Did I Make a Mistake?


13 replies to this topic
  • Coastie3202

Posted May 27, 2008 - 11:20 AM

#1

I seem to be reading a lot of posts, in various forums, where YZ 450F riders are reporting what I would call catastrophic engine failure, such as the two following posts:

[COLOR="Red"]OK. As the title reads, my '08 450 just gave up the ghost about an hour ago. I was coming into a corner when it just died. When I went to kick it over, there was very little compression for about one and a half kicks (along with a few weird clickity-clacks), then nothing. Now it won't budge and I don't really want to force the issue until I can get in there and check it out.

Just got everything to SM, did a couple of miles together with some friends, and after couple of hours, going 5th gear, full throttle, enjoying the weather and the curby road, something broke in the engine. I would guess a ring, or part of the piston, because I can easily turn over the engine, but I hear metal shrapnel moving around in the bottom of the engine. Most annoying thing that I don't have time to work on it, I have to take it to a shop.[/COLOR]


My previous bike was a Honda XR 400. To say that the bike was bullet proof would be an understatment. I rode it, and rode it hard, for over 3 years with no worries. Of course I maintained it as the manual called for (okay maybe not that tight). I went away from the XR because I wanted something lighter and faster.

I hope I did not make a mistake by going with the YZ 450F. Are all thumper MX bikes finiky and delicate? I hope not. I would hate to think that I have to stay close to roads in case a detonate something and have to walk out.

Those of you who have ridden the YZ 450F for a while......Is it a trustworthy bike and tough enough to take abuse with proper maintenance? :thumbsup:

  • cwf340

Posted May 27, 2008 - 11:23 AM

#2

sounds like you droped a valve. pull the cam cover off and take a look.

  • Camrose Cycle

Posted May 27, 2008 - 11:27 AM

#3

"Just got everything to SM, did a couple of miles together with some friends, and after couple of hours, going 5th gear, full throttle, enjoying the weather and the curby road, something broke in the engine"

No wonder you had problems, your post expains everything. Sorry, but i have no pity for someone who has no common sense.

  • thumpyz

Posted May 27, 2008 - 11:52 AM

#4

I think some people are confusing your question. I think that with proper maintenance the yz will provide you much more happiness than the xr. Just keep on top of the maintenance and you should be virtually worry free. I believe the second person you wrote about was a yz426f, not a 450. :thumbsup:

  • Kasjok

Posted May 27, 2008 - 11:53 AM

#5

Guys guys, I think he is just quoting another guy who had problems with his 08.

You won`t go wrong with YZ. Sure, every brand might have some lemons, but those are rare to concur, especially when it comes to Yamaha. More then often it is user error that is behind something blowing up or broking down.

Maintenance is the key with every bike. But keep in mind that this is high performance racing machine. Thats something different than your good old XR.

  • Coastie3202

Posted May 27, 2008 - 12:04 PM

#6

To those guys that took the time to read my entire post then reply....thank you. Your reassurances certainly help my peace of mind.

To those guys that gave their opinion on what was wrong with my bike, or were critical of my riding and/or maintenance habits......put your speed reading practices aside and read the entire post, then reply. Geeeeezzzzzeeeee!:thumbsup:

  • Emiliano

Posted May 27, 2008 - 12:13 PM

#7

I have a 08 no problems yet, few hours on it, I gess 8 or 9 tanks (dont know hours), but I had a 99 Yz400 before, took the crap out of it for 2 years, all I did was change the oil and oil filter after 4 or 5 tanks and clean the air filter after a ride, I didnt spend a single $ on the motor, and the guy that got it from me is totally abusing it, no mantenece at all, and still strong.

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  • Slinkyman16

Posted May 27, 2008 - 12:19 PM

#8

every manufacture has its lemons.. yamis are not common but happans. like someone said above me.. its usually the user that is at fault. i have two yzf's a 2002 yz426f and an 07 yz450f.. both run extremely well, never had to do anything to the bike, except for the commong maint. the 426 easily has 200 hours on it.. stock valves, stock shims. starts first kick. yami is the only bike i will buy, simply because of the way they are built.

  • BergArabia

Posted May 29, 2008 - 08:46 AM

#9

Like said maintenance is the key.
My 05 is going strong. starts right up runs strong.
change the oil a little more often than in an XR.
There is less oil and the engine is tuned more for power than durability as apposed to the XR.
But the YZ is very durable so long as you keep the oil fresh, give it clean oil (clean air filter) and do some checks from time to time..

  • grayracer513

Posted May 29, 2008 - 08:59 AM

#10

You have two threads there that you have quoted, one concerning an '08, and another on an '02 with God knows how much time on it, both of which dropped a valve head. These are totally random, and thankfully quite rare, occurrences in YZF's.

Maintenance is certainly important, but has little to do with this particular thing. The valve breaks at or near the point where the head is welded to the stem, and this has absolutely nothing to do with lubrication, or clean filters, or anything else. The exception is if you continue to run a valve that has been reshimmed more than once, or more than .10mm smaller than its original shim size. In that case, you're asking for it.

  • Wiz636

Posted May 29, 2008 - 09:23 AM

#11

Also keep in mind that this is where people are going to post when they have a problem....but they are not going to post that they are not having a problem. Hmmm...maybe that would be a good thread.

For every guy that posts a problem with his bike there are countless others with no problems at all.

  • grayracer513

Posted May 29, 2008 - 09:55 AM

#12

Also keep in mind that this is where people are going to post when they have a problem....but they are not going to post that they are not having a problem.

That's like when I was a service manager and the sales department asked me what I thought of the latest Chevrolet stuff one day. I told them that it was hard to form a fair opinion when all of the cars you see are broken.

  • 080

Posted May 29, 2008 - 12:19 PM

#13

Also keep in mind that this is where people are going to post when they have a problem....but they are not going to post that they are not having a problem. Hmmm...maybe that would be a good thread.

For every guy that posts a problem with his bike there are countless others with no problems at all.


Very true. I not a big one for poles but it would be very interesting to have one on this subject just to see. Granted alot of issues will be maintinance related but who cares. I say start with an 07' and older and only reply if there are more than say.. 100 hrs or so on the bike.

  • Coastie3202

Posted May 30, 2008 - 04:21 AM

#14

Thanks to everyone for your replies. I feel much better now. I could never go back to the XR because I would miss the power of the YZ and the lighter weight.





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