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Discussion Starter #1
Okay, so I've searched this forum and found no real answer to the above question, and lot's of speculation about sound deadening material and a cat converter being inside. No cut-away pictures that I could Google. Today I was at our local bike graveyard and spotted a mangled 2000 VN750. I offered the yard owner $10 bucks, he said it was worth $30 and I said I was just gonna cut the f'er up to look inside, he said BS, I said I'll do it right here right now, he said prove it and I'll charge you $10 bucks.

So I got the saw out of the truck and split it lengthwise across the weld. What's inside is a) on the left intake is a 9 inch pipe with a reverse gentle 90, this balances the exhaust pipe length from the rear cylinder to the front length and directs the gas flow back towards the right side outlet, b) there's a 2 inch stub on the right side for the front cyl that dumps straight into the chamber, and on the rear exit of both sides is a 2 " stub leading to the muffler clamps.

No packing, no cat converter or baffle plates like on the VN800 and beyond. Keep in mind this was on a 2000 model.

So the pre-muffler balances the exhaust lengths and the chamber provides an early pressure reduction before the exhaust hits the muffler baffles.

We were all laughing so hard at why I was doing this in the junk yard that I forgot to take at least a phone camera pic!

Now you should be able to understand why there IS a power loss when you de-goat, and you should be able to figure out why the carb mixture will be off and near impossible to balance without fiddling with all the jets and the slide vacuum ports, and you should be able to figure out why it's not a great idea even if you add an H-pipe which won't balance the exhaust path (but that's better than just what you see in the Verses, for sure!)

Turns out the Kawasaki engineers aren't as dumb as a redneck with a hacksaw.
 

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Thank You. It is worth $10.00. I was told by the Kaw Mechanic that this engine is built and carburated to run with the back presure that the stock exhaust has. It sounds like they have made every effort to balance the system. As a side note I really like this forum because of the knowledge that is available here.

Mcneuby
 

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Thank You. It is worth $10.00. I was told by the Kaw Mechanic that this engine is built and carburated to run with the back presure that the stock exhaust has. It sounds like they have made every effort to balance the system. As a side note I really like this forum because of the knowledge that is available here.

Mcneuby
My butt and my buddies who looked at the rear end of my bike a lot more often afterward says different,you will lose a little on the bottom end but with a set of right side exiting pipes you almost balance the length out.And since it was called a premuffler it does change the sound a little.

The carburetor balance and mixtures can be achieved with patience and more air pulls more fuel burned efficiently at a higher rate of speed thru any engine provided the AF mixture and ignition timing is correct makes more power.Period

And if there is so much knowledge here why do you ask one mechanic at a dealership(who often have no clue) about something several on here have already tried and used with success and then slap us all in the face with it

If you want to keep your bike stock ,fine,but don't try to convince us that it is best,when we have already found out different.if you want to leave it stock that's fine,we don't care ,it is yours to do with as you please,you don't have to justify it to us.But we have been there and done that and wanted better and found it.
 

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Wow, I didn't mean to upset you.

When I first got my vn750 I took it to the dealer and had them look at it. Since then I found this forum. I guess I don't care to go any faster than the stock bike will go. If that is what you want to do that is fine. I have kept mine stock and am satisfied with it. Like you say you do as you want with yours and I will do as I want with mine. But the bike does run pretty well stock. This is a good sorce or any modifications that you may want to make as well as just keeping it running.

Mcneuby :(
 

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Okay, so I've searched this forum and found no real answer to the above question, and lot's of speculation about sound deadening material and a cat converter being inside. No cut-away pictures that I could Google. Today I was at our local bike graveyard and spotted a mangled 2000 VN750. I offered the yard owner $10 bucks, he said it was worth $30 and I said I was just gonna cut the f'er up to look inside, he said BS, I said I'll do it right here right now, he said prove it and I'll charge you $10 bucks.

So I got the saw out of the truck and split it lengthwise across the weld. What's inside is a) on the left intake is a 9 inch pipe with a reverse gentle 90, this balances the exhaust pipe length from the rear cylinder to the front length and directs the gas flow back towards the right side outlet, b) there's a 2 inch stub on the right side for the front cyl that dumps straight into the chamber, and on the rear exit of both sides is a 2 " stub leading to the muffler clamps.

No packing, no cat converter or baffle plates like on the VN800 and beyond. Keep in mind this was on a 2000 model.

So the pre-muffler balances the exhaust lengths and the chamber provides an early pressure reduction before the exhaust hits the muffler baffles.

