Why r wr engines so crap??

Just started thinking-it seems pretty common that if you get more than 9000km/s out of a wr engine without a rebuild then you are doing well. Why do we accept such poor workmanship? The reason I ask is because I have had numerouse Yammi R1'S/r6's that have 4 x 250 cc 5 valve pots in em that are running just as bloody hard (up to around 18500 redline by memory?) and have yet to hear of any engines needing rebuilds, and have heard of a number of bikes doing over 100,000 kms without a rebuild. Sooooo what gives? wheres the flaw in our engine?

a singles life is not so smooth as a inline 4,also dirt miles are like dog years :applause:

Why is as ingle life 'not as smooth'?? Whether its connected to a crank along with 3 other con rods shouldnt make any diff to the piston/rings/valves should it? I can understand dirt causing wear, but when was the last time the inside of your airfilter was dirty??

extra vibration of a single, thats where all the power pulses come from. Rough use, and constant jarring ect. MUCH smaller oil capacity. Most of the sport bikes I've worked on hold about 4 quarts of oil, the dirt bikes one or two. Things like that.

i have no idea why you are only getting 9000km out of a WR motor.

do you ever change your oil?? and are you using good oil?

a WR should get 50 000km easily if you change the oil every 400km {or less}.

Take a CRF or a RMZ for a long spin and see how long those grenades last.

i have no idea why you are only getting 9000km out of a WR motor.

do you ever change your oil?? and are you using good oil?

a WR should get 50 000km easily if you change the oil every 400km {or less}.

Im not talking about my bike specifically, it just seems the general concensus is that they have a very short life, and it seems that this is again generally accepted (see other threads on this subject)

Im sure most peoploe would be reasonably happy with 50k kms, but it doesnt seem like they are getting it??

Navy Nuke-half the oil capacity seems to be inline with half the cylinder capacity? Compare them to xrs for example that run 100k on vegtable oil I just cant understand whythese motors (including Honda) have such accepted short life spans?

less oil capacity means more stuff in the oil, and the crank does the same number of rotations of the crank. If you change it much more often, shouldn't be an issue, but that dosn't always happen.

alos thumpers are a bit easier/cheaper to rebuild than a 4cyl. bike. from experience.

Just started thinking-it seems pretty common that if you get more than 9000km/s out of a wr engine without a rebuild then you are doing well. Why do we accept such poor workmanship? The reason I ask is because I have had numerouse Yammi R1'S/r6's that have 4 x 250 cc 5 valve pots in em that are running just as bloody hard (up to around 18500 redline by memory?) and have yet to hear of any engines needing rebuilds, and have heard of a number of bikes doing over 100,000 kms without a rebuild. Sooooo what gives? wheres the flaw in our engine?

WR engines are the best. At least my WR engine doesn't burn up valves like my old Honda did.

i suppose,maybe if you babied it on the street and kept the oil clean you might get close close to 50k km. i myself have never had a dirtbike(which was ridden in the dirt) last any more than 10k km before needing rebuild(including 2 xr600's) and i am a maintenance fanatic ( i even change my oil every wknd) i'm a little harder on a bike than your average bear though, indy_wr450 who i frequently ride with got around 25k km out of one(befoer rebuild) but his riding style is of the lugging sort and he is also meticulous with his maintenance. judging from what other people say 15k km is probly a good time to start saving for a rebuild :applause: but a 100k km! dude thats 62,500 miles :p you let me know when they build a single that survives that long offroad, maybe volvo could do it :ride:

The reason I ask is because I have had numerouse Yammi R1'S/r6's that have 4 x 250 cc 5 valve pots in em that are running just as bloody hard (up to around 18500 redline by memory?) and have yet to hear of any engines needing rebuilds, and have heard of a number of bikes doing over 100,000 kms without a rebuild.

There are a number of reasons and it's probably a combination of them. Hopefully some TT'ers in the Know can maybe point out the most important ones:

- Oil Capacity

- Valve size/weight

- Impact force at valve/seat interface due to aggresive cam profiles and heavier valves.

- Valve seat material.

- Dirt getting in through the filter damaging valves/seat interface.

- Steady RPM vs. constant throttle jerking (dirt bike).

- I think Dirt bikes tend to be ridden at a higher RPM (comparing each bike's redline, i.e % of redline) to on average ride than a street bike (unless you ride your streebike exclusively on the track).

- Single vibrations and pulsation vs. a smooth running inline-4.

- Jetting not always optimal causing over-heating, etc... on a carburated bike.

- Also, you should probably compare engine life of a guy like NCMM!! vs. a an actual street bike racer that exclusively rides on the track. I wonder how that would compare.

If you go through the above list and make a side by side comparison, I'm sure you might get close to an answer (probably a bunch of items that could also be added to the above.) It would be interesting to start comparing all the above, get actual cam profiles, valve weights, sizes, seat materials, compare valve angles, etc... and try to see if some factors start to stand out. I'm sure things will start to stand out and will explain why street bikes last longer based on hard facts/numbers.

BTW, 18500RPM is a bit high. The 2006 R6 and GSXR600s have a 17500RPM redline. That's pretty amazing and can't wait to hear how this thing will hold up to constant track abuse.

Darn, if he thinks that the Wr motor is crap, where does that leave the honda?

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