Topic: Just installed a Mac 4:1 megaphone exhaust on cb550k..

[putnaja1]

Hi All,

I just wanted to report, I just replaced my rusted out stock exhaust on my 550k, with a Mac 4:1 chrome megaphone.  I can't believe that it installed with no problems, the centerstand is still usable, it looks amazing, is lighter, sounds better, and best of all, the bike runs better!  I'm serious, the bike seems to rev a little quicker, and feels like it has a little more go between 2-4k rpm.  This is with stock jetting- no backfires either!

I've now got 2 questions for the gurus out there..
1)  Could this perceived improvement in performance possibly be from the weight loss from ditching the stock exhaust in favor of a 4:1?
2)  Could it just be that my bike wasn't making full power due to the exhaust leaks?  I had several holes, some back on the megaphone part, but also some right before the muffler attached to the header pipe, underneith the bike at the lowest point (water collected there?)

Whatever the case, I'm a happy camper!  No I just have to mount the tires, replace the chain, change the brake fluid, etc.......

Jason

[csendker]

Going from a 4-4 to a 4-1 should have an impact on your carb set-up.  I believe it typically it's flows more freely, effectivly leaning out your mixture.  If you were running rich before, this may have inadvertenly dialed things in.  If not you may be running lean and lean = running hot, which is not good.  Check your plugs to see if they're showing signs one way or another.

Also, did the exhaust come with anything that would indicate the impact on the carbs, or any suggested set-up revisions (jets, clip, etc)?

[putnaja1]

Going from a 4-4 to a 4-1 should have an impact on your carb set-up. I believe it typically it's flows more freely, effectivly leaning out your mixture. If you were running rich before, this may have inadvertenly dialed things in. If not you may be running lean and lean = running hot, which is not good. Check your plugs to see if they're showing signs one way or another.

Also, did the exhaust come with anything that would indicate the impact on the carbs, or any suggested set-up revisions (jets, clip, etc)?

According to MAC's website, no jetting is neccesary- and no clips or jets came with the exhaust.  I still need to check the plugs, as I want to make sure I am not running too lean, but I am not noticing any weird symptoms- seems to be able to take off from idle OK without any hesitation.  It doesn't stumble when I rev it, I don't notice any smoke from exhaust, etc.  Hopefully that means I am close to the mark.  I still need to do a good plug reading. 

On a side note, I got a good old laugh from some instructions I read on reading spark plugs..  The instructions start out "start off in 1st gear, and accelerate hard until wide-open in top gear.  Then pull in the clutch and shut off engine simultaniously"  I don't know about you guys, but the idea of going wide-open in 5th gear, and then shutting the motor off and pulling in the clutch makes me a wee bit nervous, as in, I don't want to be f**king around like that when I'm wide-open in top gear!  :-)

Jason

[Noel]

My understanding is that the stock Honda exhaust kind of, well, sucks. The line that always sticks with me is from Kevin Cameron: "A modern pipe can really uncork an older bike". I think maybe you've just added credence to that thought.

And yeah, I guess any exhaust with holes in it probably isn't going to be the best performer.

I don't suppose we can hope for a sound file?

[Noel]

BTW, I don't know any other way of doing a plug check but shutting down from 5th. I understand that lubrication can be a problem if you spend a great deal of time coasting with the engine off, so I get hard on the brakes as soon as I hit the switch, but so far I haven't killed anything. Myself included.

[lassenc]

Any pictures of the bike with the new exhaust?

Where did you get it?

[putnaja1]

I don't suppose we can hope for a sound file?

Any pictures of the bike with the new exhaust?

Where did you get it?

I'll post some pics (and hopefully a sound clip!) when I get home.  I think it looks and sounds great, although I realize that MAC isn't on most people's favorite aftermarket exhaust list..  I'm happy with it, so that's what counts!  :-)  I got it mail order from DennisKirk.com, for just a tad over 300 bucks.

