New for 2008: 450cc Four Stroke Spec Class

[resurection]

Dam I expected more debate on two strokes .
I guess when you shut them up all you get is a smite!!

[Burt Munro]

Evinrude E-tec. It is possible to make clean burning 2 strokes.

Brian,

I saw an Infomercial on the Evinrude E-tec's and was wondering why that technology couldn't be applied to race bikes.  Maybe you'd have to haul a 200 gallon water tank around with you to cycle coolant water through?   

[resurection]

Was that a two stroke slam?

[Burt Munro]

Was that a two stroke slam?

Not at all....

I would really like to see what this technology would do in a motorcycle.  An Evinrude 50hp 863cc I-twin weighs over 100lbs.  I wonder what it would weigh without the lower end and all the engine shrouds, etc.

http://www.evinrude.com/en-US/

[BadBoyRR]

http://www.transworldmotocross.com/mx/features/article/0,13190,485640,00.html

I think a big part of the appeal of a four-stroke is that they're extremely durable. The four-stroke motor can perform at a high level for much longer than a two-stroke can. The performance is high and very consistent. And not only that, they're generally easier to maintain, including the fact that you don't even need to mix oil with the gas. Two-strokes certainly have their advantages as well, but they've no doubt been dealt a severe hand with the success of the four-strokes. And if their demand continues to go down, we could certainly see them become obsolete in the future.

[ecumike]

How many pistons do you carry around for your chain saw bike?
How many times a weekend do you pull the head?
How much do you spend on spares and maintenance? 

I would rather freshen up the motor two or three times a season at home than play the tuning game with two strokes.
   

#1.  Currently I have enough spares for 5 full top-ends. What the biggie there? it's just spare parts. I don't understand the problem with that??
#2.  0.  I don't pull the head.  obviously you don't "really" know much about 2-strokes.  You don't have to pull the head all the time.  Only when you're doing your initial jetting setup.  once you have your setup, you never have to pull the head again.  You can get your jetting setup done in 1 good track day. 2 at most.  And if you buy a used bike, you'll most likely get the notes from the previous owner. 
#3.  Spares and maintaince are cheap.  At least I don't have to go home crying if I crash or break something... parts and engine parts are easily fixed. 

[ecumike]

If they can make a reliable, affordable, replacement for a 125GP bike (read just as fast in the corners), then I'm all for it... but until then you'll hear and smell me out on the track buzzing by on my 125.

There's a difference between holding that throttle WFO 80%+ of the time on a road-race track, with no spinning of the rear tire, vs. riding it and freeing the tire on the dirt.

[Super Dave]

OK, I forgot to mention torque and bikes that someone over 5'2" and 150 lbs can ride without looking like a monkey fornicating with a football.

Not to mention, 2-smokes suck....

One of my instructors was winning races at Blackhawk on a '95 RS125...he's football player sized at over 200# and 5'10".

[Super Dave]

I think a big part of the appeal of a four-stroke is that they're extremely durable. The four-stroke motor can perform at a high level for much longer than a two-stroke can. The performance is high and very consistent. And not only that, they're generally easier to maintain, including the fact that you don't even need to mix oil with the gas. Two-strokes certainly have their advantages as well, but they've no doubt been dealt a severe hand with the success of the four-strokes. And if their demand continues to go down, we could certainly see them become obsolete in the future.

While I understand you're direction, I feel as though you've been misled by some things.

Two stroke durability isn't a problem.  Tuning can be an individual problem, yes.  It can be so on a four stroke also. 

Four stroke motorcycle durablity with Ti valves, as the 450s all have, and so do all the supersport 600's now, has been reduced.  One cannot even lap in valves on ti valved bikes.  Failure of a ti valve is immenent because of how ti is.  Reliability comes from regular replacement of such valves at reasonable intervals.  Early failures of valves causes catestrophic destruction of other parts. 



The reason for the change from a lot of two stroke technology to four stroke has been the simple selling out of manufacturers to enviornmental pressure, pressure that potentially isn't even science, that claims that four stroke technolgy is better. 

If four stroke technology was better, don't you think a 250 four stroke would compete against a 250 two stroke?

Regardless, racing an SV650 is still good.  Given that there are many competitive '99 SV650's at the top of the expert field...well, draw one's own conclusions on how necessary it is to update.

Given that I don't see any YZ400f's or YZ426f's running around against YZ450f's...what conclusions should I have?

[roadracer162]

I don't see where the four strokes or specifically the 450 are cheaper than the two stroke 125. Like Dave has said. If the four stroke is that dominant over the two stroke then why isn't there a four stroke 125 currently running in that class.

I love the two strokes although a newb to them, working on them is very easy. It takes me a total of one hour to pull the bike apart and swap out the top end and put it all back together. Reliability at the ragged edge? I think the 2-stroke has it there. Too many thing to go wrong on the 4-stroke. I hear the 60 hp output of the 450 but I only know of the kitted 450 motors doing this, at least from my dirt buddies.

Cost? $7000 for the 450 from the manufacturer and then you gotta do modifications. $10,000 for the complete package of a new 125 2-stroke and that comes with spares inclduing the spare motor if I m not mistaken.

To run the 2-stroke for the season was definitely cheaper to run than my 4-stroke.

Mark

[BadBoyRR]

Part of the appeal of the 450 class to me is something new, interesting and different. I've been watching the same UJM's running around for the last 20 years,  I'd really like a breath of fresh air.

The two vs. four arguments will go on forever. Both have solid pros and cons and each suits personal riding preferences for different people. Can't we all just get along?? 

(Pardon me Dave but your argument for same cc 2 to 4 stroke competition is invalid, as you know.    But it is getting closer!)

Pick any newer bike with low to mid hp, that would get some support, IE sales, and I'll go for it! (two or four!)

Now, what dealership can I walk into and buy a two stroke motorcycle that would be a competitive road racer?

[BadBoyRR]

And hey, I just found a full motarded 04 CRF450, in really nice shape for a shade over $3k! I'm in!!!