06 YZ 450 Break-in Question


21 replies to this topic
  • twenty34

Posted December 29, 2006 - 05:25 PM

#1

Ok, so when I first road this bike, the thing just hauled all over the place and really pulled nice on the low end (much better than I expected after reading the reviews). I know this bike is not considered the best for low-mid range grunt, however, compared to my first rides, it seems to be getting worse.

Is this just the bike breaking in and I'm now starting to see how the engine "really" performs or did I not break it in incorrectly? :lol: It still has the very fast top end and has a strong hit towards the upper end of the midrange.

Is this normal? Even new I could see how a pipe or slip on would have helped on the low end, but it still was very impressive at this stage. Is a pipe/exhaust in order at this stage? :confused:

Thanks! :confused:

  • tmauto69

Posted December 30, 2006 - 05:30 PM

#2

my opinion on this is that you are getting used to the power delivery.

  • twenty34

Posted December 30, 2006 - 06:35 PM

#3

hmmm, interesting theory...not totally convinced..I've been riding for 30 years and I'd like to think that I am more "in-tune" to these types of variations. You could be right, but again, not completely convinced just yet. I had planned at some point to add a pipe, but I was going to hold off for a bit.

Thanks for the reply. :lol:

  • BergArabia

Posted December 30, 2006 - 08:48 PM

#4

So did you go for the hard, fast break in?
or did you take the gentle route?

  • KJ790

Posted December 30, 2006 - 09:16 PM

#5

Have you checked your valve clearances? I noticed that happen on my bike and I had checked the valves eight hours before (I check them every 10 hours). I decided to check them early and sure enough the intake valves had tightened in that short time. I had never needed to adjust them before, it was like they suddenly decided to wear a little.

  • twenty34

Posted December 30, 2006 - 10:40 PM

#6

Have you checked your valve clearances? I noticed that happen on my bike and I had checked the valves eight hours before (I check them every 10 hours). I decided to check them early and sure enough the intake valves had tightened in that short time. I had never needed to adjust them before, it was like they suddenly decided to wear a little.


Have not had them checked. I've only been through two full tanks of gas thus far - about five rides at the track, but these have been short duration sessions maybe 5 hrs or so. Could they be out of whack this early? How else will I know other then pulling the engine apart? The bike starts first kick. What needs to be adjusted if they were out of tolerance and how much does this cost assuming I would need to have it done by a dealer? I'm a 2 stroke kinda guy so the 4 strokers are new to me...

Thanks! :lol:

  • twenty34

Posted December 30, 2006 - 10:41 PM

#7

So did you go for the hard, fast break in?
or did you take the gentle route?


A little of both to be honest. Either way, what would this information tell you?

  • red7

Posted December 30, 2006 - 10:53 PM

#8

Oh Rickk you're getting me nervous man as I'm picking mine up in 2 days. I almost ordered a MRD exhaust but I wanted to first figure out how I'd want Dave to tune the exhaust. I'm sure I'll end up getting the low-end head pipe as it sounds like that's where the YZ could use a boost but we'll see. If you do decide to go with a pipe I'd look into MRD as it seems like the best bang for the buck.

  • BergArabia

Posted December 30, 2006 - 10:59 PM

#9

A little of both to be honest. Either way, what would this information tell you?


Well I am not a technical guru so the question is more out of interest than some deep techincal understanding.
I did a hard break in myself.
Well 20 minutes of babying it followed by an hour of working through all the gears and all the rev range..
Then changed the oil nd filter, plenty of metal flecks in it too. No problems since then 50 hours later.
As I said it is just out of interest as I am a learner..:lol:

  • kxman

Posted December 31, 2006 - 05:17 AM

#10

Have not had them checked. I've only been through two full tanks of gas thus far - about five rides at the track, but these have been short duration sessions maybe 5 hrs or so. Could they be out of whack this early? How else will I know other then pulling the engine apart? The bike starts first kick. What needs to be adjusted if they were out of tolerance and how much does this cost assuming I would need to have it done by a dealer? I'm a 2 stroke kinda guy so the 4 strokers are new to me...

