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Delkevic Full exhaust (Header and muffler) - Purchase, Installation, and (Excellent) RWHP Performance


Intro


I know there is a lot of interest among our forum members in Ninja 400 / Z400 exhaust systems. This posting will describe:

- Why I chose the Delkevic combination of header and 14” carbon fiber muffler

- The best way I found to purchase it given my home being in Canada

- What the kit contains and how it is packaged

- The installation process (which has a some important points)

- The features and appearance

- My performance testing to-date (not considered complete as of the first posting in this thread)

This is a long thread, for good explanatory reasons, but bear with me, as the performance results will surprise you. (very favourably).


Why Delkevic


I reviewed all the information on all the systems I could find information on, including the really good comparison commentaries and testing done by Jesse Norton and Jeremy Toye and shared on both this forum and their own website. But I also factored in my prior experiences with Delkevic exhaust systems and Graves exhaust systems.

You all know, or have easy access to, the Norton - Toye exhaust comparisons. Some of those systems, especially the Spark and Akrapovich full systems, are highly regarded for their performance. But the good ones are quite costly, and I had doubts about them being quiet enough for my taste, which is “conservative”.

My prior experiences with Graves systems has been excellent. They perform very well, they sound great and are not harshly loud, and the workmanship and material quality is very high. But, their systems have recently becomes notably more costly (1/4 the price of the new Z400!) - costly enough to make me look elsewhere.

Delkevic is not well known in The U.S. (at least yet). They are a British brand that is well known in England and internationally (including Australia). They do not market themselves as a “hotrod” performance shop. Rather, they market their products as replacements for OEM systems, that depending on the system, offer slight to major power improvements but do not REQUIRE an ECU or Power Commander tune. They are also a lot less costly than OEM replacement exhausts, which makes them popular for post-accident repairs. Delkevic says clearly in their product advertising that no tune is required, but that a tune can further improve performance in some cases. Their pricing tends to run somewhat lower than the products from companies that market themselves as performance shops.

My prior experiences with Delkevic have been excellent. Their quality has been very high. Their better systems tend to be rather beautiful, at least to my eye, especially their Carbon Fiber and the quality of their stainless steel (notably better than others inclduing OEM). Their sound is both attractive and not loud enough to anger neighbours and fellow road users. And, in at least some cases like the Ninja 400 / Z400 offerings, the performance gains are surprisingly high, well placed within the rpm range of the engine, and astonishingly good considering “no tune required”.

Delkevic’s Ninja 400 / Z400 system therefor interested me right from the beginning of my search. But then, I asked some technical questions, and a techie at Delkevic answered them, but also drew my attention to their Ninja / Z 400 header system specifically.

He pointed out that while their slip-on 14” Carbon Fiber muffler alone provided just modest performance gains, the header that could be separately bought and used with the muffler REALLY increased the performance. To illustrate, he sent me a Dynojet dyno chart that compared OEM exhaust system performance to that of the Delkevic combo, and that chart really caught my eye for both negative and positive reasons.


16564



It caught me eye initially because of three negatives.

First, it was corrected to the European DIN standard versus the U.S. / Canadian SAE standard. I soon learned via Google though that the difference between the DIN and SASE standards is tiny - barely over 1%.

Secondly, the Dynojet dyno software allows the user to select the units of measure for each of the 2 vertical axes and the horizontal axis. Naturally, most users choose “HP” and “Ft Lb of Torque” for the vertical axes, and “Engine RPM” for the horizontal axis. My techie at Delkevic unfortunately somehow set the pdf output of the chart to show “MPH” on the horizontal axis. This obscured the effectiveness of the header-mufflr combo in the different rpm ranges of interest to different riders. I realized only later how to correctly and easily convert that MPH scale to rpm.

Thirdly, the mph scale on the dyno chart showed a dyno run range from about 22 mph to about 94 mph. That puzzled me. Dyno runs on 6-speed motorcycles are normally done in the highest gear available whose INTERNAL gearbox ratio does not fall below 1.00 (i.e. the highest internal “non-overdrive” gear). That gives the best engine performance. Lower gears deflate the indicated torque and power because the Dynojet’s “sweep” versus “stepped fixed rpm” method of testing penalizes a bike that tests in a lower gear because the increased mechanical leverage of a lower gear diverts more of the engine’s power to spinning up the drivetrain more quickly - a moment of inertia effect. But the Ninja / Z400’s internal ratios are ALL above 1.00 (because it is a high rpm versus high torque engine). So, it would be logical to use 6th gear. Even if a dyno operator did not know the internal ratios, it would be very unusual to use any gear lower than 4th.

