Calling BS

[Stusmoke]

http://motocrossactionmag.com/Main/News/MIDSIZED-SHOOTOUT-HOW-TO-CHOOSE-BETWEEN-A-125-TWOS-10018.aspx

A good read. Until the most reliable bike turns out to be the 250SXF.... Lets see the 250SXF makes its peak power at, and I quote: "Well after 13 thousand RPM". While the 250SX makes its Peak HP at again I quote: "8500".

On the grand scheme of things, I know sod all about motors. I know where things go, I know why they go around and around and I know what the vast majority of them do and how they do it. So my knowledge, compared to Jerams, Sach's, 2T institutes, Uniflows etc is like comparing pre-school mathematics students to Einstein or Newton. But I absolutely categorically fail to see how the 250SXF that makes its peak horsepower above 13 grand, can go through fewer pistons, rings, gaskets than the 250sx whick makes its peak horsepower roughly 5000 RPM lower. I've asked some KTM 2012 and 2013 250SXF owners do and they claim rings at 25 hours, pistons at 40 +- five hours on both ends. On the otherhand, I asked a guy who had his 2013 250sx since new, has put 37 hours on it and said he could do another 5 but changed the rings anyway cos he started loosing compression.

I realise I'm just nitpicking, being annoying. But it seemed so excessively ridiculous, that I thought I'd post it up here. 

[evo550]

I read that to, and thought what crap....except the KTM 250sxf has a piston change interval of 100hrs, and my 300exc has only 80hrs..so I would imagine a 125 would be somewhere in the vicinity of 50hrs...but to put that into perspective my 300 piston costs $80 the 250sxf piston is $500 , with piston kit at around $750 

[Stusmoke]

If I remember correctly, the 250SXF got a konig bridge box piston in 2013. First of all, I just love saying konig. Its just a cool name. Secondly, despite being what I assume must be a kick arse piston for KTM to boast 100 hours, can it really take the abuse of 10 grand and up riding for 100 hours? I would like to point out that my arguments are based entirely around the premis that the person racing both bikes, is RACING them. Not practise riding, not toying around in the race and taking a mid moto snack when they get a little bit puffed, flat out racing is what I'm talking about. Which means you leave the 250SXF pegged at no less than 10 grand. Excluding pit riding and mistakes made during race. With all that in mind, I have serious doubts that any 250SXF rider that understands what a shattered piston will do to his motor will leave it in there for 100 hours.

On the other hand, unless KTMs lawyers came up with a clever piece of fine print in the bike manual under the bit that says replace piston ever 100 hours, there is no way KTM would risk thousands of extremely pissed off customers by telling them to leave it in there that long. And when I consider that motoGP bikes must run 2500klms without a piston change at even higher revs, it starts to be a little more believable. A little. I doubt KTM puts the same amount of engineering thought into the production 250SXF as they do their factory MotoGP teams.

But MXA deliberately said: Which bike is more RELIABLE. And if the KTM 250SXF can run flat out for 100 hours on the same piston, then it is undeniably more reliable. But not cheaper. Just more reliable. Having said that reliable can also be taken to mean: If you took 10,000 250SXFs and 10,000 250SXs and examined the failure rate while under the recommended maintenance schedule, the bike that has the least would be considered more reliable. But as I said, others take reliable to mean how many hours you're supposed to get out of it before it blows up. Which seems silly to me, but anyway. My point here is, even though the 250SXF is more reliable by the second interpretation (possibly even the first, I have serious doubts anyone has ever done that or something similar), it ultimately winds up being MUCH more expensive and spends much more time in the shop than the two stroke. More time in the shop for the four stroke, the two stroke can be done in the garage while slugging whisky.

[evo550]

The 100hrs for a piston replacement is quoted from the ktm manual...@ $500 a piston they would want to last 100hrs.
Of course there is no mention of cam chains, valves ect. A 250 f can be completely reliable....it just takes a lot more maintenance and $$$ to do so than a 250sx.

[Stusmoke]

100% agreed. People keep saying that four strokes are time bombs, thats a stupid thing to say. All motocross bikes are time bombs, whether two stroke, four stroke, diesal, rotary, dark energy magnetic based or a steam engine, motocross, and by extension all racing motors rev high. Four stroke motocross bikes are just a much bigger bomb. And are alot harder and more expenisve to defuse before they detonate.

[VintageBlueSmoke]

"Barring catastrophes, the KTM 250SXF four-stroke will prove to be the most reliable. It will require less in the way of pistons, rings, gaskets and clutch plates over a racing season than the 250SX or 125SX." (emphasis mine)

(and they point out that...) "The caveat is that, in the case of a major blowup, the 250SXF four-stroke will become a financial burden. Whereas the 125SX and 250SX can be repaired in the garage with a couple hundred dollars worth of parts, the 250SXF four-stroke will quickly crack $1000 in parts and come with a big labor bill (for the mechanically inept). "

And I can see that. Figure that most non-pro 2-stroke racers will go though at least 2 pistons in a season. Most 4-stroke riders will only replace a piston at the end of the year. Even at $500 for parts and include gas, oil etc., the thumper is cheaper. However, aftermarket parts will kill you on the 4$. You will also require more tires and suspension work over the life of the bike (more weight, tired springs) but that is not really a consideration in their quotent.

