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MX, SX & Off-Road Discussions
General Moto | Off-Topic Posts
"SOLD OUT of 250 2-strokes"
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[QUOTE="Rich Rohrich, post: 1275923, member: 16241"] While he was at it your Dad should have told you what mine told me, "check your facts ". I don't make my living or generate any income working on 250Fs or any other motorcycle engines so I could care less what people buy. Whether they break or live forever my interest is still the same, basic research doing failure analysis with my buddy Eric Gorr and trying to come up with better ways to build reliable affordable horsepower. I will admit it's always my hope that what I learn can benefit Eric's business in some way, but other than that, there isn't a mercenary component to what I post. Your question didn't get answered directly because I wasn't following this thread that closely, and honestly I've answered the question time and again. I guess the SEARCH function must be disabled. Sorry to ruin your conspiracy theory.:) The reason I think most people who don't care about AMA racing will choose a 250F or a 450F has to do with them being for most people, easier to ride. I think that holds true for a large segment of riders, not just novices. For me and for a lot of people they are just more fun to ride. I don't think the bike ridden by some guy in an SX race has much if any impact on real world sales. If it did, CRF250s & 450s would not be the perennial best sellers. Frankly, I'm surprised the OEMs put so much money in SX & MX racing. Suzuki spent a fortune and Ricky won a lot of races on an RMZ450, but people still ran to their Honda dealer and bought CRF450s in droves. No question someone who seriously races a 250F or 450F will spend more than they would on a comparable two-stroke. Only a dunce would try and argue that point, but the misinformation and BS routinely shoveled by Luddites and ill-informed two-strokes zealots is laughable. I've done enough work with both two-strokes and four to be able to separate the truth from the moronic BS, and the BS is rampant. Everything from they blow up every race, to you never have to do anything but change the oil. Never underestimate the willingness of people to be lead down the wrong path. For the [b]average[/b] rider, the cost difference between a two-stroke and a good Japanese four-stroke (CRF, YZF) will be negligible over the life of the bike IF AND ONLY IF , proper routine maintenance is performed. I rode my 2002 CRF450 twice (sometimes 3 times) a week on an SX track for two years, and then rode it playing supermoto in the local industrial park a couple of times a month for another year. I checked the valves regularly, but it took nearly 3 full seasons time before I had enough valve movement to matter. I rebuilt the cylinder head with stainless steel Kibblewhite parts and don't expect to have to do the valves again for 300 hours or so. The crank was still in excellent shape, so it will stay in there for another season. In that time I should have put a couple of sets of rings in, and a piston to maintain full power, but the thing makes enough power stock that even with tired rings it's plenty powerful for me on a hardpacked track like I was riding. That and I wanted to see what the parts would look like knowing the maintenance and rpm levels the engine was regularly subjected to. For reference, here's a 9 minute slice of typical laps and rpm ranges that the bike spent the bulk of it's life in. [IMG]http://www.chicagostories.net/images/RPM_V_time_1_CRF.jpg[/IMG] So to hopefully answer your question, the RMZ/KXF 250s are unreliable junk, but all the CRFs and YZFs have proven to be very reliable and mostly trouble-free for the average rider. Regular valve checks, maybe a top end once a year and a few model specific high wear items are all most people (non-racers) will need for the first couple of years. Some will require valve replacement after two seasons, but upgrading to high quality springs and stainless steel valves like the Kibblewhite parts makes that a non-issue going forward. Fast guys who are practicing a couple days a week and racing on the weekend, just need to up the intervals. Regular top ends, and valve springs once a year to be safe. That's nothing new, it was pretty much the same way with two-strokes (500s aside). Riders in those days just didn't get smacked as hard for being morons and ignoring maintenance. They can be more expensive to own, but I think it routinely gets blown out of proportion. If people would quit treating them like XRs and do some scheduled maintenance they would be far better off. Dave Hollub (oldguy) has had his very fast son Eric racing on four-strokes (250 & 450) for long enough to prove the validity of this approach. Eric Gorr and I have dealt with lots of other guys who approached it the way Dave has and they have had similar good results. The big honking blow-ups are more fun to talk about and make for some really compelling macro photos but the reality is they are usually the result of poor maintenance practices or just general ignorance about what wears out and when on a 13,500 rpm race motor. Wear is directly proportional to time spent at rpm. Increase the time or the rpm and things wear out faster. As a result fast guys usually wear stuff out sooner than slow guys, and four-strokes break harder if you taunt the maintenance gods. No mystery there. [/QUOTE]
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MX, SX & Off-Road Discussions
General Moto | Off-Topic Posts
"SOLD OUT of 250 2-strokes"
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