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BW header - getting your torque back

Steve in sunny Fla

Iron Butt
Industry Vendor
Being that the Black Widow header is smaller pipe diameter that the Delk or the Area P, it naturally has better low rpm power. Still, it can be better and surprisingly, adding the exhaust reducer actually made more peak power on the test bike I worked on. Again, easily done with parts you can find at any auto parts store.

You will need an exhaust reducer from the local parts store, measuring 2" ID on the entrance side and 1.75" OD (yields 1.625" ID) or 1.5" ID on the exit side.
Some examples: Nickson #17516, AP# 8936 or 8923 ; this is 2"ID to 1.75" OD (1.625" ID)
Nickson 17506, AP# 8922; this is 2" ID to 1.5" ID
Either size will work, if you have a fear of losing top end with the 1.5" reducer use the 1.625" ID reducer. If you want the most low end, use the 1.5" reducer.

You will need to shorten the adapter by cutting and removing most of the large diameter portion of the adapter. Your cut should be just above where the reducer starts necking down. After you cut, clean the cut and do an internal bevel on the leading edge, to ease the flow transition.

Now remove the midpipe and slide the reducer down until it bottoms on the midpipe's flare, where the midpipe reduces to 2". The reducer will be held in place by the header collector when you slide the midpipe back onto the header section. If you need to slide the colleector in a little more to make a little room for the header, shorten the large diameter again, but remember the flared area of the adapter mated to the flared area of the midpipe is what's holding the adapter from sliding down the midpipe. If you feel the adapter is to lose, you can use a hammer and punch. Punch 2-3 small divots from the inside of the largest portion of the adapter outward to tighten it against the midpipe.

Reassemble the midpipe and muffler onto your bike and go try it out. Post up and let folks know what you think!

I will attach the dyno charts from before and after with the 1.625" reducer. This particular bike is low miles, tight, and doesn't give up good top end, but you can see the adapter helped everywhere in the power curve.

Steve
 

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I installed the 1.625 reducer last night and just have my ride home from work, 36* - 41* and my ride back in to work, 28* - 34* so far.

33 miles one way, 90% highway and what I noticed so far is a nice increase in throttle response in the lower to mid rpm's, what feels like a stronger pull when accelerating in 6th gear at highway speeds and less popping in the exhaust on deceleration. The overall sound of the exhaust has also gotten quieter which will make me less noticeable around town.

I will probably try the 1.5 reducer when the weather gets warmer, but so far, I like the way the bike feels now.
 
I installed the 1.625 reducer last night and just have my ride home from work, 36* - 41* and my ride back in to work, 28* - 34* so far.

33 miles one way, 90% highway and what I noticed so far is a nice increase in throttle response in the lower to mid rpm's, what feels like a stronger pull when accelerating in 6th gear at highway speeds and less popping in the exhaust on deceleration. The overall sound of the exhaust has also gotten quieter which will make me less noticeable around town.

I will probably try the 1.5 reducer when the weather gets warmer, but so far, I like the way the bike feels now.

Interesting. Good feedback. Thx for sharing! Wonder how it compares with the stock header + ECU flash + slip-on.
 
I installed the 1.625 reducer last night and just have my ride home from work, 36* - 41* and my ride back in to work, 28* - 34* so far.

33 miles one way, 90% highway and what I noticed so far is a nice increase in throttle response in the lower to mid rpm's, what feels like a stronger pull when accelerating in 6th gear at highway speeds and less popping in the exhaust on deceleration. The overall sound of the exhaust has also gotten quieter which will make me less noticeable around town.

I will probably try the 1.5 reducer when the weather gets warmer, but so far, I like the way the bike feels now
Joe do you visit the higher RPM region often? If so before reducing further would be interested to see if you have any sense of any difference at all?
I know Steve said the higher RPMs is not where this modification is targeting but curious if you noticed anything?
Then Joe where did you mount your reducer?
 