We were all laughing so hard at why I was doing this in the junk yard that I forgot to take at least a phone camera pic!

Now you should be able to understand why there IS a power loss when you de-goat, and you should be able to figure out why the carb mixture will be off and near impossible to balance without fiddling with all the jets and the slide vacuum ports, and you should be able to figure out why it's not a great idea even if you add an H-pipe which won't balance the exhaust path (but that's better than just what you see in the Verses, for sure!)

Turns out the Kawasaki engineers aren't as dumb as a redneck with a hacksaw.
Glad someone finally did that. I had a pretty good idea that is how it worked, and why it was a bad idea to remove it with otherwise stock pipes. Maybe someone on here who is absolutely certain the goats belly is a bad thing and has removed theirs but still has it laying around somewhere will be nice enough to cut it open and post pictures. But from your description, it sound pretty clear how it works to me.

I have removed a lot of parts from my Vulcan, all the emissions crap, even the right front brake and the "decel" or "push" throttle cable, because IMO they were not necessary and actually counterproductive. But the goats belly stays, because I feel it is necessary to make the bike run right with stock pipes.
 

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When I first got my vn750 I took it to the dealer and had them look at it. Since then I found this forum. I guess I don't care to go any faster than the stock bike will go. If that is what you want to do that is fine. I have kept mine stock and am satisfied with it. Like you say you do as you want with yours and I will do as I want with mine. But the bike does run pretty well stock. This is a good sorce or any modifications that you may want to make as well as just keeping it running.

Mcneuby :(
My point exactly ,and you are right about them having plenty of power in stock form .I am one of those people who think good enough really never is,and do this:) not this :( ,you have good reason you have a bike,thats enough to make most:)

P.S.Sorry if I sounded harsh.
 

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It's cool to know what's inside of that thing so thanks for gutting it. Figured it was something to balance out the ex. since even though its on there, the tails of the mufflers are still staggered. Probably would be a lot more if no GB was employed. I can understand both sides of the argument to mod or leave alone. I, like Denny and many others want a little more if it can be obtained reasonably. In my case, it may be the fact that I went from a 4 cylinder GS1100 to my Vulcan. The Vulcan is quick but that GS was a rocket. And if you weren't a decent sportbike, on a straightaway... you weren't touching that thing. I was afraid of it. Stupid fast it was.
Anyway, I think both views are legit. If you're happy and you know it, leave it alone. They do perform very well without anything changed. But if you're not 100% then hey, have at some mods, what the hell. Yeah maybe there's some data that proves the life of the bike will be shortened, all be it very little I'd say if properly cared for, but if you enjoy riding it more because it's got a lil' more spunk, DO IT. Have fun with your bike, period. :smiley_th
 

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It's cool to know what's inside of that thing so thanks for gutting it. Figured it was something to balance out the ex. since even though its on there, the tails of the mufflers are still staggered. Probably would be a lot more if no GB was employed. ...
... Yeah maybe there's some data that proves the life of the bike will be shortened, all be it very little I'd say if properly cared for, but if you enjoy riding it more because it's got a lil' more spunk, DO IT. Have fun with your bike, period. :smiley_th
X2 :smiley_th

I happen to really like the stock look of my bike, including the ears, but after some recent wrenching I want to pitch all the CA crap and shave the ears just to make working on it more enjoyable. I love the way it runs bone stock and love the way it feels in the turns with the new low bars :motorcycl but all the extra tubes that do almost nothing but get in the way have got to go! I'm pretty sure my bike will run cleaner if I enjoy wrenching on it and dialing it in more often without the EPA stuff.

BTW, I like the stock exhaust and the only reason I personally think I would take the GB off would be to remove the heat source under the stock R/R location. I'm not looking for more power... yet.
 

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X2 :smiley_th

I happen to really like the stock look of my bike, including the ears, but after some recent wrenching I want to pitch all the CA crap and shave the ears just to make working on it more enjoyable. I love the way it runs bone stock and love the way it feels in the turns with the new low bars :motorcycl but all the extra tubes that do almost nothing but get in the way have got to go! I'm pretty sure my bike will run cleaner if I enjoy wrenching on it and dialing it in more often without the EPA stuff.