Thanks! :lol:

I would be VERY surprised if your valves are out of spec yet. It is a Yamaha. If it was a Honda, Kawasaki, or Suzuki then it would be about time for valve replacement.
If I were you I would clean the air filter. Remove the boot from the rear of the carb. and verify the slide is opening up all the way. If that checks out OK then remove the carb. Give it a close inspection as you may have some dirt in it blocking a jet.

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  • KJ790

Posted December 31, 2006 - 07:31 AM

#11

Sometimes valves can settle in the seats when they are new. They don't necessarily have to be wearing, but they could get a little tight after the first couple hours from breaking in. To check them you just need to take the gas tank and the valve cover off and stick a feeler guage in between the cam lobe and the bucket. It takes about 20 minutes to do. If they are out of tolerance then you need to take the cams out and put in new shims under the buckets. It isn't that hard to do it yourself if you take your time. Shims are a couple bucks.

  • flintlock28

Posted December 31, 2006 - 06:13 PM

#12

Check to make sure that the Fuel Screw is adjusted correctly. It can have a major effect from idle to 1/3 throttle or so. With the temperatures decreasing, you may be running lean. My bike will run "piggy" when the fuel screw is incorrect. Just a little tweak, to set it correctly, and it's lifting the front wheel again.

Do a search on setting th Fuel screw.

  • twenty34

Posted December 31, 2006 - 09:25 PM

#13

Check to make sure that the Fuel Screw is adjusted correctly. It can have a major effect from idle to 1/3 throttle or so. With the temperatures decreasing, you may be running lean. My bike will run "piggy" when the fuel screw is incorrect. Just a little tweak, to set it correctly, and it's lifting the front wheel again.

Do a search on setting th Fuel screw.


Interesting that you bring up this point. While at the track today, I started to try some alternate settings with the Fuel Screw just to see what impact it would make. I did notice that some of popping was getting better, but I wasn't completely certain on how to adjust the screw so I stopped playing with it since I was trying some suspension settings.

From what I understand now, you are supposed to get the idle going rapididly and while it's ideling fast, you are also supposed to turn the screw out until the RPM's rise to max and the bike sounds good. This is after turning in the screw until it almost bogs out of course. I'll try again.

  • motoag93

Posted January 01, 2007 - 07:51 PM

#14

I had my first ride today on my 07, wow that thing is powerful and feels lighter than my 2000 KX250. I rode it for about 1 hr, never over half throttle (ok maybe a few times at 3/4....). I was trying to follow the book.

Could someone clarify the idle screw adjustment procedure? I struggled with getting it lined out.

  • OcotilloBound

Posted January 02, 2007 - 04:01 AM

#15

I had my first ride today on my 07, wow that thing is powerful and feels lighter than my 2000 KX250. I rode it for about 1 hr, never over half throttle (ok maybe a few times at 3/4....). I was trying to follow the book.

Could someone clarify the idle screw adjustment procedure? I struggled with getting it lined out.


It's the fuel screw you want to adjust, not the idle screw. The idle screw will only affect the bike's revs at idle, not control how much fuel is mixed in at the carb at lower revs. At lower revs, there isn't enough vacuum pressure to force the fuel delivery into the carb, the fuel screw helps facilitate that by varying the fuel flow. Follow Rickk's instructions to do it. I think the ideal RPM's is 1800 to have it at before you start turning the screw. If you don't have a tach, then consider that 2000 rpms is about 1/5 of WOT. You will need to have a Zip-ty or equivalent fuel screw to do this easily, it's a giant PITA to do it with the stock screw. Use your initial setting as a baseline, screw it all the way in and count how many turns out to the original spot, and then fire it up and follow his instructions. you need to put it all the way in first so you know how many turns out you have it before you start, otherwise how will you know where it is?
Rickk, I'm betting that the problem is all in the fuel screw setting. It's highly unlikely you need to adjust your valves yet. That and the suggestion on cleaning your air filter will probably have you lifting the front wheel again in no time. If that doesn't do it, consider a 170 main and a 48 pilot jet and see if that helps. Where are you riding?

