Liven up the low-end on the 08 yz 450f?


38 replies to this topic
  • Wiz636

Posted August 28, 2007 - 03:35 PM

#21

If we resort to slippin clutches (that werent meant to be slipped)...


Huh? A clutch on a motocrosser not meant to be slipped? Who said these clutches are not meant to be slipped?

  • grayracer513

Posted August 29, 2007 - 08:49 AM

#22

... there is probably no one on this forum that could use all of the power of a 450 even if it was lacking power anywhere on the spectrum.

I don't know, I use all of mine, and I'm....old. I don't use 100% full power everywhere, but I definitely crank it up a lot of the time.

I do, however, agree that there is quite a bit of disagreement baout whether the engine needs to be "fixed" at all. They all said the same thing about the '06 when it first came out. Bikes like the '03/'04 YZ450 are thrilling and fun, but not very useful. Bikes like the '06 and up models are smooth and usable, don't wear you out as fast, and produce better lap times. Like the guy said, "be careful what you wish for."

  • warrior86

Posted August 29, 2007 - 09:21 AM

#23

Huh? A clutch on a motocrosser not meant to be slipped? Who said these clutches are not meant to be slipped?



Yes! I remember back in 04 when four strokes were really gettin popular and i was diligently reading mx mags and thumpertalk where they said you should "refrain" from slippin the clutch because the torque would quickly destroy the clutch. There was also something about the clutch being a somewhat different design. This is just what i recall off teh top of my head. I just remember that slippin the clutch on a four stroke was/is generally accepted as a no no....it could be done, just dont expect to slip it the way you do on a two stroke and get the same clutch life.

  • grayracer513

Posted August 29, 2007 - 09:28 AM

#24

Slipping the clutch is simply unnecessary on a 4-stroke. They are of the same design, other than they are more likely to include a cushion unit in the basket.

  • MxWFO

Posted August 29, 2007 - 11:17 AM

#25

Although I am new to TT I feel must throw in my 2 cents worth. The two cheapest and easiest fixes to solving your low end power problem is A. get a 50 tooth rear sprocket, or B. cheapest fix of all, take the slack out of you throttle. It will take some getting used to, but it will without a doubt help with the lack of bottom power. Make sure you leave just enough play so that when the throttle is shut off the slider in the carberator is closed. Once this is done ride slow until you get a feel for it, because you will have to turn the throttle further to actually let off the gas. Once you get a feel for this though you will have MUCH better throttle control.

Okay there are three things you can do. Downshift! This will help you break faster and it will help you from burning up your clutch.

  • djtroy

Posted August 29, 2007 - 12:03 PM

#26

Although I am new to TT I feel must throw in my 2 cents worth. The two cheapest and easiest fixes to solving your low end power problem is A. get a 50 tooth rear sprocket, or B. cheapest fix of all, take the slack out of you throttle. It will take some getting used to, but it will without a doubt help with the lack of bottom power. Make sure you leave just enough play so that when the throttle is shut off the slider in the carberator is closed. Once this is done ride slow until you get a feel for it, because you will have to turn the throttle further to actually let off the gas. Once you get a feel for this though you will have MUCH better throttle control.

Okay there are three things you can do. Downshift! This will help you break faster and it will help you from burning up your clutch.


51t rear sprocket works even better.

  • MxWFO

Posted August 29, 2007 - 01:45 PM

#27

No doubt a 51 will definitely help the bottom out. I haven't tried it yet with the 50 or the 51. Most likely I wouldn't go to the 51 unless I was riding a shorter supercross style track. A 51 may take too much away from the top. Like I said I haven't had the opportunity to test them out yet, so I could be wrong. It may be the cure some are looking for. I like to keep my gearing as high as I can to help with the top speed, but like I said a 51 may be what your looking for. It's all personal preference. I'll definitely try it out though.

  • jakethomson

Posted September 02, 2007 - 12:26 PM

#28

I am still slow in the turns so i am used to using the clutch like a 2stroke. Would a 50 tooth keep me from using the clutch more in the turns?

