2 stroke vs 4 stroke maintenance

[bogan]

That would have to be a pretty rare case I'd say. More likely to have a ring break on a 2 stroke than that happen.

yeh, by design powervalves are non-interference so even if they fail, they should not be expensive to fix, cept those bloody rotary ones where all the stems snap off of them I recently noticed the bike I bought a year ago had poorly adjusted valves, they were open at low revs, then tried to go even more open at high revs (fandangle spring arrangement meant they did't poke holes in side of engine cos of this) I though she was pretty quick before too! fucking rocket ship now

[KevinD]

Daily Maintenance should be similar on both depending on your handbook specs but I did hear oil changes on 4t's are more often? My 200exc is every 20hrs I do it between 10 and 15 hrs which is quite a few rides.
But clean bike, air filter and Airbox, oill fork tubes and chain after every ride even if the hour meter only shows 2 hrs riding. Brakes, tyres, forks, shocks should be similar between the 4t and 2t as well. I agree with Rupe clean filter every ride, very important on any bike!!!

My smokers get stripped every 50 hours usually its a piston kit then next 50 only rings depending on how it measures up (high revving 125's need more). Now that I'm on an exc I could shift that out to 100 hrs but I probably won't be able to help myself from looking in there, somewhere between 50 and 100 hrs. Bearing in mind Danger got 400 hours out of his 200exc and he is a lot quicker than me and runs much finer tuning. So the production 2T enduro bike should be much cheaper in the long haul to maintain!

Replacing a piston and rings is very similar between the two in time and money, which is being constantly put forward as a case for maintenance being similar?? But the way I see it this is simply not the case, sooner or later you will need to do valves, valve springs, timing chain, chain tensioner valve reseat/grind and all that goes with it. Whether that be at 50 hours or 250 hours??

If you can afford to buy a new bike put 100 or 150 hrs on it then flick it off then all well and good! But a lot of people are finding that they can only afford to buy this bike, instead of a new one, and they are the ones getting caught with the 2K top end refurbish that they cannot do themselves or get a mate to do. Because it is a 4T a shop has to do it. Sooner or later somewhere along the ownwership chain this will happen, so no one can convince me a 4T is comparable over its life to a 2T in regards to maintenance, and as per a previous comment thats why the shops like selling them. Mind you I do hear (true or not??) that Ktm (and to a large extent because they have stuck to their 2smokers) are now the highest selling dirt bike worldwide, with the 300exc being the bike of choice. I predicted that the japs would regret their decision to trash 2T's and go after the big bucks, the market is deciding.

Now touching quickly on ride-ability there is no doubt in my mind the 4T delivers its power better for overall speed than the 2T. I'd probably climb those hills better at the sandpit on a 4T and even make it up more than I do now. If I was racing MX its a 4T for sure they are simply faster because of their power delivery. But for me there's much more fun in dancing 2T over the whoop's at speed and feeling the sting of the power even if it means I don't make it up the odd sandhill, which is a rider failure not the bikes. With the power valve adjustment and tuning I have just changed my bike from a sedate kdx type bike to a much more smack you in the arse type bike its a completely different bike from say when Boom or A&R rode it last. I can't see you doing this so easily to a 4T either, they don't have a power valve and if you tune them rich they don't lug around like a 2t they simply don't go. My 2hundy will lug a bit like a 4t I just keep forgetting to not twist the bloody throttle. So its 2smokers for me they are simply more fun to play with, on and maintain.
Just wait till direct injection (or similar) hits, its looking like same power delivery and power out of a 250 2T as a 450 4T delivers. Mark my words when they stop 2smokers from smoking you will all be riding them, there is simply no way do deny the efficiency and power output of the engine.
Everyone knows I'm a 2smoke man but have tried to keep the above as balanced as I can. Just my 2c??

I still cannot see why non-competition dirt bikes went to water cooling and all the extra crap that goes with that. Aircooled 2 strokes (& 4 strokes) produce more than enough power for non-competition use. I would have a air cooled 2 stroke like shot if they ever started making them again. I'd even humble myself for a 750cc V4 similar to an Yamaha RZ500, they were great, just short of 150Mph in 1984 - stand by brothers here I come, is the greatest feeling when you screw the arse off a big two stroke road bike, and the sound. Personally I preferred the Kawasaki H2 750 rough as guts, but so much fun......... I'm off to take my pills However back to the point in hand, I support the view the simpler the better in the bush. When was the last time you saw a 2 stroke drop a valve, or break a cam chain, which means two strokes win in my view.