But I know that on the Ninja 400 / Z400, 4th gear hits the 12,200 apaprent rev limit at around 101 mph. 3rd gear hits the rev limit at 83 mph. So, neither 3rd or 4th gear OEM gearing “matches” this chart. Clearly, the actual Ninja/Z400 used had had its rear sprocket changed.

I finally realized though that because HP = T x RPM/5250, then RPM = HP/T x 5250. ALWAYS.

That allowed me to determine the rpm near the lowest MPH speed on the graph, and also at the highest MPH speed on the graph, and then the exact sprocket size used does not matter. That allowed me to mark up the pdf chart to show engine rpm at 500 rpm intervals.


16565



That showed me a number of important things:

  • The AVERAGE improvement in power across the entire 3000 to 12,200 rpm range graphed is an impressive 8%.

  • The power gain at some points within that rpm range is much higher: 13% at 6500 rpm, 14% at 7000, and 11 to 13% in the 10,500 to 12,200 rpm range (where you spend most of your time if accelerating hard or riding at very high speed)

  • The OEM exhaust apparently showed a peak of only 42.57 rwhp, which is about 6% lower than the approximately 45.25 OEM rwhp found by Norton and Toye as well as numerous other reputable sources. The chart also shows the OEM exhaust peaking in power at just under 9000 rpm, which is about 1000 rpm lower than others have found. Therefor, the bike used in the test had some deficiency. Dirty air filter? Worn sparkplugs? Or? (It’s NOT a dyno calibration error, since that would still have shown a peak at 10,000 even if a lower number of horsepower).

  • Yet, the installation of the Delkevic muffler and header still produced an average 8% gain, with a STRONGER 11 to 13% gain at very high rpm, and managed to hit 44.7 rwhp! I wonder what peak power it might have reached on a healthy bike.

Anyway, this kind of performance improvement, withOUT even an ECU tune, convinced me that I needed to buy and try this system. MY wife was sweet enough to buy it for me for Christmas.


Purchase Process


As I mentioned, Delkevic is a British company. They do have a U.S. sales company, but the combination of built-in U.S. AND Canadian import costs made that the wrong buying route for me.

Instead, because of prevailing currency exchange rates, and differing shipping costs, it turned out best for me to buy my muffler kit and header kit directly from Delkevic in The United Kingdom. My total cost that way was about $650 Canadian = $500 US, including shipping and import fees, via DHL. It arrived within about 10 days from England.


The Kit as Received


The box from Delkevic came with each of the following components carefully wrapped and packed against damage:


16566




I had ordered and received the CF muffler and its piping adaptor as an earlier purchase, to use as a slip-on solution, so the muffler and adaptor pipe do not appear in this photo.

One glaring omission: While Delkevic includes all the necessary parts, including even new OEM exhaust gaskets and silicone sealant to use on the joints to ensure no leaks, Delkevic supplies no instructions whatsoever. This is not a problem if you have done motorcycle exhaust systems before. But if you are inexperienced with motorcycle exhaust installation and its important details, hire a local shop to do the work. It would take an experienced mechanic maybe an hour, or 90 minutes at most to do a complete installation, inclduing removal of the existing exhaust.


Installation


I won’t undertake to describe the complete installation process here, but here are a few key points important on this installation:

The 2 header pipes are clearly each marked with a sticker, as either “1” or “2”. 1 goes on the LEFT cylinder (when viewed from the rear of the bike). 2 goes on the right cylinder. Don’t mix these up or it likely will create a huge fit problem.

Install all components just LOOSELY first. Do NOT tighten any bolts until you KNOW you have everything posiitoned correcttly.

