I've decided on getting a 250F in spring but I still am not convinced which is the best one. I like the dual pipes of the CRF although they aren't necessary. I've heard many good things about the YZF. I haven't heard anything of the RMZ or EXC-G but I know that KTM is good because they are austrian. Of course, the yamahas and the hondas have known to be just about bulletproof. I used to have a honda XR-70 and now a yamaha TTR-125, but I want a 250 that's fast and reliable, plus the suspension benefits. I may just decide on the YZF because of the new Kayaba forks.
I need advice from anyone with a 250F either YZF, or CRF maybe RMZ or EXC-G
- Thread starter Kew-rider
- Start date
- Aug 3, 2004
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The general consensus around here is that the Yamaha is king for reliability, honda being a close second. Unless you REALLY like kaw/suz, stay away from them until they rethink what a 250f motor should be. The thing with the KTM is, nobody really knows how good they are yet, because they haven't had enough hours put on them in real world riding. Do make sure you read this article if you are thinking of getting a racing 4-stroke bike. You need to know what you're getting into:
http://www.dirtrider.net/forums3/showthread.php?t=115201
http://www.dirtrider.net/forums3/showthread.php?t=115201
- Thread starter
- #3
Do four stroke MX motors REALLY need to be rebuilt that often?!?! I mean, 15-30 hours I could easily put on in like two or three weeks, and there's no way I could afford that time and money to go into it. I don't really even like Kawasaki or Suzuki, but I just wanted to use them in comparison. If you really have to do that much work on a four-stroke racer I might just as well go with a two-stroke 125. I'm wondering, how often do you have to rebuild a bone-stock 06' YZ125? Are there any good bikes out there that are of good performance and relatively low maintenance? I'm mainly into four-strokes because they don't attract as many cops, but then again I'm riding next to a friend that has a KX85, so I guess it really wouldn't really make a difference. Reliability is a huge key though, because I sometimes get to ride bull gap, which is around a 20 mile trail and it would be horrible to have to walk it that far. From what I've heard, all that's needed are new piston rings every season and eventually a top-end rebuild every two years or so.
- Aug 3, 2004
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250F bikes really do require that much maint.
For example, if you push the valves too far before replacement, you're looking at the head removing itself from the stem.
250F head after Ti-valve metal fatigue courtesy of Rich Rohrich:
A good Ti valve on the left VS a beat Ti valve on the right again courtesy of Rich Rohrich:
If you push the crank too long, you're looking at some major energetic dissasembely via the rod breaking at the small end. This will trash the complete valvetrain, the piston, cyl, and likely the cases.
I guess the take home point is, if you maintain it correctly, you'll have lots of trouble free riding/racing time. If you don't you're looking at lots of $$$ in the can for something that could have been prevented.
You may be suprised how little time you actually spend riding the bike when you are out on a ride. Most 4-stroke mx'ers are loud, louder than 2-strokes.
Before I can give an accurite reccomendation, and keep in mind that it is only my opinion, I need to know a few things that you haven't told us yet.
What terrain do you ride, be specific? (desert,dunes,mx/sx,play,harescrambles,etc)
How good are you? (If you race, what class?)
What is your riding style? (revver, short-shifter, lazy, aggressive, etc.)
You're 14, and that either tells me that you are working hard for the money that you have, and don't have much left for maint., etc. OR, your parents are going to buy and maintain the bike for you. Which is it?
How often you need to rebuild a 125 depends alot on how much you rev it. If you constantly rev past the power peak, you could grenade one in less than an hour, but if you always shift at the power peak, than it will last much longer. Remember, engine life is the inverse of RPM.
For example, if you push the valves too far before replacement, you're looking at the head removing itself from the stem.
250F head after Ti-valve metal fatigue courtesy of Rich Rohrich:
A good Ti valve on the left VS a beat Ti valve on the right again courtesy of Rich Rohrich:
If you push the crank too long, you're looking at some major energetic dissasembely via the rod breaking at the small end. This will trash the complete valvetrain, the piston, cyl, and likely the cases.
I guess the take home point is, if you maintain it correctly, you'll have lots of trouble free riding/racing time. If you don't you're looking at lots of $$$ in the can for something that could have been prevented.
You may be suprised how little time you actually spend riding the bike when you are out on a ride. Most 4-stroke mx'ers are loud, louder than 2-strokes.
