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wanted: 250 sx/xc gearset, barrel, piston ect.

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i've had enough of my ktm 300's power delivery, plenty of torque and bottom end, but lack's any top end/over rev, and the W transmission is just frustratingly wide, idealy i'd like a 200 but can't afford to sell the 300, so a 250 XC is the next best thing.

so i'm after a complete 250SX or 250 XC gearset, and a 250 XC barrel, piston, and powervalve (and whatever parts i might need if i've missed anything) to suite an 09 300 EXC-E

if you have anything for sale PM me (keep in mind i live in australia)

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No help with the trany, but for the power how about hopping up the 300.

Higher compression (reworked or replace head with SX head, SX ignition, (also, maybe porting, and reducing flywheel weight for the full effect if you want, but I think these are secondary). Also, maybe a different pipe depending on which one you have.

Or get the 300SXS conversion kit for the 250. Here

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have you tried 2 up on the rear sprocket?

shaved stock head?

set X to 0?

swap out some of the internal gearing for the XC. The 300XC's here are no slouches. I know you guys can't get them.

250SX CDI?

as Gary said, different pipe?

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i'm not looking for more power, i just hate the power delivery, in fact if i could get less outright hp with a more agressive delivery that would be ideal, hence why i'm after a 250 xc, i've got an FMF fatty pipe on it with the stock silencer, and ahve spent a fair bit of times playing with jetting and needles (with the help of riles, thanks mate), running 13:52 gearing, set the X to zero, havn't gotten the head shaved.

i wanna turn it into a bike i can ride agressivly more easily, as it is it has plenty of bottom end and midrange, but not a whole lot of top end and over rev, and when trying to ride it agressivly it feels unpredictable since the power sign's off so quickly when compared to my KX250F, really like likes to be ridden slowly, idealy i'd get a 200 but i can't afford to sell the 300 at the moment due to finances, and if i were to sell it i don't think i'd buy another ktm, i'd probably go for a jap 125 two stroke to replace it.

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My guess is, your bike won't rev because you put a pipe on it that was never intended to rev out, you can jet that pipe until your fingers bleed and it still will not rev like the OEM pipe.

l may be looking for a "W" CDI and 5th gear set for my sx, I'll cross the part numbers to see what works.

Yes, you should have bought 200, but they don't sing on top until you get the power valve and jetting set correctly either.

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It sounds like you are on the right track with the gears. Have you checked the classifieds here.

So do you like more MX type riding then woods stuff?

I am not sure why you reject increasing power of hopping up the 300. This will change the power delivery. It sounds like if it is fading in the RPM's you want more HP there so it doesn't fade. That is where the HP comes on with most HP increases. It sounds like you are satisfied with the low end torque, and maybe you are saying you have to much, but it doesn't come on and fades in the upper RPM's. If it doesn't come on the way you want then it seems like it would be good to increase it. Everything folks have suggested will help this although not lower the low end torque (much).

Usually having plenty of low end torque is not a bad thing. It is also a plus when pared to a wide ratio transmission. Adding more top end won't hurt.

You say you want it set up so you can ride more aggressively reinforced by the statement that it fades in the high RPMs but then you reject everything suggested to head you in that direction, saying you don't need more power just a different delivery. But you are doing everything you can to go in the other direction IMO. Like the pipe, rejecting higher compression, etc.

The power of the 300 should be greater then the 250F all around but may have more rotation inertia, rev slower, and let off slower, surge more and generally not be as snapy. Certainly the 250F has more engine braking. Maybe you like the lighter rotation mass of the 250F. All that coupled with the gear spacing makes it a lot different but I doubt that it is slower. Also having more high end won't hurt all these issues and would work nice with the wide spacing allowing you to rev further before shifting while still maintaining the low end torque for the next gear if you don't rev it out. Do you think your dissatisfaction has something to do with how fast the 300 revs vs the other? Maybe it has something to do with how you are riding it too. For example, maybe you are not using the low end torque staying up too high in the revs where you run out of the power band to quickly as you continue to increase RPM. If so I am not sure converting to a 250SX would help. It may have more to do with FFW although a little of the rotating mass is inherent to the bigger piston. Have you checked out the flywheel to see if they are the same. I suspect the 300 has a heavier one. Also the SX ignition mapping helps with the quicker acceleration, revving, or over rev.