The best order to install the components is:

Left header pipe (“1”)

Right header pipe (“2”)

THEN lubricate the 2 header pipe exteriors and the collector INterior with plain water (all these parts are stainless steel so won’t rust)

THEN, using a rubber hammer and wood block, gently knock the collector onto the header pipes, while holding the header pipes from being bent forward by the LIGHT hammer blows. Push the collector onto the 2 header pipes until the collector is FULLY seated on them as far as it will go without trying to dent the shaped headers. This is IMPORTANT, because if you don’t do this, the oxygen sensor, which will next be threaded into the collector will be too far rearward and will not have sufficient space under the crankcase to avoid colliding with the crankcase. The O2 sensor MUST end up forward of the engine crankcase, and will be HIGHER than the bottom of the crankcase!

Also, even more importantly, If you do not seat the header pipes fully, and instead somehow manage to tighten the header pipe bolts to the engine cylinder head regardless, the headers will be too far forward, and because of their broad gentle curved shape (to reduce flow restriction) they might hit the front tire when the front suspension is compressed! Pay careful attention to doing this seating properly!

continued below . . .
 

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Discussion Starter #2
Delkevic O2 sensor and header positioning: Note how the collector must be pushed forward until it reaches the "curved" portion of each header pipe.


16567



THEN lube the mid pipe with water and slide it into the collector. How Far? So that the mounting tab on the mid pipe aligns with the transmission bolt that is removed and then reinstalled to secure the mid pipe. Secure the mounting bolt only LOOSELY, and the mid pipe to collector clamp only VERY loosely

Then LOOSELY fit the muffler-to-mid-pipe adaptor pipe to the mid pipe, leaving its clamp very loose

THEN, set up the muffler hanging bracket (see photo) on either the OEM exhaust hanger or an aftermarket hanger like mine (see photo)

LOOSELY install the muffler at the correct angle and orientation. See the photos.

Make sure everything looks and feels right. Then, work your way rearward tightening 4 header bolts, then the mid pipe mounting tab, then the clamp on the mid pipe to collector, then apply the silicone sealant to the muffler-adaptor-pipe to mid-pipe junction and tighten the clamp, then do same on the muffler to adaptor piep intersection, and finally hold the muffler in exactly the position you want.


Features & Appearance


This Delkevic full exhaust system has a number of significant features:

The OEM system weighs 13.34 lb in total. The Delkevic is 8.66 lb, so just over 1/3 lighter. The Delkevic header actually weighs more than the OEM header, despite not having a CAT in it, but I think that simply reflects a thicker wall thickness. There are other exhaust systems that are lighter in overall weight, but not MUCH lighter.

The extra weight is NOT because the Delkevic is longer in length, despite the way a photo makes you believe it is. The approximate comparative dimensions of the OEM and Delkevic systems are as follows:


OEM / Delkevic


From cyl head to collector start 18 / 17 inches


From cyl head to start of muffler 51 / 52 inches


From cyl head to end of muffler 66 / 66 inches


The Delkevic APPEARS to be longer because its muffler tip (with the 14” muffler) oes further back than the oEM muffler. But that’s because the routing between the cylinder head and the muffler tips is different, especially in the shape of the header pipes. The appearance of longer length will be welcomed by some users and disliked by others.

The OEM head pipe diameters are 32mm OD and the shape is obviously very tortured and with multiple very tight bends (see the OEM photo).


16569


OEM system

In the OEM photo above, note also the obvious “burning” on the header pipes right near the cylinder head, at that very tight curve in each header pipe, and also the burning at the start of the CAT. Maybe THIS is why Ninja / Z400s run so hot?

The Delkevic head pipe diameters are the same outer diameter, and close to the same length, but the smooth shape, that comes noticeably further forward, closer to the front wheel, will obviously flow exhaust a lot easier, and therefor also cooler. This really shows on the dyno chart, especially at higher engine rpm. Look at the overall shaped path of the Delkevic system:


16570


Delkevic completed installation photo


The OEM mid pipe diameter is 44mm and it includes a CAT (the bulbous section in the OEM photo), while the Delkevic mid pipe diameter is 46mm and it is perfectly smooth and obstruction free, Also, 46mm versus 44mm does not sound like much difference, but since the cross-sectional area is proportional to the SQUARE of the radius, a 46mm pipe will flow over 9% more air than a 44mm pipe. (Although the thicker wall thickness of the Delkevic piping will reduce this flow advantage a bit)

