OK which dirt bike needs more maintenance, two or four stroke?

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I'm in the market for a CRF450R or X, and I know from experience that a two stroke needs to be maintained more frequently than a four stroke. I used to own a KTM 125 and I was always fouling plugs and I had friends who blew some rings on two strokes. I have never owned a four-stroke, but I assume that they require less maintenance, I mean first of all you don't have to mix the gas, and you have that low end torque, you don't have to stay on the powerband all the time. But I was talking to guy who was selling his CRF450, and he said that he owns an RM250 and he thinks the four stokes need more maintenance. He said that you can easily blow rods in a four-stroke. But I assume that would happen if your not maintaining the bike properly, or riding it improperly. Give me some feedback please.
 
You can have the problems you list on either motor-
Two strokes have MANY fewer moving/rotating parts and are very simple to work on/maintain/overhaul compared to a four cycle. There are no valves/cams/cam chains, etc to adjust/rebuild/break. They also make more power (generally speaking) than four strokes as they make twice as many power strokes at a given RPM than a four stroke. 2-strokes get all their engine lubrication from the oil mixed in the gas (there is no motor oil in the crankcase, just the gear box) so it is absolutely critical to use high quality premix and get the mix ratio right every time. I am a little partial to 2-strokes because of their raw power and simplicity. I feel if both motor types are dialed in, I think the 2-strokes are lower maintenance. The down side is they pollute more than 4-stroke, hence the Gov. nearly regulating them out of production.

BTW people- a 2-stroke works HALF as hard as a 4-stroke, not TWICE as hard. Hence "2" strokes for a power stroke versus "4". Guess I am the only one who took auto-shop.
 
...its swings and roundabouts....

there's more moving parts on a 4 stroke to wear,a lot more...at least with a 2 stroke there's no valve chain to snap and cause massive damage....
 
True a 2 stroke does require more maintenance and true a 4 stroke does have more moving parts but as stated previously a 2 stroke is working twice as hard, as well as head rebuilds quite often you will also be looking at engine rebuilds every 2 years or so if you wax it hard, you also need to get the two stroke oil mix right or your liable to seizure whereas my four stroke hasnt had a service in over a year, got stolen within that time, reclaimed, started first time, has had 1/4 of a can of oil and still runs like it came out of the factory. Basically 2 strokes are fun but high maintenance, 4 strokes in my experience are like the energiser bunny, they just keep going and going and going... with minimal maintenance, keep the oil, brake fluid and coolant (if watercooled like mine) in order and let the recommended service intervals do the rest and it will not let you down!
 
Years ago when four strokes were simpler and a lot slower they required less maintenance. Now that four-stroke are more complex and more powerful and more stressed that is no longer the case. A two-stroke may need more frequent top-end rebuilds but they are inexpensive and easy to rebuild. A modern four-stroke is still going to need work done on the top-end sometime during its lifetime and when it does it will always cost way more and take way more time. The crf has valves and a cam chain that need to be checked as well as separate oil for the motor and the tranny. If you neglect a high strung four stroke and let the rings and valves wear too much you will get a HUGE repair bill.

Also, plug fouling on two-strokes is due to poor jetting, properly jetted they will not foul plugs, my YZ250 never fouls plugs.
 
Hands down, the two stroke needs more frequent maintenance. I generally have to rebuild the top end on my YZ490 every 30 hours or so, maybe 40.

My XR650R is a 4 stroke and is easy to own and easy to ride -- it is also about 16 years newer to be fair.
 
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