That carbon fiber Delkevic looks great! The whole bike is chrome, black, and white!

I need to verify that the mating of the Delkevic and the stock header uses the stock seal in the header bell..? In other words, does the Delkevic slid into the stock gasket/seal or do you have to remove the seal before the Delkevic will slide into the header bell..?

 

In stock form the KLX should be very lean, with its measly 118 main and tattle-tale 5 minute warmup. Are you thinking it should be more like 13:1? That might be too hot though for reliability purposes, so perhaps 12:1 is what Kawa engineered it for stock. What AFR are you running?

 

Correct. The Delkevic slides into the stock gasket. It came with a gasket but the stock gasket looked terrific (2,000 miles) so I used it. Also laid a bead of sealant that came with the Delkevic. I really like the sound of the Delkevic, it's not obnoxious at idle/low range but is open and deep mid through high range. Even more impressed with the craftsmanship of this thing, all hand done welds, not a factory, mass produced silencer. Amazed at the value for that price. Oh, and I went for aesthetics of the carbon but discovered is dissipates heat much better than stainless.

Any suggestions of mods to the silencer? Keep the spark arrestor? baffle?

 

Interesting perspective, being I have zero experience/history with the KLX I had no expectations. Not sure I understand your question of what AFR I'm running?

 

A stock KLX would be lucky to see a 14:1 at its' richest point during WOT ops - This is my Dyno operator/owners' opinion as well.. He also said that it is quite normal for stock motorcycles to run 15.5:1 - 14:1 AFR's .. This is, of course, power robbing leanness..

My recipes are very conservative (lean). My target AFR was 12.8:1 and my recipes keep WOT AFR between 12.5 and 13 to 1.. This also allows "room" for higher altitudes without any loss of power..

12.8:1 is "lean best power".

IIRC, 12.2:1 is "best torque".

 

Oh, forgot to add that the reason we know typical operating AFR's on stock bikes is because no matter if it's a Vespa or a Hayabusa, they all get "squeezed" through the same funnel (EPA Emissions Testing) and their fueling curves all look the same when they come out..

 

What is important is that it is not possible for my recipes, applied properly/correctly to a properly functioning CVK, to over fuel a KLX250.

Quite the contrary, larger main jet sizes than mine (targeting 12.2-12.5 to 1) would show more power BUT we do not have a needle that can control such large main jets well enough to properly fuel the midrange (3.5k - 6.5k).. In case anyone is thinking the stock NNLA needle could, its' larger diameters combined with its' longer length serve to alter the top end fueling that the main jet would otherwise allow - making it useless as well..

 

Great thread guys, very interesting. And this, from a guy who was convinced to stay stock. UGH!

 

Klxster probably has a better chart, but I like referring to the one from wiki when I'm reading these discussions. See it down towards the end of the page. It also makes sense from an economic perspective why the bikes may be fueled lean. A good part of the motorcycling world is about maximizing miles per dollar and not power.



https://en.wikipedia.org/wiki/Air%E2%80%93fuel_ratio

 

Well,, you don't know what ur missin until you know what ur missin.. What's fun with all this "uncorking the power" is that it fundamentally changes the way you think about your KLX..

E.G. Your little putt putt, competent but mundane, trail or around town KLX becomes exciting. You look for excuses to kick your leg over 'er when all you really want to do is terrorize the town with it or roost the crap outta your offroad ridin peeps...lol