I’ve found several gpz900 exhaust. Considering the bikes are very similar would this work? I understand the radiator is further forward on the gpz900. What if a portion of the pipe near the exhaust port of the head was cut away and treeless back together to get it to fit behind the muffler. Also looking to go big bore. Widener makes zx11 pistons 1mm over bore and 12:1 compression. Can the cylinders handle 3mm over bore?
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I want a single exit exhaust
- Thread starter Motorcyclerider
- Start date
Might be possible.
The problem with cutting away material at the exhaust port is clearance at the lower/front of the case.
ie; the lower bend of the GPZ is close to the case. Removing material at the exhaust port could cause contact at the case.
Additionally, the exhaust runners on a GPZ run along the bottom of the engine. Can cause issues with the belly fairing.
Many tried using the ZX/GPZ headers. Some made it fit, but most found that the diameter of aftermarket head pipes was too large. I built a set from scratch and had the same issue.
Jim built a 4 into 1 using an Ontario lower, Delkevic muffler and Connie head pipes.
Dyno tests showed it was best with the Stock Connie head pipes worked best for torque/power.
NOTE: At 3 mm overbore I don't think you would have "any" cylinder left.
Ride safe, Ted
The problem with cutting away material at the exhaust port is clearance at the lower/front of the case.
ie; the lower bend of the GPZ is close to the case. Removing material at the exhaust port could cause contact at the case.
Additionally, the exhaust runners on a GPZ run along the bottom of the engine. Can cause issues with the belly fairing.
Many tried using the ZX/GPZ headers. Some made it fit, but most found that the diameter of aftermarket head pipes was too large. I built a set from scratch and had the same issue.
Jim built a 4 into 1 using an Ontario lower, Delkevic muffler and Connie head pipes.
Dyno tests showed it was best with the Stock Connie head pipes worked best for torque/power.
NOTE: At 3 mm overbore I don't think you would have "any" cylinder left.
Ride safe, Ted
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Not sure you know;
If all you want is a single exit exhaust, you could block off 1 of the pipes on an OEM Header and use just 1 muffler. Many have done so. As I recall, some seemed to be pretty good for torque/etc.
If you use this idea (instead of just blocking off the pipe) you can modify the block off to give better flow.
This is an early picture of the header I built 20 years ago for my C-10.
It started it's life as a stock C-10 header.
I started the project by just blocking off the right muffler, and then I got a "little" carried away.
In the end, the only original parts on the header were the "Y" pipes. (and they were modified)
NOTE: This is basically just a stock Connie system with bigger head pipes and 1 muffler has been removed.
I knew that it was not the best header design.
It was just an attempt to build something from the stock system that worked with the center stand and plastics.
My build;
I removed the stock head pipes and "tinker toyed" in larger head pipes.
I built anti-reversion venturi's for the head pipes.
I cut out the section of pipe with the block off plate and replaced it with a curved pipe.
I later rebuilt removed/rebuilt the crossover you see and made it larger with smoother flow.
I built a custom Jardine Muffler and mid pipe to fit on the left side.
I built a variable baffle for the muffler.
NOTE: Pipe ran ok, but seemed to loose torque. (prolly because of huge head pipes).
I later gave the pipe to Dave to put on his Cafe Connie.
Ride safe, Ted
PS: If you use the ZX Headers w/large head pipes, this is the head pipe layout you'll need to fit under the plastic and fan. Because of the bigger head pipes, it's VERY close.
If all you want is a single exit exhaust, you could block off 1 of the pipes on an OEM Header and use just 1 muffler. Many have done so. As I recall, some seemed to be pretty good for torque/etc.
If you use this idea (instead of just blocking off the pipe) you can modify the block off to give better flow.
This is an early picture of the header I built 20 years ago for my C-10.
It started it's life as a stock C-10 header.
I started the project by just blocking off the right muffler, and then I got a "little" carried away.
In the end, the only original parts on the header were the "Y" pipes. (and they were modified)
NOTE: This is basically just a stock Connie system with bigger head pipes and 1 muffler has been removed.
I knew that it was not the best header design.
It was just an attempt to build something from the stock system that worked with the center stand and plastics.
My build;
I removed the stock head pipes and "tinker toyed" in larger head pipes.
I built anti-reversion venturi's for the head pipes.
I cut out the section of pipe with the block off plate and replaced it with a curved pipe.
I later rebuilt removed/rebuilt the crossover you see and made it larger with smoother flow.
I built a custom Jardine Muffler and mid pipe to fit on the left side.
I built a variable baffle for the muffler.
NOTE: Pipe ran ok, but seemed to loose torque. (prolly because of huge head pipes).
I later gave the pipe to Dave to put on his Cafe Connie.
Ride safe, Ted
PS: If you use the ZX Headers w/large head pipes, this is the head pipe layout you'll need to fit under the plastic and fan. Because of the bigger head pipes, it's VERY close.
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Ted, ur picture locations are asking for an email address and password....jsuk
&&%^*&% !!!
I'll try another way.
I'll try another way.