I did notice that it looks like it will be a tight squeeze to get the oil filter out- It should just slide through..  I just changed the oil and filter, but I'll let you guys know how that goes next time I do that.

Jason

[carl550k]

     i am glad to hear the mac exhaust worked out for ya. i also have the same exhaust on my 76 550k. you can change the oil filter with the exhaust in place, i can. i also never had to mess with my carbs, but it does run a bit lean, not much.plugs are light gray.the exhaust definatly helped in the mid to high  rpms compared to stock pipes. i have the all black set the only #$%* is the finish,very poor, had to repaint after first year.

[Noel]

...although I realize that MAC isn't on most people's favorite aftermarket exhaust list.

IMO, nobody -- with the possible exception of the "one-off" custom makers -- offers a "good" aftermarket pipe for the SOHCs. All I see is heavy, rust prone gaspipe with big nasty welds and a "generic" can stuck onto the end.

Having said that, we make do with what's available, and if the MAC pipe works for you, then cool beans. I'm using a SuperTrapp, which is probably equivalent in quality, and would be equally happy with the MAC or the Kerker or the Jardine, I guess.

What I'd really like is for a modern maker to start producing a modern pipe for the bikes. And I figure the market for a $700+ pipe from a name maker is maybe half a dozen guys. Talk about a "pipe" dream, eh? Nyuck, nyuck...

[nteek754]

Hey there congrats on your new pipe too bad you hadnt gone with KERKER but anyway going from 4 to 4 to 4 into 1 you create a push me pull me in your engine running when  1 and 3 fire that sucks out 2 and 4 and so on and on  been running kerkers for over 30 years a bit more pricy and they intall by removeing the stock spigots and then bolt straight into head  I put one on my sisters 74 750 going from a mac and she said WOW like night and day but  Im glad your happy with the new Mac have fun seven fifty four ever

[lassenc]

Where can I get a Kerker?

[putnaja1]

I know I still need to attach a picture of mine installed, but in the mean time, here is a pic of the exact system from MAC's website:

Hey there congrats on your new pipe too bad you hadnt gone with KERKER but anyway going from 4 to 4 to 4 into 1 you create a push me pull me in your engine running when  1 and 3 fire that sucks out 2 and 4 and so on and on  been running kerkers for over 30 years a bit more pricy and they intall by removeing the stock spigots and then bolt straight into head  I put one on my sisters 74 750 going from a mac and she said WOW like night and day but  Im glad your happy with the new Mac have fun seven fifty four ever

Yeah, right on!  Kerker's sound like they make some whomp-ass power!  I'm pretty satisfied with the MAC one though- it was inexpensive, looks great, and best of all doesn't require rejetting..  I've used these pipes before on my DOHC CB's, and they always have fit and worked well.  I do want to try Kerker though..  Maybe next time, or maybe an excuse to aquire another SOHC!     If there's one trade off with this pipe, it would be that there is a little less ground cleanance than stock, as the collector part of the pipe is right under the frame..

Where can I get a Kerker?

You might be able to get them at Dennis Kirk..

[Jay B]

That's a nice looking system, IMO. I wish they were like that for the 350f. They all sweep to the right side over top of the filter like on a stock 400f system. I like the look of yours much better.

[MRieck]

I understand that lubrication can be a problem if you spend a great deal of time coasting with the engine off,

  As long as your oil pump is working there is no problem.

[putnaja1]

OK, as promised, here are the pics of my bike with the new exhaust..




I'll try to get a sound clip for you all tonight..  I tell you what, any exhaust sounds better than a stock one with multiple rust-through holes!  :-)

Jason

[DrMark]

I was looking at replacing my exhaust on my 1978 CB550K....BikeBandit had this deal at $205.16. See attached link:

http://www.bikebandit.com/partsbandit/product~pf_id~3198338~section_dept_id~1170244~terrain_dept_id~1182421~cat_dept_id~1182676~product_dept_id~1182693~mfr_name~Mac~selection_Path~4.asp