Interesting. Good feedback. Thx for sharing! Wonder how it compares with the stock header + ECU flash + slip-on.
Ask, and you shall receive!

This is the same bike:
RED is stock header, my flash, 2 brothers slip on muffler;
BLUE is BW header, my flash, 2 brothers header, 1.625" restrictor;
GREEN is BW header, my flash, 2 brothers header.

NOTES: Clearly the stock header is GREAT below about 5500 rpm. Best you're going to get overall. The dip at 5000 with the BW header is due to the lack of balance tubes and can't be tuned out. TOP END power... HMMM. Where is it? I expected the header to pick up about 6 more hp on top. Not seeing it. I did dozens of runs, changing all kinds of tuning parameters. Never better that what you see here. I need another bike with a BW header to thrash, but based on the dyno runs in the you tube video, it looks like the BW header isn't adding much at the 9000 rpm point. People can talk, but dyno's don't lie.

Steve
 

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Ask, and you shall receive!

...based on the dyno runs in the you tube video, it looks like the BW header isn't adding much at the 9000 rpm point. People can talk, but dyno's don't lie.

Steve

Thanks Steve! This is all I needed to know in making up my mind about keeping my stock header. No need for a replacement as I'm not working to reduce the weight of the bike or eliminate the cats.

I'm very happy with how my machine runs right now. I've got more power than I need, and frankly I'm glad to have the traction control. Last weekend when we were out in the cold (on a closed track of course) I got a little frisky and turned it off. When I pulled hard in 2nd through 4th gears I was breaking traction right away, even with fresh rubber.

So my limits have been tested and I got the thrill I wanted without overdoing / breaking anything. LOL

I'll put the $'s into a radiator guard and front/rear fender extenders instead. If I want anything spicier I'll get an H2 and do the flash on it. :^ ) AB
 
WOW, good job on the discovery and data.

I see on the Shoodabeen Engineering site the AreaP FE is helping engine way out perform machine with the BW FE at the least on the top end and WOT.

Have not mounted reducer yet, on the list. Interesting to see some day similar data for the AreaP as provided here on the BW with and without reducer; I know can’t have everything and a stew cooked too fast just isn’t as good…. Great work.
 
Thanks Steve! This is all I needed to know in making up my mind about keeping my stock header. No need for a replacement as I'm not working to reduce the weight of the bike or eliminate the cats.

I'm very happy with how my machine runs right now. I've got more power than I need, and frankly I'm glad to have the traction control. Last weekend when we were out in the cold (on a closed track of course) I got a little frisky and turned it off. When I pulled hard in 2nd through 4th gears I was breaking traction right away, even with fresh rubber.

So my limits have been tested and I got the thrill I wanted without overdoing / breaking anything. LOL

I'll put the $'s into a radiator guard and front/rear fender extenders instead. If I want anything spicier I'll get an H2 and do the flash on it. :^ ) AB
You gave Ted hell I heard... since he's the current roll on big dog (or so it seems) it doesn't look like you need much more unless you're trying to "make a statement". ;);)

Steve
 
You gave Ted hell I heard... since he's the current roll on big dog (or so it seems) it doesn't look like you need much more unless you're trying to "make a statement". ;);)

Steve

Right on, that does seem to be the case Steve. Without a turbo kit or nitrous we're about at the peak performance based on the mapping and muffler. The MRP absolutely rocks! 😁

BTW, with my rear suspension cranked down 14 clicks in (fairly tight but not rock hard) I pulled my first wheelie with this big girl while rolling-on. Wasn't even trying, just gave it a WOT yank and up went the front end until traction control kicked in and cut my fuel. 🤩

I can't ride around like that all the time so I've had to soften it up by setting it back to only 7 clicks for rear suspension tension. Ted and I adjusted my front fork ride height too when he was here, which now has me interested in getting my suspension professionally tuned for my typical 70/30 riding style. 70% cruising, 30% "spirited riding". 😉

I'm ready to roll-on (in Mexico of course) with anyone in the Houston area who wants to test out their new upgrade. :^ ) AB
 
Joe do you visit the higher RPM region often? If so before reducing further would be interested to see if you have any sense of any difference at all?
I know Steve said the higher RPMs is not where this modification is targeting but curious if you noticed anything?
Then Joe where did you mount your reducer?
No, I don't go into the upper rpm's that often, that's why I removed the full Muzzy exhaust last spring. (and to quite the bike down some, the Muzzy was LOUD) I'll play with it a whole lot more with some visits to red line before I swap the reducer to the smaller one.