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for me, the stitching of 3/4 on the 1/2 and too perpendicular, the flow of gases will be slowed, the ideal is to have the same lengths of tubing and a Y stitching 
Important; I am not suggesting that anyone build this.
Just posting photo's of something I tried 20 years ago.
It was basically just a stock Connie system with bigger head pipes/etc. and 1 muffler.
I knew that it was not the best header design.
It was just an attempt to build something (from the stock system) that had bigger pipes.
My target was to make it fit with the bigger pipes.
ie; The bigger head pipes had to fit under the fan and plastics, and the pipes routed so that the side and center stands could be used. I also wanted a left side muffler so that there wasn't a void behind the side stand.
Ferabern: I think you're talking about the intersection where the 2 sides (3/4 and 1/2) come together?
If so, the photo makes the connection look squarer than it actually is.
** The 3/4 pipe actually turns towards the muffler as it connects with 1/2.
Something else that isn't shown; The 3/4 pipe extends slightly "into" the 1/2 side, and it had a raised entry lip. (That lip was turned internally to make the 3/4 gasses flow downstream).
My idea was to develop a venturi. (so that the flow from 1/2 would draw in flow from 3/4)
NOTE: I built a poor-man's flow bench to try to test the venturi idea.
The venturi seemed to work.
ie; By flowing air into 1/2 I could actually pull a slight vacuum on 3/4.
Ride safe, Ted
Just posting photo's of something I tried 20 years ago.
It was basically just a stock Connie system with bigger head pipes/etc. and 1 muffler.
I knew that it was not the best header design.
It was just an attempt to build something (from the stock system) that had bigger pipes.
My target was to make it fit with the bigger pipes.
ie; The bigger head pipes had to fit under the fan and plastics, and the pipes routed so that the side and center stands could be used. I also wanted a left side muffler so that there wasn't a void behind the side stand.
Ferabern: I think you're talking about the intersection where the 2 sides (3/4 and 1/2) come together?
If so, the photo makes the connection look squarer than it actually is.
** The 3/4 pipe actually turns towards the muffler as it connects with 1/2.
Something else that isn't shown; The 3/4 pipe extends slightly "into" the 1/2 side, and it had a raised entry lip. (That lip was turned internally to make the 3/4 gasses flow downstream).
My idea was to develop a venturi. (so that the flow from 1/2 would draw in flow from 3/4)
NOTE: I built a poor-man's flow bench to try to test the venturi idea.
The venturi seemed to work.
ie; By flowing air into 1/2 I could actually pull a slight vacuum on 3/4.
Ride safe, Ted
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The photo's I posted are not the finished product. They were taken at an early stage of the project.
After those photo's; The entire crossover and 2/3-3/4 intersection was cut out and rebuilt.
Here is another angle of the early intersection.
After those photo's; The entire crossover and 2/3-3/4 intersection was cut out and rebuilt.
Here is another angle of the early intersection.
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I can't tell you much about the bike.
A friend/Dave built it, and he did a great job.
I just supplied the headers and muffler.
I do know that the gas tank is from a GPZ-900 or 1000.
I posted the photo to show how close the fit is with the big head pipes.
There isn't much room.
Ride safe, Ted
PS: After I did mine, Jim Snyder built an exhaust system.
It used GPZ-900/1000 (Ontario) header "lowers" and stock C-10 head pipes.
It had a right side (Delkevic) muffler with a short mid pipe.
It did not work with the center stand, but the Ontario lowers were easily removable when he wanted to use his center stand for maintenance.
I think he called his invention the "Contario" exhaust system.
It was really impressive on dyno tests. (smooth torquey flow)
** If anyone wants to build such a system, I have all the parts (including muffler) needed to build a copy of Jim's and he has the knowledge to give us details on how to do it. (Thinking about selling)
I think that the only welding that is required is to weld the C-10 head Pipes into the Ontario Mid-section.
NOTE: Careful fitting and aligning is needed before that weld.
** Yoo hoo; Jim, are you out there?
A friend/Dave built it, and he did a great job.
I just supplied the headers and muffler.
I do know that the gas tank is from a GPZ-900 or 1000.
I posted the photo to show how close the fit is with the big head pipes.
There isn't much room.
Ride safe, Ted
PS: After I did mine, Jim Snyder built an exhaust system.
It used GPZ-900/1000 (Ontario) header "lowers" and stock C-10 head pipes.
It had a right side (Delkevic) muffler with a short mid pipe.
It did not work with the center stand, but the Ontario lowers were easily removable when he wanted to use his center stand for maintenance.
I think he called his invention the "Contario" exhaust system.
It was really impressive on dyno tests. (smooth torquey flow)
** If anyone wants to build such a system, I have all the parts (including muffler) needed to build a copy of Jim's and he has the knowledge to give us details on how to do it. (Thinking about selling)
I think that the only welding that is required is to weld the C-10 head Pipes into the Ontario Mid-section.
NOTE: Careful fitting and aligning is needed before that weld.