The OEM piping system is technically stainless steel, but it’s not a pretty grade, while the Delkevic system is a lustrous highly polished high grade of stainless steel, and is warranted for 5 years! (NOT if you crash or drop the bike, Dreamers! :) )

The OEM muffler is an ugly painted (flat black) steel canister that scratches easily and needs an aluminum heat shield to protect the rider’s foot, which manages to interfere with virtually every rider’s heel, regardless of rider size. The Delkevic muffler is real Carbon Fiber with a fabulous finish.

The surface of the Carbon Fiber muffler stays cool enough that a cover can be put on the bike immediately after a ride.

The OEM CAT comes VERY close to the engine’s oil sump, and as you can see from the “burn” marks on the OEM CAT, it runs hot. This will obviously cause the oil to run hotter, and again, this raises the temperature reading at the dashboard. The Delkevic cat-less pipe has a couple of inches clearance to the oil sump AND runs cooler to ebgin with due to no CAT.


Performance Testing


The weather, which has been consistently wet for weeks, broke for a day and a half of no rain! This was enough to dry the roads locally, and so I was finally able to do a 51 km = 32 mile road test of the system. It was impressive.

The test ride included a good mix of city, highway, and suburban riding. The ambient outdoor temperature was 5 degrees C = 41 degrees F.

The indicated engine temperature started of course at zero bars and soon stabilized at 3 bars. Impressivley, it STAYED at 3 bars no matter what throttle openings I used or what engine rpm I ran. The only deviation was it briefly displayed 4 bars, for a fraction of a kilometer, right after I started it up after stopping at a gas station. This deviation is of course normal behaviour for any watercooled sportbike shut down, or even just idled, for a few minutes right after a ride and then restarted.

There were absolutely ZERO pops or backfires or ANY other unusual exhaust sounds, under ANY of the operating conditions .

Throttle response is notably stronger, at virtually any reasonable rpm (You shouldn’t be whacking the throttle open at under 4000 rpm on a 12,000 rpm engine).

We have speed limits and severe fines here in British Columbia, so I had to have some restraint. But going up fully through (only) the first 3 gears under full throttle, everything happens notably quicker. An average of 8% more power across the rpm range, and 11 to 13% more power above 10,500 can do that.

Pure, throttle-only wheelies are now very easy. Just whack the throttle at any midrange rpm and the front end comes up. No clutching, suspension loading, handlebar yanking, or body repositioning required. 13 to 14% power gains at midrange rpm can do that. (I know we have guys on this forum who will be excited about this).

And this wheelieing performance is despite the fact that my bike is not yet fully broken in, and that I weigh about 189 lb currently but with my safety and winter riding gear on I during this test I weighed over 206 lb. (No kidding)

Some of you might recall that I have lightened my Z400 by about 16 lb currently, on my way to a current estimated goal of over 20 lb, and you might be thinking that surely contributed to the easy wheelieing. But you would be incorrect, as I carefully recorded WHERE the individual weight reductions actually occurred, and the breakdown was:

- a loss of 14.08 lb off the rear of the bike

- a GAIN of 0.54 lb in the middle of the bike (due to the Delkevic header/midpipe being heavier than the OEM)

- a loss of only2.68 lb off the front of the bike

So, no, the weight reductions did not help to make wheelieing easier. :)

32 miles is certainly not a definitive test, and a 5 degree C = 41 degree F weather environment is representative of only our Vancouver Island winter weather, not its summer weather (which runs in the 20 to 30C = 68 to 86 degrees F range). So, more extended testing in wider temperature ranges is obviously appropriate. But, I am pretty impressed that under no operating conditions did the temperature gauge stray from 3 bars.

WHY does the Delkevic system apparently work so well? I’m no exhaust system expert so I don’t know the answer, but I have some suspicions. I suspect that the less tortuous curves of the Delkevic header pipes, and their larger diameter, keep the exhaust flow rate higher, and therefor cooler. And of course I think I can say that the midpipe obviously, with no CAT, will flow more air and that air will also be much cooler. So, my theory is that the Delkevic achives as much as it does mainly because it minimizes flow obstructions and also generates far less damaging heat that hurts engine performance. I could fo course be dead wrong , because as I said, I am no exhaust expert.

