2stroke vs 4stroke dilemma -service/maintenance $$$ perspective. | GTAMotorcycle.com

2stroke vs 4stroke dilemma -service/maintenance $$$ perspective.

Punisher

Well-known member
Site Supporter
hey everyone,
i am hoping to buy my own mx dirtbike later this year, and am facing the 2stroke vs 4stroke dilemma, more from a service/maintenance $$$ perspective.

is one going to be cheaper than the other?

i have heard that its easier to work on 2stroke's.
my son has a KX65, and i have already replaced the piston and piston rings once, and i assume that doing the same job on a bigger bike would be basically the same. so hopefully me doing the work takes the labor cost out of the equation.
but still having to buy the piston rings and gaskets every 10 hours of riding will still add up.

with a 4stroke do you still need to service the piston & rings as frequently as a 2stroke? as well do you have to check the valves as frequently and how expensive is that?

more than likely i will be buying used, because i cant afford to buy new, but i have also noticed it looks like some of the manufactures no long make 2 strokes.

PS: i have never rode a 2stroke, my gixxer 750 sportbike is a 4stroke, and the honda crf230 dirtbike my brother lent me is a 4stroke. I have 2 heard the 2stroke have a narrow and very aggressive power-band, where as the 4stroke have a even and smoother power-band.


anyway any comments are appreciated.
 
Are you planning to competitive race the bike? The maintenance schedule for competition bikes assume you are.
Replacing a piston and rings every 10 hours of service is extreme. My competition trials 250 4-stroke Honda engines call for replacing rings every half year and piston every year. Even that is excessive in my experience, ymmv. The 2-stroke version had the same schedule but added piston inspection every 3 races.

2-strokes are easier to work on but also way more likely to need the attention. 2-strokes tend to be better performers in the hands of an aggressive highly skilled rider, 4-strokes seem to have an advantage in deep mud and long slippery hill climbs. 4-strokes don't like to have the throttle blipped a lot and reward the rider who has smooth throttle control, 2-strokes spool up faster. 4-strokes enjoy very slightly better fuel range. 2-strokes don't like to idle extensively, with a PGM-Fi 4-stroke leaving it idle helps it to sort out the Fi if it's not working perfect. 2-strokes are typically a few pounds lighter.

Fuel injection is what made it possible for Honda to build a 4-stroke trials bike that is competitive with the 2-stroke machines.

2-strokes are banned from use in some of the more environmentally sensitive park lands in places like California, I haven't heard this as being a problem anywhere here yet.

Honda valves are easy to check or adjust the valve clearance, you have to service reed valves on a 2-stroke even more often but that's not hard to do either.

Bottom end seals on a 2-stroke have a fairly high failure rate with age, bad bottom end bearing seals really kill the motors performance.

4-strokes cost a little bit more up front but they also tend to hold resale value better. Is harder to find a 2-stroke that has not been beat on real hard.
 
Last edited:
Thank you very much for taking the time to explain the pros and cons of each.
it gives me a lot to think about.
I would like to race at some point, but to start i would probably just do more track days at SteelCityRiders and the 15Practise Track, probably not pushing the bike/motor to the limits of other racers.
it was a good point to note that i may have a hard time finding a used 2 stroke that has not been beat up and might need some work.

thanks again,
jason




Are you planning to competitive race the bike? The maintenance schedule for competition bikes assume you are.
Replacing a piston and rings every 10 hours of service is extreme. My competition trials 250 4-stroke Honda engines call for replacing rings every half year and piston every year. Even that is excessive in my experience, ymmv. The 2-stroke version had the same schedule but added piston inspection every 3 races.

2-strokes are easier to work on but also way more likely to need the attention. 2-strokes tend to be better performers in the hands of an aggressive highly skilled rider, 4-strokes seem to have an advantage in deep mud and long slippery hill climbs. 4-strokes don't like to have the throttle blipped a lot and reward the rider who has smooth throttle control, 2-strokes spool up faster. 4-strokes enjoy very slightly better fuel range. 2-strokes don't like to idle extensively, with a PGM-Fi 4-stroke leaving it idle helps it to sort out the Fi if it's not working perfect. 2-strokes are typically a few pounds lighter.

Fuel injection is what made it possible for Honda to build a 4-stroke trials bike that is competitive with the 2-stroke machines.

2-strokes are banned from use in some of the more environmentally sensitive park lands in places like California, I haven't heard this as being a problem anywhere here yet.