You might just try a different flywheel, SX CDI, and get rid of the fatty pipe first. Or at least do this in stages. I am just saying try them first before going to the 250SX cylinder because you have to do them anyway to get what you want out of the 250 conversion so nothing lost. It would be a loss to increase compression by cutting the head because you would be getting a new one with the 250SX conversion, but I think you would like that too.

How much do you weigh?

Gary

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i put the fmf pipe on after crushing the stock one, the only reason i went with it was because it was cheaper then a stock pipe, and from reading on here it was described as giving a noticable gain throughout the rpm range, including top end, however i noticed the biggest improvment in the midrange, right where i don't want it

i ride woods exclusivly on the 300, my 250F was origonaly bought for MX, but i find myself riding it offroad mroe then my 300, a few local fast guy's have commented on my riding style as being very agressive which is why i feel less pwoer with a more agressive power delivery would suite me better (or should i say a smoother, but peakier delivery, at the moment it's got decent bottom, massive mid range and soft on top, as every ktm 300 i've ridden has been) if i were to do it over again i don't think a KTM 300 would have been the ideal bike for me, i probably would have done with a TM EN 250 or stuck with my RM 250 (big mistake selling it)

basicly, i get out of shape alot and find myself needing to hold a gear a bit longer then ideal due to not being able to get the the shift lever, on my 250F, no problem, just hold it open until i can regain my composure, on the 300 once it start's to sign off it just hit's a wall and won't rev out anymore, i never ride anything very open, and when i do i dont enjoy it so i dont see the point of being able to do 140 KP/h, when really 80-90 would easily do me, and i like a close ratio box.

It sounds like you are on the right track with the gears. Have you checked the classifieds here.

So do you like more MX type riding then woods stuff?

I am not sure why you reject increasing power of hopping up the 300. This will change the power delivery. It sounds like if it is fading in the RPM's you want more HP there so it doesn't fade. That is where the HP comes on with most HP increases. It sounds like you are satisfied with the low end torque, and maybe you are saying you have to much, but it doesn't come on and fades in the upper RPM's. If it doesn't come on the way you want then it seems like it would be good to increase it. Everything folks have suggested will help this although not lower the low end torque (much).

Usually having plenty of low end torque is not a bad thing. It is also a plus when pared to a wide ratio transmission. Adding more top end won't hurt.

You say you want it set up so you can ride more aggressively reinforced by the statement that it fades in the high RPMs but then you reject everything suggested to head you in that direction, saying you don't need more power just a different delivery. But you are doing everything you can to go in the other direction IMO. Like the pipe, rejecting higher compression, etc.

The power of the 300 should be greater then the 250F all around but may have more rotation inertia, rev slower, and let off slower, surge more and generally not be as snapy. Certainly the 250F has more engine braking. Maybe you like the lighter rotation mass of the 250F. All that coupled with the gear spacing makes it a lot different but I doubt that it is slower. Also having more high end won't hurt all these issues and would work nice with the wide spacing allowing you to rev further before shifting while still maintaining the low end torque for the next gear if you don't rev it out. Do you think your dissatisfaction has something to do with how fast the 300 revs vs the other? Maybe it has something to do with how you are riding it too. For example, maybe you are not using the low end torque staying up too high in the revs where you run out of the power band to quickly as you continue to increase RPM. If so I am not sure converting to a 250SX would help. It may have more to do with FFW although a little of the rotating mass is inherent to the bigger piston. Have you checked out the flywheel to see if they are the same. I suspect the 300 has a heavier one. Also the SX ignition mapping helps with the quicker acceleration, revving, or over rev.

You might just try a different flywheel, SX CDI, and get rid of the fatty pipe first. Or at least do this in stages. I am just saying try them first before going to the 250SX cylinder because you have to do them anyway to get what you want out of the 250 conversion so nothing lost. It would be a loss to increase compression by cutting the head because you would be getting a new one with the 250SX conversion, but I think you would like that too.

How much do you weigh?

