• WOULD YOU LIKE TO BE ABLE TO POST AND ACCESS MEMBER ONLY CONTENT AND FEATURES
    Join / Upgrade / Renew your membership to enjoy full membership and posting privileges.
    For simple instructions, click here
  • Can't post after logging to the forum for the first time... Try Again - If you can't post in the forum, sign out of both the membership site and the forum and log in again. Make sure your COG membership is active and your browser allow cookies. If you still can't post, contact the COG IT guy at IT@Concours.org.
  • IF YOU GET 404 ERROR: This may be due to using a link in a post from prior to the web migration. Content was brought over from the old forum as is, but the links may be in error. If the link contains "cog-online.org" it is an old link and will not work.

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
 

Attachments

  • Benoit restriction vs none STD.png
    Benoit restriction vs none STD.png
    50 KB · Views: 80
Last edited:

turbojoe78

Member
Member
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.
 

texas.devops

Eager Upshifter in SW Houston
Member
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.
 

2andblue

Member
Member
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?
 

Steve in sunny Fla

Iron Butt
Industry Vendor
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
 

Attachments

  • Benoit stktoBWrestr.png
    Benoit stktoBWrestr.png
    58.8 KB · Views: 60

texas.devops

Eager Upshifter in SW Houston
Member
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
 

2andblue

Member
Member
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.
 

Steve in sunny Fla

Iron Butt
Industry Vendor
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
 

texas.devops

Eager Upshifter in SW Houston
Member
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
 

turbojoe78

Member
Member
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.
 

Attachments

  • reducer 1.5.jpg
    reducer 1.5.jpg
    40.4 KB · Views: 35

2andblue

Member
Member
@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.
 

jeffc125669499

Member
Member
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 ?
 

Steve in sunny Fla

Iron Butt
Industry Vendor
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
 

maverick9611

“tryin not to get old”
Member
yes, I believe so.
 

Attachments

  • IMG_2907.JPG
    IMG_2907.JPG
    120.5 KB · Views: 38
  • camphoto_1691952160.jpg
    camphoto_1691952160.jpg
    155.3 KB · Views: 37

jeffc125669499

Member
Member
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 in sunny Fla

Iron Butt
Industry Vendor
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
 

connie_rider

Member
Member
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.
 

Steve in sunny Fla

Iron Butt
Industry Vendor
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
 

laker9142

Member
Member
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.
 

connie_rider

Member
Member
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.
 
Last edited:

maverick9611

“tryin not to get old”
Member
just cut mine. 93mm total length. I cut off 33mm
 

Attachments

  • IMG_20211221_051727_104.jpg
    IMG_20211221_051727_104.jpg
    74.1 KB · Views: 14
  • IMG_20211221_052035_186.jpg
    IMG_20211221_052035_186.jpg
    105 KB · Views: 14

maverick9611

“tryin not to get old”
Member
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....
 

maverick9611

“tryin not to get old”
Member
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
 

Attachments

  • IMG_20211223_144222_802.jpg
    IMG_20211223_144222_802.jpg
    106.6 KB · Views: 31
  • IMG_20211223_144242_576.jpg
    IMG_20211223_144242_576.jpg
    96.7 KB · Views: 31
  • IMG_20211223_144712_267.jpg
    IMG_20211223_144712_267.jpg
    193.2 KB · Views: 30
  • IMG_20211223_144756_985.jpg
    IMG_20211223_144756_985.jpg
    184.7 KB · Views: 30
  • IMG_20211223_144810_824.jpg
    IMG_20211223_144810_824.jpg
    193.3 KB · Views: 30

Steve in sunny Fla

Iron Butt
Industry Vendor
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
 

maverick9611

“tryin not to get old”
Member
I guess getting up at 0100 bit me. plus I was drinking too.wait to I pull up along side u ted...😉
 

connie_rider

Member
Member
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).
 

maverick9611

“tryin not to get old”
Member
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
 

Attachments

  • 16403656869687034871366195455304.jpg
    16403656869687034871366195455304.jpg
    77.8 KB · Views: 19

connie_rider

Member
Member
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
 

maverick9611

“tryin not to get old”
Member
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.
 

maverick9611

“tryin not to get old”
Member
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
 

Steve in sunny Fla

Iron Butt
Industry Vendor
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


 
Top