** Yoo hoo; Jim, are you out there?
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like that, this one was made for a 4 x 4 Toyota if I remember well, there are also about twenty years
by the way, basically my job was Boilermaker
by the way, basically my job was Boilermaker
Yes Ted I'm here. Ok here goes. The biggest issue in building a 4 into 1 system is finding headpipes that clear the radiator. The stock C-10 headlines were the only ones that did without and modifications. I experimented with larger diameter headlines but they killed the low end and that's where 90% of our riding power is.
So stock headlines, then find a midpipe that doesn't block the oil filter. Most older Kawasaki headers like the GPZ900 pipes go right under the oil pan and block access to the filter and drain plugs. The mid pipe I used was from an 89-92 ZX10 pipe made by the Ontario exhaust company. Hence the name for my invention, Connie headpipes/Ontario midpipe, hence CON-TARIO. They were different than anything else I tried (and trust me I tried ALOT of different configurations). The end result was amazing. It clearly he oil filter and since I made the midpipe to simply slip on, I could remove it for maintenace and cleaning. I did dyno runs on the pipe after I settled on the Delkevic carbon fiber muffler (18") and the bike made 3 to 4 more horsepower but the real kicker was almost 5lbs more torque.
All C-10 motors have a torque dip around 4 to 5 thousand rpm. My pipe made a smooth torque curve all the way thru the rpm range with no dip. Here is a picture of my famous "Contario" exhaust. But if you decide to build one, patience is a must.
So stock headlines, then find a midpipe that doesn't block the oil filter. Most older Kawasaki headers like the GPZ900 pipes go right under the oil pan and block access to the filter and drain plugs. The mid pipe I used was from an 89-92 ZX10 pipe made by the Ontario exhaust company. Hence the name for my invention, Connie headpipes/Ontario midpipe, hence CON-TARIO. They were different than anything else I tried (and trust me I tried ALOT of different configurations). The end result was amazing. It clearly he oil filter and since I made the midpipe to simply slip on, I could remove it for maintenace and cleaning. I did dyno runs on the pipe after I settled on the Delkevic carbon fiber muffler (18") and the bike made 3 to 4 more horsepower but the real kicker was almost 5lbs more torque.
All C-10 motors have a torque dip around 4 to 5 thousand rpm. My pipe made a smooth torque curve all the way thru the rpm range with no dip. Here is a picture of my famous "Contario" exhaust. But if you decide to build one, patience is a must.
Attachments
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C'est vrai qu'un 4 en 1 donne beaucoup plus de couple, j'en ai un sur le side-car et c'est vraiment le jour et la nuit avec le GTR solo, le 1000 GPZ RX et équipé en plus d'un 4 en 1
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(Ferabern) It's true that a 4 in 1 gives much more torque, I have one on the sidecar and it's really day and night with the GTR solo, the 1000 GPZ RX and equipped in addition to a 4 in 1..
I agree that the powerband is better.
Torque vs Peak power is dependent on the header and 4 into 1 design that you use.
Ride safe, Ted
PS: What headers do you have on yours?
I agree that the powerband is better.
Torque vs Peak power is dependent on the header and 4 into 1 design that you use.
Ride safe, Ted
PS: What headers do you have on yours?
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I do not know the brand of the line, the silencer is a Devil, the whole was on it when I got it, I made myself a exit chicane before being angry with the neighborhood.
for the sidecar it’s the same design but left out to avoid odors in the basket, by cons I made a silencer, it was really too noisy and I ride much more with
engine outlet tubes
-Outside diameter 37 mm for GPZ.
-Outside diameter 31 mm for Solo.
-Outer diameter 31 mm for the sidecar.
for the sidecar it’s the same design but left out to avoid odors in the basket, by cons I made a silencer, it was really too noisy and I ride much more with
engine outlet tubes
-Outside diameter 37 mm for GPZ.
-Outside diameter 31 mm for Solo.
-Outer diameter 31 mm for the sidecar.
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I’m not building the typical Connie. I’m trying to make for peak power 5k-11k. I’ve been fairly successful so far and plan to add the zl900 bevel drive to make it easier to access the high rpm. I see the issues though with oil filters etc. I’m just thinking if the ninja 1000 which cams and carb size I’m running had larger head pipes I’d probably benefit from that. It’s just the issue of making everything fit under the fairings like you mentioned.
Maybe with the 17” front wheel I can get the radiator a smidge more forward to help them fit.
Motorcyclerider, haven't seen any postings from you in awhile. (??)
We're working on one of these systems.
We're working on one of these systems.
Wait a minute.... someone turbo'd a Connie?!? Is there a writeup somewhere?!?
-x01660
Look closely at the photo.
(In addition to the Turbo and FI) Different suspension, different brakes, different motor, etc, etc, etc..
There is more Engineering/tinkering in Rev's bike that you can possibly imagine!
Ride safe, Ted
(In addition to the Turbo and FI) Different suspension, different brakes, different motor, etc, etc, etc..
There is more Engineering/tinkering in Rev's bike that you can possibly imagine!
Ride safe, Ted
LOL!! Yeah.... Just noticed that. Maybe I'll just get an H2 SX and call it a day!!
-x01660