Hey guys, new here with a 2009. Just bought it a few weeks ago with 1500 miles. Mainly it will be used off road, with street to trail duty. I've been reading all the helpful info around here and want to say thanks, there's a wealth of great info that has saved me a lot of trial and error.

I installed a Delta full exhaust and the dj2152 and 38main. .FYI they are on Ebay for 180, for the header and silencer,I couldn't pass it up. It went on pretty smooth, but you have to use the stock gasket between pipes, leading me to believe it might not have as good of top end as some offerenings that are bigger. With this setup power was increased across the board but still nothing overly impressive. It pulls smooth to rev limiter and will slightly power wheelie in first. But I'm still going to need more and figured I would. I also have the AHL 300 kit and will most likely do the MCM

 

Interesting that the stock gasket is required.
Is the Delta slipon nipple a smaller diameter pipe than the Delta header piping ? If so, Delta has totally failed us.

 

Yes it is. So I would consider the slipon as a limiter, but I also have to put some faith that the combo was made to work together. Since I'm more concerned with lower rpm torque, I'm satisfied for now. I also figure I can go to one of the other aftermarket slipons that doesn't use the gasket later if I want. Or possibly have the midpipe flared so the gasket wouldn't be required. The midpipe does have the bung for o2, so it could maybe work for efi bikes, or give a spot for afr gauge.

Next I'll be installing a 13t sprocket , but Is there anything else I can do to improve torque in the 3-7k range. I'm trying to put off tearing down the motor to do the MCM and BB kit. I'm wanting to stay away from the lidless setup as it will be treated as a dirt bike, water crossings, pressure washing, dirt, mud, ect.

 

Well that research didn't take long..
The Delta stuff is apparently made in Japan. Wheeling Cycle Supply (Wheeling, West Virginia) has been importing (and selling) the stuff for many years (at least since '09). Now, it seems, from the Ebay listing, they are selling Delta systems on Ebay..

I'm thinking a call to Wheeling Cycle Supply (1-888-274-0886) could shed light on the midpipe-to-header fitment mismatch. I am hoping you simply have mismatched part numbers from the Delta lineup of exhaust components..

Without the option of a lidless airbox or the MCM, you are out of luck for more power EXCEPT for the losses you are incurring from the mismatched exhaust components. My testing with such a mismatch indicated significant losses everywhere.

From the reviews, reviews that are expected from the apparent construction of the Delta "TRQ pipe" , it is NOT "geared" toward low RPM Trq production.
And, you always had a better solution than that header (for the power curves you want) - your stock header. Absolutely put it back on and sell the Delta header. It will be a good upper RPM enhancement for anyone running a large midpipe slipon on a stock header. ( See the sticky on performance exhaust choices..)

None of the performance headers will even "meet" the low/mid TRQ that the stock header offers ! The Delta was the only header touting enhanced TRQ production - but that's a complete lie.

As for further tweaking, about all you can do (after reinstalling the stock header) is to get the KDX200 snorkel, use the DJ132 main jet (that came in your kit)., and back the fuel screw out 3 - 3.5 turns.

FWIW, to see what your missing, the below vid is an example of the power from (stock header + small nipple'd slipon + MCM + lidless airbox + lidless CVK setup + STOCK SPRAUGHKETS)..

 

Yeah my first choice was to just do a slipon, thanks to your exhaust info, but I came across this for less than a slipon so thought I'd try it. After some fine reading on their site, it does say stock gasket is needed for this silencer. I think they just went the cheap easy way of here's a slipon that fits the stock stuff, here's a header that fits stock, also. I'm not sure I'm willing to make to many assumptions on how your setup responded to the limiting factor of the slipon in comparison to my setup. With the difference of the headers we run and the fact that you move so much more air in, it might be that this header isn't really hurting me at all, or that a bigger slipon would help.

I'm game for a switch around though. Once it dries out and I get some good runs in as is, I'll switch back to the stock header and see if I can tell a difference.

 

Yep, you have to do one of two things, use the stock header or buy a slipon that mates correctly to the Delta header - Note: The FMF Q4 is the most quiet of all the slipons that will mate-up correctly..

The proper logic regarding your mismatch is that the larger header allows the gases to expand, slow down, and cool quicker than the stock header. Any restriction past the header causes the cool, slow, gas flow to simply re-pressurize instead of flowing smoothly through the midpipe and out the straight-thru baffle in the muffler section. This causes a loss of inertia scavenging and acoustic rebound scavenging..

Sidebar: Notice that many midpipes also expand in size from header connection to muffler connection. This is to allow the gas flow to remain "freely flowing" (as it continues to expand and lose more speed and heat) by providing a larger "pipe" .

I could go on and on about compression wave scavenging, acoustic wave rebound scavenging, etc.. suffice to say that there can be no justification for a restriction in a performance exhaust system. Even the touted "torque inserts/cones" etc, are actually just bandaids for an incorrectly chosen or designed performance exhaust system..

