how to undo the SR "detune"

Jaguar · Post by **Jaguar** » 07:18 pm Oct 29 2014

the SR is a street version of the KDX for the international market. It is "detuned" to be less ferocious on the street (and less intimidating for non-dirt riders). Kawasaki detuned it in these 3 ways:
1) the expansion chamber has a longer baffle section which lowers the supercharging effect and stretching it out over a wider RPM range
2) the carburetor is a 28mm instead of the normal 35mm. That lessens engine power at high RPM.
3) the CDI has slightly different timing and a 1.5uf charge capacitor instead of the normal 1uf. This lessens spark power which directly lessens engine power (according to the research paper "Devices to improve the performance of a conventional two-stroke spark ignition engine" http://www.dragonfly75.com/moto/ImproveEngine.pdf). I have a CDI bench tester and testing the two sizes of capacitors gave me these results:

How to undo the "detunes"
1) put a better pipe on it. I put a Pro Circuit pipe on mine and loved it. I used my KDX200SR for street, play riding, and motocross.
2) upgrade to a 35mm carburetor.
3) upgrade the CDI with my Performance CDI which has a 1uf or 1.2uf capacitor in it. It also has an adjustable timing curve for fine tuning so the curve can match your engine/pipe for best performance.
(click on my signature link for more info about upgrading the SR)

Post by **Julien D** » 10:30 pm Oct 29 2014

Thank you, sir. Stickied.

Bitteeinit · Post by **Bitteeinit** » 08:44 pm Oct 30 2014

Great info. I've always wondered whether or not the FMF pipes would fit the SR. Are you saying they fit no problem? Pre 95 and 95+?

Jaguar · Post by **Jaguar** » 03:34 pm Nov 01 2014

You have to slightly modify where the pipe connects to the cylinder but other than that all the normal KDX pipes fit the SR. If you are interested in a FMF pipe then go to their fmfracing.com site to see what is available.
Here is my paragraph on the subject on my site:
http://dragonfly75.com/moto/MX.html
The first thing to do is replace the exhaust pipe unless you are really tight on dough. If so, then just take the power-robbing insulation out of the body of the pipe (not the header. see http://justkdx.dirtrider.net and click "tech tips", then "pipe mod"). FMF has pipes for better low end and better top end (35 (torque) or 30 (rev) gnarly series pipes) but many have complained about quality control problems and mounting points not being correctly located. I chose to use the Pro Circuit pipe which enhances the high-mid and top end power. I have been happy with it. Recently I have gotten into expansion chamber design and here is a page explaining how I would custom make a pipe for it: click here

Bitteeinit · Post by **Bitteeinit** » 08:49 am Nov 18 2014

Hey Jaguar, I'm increasingly interested in acquiring a new pipe. My stock pipe has the usual "spring" attachment at the cylinder. I also have an aftermarket silencer (some weird brand no one's ever heard about), but that shouldn't be an issue. Do you have a picture of your pipe at the cylinder? I have a feeling the previous owner may have anready modified that area somewhat. I understand you don't use FMF but a Pro Circuit... Or do you use your "modified" stock pipe?

Jaguar · Post by **Jaguar** » 03:13 pm Nov 18 2014

I no longer have the KDX. But the modification for the pipe is easy to do. Don't worry about it.
Once I get another KDX I plan to put my own design of pipe on it. (details on my site)

mxkdx250 · Post by **mxkdx250** » 03:05 am Jan 18 2015

Hey you guys still here.......

Beer! · Post by **Beer!** » 05:57 am Feb 08 2015

I am in the process of doing this, sent an email to the OP on his site, but no reply, I need the CDI and recommendations on jets. I am riding at sea level but do some mountain riding up to 1500 feet sometimes, Just got the 35mm carb v force triple reeds and the FMF fatty pipe installed. Hoping to get in on the steel kips deal in march as mine are sheered off at the teeth.

Jaguar · Post by **Jaguar** » 01:57 pm Feb 08 2015

sorry about that bad contact form on my site. In place of it I just listed my email address that you can use. Or you can ask me here.

Beer! · Post by **Beer!** » 04:21 am Feb 09 2015

Thanks Jaguar, So then you still have these CDI for sale?

Jaguar · Post by **Jaguar** » 12:00 pm Feb 09 2015

yes they are available. You can order them online on my site.

crs · Post by **crs** » 07:01 pm Dec 20 2015

Just spotted this thread... My '99 SR 220 has a trigger pickup on the the stator - after checking with the OP about his CDI, found you can't use with this setup. Check before you buy...

Jaguar · Post by **Jaguar** » 12:53 am Jul 18 2020

those CDI's are no longer available from me but I am doing jetting consultations using my jetting calculator and my many years experience.
www.dragonfly75.com/moto/carbjetting.html

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