Putting the reducer in is super simple. Loosen the clamp at the mid-pipe to header connection, remove the nut and bolt at the muffler hanger and remove the slip-on and mid-pipe as one piece. Cut the reducer back to just where it becomes it's larger size (2" for the BW) and slip it into the front of the mid-pipe where it slips over the header, small end first. I cut mine a little after where it reaches it's larger size (can't cut it back if you cut it too small) and used a belt sander to take it back evenly until it just fit inside the flared end of the mid-pipe and then filed an angle on the edge of the reducer where it will meet the header. Slip the modified reducer into the front of the mid-pipe, slip the mid-pipe and slip-on back onto the header, put the nut and bolt back at the muffler hanger and tighten up the clamp on the mid-pipe to header connection and fire it up.

I used a sharpie to mark the mid-pipe to header connection so I could put it back in the same position it came off from.

Joe C

Here is a picture of the 2" to 1.5" reducer after cutting it down. From here I'll sand the top edge back to where it just fits into the flared end of the mid-pipe.
 

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@turbojoe78 Thank You for sharing.

I should have some results to share as well shortly.

Note on RPM impact - I do not hit the rev limiter but run to >9K RPM often, arms are stretched longer and brain sits a little further back in my cranium.

My riding habits are for pure fun and adrenaline and lucky to have my wife with same mindset.
 
Ask, and you shall receive!

This is the same bike:
RED is stock header, my flash, 2 brothers slip on muffler;
BLUE is BW header, my flash, 2 brothers header, 1.625" restrictor;
GREEN is BW header, my flash, 2 brothers header.

NOTES: Clearly the stock header is GREAT below about 5500 rpm. Best you're going to get overall. The dip at 5000 with the BW header is due to the lack of balance tubes and can't be tuned out. TOP END power... HMMM. Where is it? I expected the header to pick up about 6 more hp on top. Not seeing it. I did dozens of runs, changing all kinds of tuning parameters. Never better that what you see here. I need another bike with a BW header to thrash, but based on the dyno runs in the you tube video, it looks like the BW header isn't adding much at the 9000 rpm point. People can talk, but dyno's don't lie.

Steve
Steve , is the BW header a true Tri Y ? I’m interested in this dip at 5 grand the reason of the Tri Y is too boost torque by boosting or maintaining velocity of one tube rushing past the other, Usally see a dip like that with race four into ones with no balance tubes but the OEMs added them to boost torque by using positive and negative pressure waves alternating in the pipe. Back in the old days four into ones caused an over Rich mixture at around 4500 do to positive waves traveling back up, got off track.. back to the Tri Y. Collector Diameter is based on primary tube size, a large collector make more torque below peak and smaller above peak. What about collector length ?
 
Y
Steve , is the BW header a true Tri Y ? I’m interested in this dip at 5 grand the reason of the Tri Y is too boost torque by boosting or maintaining velocity of one tube rushing past the other, Usally see a dip like that with race four into ones with no balance tubes but the OEMs added them to boost torque by using positive and negative pressure waves alternating in the pipe. Back in the old days four into ones caused an over Rich mixture at around 4500 do to positive waves traveling back up, got off track.. back to the Tri Y. Collector Diameter is based on primary tube size, a large collector make more torque below peak and smaller above peak. What about collector length ?
Yes, it's a true tri-Y. So is the stock header. The stock header has 1/8" smaller head pipes, balance tubes, and catalytic converters between the initial set of Y's and the last set. I feel like you do, the tri-Y shouldn't have the dip, but it does. My versys 1000 with the black widow header does the same thing. It can't be tuned out. Again, if you look at the other dyno chart I posted in the roll-on thread with tuning from 2 other different tuners, the dip is still there. These are budget pipes, nobody tried different sizes and locations for the Y's. Even the AreaP header shows the same exact dip. Surprisingly it's not as pronounced on the Delkevic header which is a takeoff of the zx14r stock header. It looks like a 4 into 1, but there's actually a bifurcating plate in the collector that effectively makes an internal tri-Y. The issue with that pipe is that the head pipe diameter is big for the zg application, but it does respond favorably to the exhaust reducer nozzle I'm talking about on this thread.
Steve
 