Gary

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you are on the wrong bike from what you have posted. The 300 is hard to ride aggressively unless you are very good. You will either have to learn to adapt to how the 300 likes to be ridden, or sell it and get another bike.

unfortunatly many end up like this, thinking bigger is better instead of really analyzing what and how they ride. I know I did the same thing....

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Yeah, I see where you are coming from a little better.

I think the 300 is harder to ride competitively or aggressively then a smaller bike but easier to ride casually then anything else making it a great trail bike. I have always felt that way about big or open class bikes as we called them at one time. The difference mostly has to do with whether you use the throttle as an on/off switch or a whether you modulate it IMO or in my experience. Granted the power delivery, massive low end torque and mid range surge has something to do with it, but mostly just the shear power available especially at low end. I feel kind of the same way as you as you on a 450F but it is a little different for some reason. I think because of the light flywheel and super fast rev time, and then of course the 4 stroke engine braking.

In the early '70's I had a Yamaha 360 MX and it was like that. Of course it handled like crap too with no suspension. The first Yamaha YZ400 I rode was even more like that. I was coming out of a burm on one of those in 4" deep mud with 1/4" of ice on top, breaking through the ice, and blasting roost with the back tire spinning, hanging out all sideways with the front wheel coming up. I thought wow this is pretty cool. I was climbing up on the tank to keep the front down, unsuccessfully, and finally had to let off. The back tire was spinning so fast and there was so much rotating mass that when I let off it started getting more traction and I looped it. Busted my knee up pretty good going through the ice layer with no knee pad's. Everything hurts worse when it is cold. I was probably around 130# at that time. It was easy to ride casually as a trail bike but it was just a beast to race. I came to hate that bike.

Then there was the Honda CR500.

I guess the 300 has some of all that going on but I have slowed down a lot in my old age and I like it. I think I would like it better set up as a SX although I would probably not use the extra top end power I like that kind of delivery as you say.

I have always liked 250's the best in a two stroke. The best compromise of power, low end torque, and weight for me. I suppose if I were 250 lbs I would like bigger bikes better and if lighter maybe smaller ones. Maybe altitude would make be change too.

Gary

Edited by Gary jp4

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When I first converted my 250SX to a 300 it was pretty bad. All violent low end and no top end hp at all or over-rev.

Let me tell you how to fix it.

1) Adding base gaskets in .2mm increments makes a HUGE difference. This is basically free and helps the most. Adding a full .4mm base gaskets will turn a low end monster into a top end screamer. It does this two ways, it lowers compression but more importantly it alters port timing and gives the piston more dwell time at the bottom of the stroke. Basically it lowers the piston in relation to the intake ports making the ports stay open longer at high RPMs. This causes more reversion at low RPM (less hp) but helps at high RPMs.

2) FMF SST pipe and silencer did wonders for the width of my powerband on my 300.

3) Get rid of the 36mm carb as it favors low end response. You can have them bored to a 38mm for a very reasonable cost.

Don't go backwards by running the 250. Just do some or all of these mods to get it straightened out.

I can't help you w/ the gear set.

Lastly there is a lot of confusion about what comes w/ the 300 SXS set up. it is exactly what you currently have so don't waste your money. It comes w/ the 300XC ignition, head and piston.

Edited by PSD_Sun

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you are on the wrong bike from what you have posted. The 300 is hard to ride aggressively unless you are very good. You will either have to learn to adapt to how the 300 likes to be ridden, or sell it and get another bike.

unfortunatly many end up like this, thinking bigger is better instead of really analyzing what and how they ride. I know I did the same thing....

you didnt have to tell me that, i already knew it's the wrong bike, only reason i still ride it is because it's reliable as a brick, where as it seems everytime i ride my 250F i have to fix something, however theres no way i can afford to sell the 300 at the moment so i kinda just have to live with it until i can afford to get rid of it, so i was planning on making it more to what i want for the short term.

my plan was to find somone to sell me a 250 top end, sell or trade the 300 parts and there i've invested minimal into it, also a secondhand gearset i was hoping i could get for a reasonable price.

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When I first converted my 250SX to a 300 it was pretty bad. All violent low end and no top end hp at all or over-rev.

Let me tell you how to fix it.

