impartial and honest advice from 4 stroke experts please.

[syko]

Hi guys.
Just wanted a bit of advice before i start parting with my hard earned cash.
I've been riding 2 strokes all my life but I got the chance to ride an YZ250f 04 yesterday and fell in love with it.
I want a four stroke but I've always put it off because of the horror stories i've heard about them going bang.
so basically i want to know how hard are they to maintain, what are the chances of them going bang REALLY! and what do you need to do to keep them ticking over nicely.
Bearing in mind i'm not a great mechanic and i struggle with 2 stroke maintainance a lot of the time so is a four stroke just gonna give me one big headache and a very empty wallet.
cheers guys.

 

[jmics19067]

change the oil and filter often, keep the air filter clean, keep it off the rev limiter, and keep an eye on the valve adjustment and you should have a reliable bike. If you notice something wrong repair it then to avoid a catastrophic problem.There is nothing "BAD" about four strokes except the misconception of having to do no maintenance. That is when things get real ugly, real quick.
Plenty of discusions on how to avoid issues just peruse the archives.

 

[CaptainObvious]

Valve checks take less than 5 minutes. When they go out of range, you remove the cams and change the shims...20 minutes.

The advice I got from Rich Rohich (for a Yamaha 250) was when I need a .170 shim to keep the valves within range, it's time for a valve job. I will follow that as gospel.

As Jmic’s said, keep it off the rev limiter, change the air filter and oil often (just like on a two stroke) and there is no reason to expect that the engine will be some kind of time bomb. I use a stainless steal oil filter and clean the oil filter every-other oil change.

The bottom line is this, if you like the bike, you’ll do what it takes to maintain it. I really liked my KX125, but I have greater confidence on the YZ250F. That confidence is worth the extra maintenance.

 

[Shig]

The two CRF 450s I've owned have been rock solid reliable. I got two hard seasons out of the original piston in my 02 with no valve problems. I beat that bike like it owed me money.

My 04 is going into its second season on the original piston with no problems whatsoever. I'm an aggressive Vet-A rider who follows a very average maintenance schedule. I change the oil and clean the air filter after every 3 to 5 hours of running time.

The best advice I can give is to buy a new bike rather than used. A used 450 with alot of hard hours on it would be a risky purchase.

 

[Barbarian]

Maintenance is about the same really. You have to check and adjust valves, but you don't have to mix gas or repair dented pipes all the time.
Plus, no reeds to worry about, no power-valve to get gummed up, piston, rings, and crank last longer, and you don't have to pack the silencer nearly as often.
The only difference is that if you ride a 2-smoke for a few years with no maintenance, it will just quit running, then you'll need to spend 2-3 hundred dollars to get it running again. A four-stroke will eventually blow and cost you nearly a grand to fix.

 

[Zerotact]

I noticed you were in the UK, and you mentioned that even maintaining a 2 stroke give you troubles.
You should check the cost and availability of parts, and someone to perform the labor, if you are not skilled enough to do it. 4 strokes are fun, but they do require frequent oil changes, and you have to check your valves. This is a simple task for someone who knows what they are doing, but can be a headache to perform, or pay someone else to do if you are not comfortable with doing it yourself. Personally, I can't afford to take my bike into a shop, forcing me to learn myself. And a total lack of a qualified sop in my area for my 4 stroke, forces me to learn really quick.

 

[Reggin]

Maintenance should be a huge issue regardless of the bike. It would do you well to try to watch and learn from other mechanics, like at your local shop (if they are nice enough). At least ask tons of questions. You won't necessarily learn how to do things right away, but you can pick up tips and shortcuts.

 

[berudd]

From a strictly relaibilty stand point the Yamahas and KTMs have the edge here. And I would lean toward a 450 because they are not being pushed quite as hard. The other brands are good bike and I would not call any of them bad or unreliable it is just the Yamaha and KTM do have a better track record in the regard.