yes, I believe so.
 

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Y

Yes, it's a true tri-Y. So is the stock header. The stock header has 1/8" smaller head pipes, balance tubes, and catalytic converters between the initial set of Y's and the last set. I feel like you do, the tri-Y shouldn't have the dip, but it does. My versys 1000 with the black widow header does the same thing. It can't be tuned out. Again, if you look at the other dyno chart I posted in the roll-on thread with tuning from 2 other different tuners, the dip is still there. These are budget pipes, nobody tried different sizes and locations for the Y's. Even the AreaP header shows the same exact dip. Surprisingly it's not as pronounced on the Delkevic header which is a takeoff of the zx14r stock header. It looks like a 4 into 1, but there's actually a bifurcating plate in the collector that effectively makes an internal tri-Y. The issue with that pipe is that the head pipe diameter is big for the zg application, but it does respond favorably to the exhaust reducer nozzle I'm talking about on this thread.
Steve
Steve, going to follow this it’s interesting yea that dip has me thinking of the of engine internals. Tried to find camshaft specs for the ZG motor and asked a friend if he can obtain them. I do have my cams out and can measure if we can’t come up with them. Really strange how Kawasaki reduced the one thing that builds power. Higher compression does three things
Extract more energy from the combustion process
Allows the same combustion temperature to be achieved with less fuel
Longer expansion cycle leads to more power.
The three things above equals torque and HP and Kawasaki builds it with 10.1 I really feel there is a lot left on the table not increasing compression a full two points but with out knowing camshaft specs I don’t know if fitting 12.1 ZX14R pistons what the outcome would be, and it’s not like the Busa where you can pull the head and cylinders and change them. The stock head gasket is .021 Cometic makes .018. Might be worth a try right ? You won’t get a full two points but enough for a Dyno to measure especially if the squish is corrected, But if Kawasaki was striving for fuel efficiency and torque Something is not adding up with the ZG engine compared to the Efficiency of the ZX, fuel mileage wise there both mid upper thirty’s what missing Steve ? Hopefully you don’t feel I hijacked your thread
 
Steve, going to follow this it’s interesting yea that dip has me thinking of the of engine internals. Tried to find camshaft specs for the ZG motor and asked a friend if he can obtain them. I do have my cams out and can measure if we can’t come up with them. Really strange how Kawasaki reduced the one thing that builds power. Higher compression does three things
Extract more energy from the combustion process
Allows the same combustion temperature to be achieved with less fuel
Longer expansion cycle leads to more power.
The three things above equals torque and HP and Kawasaki builds it with 10.1 I really feel there is a lot left on the table not increasing compression a full two points but with out knowing camshaft specs I don’t know if fitting 12.1 ZX14R pistons what the outcome would be, and it’s not like the Busa where you can pull the head and cylinders and change them. The stock head gasket is .021 Cometic makes .018. Might be worth a try right ? You won’t get a full two points but enough for a Dyno to measure especially if the squish is corrected, But if Kawasaki was striving for fuel efficiency and torque Something is not adding up with the ZG engine compared to the Efficiency of the ZX, fuel mileage wise there both mid upper thirty’s what missing Steve ? Hopefully you don’t feel I hijacked your thread

This is common for what kawasaki does, and has done in the model line since the zg1000 / zx1000 came out in 1986. I'm not going into it because it is a full on hijack. You might want to post a thread comparing zg and zx, and why kawasaki made the choices they did in the c-14 section, and see what comes of it.