1) Adding base gaskets in .2mm increments makes a HUGE difference. This is basically free and helps the most. Adding a full .4mm base gaskets will turn a low end monster into a top end screamer. It does this two ways, it lowers compression but more importantly it alters port timing and gives the piston more dwell time at the bottom of the stroke. Basically it lowers the piston in relation to the intake ports making the ports stay open longer at high RPMs. This causes more reversion at low RPM (less hp) but helps at high RPMs.

2) FMF SST pipe and silencer did wonders for the width of my powerband on my 300.

3) Get rid of the 36mm carb as it favors low end response. You can have them bored to a 38mm for a very reasonable cost.

Don't go backwards by running the 250. Just do some or all of these mods to get it straightened out.

I can't help you w/ the gear set.

Lastly there is a lot of confusion about what comes w/ the 300 SXS set up. it is exactly what you currently have so don't waste your money. It comes w/ the 300XC ignition, head and piston.

Wow, good advice. Sounds like a fun bike. I have heard bits and pieces about your mod before.

I think I would at least try bumping down the x dimension with some additional base gaskets first before going to a 250. Like you say, that is basically free.

PSD_Sun, do you know the difference between the 250SX and the 300 as far as crank and flywheel weight?

Gary

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Not sure about the flywheel weight but the bikes you mentioned in the years we are concerned w/ use the same part number for the crank.

Your '03 250SX has a lightweight crank that some racers install into later models to get extra snap.

One more suggestion for the OP: I hear that the Boyesen RAD valve adds some top end by robbing a bit from the low end as well.

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The SX and XC have the same Fly wheel.

I'd consider swaping 5th (from 2010 250sx) gear sets out with you, but I'm kind of swamped until after the Aligator, I'm sending the 200xc on down there.

Since 98' I've had just about every year 300, I found it really tough to run a fast race pace and stay off the ground, a few years ago I swapped bikes with a slower rider that thought his 200 was a turd, he fell in love with my 300 and I instantly went faster on the 200.

The next week I bought a new 200xc and he showed up with a 300, I'm a hold it wide open and clutch rider (which is hard on a 300) and the other guy was a chugger, it only took me 12 years to figure that out.:ride:

Edited by ktm300

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The SX and XC have the same Fly wheel.

I'd consider swaping 5th (from 2010 250sx) gear sets out with you, but I'm kind of swamped until after the Aligator, I'm sending the 200xc on down there.

Since 98' I've had just about every year 300, I found it really tough to run a fast race pace and stay off the ground, a few years ago I swapped bikes with a slower rider that thought his 200 was a turd, he fell in love with my 300 and I instantly went faster on the 200.

The next week I bought a new 200xc and he showed up with a 300, I'm a hold it wide open and clutch rider (which is hard on a 300) and the other guy was a chugger, it only took me 12 years to figure that out.:ride:

i'm a hold it open with the clutch rider, luckly it only took for me to ride a CRF250 for me to figure it out.

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Yeah, I hear you. You have to change your throttle habits on bigger bikes. That's what I thought you might be saying, what I was talking about in my previous post, and that is why I have always liked 250 two strokes myself. Even the 250 two stroke (at least the SX) is going to have some of that problem compared to a 250F because it has a lot more power then the 250F, but it is more in the top end. Since it is more in the top end maybe you would like it better, but I would give the tuning suggested for the 300 a try first. At least the free stuff. If you think it is going in the right direction you could continue.

The extreme example of what you don't like would probably be a 450F. It took me several rides on a 450, on a track, to realize, or accept, that I didn't need to do much clutch work or shifting and I couldn't always crack full throttle when I wanted to get it going as fast as possible. To me it is a monster in the woods. I could get used to it though, but it's amazing what you can get used to. I think this is what you are feeling. It just has so much raw power everywhere and you can't always use full throttle. A tuned up 300 would be like that with all around power but with a little less low end and the light weight (same as a 250) making it the ultimate in the all around riding I would think, although I never rode a tuned out one like PSD_Sun's. Guys on 450's in the woods tend to roost a lot, dig big ruts, and are debatably not as fast in a lot of situations, or at least they are harder to ride. Throttle now becomes an additional variable instead of an on or off switch in more situations making it harder if you don't accept that. Like accepting that it is getting the output you want with less throttle to go just as fast or faster with a given (less) throttle input. You actually have more control available (or options) with the extra power but you can't always use it.

