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55-60rwhp possible out of a 300 2-stroke?


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Im trying to decide between an 07 yz450f or an 07 ktm 300xc. I do a mixture of trail riding and free riding in New England and south florida. I know the ktm will rock in the new england woods and HS races but im not sure how it will do for free riding in the dunes or mining areas up north that have long, steep, multi-story coal hills that me and my riding buddies like to hit.

Ive ridden a ktm 300 once and i never really got to open it up. What i've read is it has monster bottom, good mid but signs off quick on top. which makes me nervous. It felt like a kdx200 on major steroids. Which i like, because the kdx200 is a fun bike in the tight stuff but is super boring when things open up and the hills get steep. Also i need a bit of power and snap for the south florida sand and the oklahoma dunes.

SOOO.... how expensive and time consuming would it be to give the ktm a killer screaming top end without killing too much of it's bottom and mid? would it be possible to get 55-60rwhp out of this thing on pump gas? I've read that it doesn't have a domed piston and it could benefit from one. What i would like ideally is for the bike to be close to stock power on the tamer, wet setting and then on the normal dry setting be an arm puller.

Is that possible or am i looking at the wrong bike here? maybe the yz450f is where i should go?

And no i can't afford two bikes.

If it helps im 6'1 220lbs.

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A friend of mine has an 07 300XC and he is 6' 195. It is definitely an open class bike because it has open class power. I'm 5'7" 135 and it has more power than I care to ever have in the woods or in any terrain for that matter. If all you ride is off-road, it is going to be 100 percent more off-road friendly than the YZF. It should have ample to climb all the hills, etc. Dirt Rider did a comparison of it and the 400cc 4Ts recently http://www.dirtrider.com/reviews/motocross/141_1007_midsize_offroad_comparison/index.html .

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The 300 will do fine in the dunes. I ride my 250 in the dunes with a paddle and yes the big 450 will eat it up, I think the problem lies more with the tranny and not the motor. Bigger transition is gear shifts. When draggin racing (i really dont care much about this cause I made my bike shine for the single track) first is too low and second is too high. With the 300 you could have too setups one for woods and one for dunes. I know my 250 is not boring on the top end so a 300 should be far from it. It is hard to haave one bike do everything well. But a few spins on a 450 in the tight stuff makes me happy with my smoker. I only ride dunes a few times a year so if my bike is not top notch there I am fine with it.

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Thats weird because I love XC races when I get to run a top gear straight and go by all the 300's on my YZ250 that were hauling butt in the tight sections. My experince with the 300 is not that it signs off but that it never signs on like a tractor in low gear.

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Thats weird because I love XC races when I get to run a top gear straight and go by all the 300's on my YZ250 that were hauling butt in the tight sections. My experince with the 300 is not that it signs off but that it never signs on like a tractor in low gear.

My 300 outruns my old '02 YZ250 (sold to a buddy I still ride with sometimes) pretty easily and another friend's '05. He roached a piston trying to pull me WOT in a fast wash. It'll also pull another friends '07 CR250 without too much fuss. All of these 250's have had some 'spensive motor work too. As far as top speeds go, the 300 probably has 15-20 MPH better top speed with stock gearing. That reminds me...after today I have to order some parts.....😏🤣😏

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My 300 outruns my old '02 YZ250 (sold to a buddy I still ride with sometimes) pretty easily and another friend's '05. He roached a piston trying to pull me WOT in a fast wash. It'll also pull another friends '07 CR250 without too much fuss. All of these 250's have had some 'spensive motor work too. As far as top speeds go, the 300 probably has 15-20 MPH better top speed with stock gearing. That reminds me...after today I have to order some parts.....😏🤣😏

Hmmmm must be my super bad 08 YZ250 because it will blast past my 09 300xcw in sand whooped straights like the 300 needs another gear. Now if I'm going to ride a wet moss covered rock stream XC race the 300 with rekluse is great bike especially with the choice in map switch postions. Typical mixed terrain XC race I go with the YZ for those open sections

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saw on youtube : dyno'ed at 58Hp@8k with the red PV spring and some head mods

true or make-up number? that i don't know but i think it very doable to hit 60 whp on those. head work + porting , bigger carb , SX ignition and a full pipe should get you above the mark.

I have a 2010 300 xc-w. If i want to put a sx ignition on it, do i get the 2010 250sx ignition? If so, is the actual cdi unit the only thing i have to swap to make the change?

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I've got a riding buddy with a sweet 07 YZ250 and it will NOT out pull my 300, but it hangs on pretty well until we get to around 60ish and then I leave him. The YZ just runs out of gear though and my 5th will pull me well into high 80's.

I should clarify though, that was on my 09 XC and I think it was a little quicker than my current W, this all b/c of gearing. The XC ran out of gear in a hurry though, 60mph was about top speed but it would wheelie over at will even topped out at that speed.

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Well good to hear that the stock 300 motor gets some high ratings, because i talked to the owner today and it sounds like it's a done deal. I'm still interested in squeezing more power out of it. I think it'll be fun to modify, and i love more power. But i wont have the time or money to really get into it this season. Hopefully in time for the dunes though.

Im thinking sx ignition, cut head, port/polish, domed piston..... anything else i should look into? bigger carb maybe?

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I've got a riding buddy with a sweet 07 YZ250 and it will NOT out pull my 300, but it hangs on pretty well until we get to around 60ish and then I leave him. The YZ just runs out of gear though and my 5th will pull me well into high 80's.

I should clarify though, that was on my 09 XC and I think it was a little quicker than my current W, this all b/c of gearing. The XC ran out of gear in a hurry though, 60mph was about top speed but it would wheelie over at will even topped out at that speed.

Im a little confused by your post. Did your xc out run the yz or your xc-w?

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Ya I made that a little confusing, sorry. The XC was what I was on when I out ran the YZ but it topped out around 65ish. I think YZ's top out around the same speed and he was not able to catch me, though it was close.

The W on the other hand can run 80+ mph.... If I can hang on up to 5th I'd be able to run away from the YZ 250.

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KTM world has some stuff on their web site about stroking a 300 and somewhere inside the motor applied epoxy to make more comprssion. http://www.ktmworld.com/ktm_article.asp?id=54

The last race I had done in May there was about 5mi of fire road with about 5-6 whoops dead center of it I was behind a guy going a little slower he went to the side I figured I would hammer through the center rolled on and hit the powerband in 5th and the bike stood up on the rear tire hit the first whoop missed a few in the center and caught the last one or two still on the back tire my feet came off the pegs lucky for me the seat grips well otherwise I would have needed an air lift out of the desert. A mile later I thought to my self man that was stupid.

I have had this bike at the dunes and tight trails at 8k+ it has more ability then I have skills. Had a FMF Fatty on it with a Q sliencer I have since move to a PC combo. Other wise unmodified bike powerplant wise. (Running red spring with the adjuster back out to flush with the housing)

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I think the Slavens Mule kit achieves around 52 hp but even better it's puts you around 36-38ft lbs of torque.

hmm. i was just checking their site. looks like the oldest they offer parts for is 08 and the bike im looking at getting is an 07 : (. I really hope that if i get this 300 i can go in the direction i want to go with it....

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