My intention is not to build a shaft drive zx, and almost no zg owner will ever change the cylinder head, in fact most won't even do valve adjustments.

Steve
 
I don’t know if fitting 12.1 ZX14R pistons what the outcome would be.

{If my memory is correct} (??) the Turbo guys tried installing the ZX Pistons.
I think the wrist pin was in a different location than the ZG Piston's.
 
I don’t know if fitting 12.1 ZX14R pistons what the outcome would be.

{If my memory is correct} (??) the Turbo guys tried installing the ZX Pistons.
I think the wrist pin was in a different location than the ZG Piston's.
Ted, he's talking about installing the reducer, not pistons.

MAVERICK - install the reducer with the 1.625 ID, that's the one I used and posted the dyno charts from. Steve
 
I think the wrist pin was in a different location than the ZG Piston's.
Zg1400 and zx14r pistons are dimensionally the same. Except for the added (not removed) material on the top. The 14r pistons are forged, zg pistons are cast. I have a set in pristine condition and have tried them in a zg block. Perfect fit, both diameter and deck height. Valve pockets are the same.

So they would fit and function just fine with the proper tune.
 
I mentioned the ZX Pistons as a reply to Jeff, who said something about installing them.
(At the time I didn't pick up that he said ZX-14R.)
I just recall that the guys who initially installed Turbo's in their Connies all broke pistons and were unable to us the (forged) ZX Pistons.
Thought it weas wristpin location but may have been too high of compression.

But ya'll have confused me.
I know that the ZG/Connie and the ZX-14 are 1352 cc's, and the ZX-14R is 1441cc's.
So I don't see how the ZX-14R piston can be dimensionally the same as a ZG Piston?
If it is, (to get 1441 cc's) they had to increase the stroke in a 14R and change the deck height or use a short rod?

Ride safe, Ted

PS: Getting back to Reducers;
I now have a reducer installed in one side of my ZX-14 header and I removed the reducer from the other side.
 
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just cut mine. 93mm total length. I cut off 33mm
 

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got me locked on 12's🥺
0300-1500
all I want when I get off is booze. try to install x-mas eve. stayed tuned....
 
installed. I like the two brothers midpipe verses black widow as it has a bracket for stock mount and the can mount.lack widow only does can mount
1. loosen remove all bolts, loosen collector clamp
2. insert reducer, small size first(I had 10mm hanging out)
3. clean midpipe while ya have it off
4. reinstall, have a beer
 

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something doesn't look right... the pic where you're installing the reducer looks like you're installing it so the small end is toward the engine. Am I seeing something wrong?

You are installing this where the midpipe connects to the header, correct?

you should be installing it so the smaller diameter of the reducer is towards the muffler, not the engine.

Steve
 
Sounds like a plan. I'd like to ride with you someday. (y)
I'll wait for you at the stop light. 🤠
I'll be the guy on a RED Connie.

Ride safe, Ted

PS: Please refresh my old memory. Which header did you install the reducer in?
(Thinking, it's the BW).
 
are you joking with me ted? this thread is all about Black Widow only😉
did the red go to your head?
anyways guys I think I got it right this time
 

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I asked because I thought you had multiple headers from which to choose, and I wasn't completely sure of your final decision.
I'll be happy to see you zoom by.
Will give me an excuse to look for more Powah!

Ride safe, Ted
 
I asked because I thought you had multiple headers from which to choose, and I wasn't completely sure of your final decision.
I'll be happy to see you zoom by.
Will give me an excuse to look for more Powah!

Ride safe, Ted
I just have a stock header and the BW.
 