But, as you can see, the Delkevic system, for whatever reason, WORKS.

I’m really looking forward to doing more extensive testing. :)

Jim G
 

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Awesome write up.

Out of interest what made you go with that silencer, given your love of dropping weight. It looks like the short carbon is the lightest (1.4kg) if I'm reading their website right. Sorry if you explained that in the post and I missed it.

Considering one myself, the price is pretty decent compared to a Spark, and I also prefer to keep the sound levels reasonable. I'm only really considering an aftermarket exhaust because my feet hit the OEM even with the heat shield off.
 

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Discussion Starter #4
Awesome write up.

Out of interest what made you go with that silencer, given your love of dropping weight. It looks like the short carbon is the lightest (1.4kg) if I'm reading their website right. Sorry if you explained that in the post and I missed it.

Considering one myself, the price is pretty decent compared to a Spark, and I also prefer to keep the sound levels reasonable. I'm only really considering an aftermarket exhaust because my feet hit the OEM even with the heat shield off.
dbrain: I selected the 14" carbon muffler because I wanted to be SURE that the sound level was not going to be too loud. I resisted the longer 18" muffler only because it would have extended too far rearward and thus looked funny on the tiny Z400.

Jim G
 

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dbrain: I selected the 14" carbon muffler because I wanted to be SURE that the sound level was not going to be too loud. I resisted the longer 18" muffler only because it would have extended too far rearward and thus looked funny on the tiny Z400.

Jim G
Ahh, thanks for the info. The UK website lists the noise level, while the AU one does not, so I missed the volume change initially. Now I see what you are talking about in regards to sound, I'd probably make a similar choice.
 

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Ahh, thanks for the info. The UK website lists the noise level, while the AU one does not, so I missed the volume change initially. Now I see what you are talking about in regards to sound, I'd probably make a similar choice.
Yes, the UK website is the most authoritative and informative. Even if you buy from a more local sales outlet, go to the UK website for the best info.

I managed to get that dyno chart simply because I connected with one of the technical people with a couple of questions, and he volunteered the chart, which turned out to be VERY helpful.

Jim G
 

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Delkevic O2 sensor and header positioning: Note how the collector must be pushed forward until it reaches the "curved" portion of each header pipe.


View attachment 16567


THEN lube the mid pipe with water and slide it into the collector. How Far? So that the mounting tab on the mid pipe aligns with the transmission bolt that is removed and then reinstalled to secure the mid pipe. Secure the mounting bolt only LOOSELY, and the mid pipe to collector clamp only VERY loosely

Then LOOSELY fit the muffler-to-mid-pipe adaptor pipe to the mid pipe, leaving its clamp very loose

THEN, set up the muffler hanging bracket (see photo) on either the OEM exhaust hanger or an aftermarket hanger like mine (see photo)

LOOSELY install the muffler at the correct angle and orientation. See the photos.

Make sure everything looks and feels right. Then, work your way rearward tightening 4 header bolts, then the mid pipe mounting tab, then the clamp on the mid pipe to collector, then apply the silicone sealant to the muffler-adaptor-pipe to mid-pipe junction and tighten the clamp, then do same on the muffler to adaptor piep intersection, and finally hold the muffler in exactly the position you want.


Features & Appearance


This Delkevic full exhaust system has a number of significant features:

The OEM system weighs 13.34 lb in total. The Delkevic is 8.66 lb, so just over 1/3 lighter. The Delkevic header actually weighs more than the OEM header, despite not having a CAT in it, but I think that simply reflects a thicker wall thickness. There are other exhaust systems that are lighter in overall weight, but not MUCH lighter.

The extra weight is NOT because the Delkevic is longer in length, despite the way a photo makes you believe it is. The approximate comparative dimensions of the OEM and Delkevic systems are as follows:


OEM / Delkevic


From cyl head to collector start 18 / 17 inches


From cyl head to start of muffler 51 / 52 inches


From cyl head to end of muffler 66 / 66 inches


The Delkevic APPEARS to be longer because its muffler tip (with the 14” muffler) oes further back than the oEM muffler. But that’s because the routing between the cylinder head and the muffler tips is different, especially in the shape of the header pipes. The appearance of longer length will be welcomed by some users and disliked by others.