Before I can give an accurite reccomendation, and keep in mind that it is only my opinion, I need to know a few things that you haven't told us yet.
What terrain do you ride, be specific? (desert,dunes,mx/sx,play,harescrambles,etc)
How good are you? (If you race, what class?)
What is your riding style? (revver, short-shifter, lazy, aggressive, etc.)
You're 14, and that either tells me that you are working hard for the money that you have, and don't have much left for maint., etc. OR, your parents are going to buy and maintain the bike for you. Which is it?
How often you need to rebuild a 125 depends alot on how much you rev it. If you constantly rev past the power peak, you could grenade one in less than an hour, but if you always shift at the power peak, than it will last much longer. Remember, engine life is the inverse of RPM.
- Thread starter
- #5
The terrain that I ride is mostly woods, but when i go to the actual ORV trails there's alot of harsh whoops that i have to go through. I pretty much ride sand, jumps, whoops, hardpacked dirt, mostly play-riding but I will be racing my friend on occasion and i might decide to hit the tracks when i get my driver's license. I'm a good rider, but not great because I've only about a years or two experience jumping, although i can absolutely blast through sand. I might be in the beginner class or in the intermediate if I were to race. I'm a very aggressive rider at times, but then I tire out after a while and have to either take a rest or ride more mellow. Right now, I have to rev ALOT to get into what i even consider "power" on my bike, but when I get a faster bike it probably won't be a problem. I don't ever try to push it past the power peak because of fear of blowing a piston ring or frying it. My shifts are very quick and timed well, not too short, not too far. I try to work for money whenever I can to back me up in case my dad decides not to help me out, but even if I don't get help I can still sell my old bike and get a used one with the money I have or wait another year. If i end up having to pay for everything myself I probably won't have much left over for maintenance but I can make more. If i do have help for it then I will have plenty to throw at maintenance and maybe even some at upgrades although that might not be for a while. I'd like to lean it towards that my dad will take care of me because he has almost always kept his word and already said that I can get a new one in spring. Another way I could get money for it is by selling my airsoft gun and some other stuff.
I still can't believe that a four-stroke racer can actually be louder than two-stroke. I know that i would certainly love the powerband and sound of the two-stroke but I still want something dependable. I think I might just spring for the 06' YZ125 if it's quieter or requires less maintenance.
by the way, how does your KTM 125SX go for you? I'd thought about getting a SX but then I learned that they can lose power over time if you don't tune them right.
I still can't believe that a four-stroke racer can actually be louder than two-stroke. I know that i would certainly love the powerband and sound of the two-stroke but I still want something dependable. I think I might just spring for the 06' YZ125 if it's quieter or requires less maintenance.
by the way, how does your KTM 125SX go for you? I'd thought about getting a SX but then I learned that they can lose power over time if you don't tune them right.
- Aug 3, 2004
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If you go to the track, you will believe just how loud a thumper is...
I love my 125SX, If you don't mind getting used to a sub-200 pound bike that handles like you wouldn't believe, than it sounds like what you want. The 125sx has a very strong motor for a 125. It hauls my 180lbs around with plenty of speed, just twist a little further, tap the clutch, and you're gone. Any bike will lose power over time if not tuned right.
I love my 125SX, If you don't mind getting used to a sub-200 pound bike that handles like you wouldn't believe, than it sounds like what you want. The 125sx has a very strong motor for a 125. It hauls my 180lbs around with plenty of speed, just twist a little further, tap the clutch, and you're gone. Any bike will lose power over time if not tuned right.
ok now im confused from what i had heard if you only trail ride or stuff like that and if i was to get a 4 stroke you would not have to ruild build it for a while where as if i got a 2 stroke i would have to rebuild once to twice a year which is no biggy becuase when my dad raced locally back in the 70's he had the tools and still has them. so can someone help me because im still decideing on what to buy, i dont want to blow my money on something thats is going to work and not be broke and costing me big $$$$ thanks, sorry to hijack
ok thanks, im just wondering about the 4-stroke rebuilding issue because im saving up my money and dont want to buy something that is going to cause me problems. so in the longer run which is better a 125 2-stroke or a 250 4-stroke, i know 4 stroke will outlast a 2-stroke so that is why i have a 4-stroke yamaha snowmobile, thanks
- Aug 3, 2004
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dirtrocks said:
Whatever you say, boss.
