:06 PM »

I don't know, these things retail at about $250. I just think that this guy is tired of sitting on them in his stock and is desperate to sell. My problem is figuring out how hard it is (if its even possible) to make pipes made for this:
cb650 custom

fit onto this
cb650

I don't know that I would particularly mind them flaking off and rusting *eventually*. I know it may be considered ineloquent to some (understandable), but I'd just like to fix this noise problem for right now, and worry about the consequences when they come.

DammitDan · « **Reply #6 on:** December 21, 2006, 09:12:21 PM »

Well, the MAC still looks decent after I re-painted the headers with high-temp grill rattlecan, although I don't know what caused the chrome to flake (it's a spot about the size of your thumbnail on the top, right next to the flange that bolts it to your rear pegs). And $250 really isn't much when you're looking at a whole new exhaust (that isn't MAC).

Anyways, if you chop at the right place on the original headers it may be possible to put a slip-on on there. And while it may not look pretty, if you clamp it down securely it would work (although it may screw with your mixture). And if he gutted the mufflers and it still runs OK, it's quite possible he already re-jetted to compensate. Just something you might want to look into if you put the baffles back on the bike.

If you're not wanting to dig deep on this bike, I would just wait around for a new exhaust system to come around. I've got a CB650 4-2 sitting in my (parents'

) basement right now that would shine up nicely, although it does have a large dent in the #4 header pipe.

jwhazel · « **Reply #7 on:** December 21, 2006, 09:48:40 PM »

I know that it *kind of* looks like it could be fit on there, but I can't definitivly tell because of the spacing of the pipes at the collector plus the angle that it mounts. Thats why I was wondering what peoples opinions are because I'm very new to this (well not bike maintanence, but the CB's). I think I'm going to go ahead and hold off on buying new pipes until I get there. I plan on fixing up the bike starting with the front and slowly working my way to the back. Thanks alot for the tips on the rejetting, I would of not have thought about that. Mainly because the guy I bought it from was not the sharpest tack. When I say the exhaust were gutted, I mean he litterally took a hacksaw to the ends of the cans and just started cutting, did the exact same with the rear turn signals. Didn't bother to take the actual signals of the stems or anything, just chopped the whole thing, wires and all, so it would be flush with the licence plate. All of his cuts are jagged and burred. Hence I have a feeling no thought was put into rejetting the carbs when this was done. But I will keep that in mind when I put new different pipes on it. Worst case it looks like new complete exhaust on ebay only runs about $300 (cheaper for 4 into 1, but I don't much care for those).

Pinhead · « **Reply #8 on:** April 18, 2007, 10:13:00 PM »

Bringing an old topic back to life...

My '79 CB650's silencers have finally rotted through and sound terrible. I'm in the market for some new silencers. Hopefully I'll be able to chop the silencer just in front of the rust and add a "slip-on" style muffler and keep my good headers (they're in excellent shape). Has anything come of this thread?

c_kyle · « **Reply #9 on:** April 19, 2007, 06:27:05 AM »

I'll add to this thread the list of complete systems I've found for the 1979 CB650:

BSM Classic 4-1, davidsilverspares.co.uk, $418.25

Marshall Deeptone 4-1, lmspares.co.uk, $338.21

MAC 4-1 and 4-2 systems, available all over, <$300

Motad Advert 4-1, lmspares.co.uk, $398.24

Another solution would be like Pinhead said, cutting off the old mufflers and clamping new mufflers on. I like the 4-2 system, but my header is rusty and discolored, so I would have to rechrome it and buy two mufflers, which would cost just as much as a new 4-1 system. So, I'll probalby just go 4-1 with BSM or Marshall Deeptone.

pae · « **Reply #10 on:** April 19, 2007, 12:20:16 PM »

Quote from: Pinhead on April 18, 2007, 10:13:00 PM

Bringing an old topic back to life...

