Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: KTMguy on April 28, 2010, 05:36:39 AM
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http://www.motocrossactionmag.com/Main/News/WE-BUILD-A-KTM-300SX-BIGBORE-6884.aspx (http://www.motocrossactionmag.com/Main/News/WE-BUILD-A-KTM-300SX-BIGBORE-6884.aspx)
I never knew about this until this artlicle. I'm tempted to get it for my 250SX. An 800 bolt on mod that increases up to 4 HP? That's a bargain. I'm just worried about this "brutal powerband". I've never once been riding my 250 and thought "hmm, I wish I had more power."
(http://motocrossactionmag.com/Uploads/Public/Images/April/ktm300sx/ktm300sxparts.jpg)
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Just so you know... that was on the TSM site in October..... :-* :-*
http://twostrokemotocross.com/2009/10/ktm-300cc-sxs-engine-kit-for-250cc-2-strokes/ (http://twostrokemotocross.com/2009/10/ktm-300cc-sxs-engine-kit-for-250cc-2-strokes/)
Although the test in MXA was helpful, I had read some different observations on the kit at KTM Talk....
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An 800 bolt on mod that increases up to 4 HP? That's a bargain...I've never once been riding my 250 and thought "hmm, I wish I had more power."
I have to ask, why get a big bore kit then?
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I was thinking that if it smooths out the power, and gives it some more bottom it would be the way to go. But reading the article, it sounds like it makes it a snarling beast. You could probably gear it up a little and smooth it out, plus use the stiffer power valve spring.
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And the four pigs will still be cheating... hahahahahaha
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Interesting note here. The KTM uses a 36mm carb. I think peak power, would be a bigger carb, atleast 38mm if not up to a 40mm. So might be the perfect power add on with this 300 kit. :-) The 125 uses the Keihin PWK 38S AG, maybe just a bolt on swap?
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If you are after torquey engine buy the XC kit which has a different ignition box.
Interesting reading the article that the cylinders on the XC,EXC & Sx are all the same.
Just a different head and ignition box.
Would be nice to see what the power curve is like on a 250SX with the 300XC kit.
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I've done this swap before back in 04' and 06' and it's great way to got more power and broaden the power band. back then you had to buy all parts from ktm and buld the kit yourself at the cost of $1,100.00 way cheeper now in kit form. I just put one on for the the two stroke world championship race and i forgot nice it is. hits alot harder off the bottom. KTM111
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I've done this swap before back in 04' and 06' and it's great way to got more power and broaden the power band. back then you had to buy all parts from ktm and buld the kit yourself at the cost of $1,100.00 way cheeper now in kit form. I just put one on for the the two stroke world championship race and i forgot nice it is. hits alot harder off the bottom. KTM111
wait....ktm111??? is this mike sleeter??
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No thats not me i ride a ktm #111 as he doe's he. but I had that number on my bikes sence 03' . I met him at the two stroke world cham. race and had laugh about it, he's a realy cool guy. KTM111
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Interesting note here. The KTM uses a 36mm carb. I think peak power, would be a bigger carb, atleast 38mm if not up to a 40mm. So might be the perfect power add on with this 300 kit. :-) The 125 uses the Keihin PWK 38S AG, maybe just a bolt on swap?
Found an article in an old dirt rider mag Jan 2008.
Dirt Rider mag modded a 300XC with the help from Dicks Racing to run in the Glen Helen 24hr. One of the mods was to the carb.
(from the mag)" The 36mm carb is great for for low-end response, but not stellar for mid-top power. To remedy this, Dick's Racing bores the carb in such a way that from 0-1/4 throttle the carb remains a 36mm. After that, it graduates to the flow characteristics of a 39mm carb. In order to compensate for the changing bore sizes, a Dial-a-jet is added which allows for precise jetting for max power without the risk of siezure"
"Dicks mods (carb, porting, compression, rad valve and FMF exh) broadens the appeal of the motor dramatically and it retains the good early response, but now hurls harder into the mid range and pulls like a missile on top"
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Yeah Graham472 I also read that article in Dirt Rider and I just wanted to ad that Dicks Racing is now selling the taper bored carb with the Dial-A-Jet on it!I just thought that was good news for any KTM-300 owners out there. :)