The time interval between rebuilds is shorter for a 2-stroke, but they are much cheaper. If you read the article at the top of the page, you will read how the most reliable 250f, the yamaha, generates about a $20/hr maint. cost when ridden by an intermediate. If you are talking a 125 expertly ridden, then do the rings at 5 hrs and the piston at 10hrs. Let's add up 20 hrs of time. Two piston kits $80. Two spare rings 24. Two gasket kits 40. Two spare base gaskets for ring changes 8. A wrist pin bearing every other piston 12. Let's say you need a new set of reeds every other piston as well, 50. Add them up, and you get a $10.70/hr of runtime. Half the cost of a 250f. Hell, let's say that you also burn up a clutch each piston as well, that's another 75 each for an ebc. That's an 18.20/hr runtime cost. The runtime cost for the 250f does not include clutches. It would take a rather abusive 125 rider to go through that much stuff in only 20 hours of ride time, though.
Oh, I forgot to leave out one minor problem with all of that. Those service intervals for the 250F are twice what yamaha reccomends and are for intermediate riders. The intervals for the 125 are considering an expertly ridden bike. Oops
Kew-Rider,
Good information above. However I must say that the larger 2 strokes do last a long time under play riding conditions. My Husky 360 bike goes 4-6 years between overhauls. Such is the nature of a big bore 2 stroke. Keep in mind that a 500cc 2 stroke will outlast almost anything out there. It is interesting how that works out.
Another long life example of a 2 stroke is the KTM 200EXC.
Keep in mind that, bikes such as the Yamaha pictured above were ridden hard. large amounts of time spent at high revs really do wear out a small 4 stroke quite quickly.
However, that same engine is used on the WR250F and it will go a really long time between overhauls if ridden in a mild manner (trail riding).
I prefer 2 strokes due to the excellent power to weight. All the other factors about large 2 strokes are just icing on the cake to me. I can afford to overhaul an engine be it 2 or 4 stroke.
Hope this helps.
Good information above. However I must say that the larger 2 strokes do last a long time under play riding conditions. My Husky 360 bike goes 4-6 years between overhauls. Such is the nature of a big bore 2 stroke. Keep in mind that a 500cc 2 stroke will outlast almost anything out there. It is interesting how that works out.
Another long life example of a 2 stroke is the KTM 200EXC.
Keep in mind that, bikes such as the Yamaha pictured above were ridden hard. large amounts of time spent at high revs really do wear out a small 4 stroke quite quickly.
However, that same engine is used on the WR250F and it will go a really long time between overhauls if ridden in a mild manner (trail riding).
I prefer 2 strokes due to the excellent power to weight. All the other factors about large 2 strokes are just icing on the cake to me. I can afford to overhaul an engine be it 2 or 4 stroke.
Hope this helps.
the trail rider
Member
- Jul 25, 2005
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if the kid rides trails and wants a lot of power and not much weight a whole lot of reliability. then i would say kdx's or a little bit older xr honda. the honda weighs more but will last a life time on the parts that came from the factory. infact i have a little 1982 honda z 50 that still has had no rebuild or parts put into it, besides oil and a new spark plug every year or so. and i weigh 185 doesn't that tell you how good honda's are built(besides the new racers that have to be rebuilt every few times you use them.
- Aug 3, 2004
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You can't really beat the KTM offroad line or a KDX for 2-stroke reliability in the woods. An xr would have to be the most reliable line of bikes ever built.
- Aug 3, 2004
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It seemed as though you were implying the same logic toward dirt bikes as well. If not, no harm, no foul.
I think you have to look at one major factor here.... MONEY! A 250f is going to cost you more to buy and more to maintain... period. Now, if you take money out of the issue then it really comes down to wether you like 2 strokes or 4 strokes. I personally think 2 strokes are more fun and they take more skill to ride, and I like that challenge. Getting the most out of a 125 2 stroke will make you a good rider. I spent about 3 hours today on a badly tuned 1991 RM 125 as my 250sx needs new bearings and my 200xc will not arrive until friday. The 125 was a blast to ride in the woods, though I did have some issues with a couple of climbs I would love to try a new, well tuned 125 in the same conditions. I ordered the 200xc because I think it is the best of both worlds... 125 size with more torque and power without the extra weight like a 4 stroke. I think the 2 ultimate bikes are both KTM's, One is a 200 and the other is a 300 and neither one of them have valves.