BTW, I like the stock exhaust and the only reason I personally think I would take the GB off would be to remove the heat source under the stock R/R location. I'm not looking for more power... yet.
I did remove all the CA evap crap and the complete air injection system form mine. But I have left the engine/intake/exhaust completely stock, other than going from ACCTs to MCCTs. I have never had any need to work on mine. I did remove the carbs twice, when I briefly installed aftermarket pipes, to rejet, then had to remove them again to change the jetting back after going back to stock pipes. Not exactly what I would call easy, but not that hard either. It seems many people try to remove and reinstall the carbs with the gas tank still in place, and that is virtually impossible. If you remove the tank, and tie the "surge tank" up so it can't keep falling down on you, you would be amazed at how easy it is to remove and reinstall the carbs. First completely remove the ducts that go from the carbs to the surge tank, then use LOTS of WD-40 on the manifolds between the carbs and the heads.
 

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Kawasaki referred to the goats belly as a "Power Chamber"... so it really was not a big mystery as to what was inside, but thanks for confermation, too bad we still have no photos..:(

Removing the GB to take heat off the R/R sounds logical.. But as it is so much easier to simply relocate the R/R compared to removing the GB it really makes no sense...as lopping off the GB will effect power output and make the bike sound like crap. :)
 

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Kawasaki referred to the goats belly as a "Power Chamber"... so it really was not a big mystery as to what was inside, but thanks for confermation, too bad we still have no photos..:(

Removing the GB to take heat off the R/R sounds logical.. But as it is so much easier to simply relocate the R/R compared to removing the GB it really makes no sense...as lopping off the GB will effect power output and make the bike sound like crap. :)
You mean we actually agree on something? Amazing.
 

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Kawasaki referred to the goats belly as a "Power Chamber"...
You are correct. The Goats Belly was never meant to be a muffler. It is there to create equal back pressure to both cylinders at a continuous RPM. Without back pressure you have straight through flow of the air and gas mixture which is power robbing. Too fast of air flow will cause the mixture to come to a fast stop of the flow in the inlet value camber when the valve closes and cause it to flow backward, then as the value opens the mixture has to change directions again to go in the cylinder. This can cause hesitation in the throttle and poor idling at lower RPMs also. All of this can cause an unsteady mixture because of the lack of intake area(mixture storage after carburetion). Rich on takeoff and turn lean at higher Rpms leading to burnt values. But to open of a tail pipe/muffler can cause a burnt or warp valve by allowing cool air to be sucked back in through the exhaust value port on deceleration. This is why a lot of guys with years of cycling miles will suggest, if you change from the stock system , go with the system that has a cross over to the right side for the rear cylinder muffler. Helps equal the cylinders through equal pipe length.

2 years of mechanic school. We built a few race engines and this is what we had drilled in our heads.
 

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Discussion Starter #13 (Edited)
Seems nine out 10 other riders disagree with you, including some of the most respected and long time posters here...but more importantly you misunderstand. I didn't say you couldn't retune, I said that that the average rider doesn't have the tools or the experience to regain the power that is lost by just chopping and using flex tube to connect the stock cans one to one. Duals, like the V&H, at least mimich the OEM back pressure and with the loop design under the bike from the rear cylinder balance the reversion waves to match the individual F/R cylinders in seperate pipes. If you want to go to extremes, you could use any of several online calculators and come up with a set of straight, unbaffled pipes that would give you the ultimate power at 8500 rpms; but I guarantee that it will suck at anything less than WOT.

Your reply seems more designed to defend an archaic point of view rather than benefit from any specific reality. That's fine, it's your ride. I just finally did what no one else has to give a factual answer as to what's really inside that chamber...no baffles, no packing, no cat converter, no diverter plenums, no screens, none of the other assumed or imagined designs.

Do with it what you want.
 

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Discussion Starter #14
Crap I don't get this blog format

Hey, my last post was aimed at a reply to Denny 6006 on the first page. Why I sometimes get a reply in the correct order and others times, yech, i dunno.

Yeah, Knifemaker, it's amazing, probably because I'm not drinking today, and hence, not looking to start a fight over trivial personal matters. Let me take this opportunity to apologize for some of my previous outbursts
 

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Kawasaki referred to the goats belly as a "Power Chamber"... so it really was not a big mystery as to what was inside, but thanks for confermation, too bad we still have no photos..:(

Removing the GB to take heat off the R/R sounds logical.. But as it is so much easier to simply relocate the R/R compared to removing the GB it really makes no sense...as lopping off the GB will effect power output and make the bike sound like crap. :)
ditto.

IMHO, the stock setup (with gb) has enough loudness to have presence (for cagers), and muffled enough for all day rides with no ear plugs required. I like to hear the engine as well as the explosions it makes.
 