Weather’s been crappy around here plus I’ve been working on the dorsoduro. i broke the the fly by wire throttle assembly trying to put on hot grips. it kept triggering a urgent service alarm. took 2 weeks to find right plugs and software to read fault code. i have used one coming from ebay
 
Weather’s been crappy around here plus I’ve been working on the dorsoduro. i broke the the fly by wire throttle assembly trying to put on hot grips. it kept triggering a urgent service alarm. took 2 weeks to find right plugs and software to read fault code. i have used one coming from ebay


 
I read it all, and Ted's never-ending roll-on thread lol.

As a newbie to this stuff (I only know how to break frames better than anyone) but, this is what I have learned from the above-mentioned threads.

1) ANY aftermarket slip-on exhaust is going to give you a solid boost in performance.
2) An ECU flash will also give you another substantial performance gain and overall better drivability of this bike.
3) The BW header system is a nice exhaust system, but it only adds minute performance over line 1, which is debatable when comparing apples to apples.
4) The Area P header and Delkevic header DOES add measurable performance in the 5,000 and up RPM's but loses some below 5,000 RPM.
5) The "velocity nozzle" (better patent that or might get stolen...jkjk) is a legit add on to improve the properties of any aftermarket headers.
6) @maverick9611 has a BW exhaust system and has added the 1.5 Velocity nozzle and we are waiting to see his seat of the pants observations.

If any of these statements are off, please clarify

just trying to keep my headstill.
 
I read it all, and Ted's never-ending roll-on thread lol.

As a newbie to this stuff (I only know how to break frames better than anyone) but, this is what I have learned from the above-mentioned threads.

1) ANY aftermarket slip-on exhaust is going to give you a solid boost in performance.
2) An ECU flash will also give you another substantial performance gain and overall better drivability of this bike.
3) The BW header system is a nice exhaust system, but it only adds minute performance over line 1, which is debatable when comparing apples to apples.
4) The Area P header and Delkevic header DOES add measurable performance in the 5,000 and up RPM's but loses some below 5,000 RPM.
5) The "velocity nozzle" (better patent that or might get stolen...jkjk) is a legit add on to improve the properties of any aftermarket headers.
6) @maverick9611 has a BW exhaust system and has added the 1.5 Velocity nozzle and we are waiting to see his seat of the pants observations.

If any of these statements are off, please clarify

just trying to keep my headstill.
I disagree with #1, I have never seen a slipon allow more than a 3 hp gain of a concours with a stock header.
I disagree with #2, the ECU flash gives more torque gains from 5k down than any other non forced induction modification.
I disagree with # 3, the BW header gives a nice 6-7 hp gain through the midrange, and doesn't snuff light throttle response where people actually ride.

Steve
 
finally guys! I head to the mountains on the 14th for a overnighter. gonna pick up blue ridge parkway at pisgah section(us276) and ride it to cherokee. stay overnight, might do wheels thru time in maggie valley and head back to augusta.
 

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finally guys! I head to the mountains on the 14th for a overnighter. gonna pick up blue ridge parkway at pisgah section(us276) and ride it to cherokee. stay overnight, might do wheels thru time in maggie valley and head back to augusta.

Which tires are you running this spring? Are those Avons? I just mounted RS III in front and RS II on the rear. Hoping to get more than 5k miles out of them. Will see how good they last. Next set I may try the Metzler Z8 as they're supposed to have the new silica formula that gives great highway mileage while staying sticking for carving.

Ride safe. Send pics and/or vids if you can. Cheers, AB
 
How did a Convo about a header turn into a tire thread?
What kind of oil do you recommend?😄

Personally, and I know this may seem strange to say, but my preference is always oil that comes in a sealed bottle of some sort. Usually has a sticker on the front that shows a motorcycle in one of the corners, but not always. LOLOLOL

That’s the best kind. What kind of blinker fluid do you recommend? 🤣😂
 
Personally, and I know this may seem strange to say, but my preference is always oil that comes in a sealed bottle of some sort. Usually has a sticker on the front that shows a motorcycle in one of the corners, but not always. LOLOLOL

That’s the best kind. What kind of blinker fluid do you recommend? 🤣😂
Blinkers? I don't need em. I know where I'm going😄
 
Sorry Steve, got carried away mi amigo. Looking forward to hearing from Maverick about his experience with the reducer. He's finally getting the C14 out to see how it runs. My curiosity about what skins I saw on it got the best of me... mea culpa.
 