I always compare 450F's since they are in the same class with the 250 two strokes and the 250F with the 125's although after much manipulation of the four stroke sizes they now outdo the 2 strokes in MX. The 300 is somewhere in between the 250 two stroke and 450F's IMO and more suited to the woods then the 450F. I think the 300 would be the ultimate woods bike in most cases, more then the 250, depending on rider preference, rider weight, how tight or open the woods was, altitude, etc. I do like my 250SX although there are some places where I could use more low end and some open places where I could use more top end and even the wide gearing for 4th and 5th I think. Are you ever actually using 4th and 5th gears in the woods? If I was ever going that fast in the woods I don't think I would be racing. More like cruising very fast.

I think if you tuned it as suggested and learned to not always crack full throttle to launch it that you might like it.

I used to race MX with a guy that was about 130 lbs and raced the open class (Back then 251cc or greater) on a Yamaha 400 YZ. His philosophy was that anyone could ride a 125 or 250, everyone did, and if the back tire spins then up shift. He did quite well.

Gary

Edited by Gary jp4

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Yeah, I hear you. You have to change your throttle habits on bigger bikes. That's what I thought you might be saying, what I was talking about in my previous post, and that is why I have always liked 250 two strokes myself. Even the 250 two stroke (at least the SX) is going to have some of that problem compared to a 250F because it has a lot more power then the 250F, but it is more in the top end. Since it is more in the top end maybe you would like it better, but I would give the tuning suggested for the 300 a try first. At least the free stuff. If you think it is going in the right direction you could continue.

The extreme example of what you don't like would probably be a 450F. It took me several rides on a 450, on a track, to realize, or accept, that I didn't need to do much clutch work or shifting and I couldn't always crack full throttle when I wanted to get it going as fast as possible. To me it is a monster in the woods. I could get used to it though, but it's amazing what you can get used to. I think this is what you are feeling. It just has so much raw power everywhere and you can't always use full throttle. A tuned up 300 would be like that with all around power but with a little less low end and the light weight (same as a 250) making it the ultimate in the all around riding I would think, although I never rode a tuned out one like PSD_Sun's. Guys on 450's in the woods tend to roost a lot, dig big ruts, and are debatably not as fast in a lot of situations, or at least they are harder to ride. Throttle now becomes an additional variable instead of an on or off switch in more situations making it harder if you don't accept that. Like accepting that it is getting the output you want with less throttle to go just as fast or faster with a given (less) throttle input. You actually have more control available (or options) with the extra power but you can't always use it.

I always compare 450F's since they are in the same class with the 250 two strokes and the 250F with the 125's although after much manipulation of the four stroke sizes they now outdo the 2 strokes in MX. The 300 is somewhere in between the 250 two stroke and 450F's IMO and more suited to the woods then the 450F. I think the 300 would be the ultimate woods bike in most cases, more then the 250, depending on rider preference, rider weight, how tight or open the woods was, altitude, etc. I do like my 250SX although there are some places where I could use more low end and some open places where I could use more top end and even the wide gearing for 4th and 5th I think. Are you ever actually using 4th and 5th gears in the woods? If I was ever going that fast in the woods I don't think I would be racing. More like cruising very fast.

I think if you tuned it as suggested and learned to not always crack full throttle to launch it that you might like it.

I used to race MX with a guy that was about 130 lbs and raced the open class (Back then 251cc or greater) on a Yamaha 400 YZ. His philosophy was that anyone could ride a 125 or 250, everyone did, and if the back tire spins then up shift. He did quite well.

Gary

i rode the 300 for a year being quite happy with it, it always frustrated me that i liked other peoples bikes mroe thne mine, eventually i bought a KX250F after riding a CRF250 and being that it likes to be ridden how i like to ride, i'm much faster on it, and yes i often hit 4th and 5th gear, some tracks are just miles of wooped out sand track, where i can easily top out the 250F, and i have a ball doing it, alot of the tracks though i dont see past 3ed (and i ride most single track in 2nd/3ed, never going slow enough to use 1st, and when i am i clutch instead)

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