Honda valves are easy to check or adjust the valve clearance, you have to service reed valves on a 2-stroke even more often but that's not hard to do either.

Bottom end seals on a 2-stroke have a fairly high failure rate with age, bad bottom end bearing seals really kill the motors performance.

4-strokes cost a little bit more up front but they also tend to hold resale value better. Is harder to find a 2-stroke that has not been beat on real hard.
 
I know that track, we had a CMA Trial there once, very little rock, rained like mad and everything turned to incredibly slick mud that totally stuck to everything!
 
A 4stroke dirt bike will be much more expensive to maintain especially a honda they tend to need a new head and valves regularly if ridden hard. A two stroke will need a few hundred every year that could be a few thousand on a 4 stroke.

Sent from my SM-G935V using Tapatalk
 
A 4stroke dirt bike will be much more expensive to maintain especially a honda they tend to need a new head and valves regularly if ridden hard. A two stroke will need a few hundred every year that could be a few thousand on a 4 stroke.

Sent from my SM-G935V using Tapatalk
Exactly. Top end on a 2t is 300ish if you do it yourself. Top end on a 4t is 1400-2000, less if you have the machine work done and do assembly yourself. There are a multitude of 2t out there in good shape, however there are very few 4t mx bikes I would buy used.

Sent from my SM-A500W using Tapatalk
 
anyway any comments are appreciated.

Are you planning to be the fastest guy on the track? Are you changing careers and going pro-motocrosser?


The difference in maintenance cost for average-Joe/Josephine dirt bike rider is likely negligible. If somebody wants to pretend that they NEED to "freshen up" their top end so they can be competitive in their club level race have at it, but the reality is you can put plenty of hours on beyond the recommended service intervals FOR COMPETITION USE and be fine as long as you're diligent about maintenance like oil & filter changes and cleaning your air filter.

having said that, I'd buy a 2 stroke. I find them more fun, more versatile, more forgiving and more reliable, but I like to ride in the woods so your experience may be different.
 
Are you planning to be the fastest guy on the track? Are you changing careers and going pro-motocrosser?


The difference in maintenance cost for average-Joe/Josephine dirt bike rider is likely negligible. If somebody wants to pretend that they NEED to "freshen up" their top end so they can be competitive in their club level race have at it, but the reality is you can put plenty of hours on beyond the recommended service intervals FOR COMPETITION USE and be fine as long as you're diligent about maintenance like oil & filter changes and cleaning your air filter.

having said that, I'd buy a 2 stroke. I find them more fun, more versatile, more forgiving and more reliable, but I like to ride in the woods so your experience may be different.

Agreed.Most trials bikes are 2 stroke and the motors spend a lot of time at low revs.The top end can last years before any work and sometimes just a cleaning with fresh gaskets.
 
It's really tough to beat a 250 2 stroke mx bike as a do everything bike and as a affordable entry point to the sport. Very easy to maintain and works really good on the track and trails if you ever decide to go that route.

I would only buy a low hour 4 stroke used and hopefully you know the previous owner and their maintenance habits. If you blow up a 4 stroke the bill to rebuild will make you cry.
 
4strokes as well as 2strokes have come a long way since 2003.If youre a trail/woods rider I bet a 2stroke top end would last two or more seasons,you still need to check jetting,reeds,oil,air filter.....newer 4strokes are mostly fuel injected now so no jetting issues,great gas milage,checking valves is not difficult(my valves have not gone out of spec ever)so those old horror stories about 4strokes need to be put to rest, like all 2strokes have a powerband like a light switch not true.I was a diehard 2stroke rider.
 
Last edited:
Are you planning to be the fastest guy on the track? Are you changing careers and going pro-motocrosser?


The difference in maintenance cost for average-Joe/Josephine dirt bike rider is likely negligible. If somebody wants to pretend that they NEED to "freshen up" their top end so they can be competitive in their club level race have at it, but the reality is you can put plenty of hours on beyond the recommended service intervals FOR COMPETITION USE and be fine as long as you're diligent about maintenance like oil & filter changes and cleaning your air filter.

having said that, I'd buy a 2 stroke. I find them more fun, more versatile, more forgiving and more reliable, but I like to ride in the woods so your experience may be different.


I'm still a reletive noob in the dirt bike world, and I have a 4T. reading my owners manual for my WR250F, the service interval for valve checks for example is 5000km for "regular" use, and 1000 kms for "Competitive use". I picked up the bike used with 200kms on it so pretty much know its maintenance history since then

The 4T is great for linear power deliver and engine braking when riding. 2T tends to "bark" a lot with explosive power if you're not careful, but can be fun. I went with a FI 4T to keep it easier for me with the Fuel injection, so I dont have to worry about "jetting" and other things which are all too new to me.