Getting back to getting your Torque back.
I didn't want it back. I wanted Mooooorrrrrreeeee!

So, {for a torque test} I previously installed 2 restrictors in my ZX-14 dual muffler system.
I noticed immediately that something wasn't exactly right. Bike felt strange. Seemed to hesitate slightly.
Later did a Roll On, and the bike had lost a bit of low-end snap.

After that I removed 1 of the reducers.

Until this weekend, I hadn't got to try it out with 1 reducer.
I went to the Texas Hill Country this weekend. (y)
That annoying (something wasn't exactly right) feeling wasn't there.
Power was instant, smooth, and torque was great..
I LIKED it!!
I did not do any Roll-on's, but I'm waiting for a certain buddy to do a roll on comparison.

More later, Ride safe, Ted
 
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This mod works as advertised.. Im running an 09 with the mountain runner 89 flash and BW full system. I opted for the 18" oval can and while it sounded great was a bit loud leaving for work early am. Was very surprised there was a noticeable drop in noise with this insert along with the bump in throttle response everywhere. Sounds perfect tone and volume wise now! I am running the 1.65 or 1 5/8 id larger insert by the way
 
Getting back to getting your Torque back.
I didn't want it back. I wanted Mooooorrrrrreeeee!

So, {for a torque test} I previously installed 2 restrictors in my ZX-14 dual muffler system.
I noticed immediately that something wasn't exactly right. Bike felt strange. Seemed to hesitate slightly.
Later did a Roll On, and the bike had lost a bit of low-end snap.

After that I removed 1 of the reducers.

Until this weekend, I hadn't got to try it out with 1 reducer.
I went to the Texas Hill Country this weekend. (y)
That annoying (something wasn't exactly right) feeling wasn't there.
Power was instant, smooth, and torque was great..
I LIKED it!!
I did not do any Roll-on's, but I'm waiting for a certain buddy to do a roll on comparison.

More later, Ride safe, Ted
Ride report;
Me and texas.devops went to Mexico yesterday and did some Roll-on Test's.
After Steve came up with the idea for a restrictor in a Delk or Black Widow system, I decided to do this on a dual muffler system to see if the reducer idea would do anything. I wasn't sure, and Steve wondered too.
(Quick answer. It does, and can be used to tune your torque curve). See below.
,,With no restrictor's, the bikes were basically even with neither pulling away at low/mid rpm's. (bike seemed a little abrupt at lower throttle openings)
,,With 2 restrictor's, his bike pulled away slightly at low/mid rpm's. (bike seemed to hesitate at lower throttle openings)
,,With 1 restrictor, my bike now pull's away slightly at low/mid rpm's. (bike feels really smooth at lower throttle openings)

NOTE: Texas and I have 2 bikes that are very close to one another in performance. At high RPM's their even.
ie; (The restrictors changed high RPM power very little. (If at all)
Because we have such closely matched bikes, we are able to "see" what is happening.
If you don't have another (closely powered) bike to compare with, it all comes down to your Butt Dyno and Butt Dyno's lie!

That said: A Butt Dyno does tell you differences.....
When I installed 2 restrictors, I could "feel" that something wasn't right.
Removing 1 of the restrictor's, the "feel" was noticeably better.
I'm NOT talking about the feel at WOT.
,,, I'm talking about partial throttle/low RPM torque.
And I'm also NOT talking about huge HP improvements.
,,, This modification doesn't do that. It works to improve/fine tune the torque curve.


More tests to follow...
{That is, "If" I can decide what we want to do next}.
"Suggestions"?

Ride safe, Ted
 
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Right on Ted, was a nice ride yesterday! A little windy but otherwise the temp was perfect with clear blue skies in Mexico.