[Crasherfromwayback]

I'm off to take my pills However back to the point in hand, I support the view the simpler the better in the bush. When was the last time you saw a 2 stroke drop a valve, or break a cam chain, which means two strokes win in my view.

Sounds like you need to get yourself a lovely old air cooled 2 stroke vmx bike!

[oldguy]

Funny thing about 2 stroke riders, is most of the time they are chasing the guy on the 4stroke unless its me
you would have thought KTM would of gone the 2 stroke way, and made a bike to race in the AMA, instead of making a 350f or have 2strokes been ruled out in the AMA supercross?

[scott411]

they have not been ruled out, they just have to be 250cc, and you can not get them to beat 250F's on slick dry tracks like the sx's are

[Crasherfromwayback]

they have not been ruled out, they just have to be 250cc, and you can not get them to beat 250F's on slick dry tracks like the sx's are

Hell yeah. Now that they've got 4 strokes light enough...they just hook up so much better eh! I've had the same old argument here with a certain KX500 rider (can't remember his name...but he's got a Busa as well), that a modern 450 is faster than his KX500. His argument is KX500 = 102Kg's and 64hp. RMZ = 112?kgs and approx 56hp?. But he no listen about drive out of corners = speed down straight.

[Jay GTI]

'tis true, my Kato makes about or if not a little less power than my old RM, but by fecksicles is it a faster bike to ride. The RM would just turn it's power into roost, the SX-F just hooks up and goes.

Then there's the lack of arm pump, considerably less vibration, far less aggressive power, ability to stay fresh and ride all day without fatigue, blah blah...

... although I do sometimes miss the 'holy shit' moments of pure 2-smoke snot...

[Crasherfromwayback]

... although I do sometimes miss the 'holy shit' moments of pure 2-smoke snot...

Yep. Don't get me wrong...I'm a huge 2 stroke fan (there's still nothing like the feeling of a strong one coming on song), but for dirt usage...4 strokes are faster and here to stay.

[meteor]

I just had a look at the spreadsheet I run for the maintenance/cost/hours of the bikes. My son's KX85 cost me $2.6K and to date (from Aug 08) has cost $2.4K in maintenance... full rebuild, top end twice, gaskets, suspension seals, tyres etc etc. Whereas my trusted old XR was bought for $3.8K in Jan 09 and has so far cost me $170. And $70 of that was for a petrol cap that I lost (don't ask!).

[Stylo]

hondas more recent power valves have very few moving parts to fail

No power valve in my CR500 but the KX500 has one , guess the difference is down to the paperwork and the math's . I have a 40 hour KX500 last model '04 and, being my 5th 500 it still puts a smile on my face in 5th gear at over 100kmh when it lifts the wheel when I roll it on ... , wooohooo !, traction permitting , of course..

It's the powerband that keep's me smiling , go the two strokes and guys, you ain't kicking ass unless you're mixing gas . My 5 cents ...

[B0000M]

I just had a look at the spreadsheet I run for the maintenance/cost/hours of the bikes. My son's KX85 cost me $2.6K and to date (from Aug 08) has cost $2.4K in maintenance... full rebuild, top end twice, gaskets, suspension seals, tyres etc etc. Whereas my trusted old XR was bought for $3.8K in Jan 09 and has so far cost me $170. And $70 of that was for a petrol cap that I lost (don't ask!).

an xr vs a kx isnt a fair comparison.

how about we compare a kx85 vs a CRF150R - both being a youth sized competition designed mx bike

kx will be a cheaper bike to own

[Reckless]

an xr vs a kx isnt a fair comparison.

how about we compare a kx85 vs a CRF150R - both being a youth sized competition designed mx bike

kx will be a cheaper bike to own

Agreed and I was also thinking that when the Xr finally needs doing from top to bottom (as its had nothing done) it's gonna cost quite a few a bucks in one big hit.

[Crasherfromwayback]

No power valve in my CR500 but the KX500 has one , guess the difference is down to the paperwork and the math's ..

Are the running costs similar for both ya 5 hundies?

[meteor]

... when the Xr finally needs doing from top to bottom (as its had nothing done) it's gonna cost quite a few a bucks in one big hit...

Probably true but my point was for the OP and even so I still reckon the XR would be less in the long run. But as Boooom says, apples with apples. Maybe a KDX v XR then? Haven't got the figures for that tho'

[Stylo]

Are the running costs similar for both ya 5 hundies?

Good question Crashman.....funny how the Honda costs a lot less to run , hmmmm

Maybe it's jetted a little lean ? :-)