My '79 CB650's silencers have finally rotted through and sound terrible. I'm in the market for some new silencers. Hopefully I'll be able to chop the silencer just in front of the rust and add a "slip-on" style muffler and keep my good headers (they're in excellent shape). Has anything come of this thread?

That's just what I'm going to do. One of my silencers rusted right through just ahead of the welded joint. The other ain't too god, so I'll cut that off, paint the headers black, as they are pretty rusty too, and clamp on the Dunstalls. See pics below...

motorbikeman · « **Reply #11 on:** April 19, 2007, 02:31:55 PM »

funny story. I just got done doing exhaust work today. Except I went down to advanced auto parts and picked up a thrush Glasspack, and addapter and 2 clamps. I must say that it looks a bit funny having a bright red pipe on the side of my POS. But it drastically reduced the noise from the once open 4 into 1. however I suggest you advise someone else, since I like to cobble and you might want something with a little more class.

cheers from Michigan

Pinhead · « **Reply #12 on:** April 19, 2007, 08:53:04 PM »

I was thinking of doing the same thing, actually. The problem would be attaching them to the frame (so they're not just hanging off the headers). Most auto glasspacks don't have any mounting, they expect you to attach the piping before and after the muffler. How'd you get around that?

Wonder what it'd look like painted black... Or maybe even simply polished and clear-coated?

cb650 · « **Reply #13 on:** April 20, 2007, 02:41:52 AM »

A guy at the track who ones a muffler shop has been using some of the carbon fiber muffs for cars on his sportbikes.

Terry

motorbikeman · « **Reply #14 on:** April 20, 2007, 06:42:07 AM »

Ad of right now, they are just clamped to the collector, however not for log. I was going to take a muffler clamp, and bolt it about mid way down the glasspack. Then weld a bolt on the back of the clamp in the dirrection of the original muffler mount. For now, it just bounces there.

Suggestions: If you buy a 2" it will not slide on. I think, but I am not positive, that if I took the glasspackl to the muffler shop that they could stretch the pipe to 2 1/8 to fit over the collector. That would get ride of the adapter I used. Once again, I play the poor college student card. So haha.

Cheers from michigan

bill440cars · « **Reply #15 on:** April 20, 2007, 08:23:33 AM »

Not for sure but, I think it was "The Great Lumbee" who uses a Cherry Bomb Glasspack on his 750 and I think it's pretty tasteful myself. Couldn't seem to find a picture of it to post though. I've always heard that "Necessity Is The Mother Of Invention".

Later on, Bill

grumburg · « **Reply #16 on:** April 20, 2007, 11:04:46 AM »

Had a beautiful cb650 exhaust system I offered under "Free to a Good Home". Couldn't give it away so I scrapped them.

DammitDan · « **Reply #17 on:** April 20, 2007, 11:32:15 AM »

Shoulda put em up on Ebay... I just got $120 for my old (good condition) exhausts

grumburg · « **Reply #18 on:** April 20, 2007, 05:06:03 PM »

I put them on ebay with $9.99 starting bid. Not a bid.

physician · « **Reply #19 on:** April 20, 2007, 07:11:54 PM »

damn. i would have bought them..

Pinhead · « **Reply #20 on:** April 20, 2007, 10:09:12 PM »

Yeah, me too!

wingman1946 · « **Reply #21 on:** June 20, 2011, 10:49:42 AM »

I have just bought a set of 4 into 4 off a 1980 custom and I am trying to find out if they will fit onto an 81 standard that now has 4 into 2. The 4 into 4 cost me $100 and they don't even has surface rust. On the 4 into 2 I am running large Harley chrome mufflers off a full size road bike. They look very good and sound similar to an older Goldwing. They are held on with a chrome clamp at the header and my own custom brackets that mount to nuts factory installed in the sides of the mufflers and at the same place as the stock pipes mounted.

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Author Topic: Exhaust options for a CB650 (Read 15818 times)

jwhazel

jwhazel

jwhazel

jwhazel

motorbikeman

motorbikeman