  • Tobyforlife

Posted January 02, 2007 - 04:30 AM

#16

I agree with OcotilloBound. Start by getting the 42 pilot jet out of there, replace it with a 45 to 48 and while your at it install an aftermarket fuel screw. I ride at a differerent altitude so main jet size would differ. One thing to remember though, one sign of "tightening valves" would immediately be difficult starting. Although my bike when new was difficult to start because of jetting and fuel screw problems.

  • motoag93

Posted January 02, 2007 - 07:12 PM

#17

Thanks OcotilloBound, that makes sense. My buddy told me today that I need to get an aftermarket fuel screw. That may be the first aftermarket addition for me.

  • twenty34

Posted January 02, 2007 - 08:58 PM

#18

Rickk, I'm betting that the problem is all in the fuel screw setting. It's highly unlikely you need to adjust your valves yet. That and the suggestion on cleaning your air filter will probably have you lifting the front wheel again in no time. If that doesn't do it, consider a 170 main and a 48 pilot jet and see if that helps. Where are you riding?


I'm starting to think so as well. Filter has been cleaned and I'm runing a 170/48. Bike starts first kick so glad that the valves are likely ok. I played with the fuel screw a bit and it's been helping. I think that just getting used to the power and the fuel screw may be what has been percieved as a lack of power or degradation. I think it's good now. I'm really getting comfortable on this bike and it feels great.

I ride LE and Cahuilla mostly.


Thanks for the tips.:lol: :confused:

  • OcotilloBound

Posted January 03, 2007 - 03:50 PM

#19

I'm starting to think so as well. Filter has been cleaned and I'm runing a 170/48. Bike starts first kick so glad that the valves are likely ok. I played with the fuel screw a bit and it's been helping. I think that just getting used to the power and the fuel screw may be what has been percieved as a lack of power or degradation. I think it's good now. I'm really getting comfortable on this bike and it feels great.

I ride LE and Cahuilla mostly.


Thanks for the tips.:lol: :confused:


Well, Cahuilla is what, 1800-2000 ft. elevation?, and Elsinore is maybe 800 ft, so you likely don't have jetting problems running a 170/48. I'm guessing on those elevations - All I know for sure is that my house is 1008 ft elevation, and it sits on a plane about equal with elsinore, right at the base of the hill up to De Luz on the back side of old town. And I know you've got to climb a pretty big hill to get to Cahuilla, so I assume it's higher than home is. But fuel screws are pretty crucial to how your bike runs - when I got my 06, the stocker fell out in the 1st 15 minutes I rode it, and let me tell you, it didn't want to run without it. I was damn lucky I got it back to my trailer from Devil's Slide. And my trailer is in Desert Ironwoods. So read up on it - MXA has some good articles about doing it right, or read it here. I like to get my info from the mags though, because lots of people here, me included, have been known to be wrong before, and will most likely be wrong again!

  • red7

Posted January 06, 2007 - 08:49 AM

#20

I'm starting to think so as well. Filter has been cleaned and I'm runing a 170/48. Bike starts first kick so glad that the valves are likely ok. I played with the fuel screw a bit and it's been helping. I think that just getting used to the power and the fuel screw may be what has been percieved as a lack of power or degradation. I think it's good now. I'm really getting comfortable on this bike and it feels great.

I ride LE and Cahuilla mostly.


Thanks for the tips.:lol: :confused:


Give us an update. I just got back to Mexico last night and haven't even ridden my new '06 YZ450. I'm going to break it in today and then I'm thinking of going with the same 170/48 jets since I'm on the beach. How are you liking that jetting?





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