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Topic: YFZ Motor Problems (Read 2648 times)
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2fun
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Unless there is a specific problem causing the motors to let go??
And the YFZ was made to be a racer right out of the box!
Comparing the YFZ to your wifes car is kinda like comparing a Ford focus to an F1 racer
I know the older Hondas go for decades sometimes (on the same piston and rings), and I can assure you they are also ran at full throttle a lot of the time.
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DuneJunkie
DJ for short............
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you all are somewhat correct, but, here is what Yamaha did with the YFZ.
Yamaha took the motor size, just like taking a big block of metal, and drilled the hole for the piston, Yamaha made that hole as large as they safely and efficeintly could, without risking blowing a hole out the side, or destroying anything. Then, they built motor around that. That is why the YFZ was the FASTEST showroom produced quad at the time when it came out. (argue that point all day, its true!)
So, when you take that motor that was made that large and build it, then sell it to someone that wants more. So, the customer takes it and modifies the hell out of it. Aftermarket CDI Rev Box, for and extra 1000 rpm, aftermarket exhaust, advance the cam timing, and all the other stuff we do to these bikes, we have taken a bike that was built to max performance and pushed it even farther!
THEY ARE NOT MADE TO BE PUSHED LIKE THAT! and last for long periods of time. I may not ride as often as others (Towman) but, when I do, I push that YFZ to the limit! No questions! I ask a lot of it!
Do I think it should have failed? NO
Do I think Yamaha owes me something? maybe.......(only cuz it sucks rebuilding a motor)!
Is it Yamaha's fault that it's in the shop? NO!
It's mine................end of story! I have no hard feelings about any of it, and once I get my bike back, I will continue to push it just as hard as before, (maybe with a change of throttle usage though).............
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Dune Dude
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It would be interesting to see if pushing the machine to its limits for extended periods of time causing it to fail is an inherent problem with any engine or just specific to Yamaha?
Does anyone have any of these same stories with Honda? Suzuki?
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Political correctness is a doctrine, fostered by a disillusioned,
illogical minority, and rabidly promoted by an unscrupulous mainstream
media, which holds forth the proposition that it is entirely possible to
pick up a turd by the clean end."
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DuneJunkie
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I don't think you will find the problems with the other makes, because they didn't design the engine the way that yamaha did..........just my .02....................
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Towman 1
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Well there is no doubt that some of the YFZ's has problems. But there is other YFZ's that don't. There all built the same way in the same mold. So that means one thing. The 3 YFZ's that froze up was simply rode different than all the others in our group. These three guys all have admitted that they ride a lot of the time full throttle for great periods of time. While I will open mine up full throttle for just a short time. Maybe 5 seconds. We also know that the YFZ's are still the fastest 450's out so far. Thats acording to the magazines.
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And on the seventh day,
god went ATVing
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2fun
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I know the YFZ is a highly modified motor right out of the box, but you can't help but change the exhaust and intake to let her breathe a little better!  As for the rev box, I left mine stock. I DID however retard the exhaust cam one tooth to set it to the dirtbike timing...  |
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Towman 1
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You are right there about the exhaust and intake. I done the valve adj. on mine to and also I put the rev box on. I really didn't plan on using it that much, but my friend in Portland got me a good deal on it. I am glad I did because in the trails down here in the sand, it lets you rev up a little higher and really eliminates a whole lot of shifting.
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And on the seventh day,
god went ATVing
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2fun
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You are right there about the exhaust and intake. I done the valve adj. on mine to and also I put the rev box on. I really didn't plan on using it that much, but my friend in Portland got me a good deal on it. I am glad I did because in the trails down here in the sand, it lets you rev up a little higher and really eliminates a whole lot of shifting.
You said you did the valve adj?? Do you mean you did the cam mod or no??  I checked the valve clearance when I did my cam mod and they were still in spec! |
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Dune Dude
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Did ya get sand on the tires yet?
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Political correctness is a doctrine, fostered by a disillusioned,
illogical minority, and rabidly promoted by an unscrupulous mainstream
media, which holds forth the proposition that it is entirely possible to
pick up a turd by the clean end."
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