Topic: to leave the baffle in OR not to leave the baffle in?

[cben750f0]

g'day all, just got back from a great ride with the club i am in, and there was a CB there that had a pretty much straight through system on it... now it WAS rude, and nasty and was bloody unreal to behold ot noise... was wondering, if i was to take the baffle out of my Tranzac system(remove two pop rivets), what in the way of carb set up would be reommended?, the carbs at the moment are in the middle clip on the needles and 112 on th mains, i have a 836 kit,UNI filter, and Dyna'S'.. VF1000 coils, and new leads... should i ride it and see, or what would you recommend as a base to start from... thats for the time... peace

[stanghater]

i hope somebody answers this becuase i am curious abou almost the same issue

[eldar]

Well if you remove the baffles, you will have less backpressure. Every engine needs some backpressure, but there is no way of really knowing how much pressure you need. If you are using a 4-1 system, I dont think it will be as much of a big deal though than say the stock system. You are not likely to gain much power or anything else besides noise. If you do try it, rejetting may be needed but again every bike is a bit different.

[rob]

What do you mean by a 'straight through system'?

Rob

[Raul CB750K1]

I'm not expert in engine tuning, but I don't think backpressure is necessary, at least in 4-strokers. Once the exhaust valve is open, the piston goes up and evacuate the combustion gases. The lesser the pressure outside, the better the air transfer. Muffler is needed though in order to give a pleasant ride, and using a muffler means creating backpressure. I guess the point is reducing noise without creating too much backpressure, but as long as you can keep it with the noise I don't think there is nothing wrong with open pipes.

Raul

[heffay]

raul... you are correct that 2 strokes need back pressure much more than 4 strokers... hence the 2 stroke expansion chamber. 
cben... its not such a big deal to remove baffles... harley guys rarely have them.  in my opinion  motors dont want baffles in their exhaust it stifles hidden energy and lets it breath better.  compare it to a human... good non smoking lungs vs. phlem and junk from smoking or being sick... you know about restrictors on childrens bikes?  well, its pretty much the same.  you may have to work on jetting it just depends on how free flowing your exhaust is before baffle removal. 
heffay,
p.s. its snowin like a $#@* here!    ??

[cben750f0]

so by the sound of it...out with the baffle then!!!looking forward to this... will let you guya know how i went...what i ment by straight through, the transaz system, has about an 1/4in bigger header pipes, and the muffler will be a megaphone....not like the standard system that had the pipes comming into that ugly collector box then trying to get out...... gonna go try it now ... peace

[Spear]

Ben. I have an original set of HM341 4>4 pipes on my K2, MINUS the baffles. They replaced a set of 4>1 extractor pipes with an unbelievable megaphone on the end. Sh!t that thing used to cackle. Now with the 4>4 on board it's like there are 4 single cylinder bikes blatting along behind you. You give it a boot full and take it out to around 5,000rpm and she sounds pretty good. Nowhere as loud or as illegal as the after-market pipes the HD boys use. And that's one thing to be aware of, if the pipes are after-market and do not comply with the usual EPA bull-sh!t sheet you are liable to fines for either or both 'undue noise' and/or 'exhaust not comply'. Anyone who owned a K or K1 with the HM300 pipes will attest to the fact that the un-baffled HM341 pipes sound just as nice - and just as noisy (or should I say just as loud?)  Actually Ben, I bought the HM341 pipes from Al in Lavington. If you're talking to him at all, ask him if he has an e-mail address. I'd love to send him a couple of photos of my K2 now that it's restored.

[Raul CB750K1]

That's bring a question that was lingering in my mind for so long.

I have the factory stock HM300 pipes and mufflers. Suppousedly, they are very hard to find. But the HM341 look exactly the same. What's de difference? If mufflers are bolted on, you can always remove the mufflers, replace the pipes, reinstall the HM300 mufflers and there would be no difference in performance or noise, isn't it?

Because, it the exhaust is composed by mufflers and pipes, as long as the pipes are well chromed, with no rust or dings, making an aftermarket muffler shouldn't be that difficult because they are nothing more than a holed piece of tube. Am I right?

[cben750f0]

spear mate, was talking about you the other day... he remembers you, but i cant remember if he could remember your name.... but yeah, he still remembers.... mate nothing has changed there, technology is a dirt word, you should know that  ... NEway will ask NEway, he is the bloke that does all the work on my bike... AND TO EVERYONE ELSE....ah the baffle out was...er.....um..... fruity......  ...... went for one ride on it... the plugs were good, but jeeeeeeez.... you wouldnt want to be sitting on that for a long trip!!!!! at idle 1100rpm... really beefy... but if you upped it to say 1150rpm.... GODDAM!!!!... needless to say the baffle is back in... nothing like haveing a foot and a half of megaphone to wake the neighbours.... IN THE NEXT STATE!!!!!... ...peace

[MRieck]

at idle 1100rpm... really beefy... but if you upped it to say 1150rpm.... GODDAM!!!!... needless to say the baffle is back in...

To much of a good thing?

[cben750f0]

yeah, it did sound cool... in a 'i have a headache' kind of way, i first started it with the muffler off, straight out of the point where the four pipes meet, and it wasnt that bad....BUT after the humungas trumpet went on... well that was another mtter, though did consider rideing around without a muffler, but i think my boots might have caught fire... ... am still trying to talk my missus into one of your heads.... i am looseing.... ...peace

[mcpuffett]

hey, you have to try things to satisfy your curiosity don't you  i run my 76 f1 on a straight through pipe cut down short just to the pillion pegs ,it has a piece of plate welded across the opening and i have drilled five holes in it to let the gases and noise out ,it dose'nt hold it back it breathes better and it sounds damn good not to loud and not to quiet i also run k+n air filters pod type and it is up jetted and it just pulls like a train  mick.

[SteveD CB500F]

The Piper 4-1 shown on the 500 in my avatar had removeable baffles.  One crosshead screw and the whole thing slid out of the end! When new, there was fibreglass wadding wrapped around it (that didn't last long!).

When run without the baffles it was a neighbourhood (not just neighbour) waker!

I don't know about jetting and stuff because I never plucked up the courage to ride it down the road in that state. Even at 18, there are some things you can't get away with (not in 1976 anyway!)