Of course, you could add in the extra cost of grips and carpel tunnel surgery for the 250sx or the dental work to get the mud, rocks, and bugs out of your big smile on the 125sx...

[evo550]

"Barring catastrophes, the KTM 250SXF four-stroke will prove to be the most reliable. It will require less in the way of pistons, rings, gaskets and clutch plates over a racing season than the 250SX or 125SX." (emphasis mine)

(and they point out that...) "The caveat is that, in the case of a major blowup, the 250SXF four-stroke will become a financial burden. Whereas the 125SX and 250SX can be repaired in the garage with a couple hundred dollars worth of parts, the 250SXF four-stroke will quickly crack $1000 in parts and come with a big labor bill (for the mechanically inept). "

And I can see that. Figure that most non-pro 2-stroke racers will go though at least 2 pistons in a season. Most 4-stroke riders will only replace a piston at the end of the year. Even at $500 for parts and include gas, oil etc., the thumper is cheaper. However, aftermarket parts will kill you on the 4$. You will also require more tires and suspension work over the life of the bike (more weight, tired springs) but that is not really a consideration in their quotent.

You can't just compare 2t vs 4t reliability with a piston and ring comparison...what's the longevity of cam chains, cams, valves ect ? this needs to be taken into consideration in 4t reliability. We need to remember that the KTM 250f is the exception to the rule when it comes to piston life, most of the Japanese manufactures are around the 15 hr mark, with Husky specifying their first piston change at about 7.5 hrs.

[SachsGS]

Bunch of BS. Lots of blown 250 SXf's locally.

[VintageBlueSmoke]

 

OK, I agree with you all but that is not the parameters of the statement. If you are given these three bikes and race them all for 1 season, the SXF will be the cheapest - baring catastrophic failure.

At the end of the season, when you change psiton, cam, cam chain, etc. You will prolly spend more - but that is not the parameters of their statement.

It is not BS. It is carefully worded disinformation.

[SachsGS]

If it walks like a duck and quacks like a duck.....

So the idea is you race the f for a season and then unload it before it lets go like a hand grenade?

[lauterbacher]

Just ran into a young man while picking up some race gas, He proceded to show me his 3 bikes in his Van of which one was the KTM 250 F that he does'nt race anymore because it goes through pistons like candy. He said when racing it was every 3 months for a piston. The laugher was that he just picked a 250 YZ 2 stroke and now it's his bike of choice.

[twosmoke595]

If it walks like a duck and quacks like a duck.....

So the idea is you race the f for a season and then unload it before it lets go like a hand grenade?

seems to be the consensus on craigslist of late lol

[motoxr377]

If it walks like a duck and quacks like a duck.....

So the idea is you race the f for a season and then unload it before it lets go like a hand grenade?

I'm sure it's been done!

[factoryX]

Yeah read that a while back and promptly put the mag back on the shelf haha.

[Stusmoke]

If it walks like a duck and quacks like a duck.....

So the idea is you race the f for a season and then unload it before it lets go like a hand grenade?

I'm sure it's been done!

Are you kidding?! Its all that ever gets done! Thats how they roll, the poor bastard on the other end that thinks he will be able to pick up a only one year old bike for cheap is devastated. I know because I was once one of those poor bastards. Well mine was 6 yers old at the time, but the same thing.

If you are given these three bikes and race them all for 1 season, the SXF will be the cheapest - baring catastrophic failure.

First of all, I agree with the bottom part of your statement, they never actually told any falsehoods, they just made it look like the 250F was the cheaper option. The second part that I've quoted, is just not true.

It might be if you only hang around the low end and occasionally breach 10 grand down a straight, but as far as high revving, flat out racing goes, the 250F will out spend the 125 or 250 any day of the week. Engine oil: Needs to be changed after every race and practise day. No exceptions, no excuses. For a good bottle of oil in Australia, you're looking at about 40-70 bucks. I don't know about everyone else, but at 32:1 mixed into 20 litres of fuel I don't burn through the oil that qickly. Roughly as quickly as an entire 20 litres for a single practise or race day to be equal to the roughly 600-700 mil required for a four stroke oil change. So thats instant favour to the 2 stroke in oil costs alone.

Pistons and rings: The KTM might be able to pull 100 hours on its piston, but there is not a chance in hell that its rings will go that far. No way. So you'll have to pay a mechanic about 80 bucks in labour to get the head along with its valvetrain off to replace the rings. Thats about $150-170 in Australia all up, if you're lucky. I can do a piston and ring change in my shed for $120 including postage from NZ in about 1 and a half hours if I'm feeling lazy. Three heat cycles and I'm good to go.

Valve clearances: If you like rev limiting just before touch down on jumps, you'll need to have your valve clearances checked regularly and depending on the abuse that those poor little cams and valves take in the air, replaced. About $100 bucks to have valve clearances checked here in Aus. You would have them done at the same time as the rings if you had the slightest scrap of intelligence so thats about $40 instead cos they've already got it off. If you need to replace the springs or any part of them, thats more expense though I don't know have a clue how much.

If you are good with maintenance there is simply no way in hell the 250F is cheaper or as cheap as a 250 or 125. And this is all based on the 250sx v. 250sxf argument! The 250sxf has a long piston life (apparently) so what happens when you compare the 250sx to an RMZ250 that recommends a $300 piston replacement ever 40 hours? I reiterate, in no possibly way, over a full seasons racing is the 250F cheaper or as cheap.