The OEM head pipe diameters are 32mm OD and the shape is obviously very tortured and with multiple very tight bends (see the OEM photo).


View attachment 16569

OEM system

In the OEM photo above, note also the obvious “burning” on the header pipes right near the cylinder head, at that very tight curve in each header pipe, and also the burning at the start of the CAT. Maybe THIS is why Ninja / Z400s run so hot?

The Delkevic head pipe diameters are the same outer diameter, and close to the same length, but the smooth shape, that comes noticeably further forward, closer to the front wheel, will obviously flow exhaust a lot easier, and therefor also cooler. This really shows on the dyno chart, especially at higher engine rpm. Look at the overall shaped path of the Delkevic system:


View attachment 16570

Delkevic completed installation photo


The OEM mid pipe diameter is 44mm and it includes a CAT (the bulbous section in the OEM photo), while the Delkevic mid pipe diameter is 46mm and it is perfectly smooth and obstruction free, Also, 46mm versus 44mm does not sound like much difference, but since the cross-sectional area is proportional to the SQUARE of the radius, a 46mm pipe will flow over 9% more air than a 44mm pipe. (Although the thicker wall thickness of the Delkevic piping will reduce this flow advantage a bit)

The OEM piping system is technically stainless steel, but it’s not a pretty grade, while the Delkevic system is a lustrous highly polished high grade of stainless steel, and is warranted for 5 years! (NOT if you crash or drop the bike, Dreamers! :) )

The OEM muffler is an ugly painted (flat black) steel canister that scratches easily and needs an aluminum heat shield to protect the rider’s foot, which manages to interfere with virtually every rider’s heel, regardless of rider size. The Delkevic muffler is real Carbon Fiber with a fabulous finish.

The surface of the Carbon Fiber muffler stays cool enough that a cover can be put on the bike immediately after a ride.

The OEM CAT comes VERY close to the engine’s oil sump, and as you can see from the “burn” marks on the OEM CAT, it runs hot. This will obviously cause the oil to run hotter, and again, this raises the temperature reading at the dashboard. The Delkevic cat-less pipe has a couple of inches clearance to the oil sump AND runs cooler to ebgin with due to no CAT.


Performance Testing


The weather, which has been consistently wet for weeks, broke for a day and a half of no rain! This was enough to dry the roads locally, and so I was finally able to do a 51 km = 32 mile road test of the system. It was impressive.

The test ride included a good mix of city, highway, and suburban riding. The ambient outdoor temperature was 5 degrees C = 41 degrees F.

The indicated engine temperature started of course at zero bars and soon stabilized at 3 bars. Impressivley, it STAYED at 3 bars no matter what throttle openings I used or what engine rpm I ran. The only deviation was it briefly displayed 4 bars, for a fraction of a kilometer, right after I started it up after stopping at a gas station. This deviation is of course normal behaviour for any watercooled sportbike shut down, or even just idled, for a few minutes right after a ride and then restarted.

There were absolutely ZERO pops or backfires or ANY other unusual exhaust sounds, under ANY of the operating conditions .

Throttle response is notably stronger, at virtually any reasonable rpm (You shouldn’t be whacking the throttle open at under 4000 rpm on a 12,000 rpm engine).

We have speed limits and severe fines here in British Columbia, so I had to have some restraint. But going up fully through (only) the first 3 gears under full throttle, everything happens notably quicker. An average of 8% more power across the rpm range, and 11 to 13% more power above 10,500 can do that.

Pure, throttle-only wheelies are now very easy. Just whack the throttle at any midrange rpm and the front end comes up. No clutching, suspension loading, handlebar yanking, or body repositioning required. 13 to 14% power gains at midrange rpm can do that. (I know we have guys on this forum who will be excited about this).

