2 stroke vs 4 stroke maintenance

**motor_mayhem** · 26th May 2010, 23:32

I am a bit down about my RMZ at the moment as I have just bought a top end rebuild kit and while installing it discovered I also need new intake valves. By the time all that's completed I will be down about $800 and that's when I have done most of the labour myself, had some help from friends in the know but has all been free so far thankfully.

I am vaguely wondering if I would have avoided this with a 2 stroke. Can someone give me some objective comparison between 2 stroke and 4 stroke?

**Stylo** · 27th May 2010, 08:00

Originally Posted by motor_mayhem

I am a bit down about my RMZ at the moment as I have just bought a top end rebuild kit and while installing it discovered I also need new intake valves. By the time all that's completed I will be down about $800 and that's when I have done most of the labour myself, had some help from friends in the know but has all been free so far thankfully.

I am vaguely wondering if I would have avoided this with a 2 stroke. Can someone give me some objective comparison between 2 stroke and 4 stroke?

The joys of owning a 4stroke ...go to twostrokemotocross.com , there's an interesting article on the 2t vs 4t maintenance comparison ....

**Crasherfromwayback** · 27th May 2010, 08:25

Make sure you put some new valve springs in while you're there mate. VERY important!

**motor_mayhem** · 27th May 2010, 09:20

Can someone give me some objective comparison between 2 stroke and 4 stroke?

From a brief browse of twostrokemotocross.com I very much doubt any of their articles are completely objective.

**bogan** · 27th May 2010, 09:37

Originally Posted by motor_mayhem

I am a bit down about my RMZ at the moment as I have just bought a top end rebuild kit and while installing it discovered I also need new intake valves. By the time all that's completed I will be down about $800 and that's when I have done most of the labour myself, had some help from friends in the know but has all been free so far thankfully.

I am vaguely wondering if I would have avoided this with a 2 stroke.

yup, two stroked don't even have intake valves

Originally Posted by motor_mayhem

Can someone give me some objective comparison between 2 stroke and 4 stroke?

imo, two strokes are the safer bet, if something goes wrong it's likely to be much cheaper than for four strokes, as far as routine maintenance goes, rebuilds a lot more often on 2T, but also a lot cheaper. I also think with 2T, you're not hit with unexpected costs as much, so while you probably pay out the same amount, cos you expect to it easier to pay. I've never had a 4T mx bike btw, so just going from what others have said. Also, how long have you had yours, and how much spent, how much riding etc?

With the huge difference in power deliver between 2T and 4T, I reckon just pick the one you like riding the most, and expect to pay heaps

**vazza** · 27th May 2010, 11:03

Yes buy a 2stroke. Far less maintenance/cost.

Preferably buy a 2T enduro bike.. You dont have to do anything to them for 100hours if your lucky!

**yokel** · 27th May 2010, 11:57

[QUOTE=

I am vaguely wondering if I would have avoided this with a 2 stroke. Can someone give me some objective comparison between 2 stroke and 4 stroke?[/QUOTE]

Yip, my YZ 125 top end = about $110-$150 for a piston kit + 30 mins work and all done (reused the gaskets cos im a tight ar$e)

To me the use of a high "tech" and strung F1 type 4 stroke engine to go hooning around a paddock and making ruts up the side of hills just doesnt make sense??

**Shane06** · 27th May 2010, 13:39

dealers want you to buy 4 strokes,they are more expensive and they do well off the parts

i had a crf450 for a while but sold it to get back to 2 strokes, when ever i rode i was worried it would shit itself leaving me with a bill i couldn afford

**barty5** · 27th May 2010, 14:41

well ive did 100 hrs on my 450 before swapping out the piston i did do the rings at round 70hrs all the valves etc etc are still well within the specs and was only 250 for the piston kit and yes i do use and have trade account but not for a genuine piston i put back into it.
Rupes 250 has done round 170hrs and its all still sweet and with in spec.

**barty5** · 27th May 2010, 14:42

hows many hrs has it done ???

**Rupe** · 27th May 2010, 18:13

Originally Posted by barty5

well ive did 100 hrs on my 450 before swapping out the piston i did do the rings at round 70hrs all the valves etc etc are still well within the specs and was only 250 for the piston kit and yes i do use and have trade account but not for a genuine piston i put back into it.
Rupes 250 has done round 170hrs and its all still sweet and with in spec.

Nah it's on 195hrs, the valves are all still in spec and haven't moved in 100hrs, the cylinder still has the hone marks etc. Everything is mint inside.

the late model 4strokes don't cost much to run, unless you are slack with your preventative maintenace.

Whats your maintenace schedule on the RMZ?

**oldskool** · 27th May 2010, 18:28

food for thought.

4T=
more moving parts
much higher rpm
pressurised lubrication- dirt and heat = premature wear.
more wear on parts as needs 4 strokes as opposed to 2

"Four-stroke engines have all the moving parts (piston, bearings, rods, crank, etc.) that a two-stroke does, but adds valves, camshafts, springs, timing chains, and oil pumps all operating at hummingbird speeds." http://twostrokemotocross.com/2010/0...ines-compared/

$50 Reed Valve compared to $800 cam and valve job

**flyingcr250** · 27th May 2010, 18:32

Originally Posted by vazza

Yes buy a 2stroke. Far less maintenance/cost.

Preferably buy a 2T enduro bike.. You dont have to do anything to them for 100hours if your lucky!

i know someone whos selling a good enduro 2T bike lol

**B0000M** · 27th May 2010, 18:37

another for the 2 stroke is cheaper vote.

example - a mate just did a full top end on his crf - new valves, springs, piston, rings, etc etc etc, cost $750~ in parts alone.
for my 2 stroke its $230 for a full top end. though does need doing more often.

another guy just did a top end, using new valves as well, then the valves failed.... and now its even more fucked and even more costly-

this vs $50 worth of reeds, which dont destroy pistons and cylinders - ill take the reeds any day.

still comes down to rider preference though. some people just cant ride (handle) a 2 stroke, others find 4 strokes boring.