The technology in Modern dirt bikes have come a long way. Now they're making Fuel Inject 2Ts :)
 
Last edited:
I agree with the first statement.
I'm still a reletive noob in the dirt bike world, and I have a 4T. reading my owners manual for my WR250F, the service interval for valve checks for example is 5000km for "regular" use, and 1000 kms for "Competitive use". I picked up the bike used with 200kms on it so pretty much know its maintenance history.

The 4T is great for linear power deliver and engine braking when riding. 2T tends to "bark" a lot with explosive power if you're not careful, but can be fun. I went with a FI 4T to keep it easier for me with the Fuel injection, so I dont have to worry about "jetting" and other things which are all too new to me.

The technology in Modern dirt bikes have come a long way. Now they're making Fuel Inject 2Ts :)
The difference is that a wr250f is not a high strung 4t mx engine. It is more of a trail bike hence the maintenance schedule.
The trail type 4t are completely different from mx bikes, 2t or 4. They are designed for years of trouble free fun. This is achieved with a milder state of tune in every way when compared to an mx bike.

Sent from my SM-A500W using Tapatalk
 
Shiiit...OP you started another
endless 2t vs 4t thread...
BUT keep in mind that as far as off road bikes - they are very specific
so decide what type of riding you gonna do, then get a bike to suit
They are all good bikes if you take care of 'em...
my 2c...


Sent from my iPhone using GTAMotorcycle.com
 
The difference is that a wr250f is not a high strung 4t mx engine. It is more of a trail bike hence the maintenance schedule.
The trail type 4t are completely different from mx bikes, 2t or 4. They are designed for years of trouble free fun. This is achieved with a milder state of tune in every way when compared to an mx bike.

Yes, thats true, But also the late model 2015+ WR's are actually using the same engine as the YZ250FX, just different gearing and in USA/Canada they are detuned with the std factory ECU. $USD100 buys you the GYTR competition kit, plug that in, remove the airbox snorkel, pipe restrictor and change out the throttle stop screw that then pretty much changes the bike to a YZ250FX with lights

"By calling the YZ250FX a closed-course vehicle, Yamaha sidesteps all of the bureaucracy. The FX is basically a WR stripped of all its noise and emission restrictions."
Read more on the differences of all three bikes here: https://dirtbikemagazine.com/yamaha-wr250f-yz250fx-review/

In Australia and NZ the Yamaha's are very very popular, I believe its one of the largest markets for the bike.
 
A friend of mine has been playing with a Frontera,(farkled Honda?)Can't find much info about it.Anyone?
Frontera_zpss5cbrmnt.jpg
 
Last edited:
4T - 250's are higher strung and often need a rebuild sooner compared to a 450. As well dfferent manufacturers have better reliability. A mx based bike will need more checking compared to a enduro. Yamaha wins in the reliability game for 4T's. Doesn't mean a clean but beat-on Yamaha 4T won't grenade an hour after you buy it though. Most trail guys with Yamaha YZ450F's similar to mine go 200hrs before changing the piston. But you've got valves to check....
If a 4T grenades it's big money.
As a track bike I prefer 4T. All that reciprocating mass makes it very stable especially in the air. Hooks and goes instead of steering with the rear tire/throttle.

2T - doesn't stall nearly as easy and it's cheaper if it blows up. My KTM 300XC 2T usually gets a new piston between 150-300hrs of use for trail riding. 2T FEELS lighter than the scales suggest because less recip mass. It feels like riding a mountainbike in the forrest and is much less tiring that's why it is my choice for woods riding.

Couple things to add: a 450 4T MX is a LOT of bike. It'll wear you out fast and you'll feel more like the bike is riding you than the other way around.
Fuel Injection has been available on 4T for a while. $4000 can get you a clean FI bike with no carb jetting to annoy you.

YZ250 2T have been virtually unchanged since 2005. Because it's a great bike and can be made into a great trail or track bike depending on mods. Parts are everywhere and cheap.
 
Last edited:
I won't repeat everything that's been said. Get a 2T. You already know how to work on one so you know how easy it is. I ride a KTM 200XCW and find it very tame (I also race it with SCR), whereas I found a 250SX to be way more powerful.
 

Back
Top Bottom