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The Toad
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So, what's the point of a road bike that has to have it's engine rebuilt every 50 hours? For some people that might be 10 years of riding but for many it's only a few days or weeks.



I don't get these new MX 4-strokers with their delicate top ends. If one is a pro racer with support maybe, but the idea of rebuilding the engine every year myself is unacceptable. Guess I'll have to keep the old two-poppers.
 

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Forbidden fruit, marketing demons

I was walking around for weeks with a twitchy throttle hand when we had the rumors of the RSV450 a few years ago. I've always thought that Ducati could sell a fleet of neo-Mach Is - light, agile Singles at newbie prices - if they ever had the drive to make one. I'm constantly irritated by the reality of (increasingly hard-edged, increasingly pricey, increasingly insurance-y) 600 Supersports being the first really desirable models in any of the Big 4's lineups.

Aprilia doesn't even have a decent entry-level bike, for God's sake. (At least until the Shiver comes online - let us pray....) Somebody - somewhere- please do the right thing!
 

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Sounds like great fun but < 3K rebuilds? That won't work for a street bike. If they could take 10HP off (that "Race" engine) and make it reliable/durable they'd be doing good. Still, sounds like it would be a fun bike.
 

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Maybe I missed something but I got the impression that this was supposed to be primarily a track bike. With the skills and resources these guys seem to have, doing a top end rebuild every now and then wouldn't be too much of a deterent.



I agree that it would not be a practical or economical street bike in any sense, but I'm sure it would be a kick on the track. If they've got the money and time to maintain it, I say good job.



But they've got to find another tailpiece. The ZX-10 unit looks wrong; it's just too big.
 

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I really like projects like this and thanks for posting this one. But, having built and modified a few bikes I've found it's pretty easy to lose the goal of improving on what's available already. So for those of you who say, "what's the point of this when I can buy a supermotard from KTM, Suzuki etc. that lasts longer than 3k miles"... enjoy your smugness. For the gearheads among us I totally get the means of the project, but the endpoint sometimes requires shaded glasses.



Hey it's my ride and I'll do what I want.
 

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I agree, and it doesn't make any sense either. A Ducati 999 makes 120 hp from 2 500CC cylinders. That's 60 hp / cyl, and they certainly last more than 50 hours! Even my crappy Superhawk is over 50 HP / cylinder with mild cams and low compression and should be good for 100K miles. MX 450's only make 52 HP and they are grenades. Why?
 

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The Toad
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The MX 4strokes use extremely light components in order to be able to compete with two strokes of half the displacement. This way they rev extremely quickly and keep the weight down. Streetbikes can get away with stronger valves and crankshafts since they don't require the extremely quick reving and weight savings.



It might be smart to pick up a couple of older open class 2smokers like CR500s or IT490s now. If things progress like they usually do all the offroad bikes will be using the new weakly built 4stroke engines soon.



 

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Actually, its two of your rides, (neither of which was free) both sacrificed to create a neato but quirky trackbike. Did I mention a lot of time spent on fabrication?



Enjoying my smugness, immensely.



- Boru

 

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Re: Forbidden fruit, marketing demons

Pray for the Cagiva Mito to make it into production. I saw it at the Washington IMS and was impressed. A tasty thumper sport bike . Engine was a Husky single and projected price range was 6-9 K depending on how many of the tasty bits make it to production.
 

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I'm with you, but we are in the minority in the modern bike culture. In the day,you could make frankensteins with the hope of improving the breed...lots tried. But current bikes are so good with just a few tweaks most dont see the purpose of "Specials" It takes all kinds......
 

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What happened to common sense? Engines that last 3000 miles between rebuilds? How about all the new sportbikes that crack their frames from use never mind that if you crash a newer bike they are more often than not unrebuildable.A few years ago you could drop a bike and more often then not straighten a crashed bike. Now they turn to junk.
 

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i dont think the 4 stroke mxers are any more delicate than the 2 strokes ...sure pulling the engine apart after 100 hundred hours might seem very early but for most people who ride them thats a full season of racing....



people i think are afraid of the bigger complexity of a 4 stroke engine have nothing much to fear ..shimming the valves on most of these is a 1 hour operation at most ..except maybe the crs cos of the unicam setup...but any of the dohcs is pretty simple



i remember changing about 6 pistons one year with a cr125 ...i think the term *piston slap* was invented for cr 125s.



if you just trail ride an mxer and not race it then there is no problem once you keep on top of the maintence ...



the 450s i think now are pretty bullet proof ..the 250s not so much mainly due to the extreme high revs they have the big ends tend to wear out after 2 years or so..

but from the market they are aimed at ..people dont tend to race the same bike for over 2 years
 

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The number of 2-stroke engines Honda now produces can be counted on "no" hands.......
 
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