Just for clarification on the above write-up:
I'm running a stock header with a Black Widow midpipe and de-baffled slip-on.
Ted has the ZX14 4-into-2 header with two de-baffled cans... I believe his header is without a crossover.
We've both had our ECUs flashed with the MRP from @SISF (Steve @ Shoodaben Engineering).

Rolling starts from roughly 2k to 2.5k RPM in 3rd gear on each pull. 1st run I was late on the launch and didn't pull wide open right away (I checked mirrors as we were getting started), which let Ted pull ahead by a bike length... but he didn't get away. I actually started pulling up on him before we let off just shy of 10k RPM.

2nd run Ted was a bit late on the launch and I pulled out front half a length, but then he caught up between 6-8k RPM until we got to the top of the power band at which time I started to gradually pull ahead a little before we let off right at 10k. From about 3k-5k he was a bit more torquish with his setup, so there's a noticeable improvement with only one insert compared to last year when we ran without the restrictors and when we ran with two restrictors in his pipes.

3rd run was really well timed, and we stayed neck-and-neck up through the range with his bike just ever so slightly tugging a few feet ahead again in the 3k-5k range until we got toward 8k-9k and I slowly crept back before we let off.

All in all it was a clear improvement over his original double-restrictor setup we tested late last year. After we were done we talked about him switching the restrictor to the other pipe to see if he gains or losses any torque on the other side, not being sure if there is a side that will make a difference in performance.

On the way back home we stopped for a beverage and reminisced about the old days when RC Cola was a big deal. :^ ) A good time was had! Check out Ted smiling from ear to ear...
Ted & Co.jpg
 
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well guys my route just got changed. blu ridge parkway shut down till the 16th. i will do loop b and head west , prob do ga180 and 60/68 to tellico plains and hit cherohala skyway back to cherokee
still leaving 4/14 in the morn
picture uploader
 
will pick up 180 from helen side ga17 and take it all the way to ga60 at wheels/suches side. 180 doesn't get good until ya cross 129/19, this will be good area to check the reducer. then i head north
 
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I like 17, it's quite good. But if you're not aware of the Richard Russell, 348, Hog Pen Gap rd (all one in the same). You really should try it. Perfect for testing your torque, and I'm not kidding. Especially leaving Helen and going up hill.
 
I see it. I will take it. most of time we start in Walhalla and take 28 to deals gap. it looks good, thanx
i drove right by going west to east on the duro in jan. but it was snowing that day. i have flagged it on my map from both sides. thanx lake
 
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is the reducer based on converging/diverging engineering? we have learned about why, but how it works is what i'm interested to know steve.
we studied this in the navy and its cool.
what you've depicted is a venturii, which is what makes a carburetor work. That's not the same as the velocity cone. The cone is dumping into a larger pipe, and the idea is to prevent backpressure from the downstream side of the cone from being able to travel back up the header to the cylinders. Basically it keeps the air moving in one direction, toward the muffler.
 
Put the 1.5 reducer in last weekend. Seems that I have more decel pops now then before with my Hammer Flash and not blocking pair valve.

Should have waited for a time I have been riding more frequent then a couple times a week for a before after comparison.

Power since hammer time flash has been to my liking anyway.

Thanks Steve for continuing to improve our performance.

DaElkman
 
I am running with the 15/8 reducer. I do notice a improvement in the low rpm throttle response, so I like that.

I have a decel pop now that wasn't there before. Not annoying.

The thing is though I have a buzz now that I didn't have before and it is a bit annoying.

The BW silencer is right on the edge of being too loud for my ear as well, and with the buzz it started me to look to see if another silencer would work better.

I just put on a Delkevic 18 inch carbon fiber oval and that has made a big difference to my ear. It seems probably about 2-3 dB quieter, and it has a lower pitch as well and no buzz.

Was able to use the BW mid pipe and hanger hardware, so it only took about 15 minutes to change out.
 
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