And this wheelieing performance is despite the fact that my bike is not yet fully broken in, and that I weigh about 189 lb currently but with my safety and winter riding gear on I during this test I weighed over 206 lb. (No kidding)

Some of you might recall that I have lightened my Z400 by about 16 lb currently, on my way to a current estimated goal of over 20 lb, and you might be thinking that surely contributed to the easy wheelieing. But you would be incorrect, as I carefully recorded WHERE the individual weight reductions actually occurred, and the breakdown was:

- a loss of 14.08 lb off the rear of the bike

- a GAIN of 0.54 lb in the middle of the bike (due to the Delkevic header/midpipe being heavier than the OEM)

- a loss of only2.68 lb off the front of the bike

So, no, the weight reductions did not help to make wheelieing easier. :)

32 miles is certainly not a definitive test, and a 5 degree C = 41 degree F weather environment is representative of only our Vancouver Island winter weather, not its summer weather (which runs in the 20 to 30C = 68 to 86 degrees F range). So, more extended testing in wider temperature ranges is obviously appropriate. But, I am pretty impressed that under no operating conditions did the temperature gauge stray from 3 bars.

WHY does the Delkevic system apparently work so well? I’m no exhaust system expert so I don’t know the answer, but I have some suspicions. I suspect that the less tortuous curves of the Delkevic header pipes, and their larger diameter, keep the exhaust flow rate higher, and therefor cooler. And of course I think I can say that the midpipe obviously, with no CAT, will flow more air and that air will also be much cooler. So, my theory is that the Delkevic achives as much as it does mainly because it minimizes flow obstructions and also generates far less damaging heat that hurts engine performance. I could fo course be dead wrong , because as I said, I am no exhaust expert.

But, as you can see, the Delkevic system, for whatever reason, WORKS.

I’m really looking forward to doing moIre extensive testing. :)

Jim G
Wheelies???!!!. I prefer to keep my tires on the road surface where they can operate at optimum efficiency 🐉
(Edit) wait!! And of course the maximum mechanical grip.
 

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Pure, throttle-only wheelies are now very easy. Just whack the throttle at any midrange rpm and the front end comes up. No clutching, suspension loading, handlebar yanking, or body repositioning required. 13 to 14% power gains at midrange rpm can do that. (I know we have guys on this forum who will be excited about this).

And this wheelieing performance is despite the fact that my bike is not yet fully broken in, and that I weigh about 189 lb currently but with my safety and winter riding gear on I during this test I weighed over 206 lb. (No kidding)
I'm sceptical. A demonstration is needed.
 

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I have that same exhaust on my 400. I put it on in Nov of 2018. Paid in the mid 300s during a Black Friday sale. I also changed the air filter
to an aftermarket one which flows more air than stock and can be cleaned and re used. There were blue flames coming out the exhaust and I had it dyno tuned right away. Don’t have any numbers since my dyno tuner never have me a print out and later lost the info 😡😡😡. I broke the exhaust and bike in on the track a few months later. No complaints the bike pulls very strong and can power wheelie in 1st!!! I just wish I went with the 9 inch can instead of the 14! Great exhaust for the money and is holding up fine after 2 track seasons on it!!!
7E0B6981-788D-47F1-B4E1-2D177B77FCDC.jpeg
 

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Discussion Starter #10
One of the thread readers asked if I could record the sound of the Delkevic with the 14" muffler as I installed it. I need some help though converting the .mov format of the iPhone's video to a format that the forum will accept.

I will warn everyone right now before even positng the video: Don't even bother to play it if you are listening through your computer's built in speaker. The combination of my iPhone's microphone's very limited ability to capture low frequency sounds coupled with the typical computer's tiny and tinny speaker, makes playing the video futile, as virtually none of the low frequencies will be heard.

I just played it 2 ways myself:

1. With my computer's speaker outputting the sound: Awful. Most of the low frequency growl is lost, especially at idle

2. With a not wonderful, but decent, set of earphones: NOTABLY better, especially at idle. But still not like what you hear in person.

But, I suppose something is better than nothing at all, so if someone can either tell me how to do the required format conversion, or can simply post it for me below if i email it to you, let me know how to reach you by email.

Jim G
 

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But, I suppose something is better than nothing at all, so if someone can either tell me how to do the required format conversion, or can simply post it for me below if i email it to you, let me know how to reach you by email.
You could upload it unlisted to YouTube and just put the link here?
 