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Hey, my last post was aimed at a reply to Denny 6006 on the first page. Why I sometimes get a reply in the correct order and others times, yech, i dunno.

Yeah, Knifemaker, it's amazing, probably because I'm not drinking today, and hence, not looking to start a fight over trivial personal matters. Let me take this opportunity to apologize for some of my previous outbursts
No problem Chief...;) I've been offending folks here for 7+ years....

The key to getting more power out of this ride starts with the intake anyway, no exhaust I know of makes any significant increase alone.

The stock system, upon release of this model, was called a "tuned exhaust". Contrary to most folks opinions here, there is not much you can do to improve upon it. Many just make theirs louder and somehow they think the bike is then faster....;)

You keep telling it as you see it and just try to be a little less heavy handed in your replies. Some folks here are old and stubborn, but still real nice folks....
 

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Discussion Starter #17
Intake thoughts

I've often thought the same. And researched just about every obscure article on modifying a Keihin. Since ours are a particular variant of the 34 with tilted floats and linkage, not much seems possible.

I did, however, buy a set of vertical 36mm's just for the butterflys, and then used a drill press and arbor setup to hone out the throats of a stock set of 34's and then swap butterflys.

Unfortunately, it was a botched quicky experiment. There appeared to be a vastly improved top end, but the lack of precision in my attempt resulted in a carbs that wouldn't sync or seal at idle/midrange resulting in bizarre idle and cruising problems. I just haven't revisited the issue because of other distractions.

However, sine then I've got a few new tool toys and I'm confident the machining can be done properly. Now, about finding another set of carbs to butcher...

Currently I have rejetted on the mains, modified the decel valve to eliminate the popping after cutting a baffle plate (instead of marbles) for the EPA reeds, and replaced the slide springs with faster opening tensions from the HD Sporty 40CVK's you'll find online for about $30, and increased the vacuum slide ports by .002 and keepin the idle jet at 1 5/8's out and the idle @ 1200.

Seems to be hummin much stronger above 7K without any adverse below 4K, and throttle response off the line is much improved.Yeah, I know, this could have gone on a new thread.

The FI conversion probably won't help that much more, if any, but it's like cutting open the GB, I just figure it'll be worth the learning curve.

I am considering taking the throating approach, plus building a Microsquirt controller and going FI with the 36mm boreout and spring replacement in concert.

What I need is accountability to get the project out of thought and into reality!
 

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I know many spend much time, money and thought trying to get a few more ponies out of the Vulcan. Guess it's a "because it's ther type thing...

Me, if I want more power, I find a more powerful bike. I'd rather be riding then building I guess.

You can pour a few thousand dollars into getting the bike to go faster, but still some kid on a stock R1 is going to pass you like you're sitting still. Just don't see the point making all that effort.....
 

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I know many spend much time, money and thought trying to get a few more ponies out of the Vulcan. Guess it's a "because it's ther type thing...

Me, if I want more power, I find a more powerful bike. I'd rather be riding then building I guess.

You can pour a few thousand dollars into getting the bike to go faster, but still some kid on a stock R1 is going to pass you like you're sitting still. Just don't see the point making all that effort.....
that same kid will smoke you on the FJR ;) but you are right it's about enjoying tinkering,I ride with a CBR1000 RR most of the time so I have no illusions about being faster than everything else around,I just like hurting peoples feelings with much more expensive bikes in the same type class as mine.I put almost ten thousand miles on mine this summer and I do my upgrades in the winter when there is nothing else to do,I hate working on mine when it is warm enough to ride.
 

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No problem Chief...;) I've been offending folks here for 7+ years....

The key to getting more power out of this ride starts with the intake anyway, no exhaust I know of makes any significant increase alone.

The stock system, upon release of this model, was called a "tuned exhaust". Contrary to most folks opinions here, there is not much you can do to improve upon it. Many just make theirs louder and somehow they think the bike is then faster....;)

You keep telling it as you see it and just try to be a little less heavy handed in your replies. Some folks here are old and stubborn, but still real nice folks....
I aggree with KM here Louder doesn't make faster. I like a well engineered piece of equipment. I spent my life running machines, printing presses, and a good running one was one that ran like sewing machine, quiet and smooth. I guess that is the way I like my motorcycle to run. I have enjoyed this thread. It has been a real interesting exchange of ideas. That is what I like about this forum.
Mcneuby :smiley_th
 
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