 

I've gotten some good runtime in on the bike and I'm very happy with how it's running. Starts like a dream and the extra power is much more pronounced off road. I'm not sure how much is exhaust, how much is jetting, but I'm happy with the overall combo effect.


I don't entirely agree with your assesment. This pipe does not mismatch as the fmf and dg did that you ran. These are made to run together, just not as big of diameter at the joint, just like stock. As you have shown in your stock vs aftermarket tests, it seems even with the expansion chamber, you still lose lowend over the stock pipe. Being that this pipe and header are made to fit together at the smaller diameter, and that this pipe is based on the stock one, but flow better, I see no reason it couldn't make better power through the lower rpm's, to maybe 7000 over the full FMF setup, and make more than the DG slipon/ stock header or FMF header, everywhere. I can see where the FMF header, at the larger diameter and made to mate with the bigger slipon, would have adverse effect to performance, and I don't think it's a relative comparison to this combo. I think the Barker minus some topend would be a better comparison. Being that they are both stepped headers, megaphone midpipe exhausts.

I also wonder how the retiming the exhaust cam can play in to exhaust needs and the effects on scavanging, FMF header performance, ect. .

I have much more experience with cars then bikes, when it comes to looking for performance. My last big build was a 5.0 Foxbody. I talked to an exhaust guy, who literally does nothing but headers, and he said 1 3/4 headers at most. My custom cam guy said he wanted at least 1 7/8 headers. Point being these were 2 well known, very experienced guys, telling me 2 different things, on a vehicle that literally has been built millions of times and they couldn't agree. I don't think we as consumers, or companys have all the answers to exhausts yet.

 

Well, now I'm confused.

You stated previously that the pipe size of the Delta header was a larger O.D. than the nipple on the midpipe. The pictures of the Delta TRQ pipe seem to corroborate that it carries the larger pipe size that all performance headers (for the KLX) do.

NOTE: The size of a KLX header bell (slipjoint) is a non issue - All KLX headers will have the same exact size on the bell (slipjoint for the midpipe).

All KLX slipons will have a midpipe with a nipple.
The size of the nipple will be one of two :
1. "as stock" and require the use of the stock gasket.
2. The larger size that slips into any KLX header bell without a gasket.

The size (I.D.) of the nipple MUST MATCH the size of the header's piping. Otherwise, the nipple is a restriction to gas flow, causing a loss of power everywhere compared to a correctly sized header/midpipe..

@asheck , your nipple is either smaller or the same, in size, as the piping on the header, as measured at a point just before the bell.

Please confirm this as I am providing the membership with knowledge on exhaust choices through my/the sticky - https://www.kawasakiforums.com/forum...rations-44444/ which I have already updated with your previously stated mismatch information.

 

You're not confused on how they mate together. The Delta uses the stock header gasket.

But what I'm saying is that this exhaust system was made to use that stock gasket. The header you ran was made not to, it's no surprise to me that it didn't perform well with it. I don't think you can just generally surmise that this system is hurting performance based on testing with just that MB header and one slipon. I have a hypothesis the MB expansion chamber could need that bigger pipe coming out of it, and the turbulance coming straight out of the chamber into the joint could also amplify turbulence more with the smaller slipon. A PB header might give totally different results, since it's chamber is much further from the joint. Where your DG slip on was made to go with the stock header, not surprising it gave the better results with it.

BTW busted out the calipers. The Delta is 1.36 OD out of the head , then steps to 1.47 ,after the curve, to the joint, where it flares to 1.58 to go over gasket. The mid after the joint is 1.51 . Next time I have it off I'll measure the inner nipple of the joint. Stock is 1.25 all the way.

 

Thanks for taking those measurements. I'd hate to have misinformation on the sticky..

Ok, so the O.D. of the piping, just before the slipjoint (bell) is 1.47" .....
The bell is .11" larger. And is the same size as all KLX250 headers (stock or aftermarket)..
The problem is the nipple is designed to use the stock gasket - which means it is the same size as a stock nipple, which is far smaller ( O.D. and I.D ) than the piping leading to the bell (1.47" O.D.) ....
The 1.51" midpipe O.D. , just after the nipple, seems good-to-go....
IF the nipple did not require the gasket ( meaning it would be a tight, metal-to-metal, fit into the bell) you would have a proper match of components.


I understand that you want to rationalize this mismatch as being benign.. I assure you it is not - you have the knowledge needed to understand the simple truth, just not the will to accept it - put the stock header back on and expect increased power and throttle response, throughout the RPM band.

Since you are their customer, I'd call Wheeling Cycle Supply (1-888-274-0886), to find out if you simply have mismatched part numbers - if so, maybe they will exchange your slipon for the proper one.

If the I.D.s prove the midpipe and header piping to be compatible, modifying the nipple (expanding or replacing it) to fit the bell without any gasket, would be a good solution.