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Discussion Starter #12
I've never done an upload to Youtube, and don't particularly want to learn how to do it since I'll never likely need to upload a video again to YouTube! The only reason I am trying to do this at all is because one of our members asked for it. Can I just email it to someone who can post or upload it?

I've told the requester that I will email the video to himif he sends me his email address via PM.

Jim G
 

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Discussion Starter #14
I made a second 2 minute video, this time while RIDING, so that you can hear what the system sounds like from the rider's position while actually riding.

As before, play it through a decent set of speakers. otherwise, you'll lose most of the low frequency sound.

My thanks to dBrain for setting up the YouTube video, just like he set up the first video.


Jim G
 

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There were blue flames coming out the exhaust and I had it dyno tuned right away.
I'm looking at purchasing this soon. Just to be clear, because I'm dopey, are you saying it needed a tune due to the blue flames? I.e. the whole "no tune required" thing may not ring true?

Going to have money for exhaust, but probably be a while until I can get it near a dyno.
 

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Discussion Starter #16
dbrain: Since i installed my Delkevic system, I have experienced no blue flames, no backfires, no popping, no adverse sounds or visuals at ALL. However, do note that if you have not yet disabled your Air Injection System ("AIS"), that system injects air into your exhaust ports right after the exhaust valves, and THAT can cause significant audible and visual symptoms if you alter your exhaust OR tune from the OEM specs. On my bike, I had disabled the AIS some time before I installed the Delkevic exhaust.

My bike still has its OEM ECU tune.

My engine temperature gage also continues to display only 3 bars 90% of the time, only going to 4 bars right after the engine has been restarted at a gas station, or if I have to go through dense in-town traffic for several minutes. Mind you, it is fairly cool here on Vancouver Island this time of year, so I'll need to see how the engine temperature behaves under warmer conditions on hot summer days.

Jim G
 

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However, do note that if you have not yet disabled your Air Injection System ("AIS"), that system injects air into your exhaust ports right after the exhaust valves, and THAT can cause significant audible and visual symptoms if you alter your exhaust OR tune from the OEM specs.
Oh, thanks! I'll have to look into this. Are there any negatives to disabling this?
 

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Oh, thanks! I'll have to look into this. Are there any negatives to disabling this?
Ah, looks like the negative for me at least is that it requires block off plates which is more $.

EDIT: Eh, sorted, ordered the block off kit from TST and some fork sliders while I was at it. Exhaust is also ordered.

I'm mostly looking forward to getting rid of the stock exhaust, as it was made for someone with childrens feet. I removed the heat guard so I could put my foot down properly, but in removing that I now had my foot on the exhaust itself. Ruined a pair of overpriced boots at the track on the weekend, melted all the way through to the inner boot.

Anything outside of "putting the exhaust in a reasonable place" will be a bonus.
 

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Discussion Starter #19
dbrain: Yes, you need the blockoff plate AND also a quality resistor of the right electrical size to replace the AIS valve in order to avoid a CEL. Kawasaki Brad sells a quality (honkin' BIG) resistor that worked fine on my Z400.

Jim G
 

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dbrain: Yes, you need the blockoff plate AND also a quality resistor of the right electrical size to replace the AIS valve in order to avoid a CEL. Kawasaki Brad sells a quality (honkin' BIG) resistor that worked fine on my Z400.

Jim G
Thanks, I ordered the TST kit. I'm in Australia, which makes it a bit of a pain ($75 USD postage). Has the plate, resistor and some other plugging bits. Grabbed their fork sliders at the same time so it felt a little less ridiculous postage wise.

Hopefully all rocks up around the same time. Delkevic AU actually had the item in stock rather than the usual "in stock", "oh that will be 3-4 weeks wait" I've had recently with motorcycle parts, and TST postage is express.

Going to be nice to not be either holding my foot in an uncomfortable position, or burning boots on exhaust.

Thanks for the install information, will definitely use it for the install. STG has some full exhaust install videos as well, so will mix and match.

My only concern is it will be flagged on track for sound. Local track wants 95db max at 30mt. I guess given 30mt it would probably need to be super loud, and 98-100 at 60% throttle probably isn't that bad over a 30mt distance.
 
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