  • MxWFO

Posted September 02, 2007 - 04:27 PM

#29

Yes it will help you out. Also try downshifting. Since 4 strokes came on the scene people have gotten lazy and try to put in 3rd gear and leave it there. It has 5 gears for a reason. Use them. If you downshift you can use the power of the motor to roll on the throttle. This will allow you to save your clutches. Trust me they will last longer if you use the power of the bike. Also by downshifting before you go into a corner this will help you slow down a whole lot faster. When doing this try to get used to braking without pulling in the clutch. The engine braking will help you tremendously. It will take practice and time to get the feel for the rear brake, because you want to try to keep from locking up the back brake. Just before you get into the corner and your momentum has slowed enough the back wheel will lock up is when you pull the clutch in. With practice you will save clutches, charge harder into the corners, brake latter, and keep from stalling. But, to get back to your question, yes a 50 tooth sprocket will help out your bottom power, and require less clutching to bring the bike to life.

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  • warrior86

Posted September 02, 2007 - 06:09 PM

#30

kinda weird, i just read the review in TWMX and they are saying teh low and mid power is much IMPROVED over the 06 and 07. They refer to the low end of 07 as being weak and the 08 being robust. Im confused.

  • grayracer513

Posted September 02, 2007 - 06:11 PM

#31

Im confused.

No more so than some of the writers apparently are.

  • alstar250

Posted September 02, 2007 - 08:32 PM

#32

After spending the day tearing up the desert outside of Vegas for a better part of today...I have one thing to say to all those who said it needs more bottom ~

You're spending TOO MUCH TIME ON THE BOTTOM!!!

Seriously, this thing rips...!

  • todds924

Posted September 02, 2007 - 08:59 PM

#33

I guess nothing...? Or too new...?:thumbsup:


I just raced my 08 for the first time today. I ended up with alot of mixed feelings when comparing it to my 06. I am almost ready to throw my 06 motor in the 08 chassis. The 08 feels like a totally different animal. The handling is beautiful, it feels way lighter and then you get to the motor. It feels like it is way down on power. That silencer on the bike is garbage. I am either going to try the Dr D pipe i have on my 06 or just maybe the stock 06 silencer on the 08. Either way, I'm glad I kept the 06 also....Best bike i've owned yet.

  • warrior86

Posted September 03, 2007 - 07:39 AM

#34

so weird... quote off twmx "the port and cam refinements hit the mark in breathing new life into the low end and mid range power ...." "While the bike exudes a significant power increase down low, it still remains a very manageable delivery". "if there were one element of the power delivery the we could adjust, it would be to add a little more overrev up top"

There saying the exact opposite of what our guys are saying. Sometimes i wonder if they even ride these bikes.

  • skatpex99

Posted September 03, 2007 - 07:56 AM

#35

Wow, that is rediculous. I have never heard of a bike that is less powerful than the previous year. I think that the less noise is not enough to make up for power. This is pretty dissapointing. A lot of people are probably going not going to get the 08 cause of the bad reviews.

  • racerxx276

Posted September 03, 2007 - 09:57 AM

#36

I'm wondering if anyone has changed out the whole exhaust on the 08. Yamaha enlarged the header quite a bit in size but shortened it also. 07 has a tapered header. The smaller size should give it more low end?

I don't need much low-end when racing the desert either Alstar, but when racing MX , its a must have for coming out of the corners...

  • warrior86

Posted September 03, 2007 - 07:43 PM

#37

I don't need much low-end when racing the desert either Alstar, but when racing MX , its a must have for coming out of the corners...


THere nothing like some nice low end to slingshot outta the corners. There are a few corners where second launches me nice but doesnt pull long enough...i have to shift to third for a second, and then get on the brakes again. Lately ive just been slippin it in third and it pulls until i need to get on the brakes. Its less awkward than bangin third right before i have to brake anyway. Ahh, so much to learn, so much to learn....i love this sport:applause:

  • honda597

Posted September 04, 2007 - 12:11 AM

#38

Wow, that is rediculous. I have never heard of a bike that is less powerful than the previous year. I think that the less noise is not enough to make up for power. This is pretty dissapointing. A lot of people are probably going not going to get the 08 cause of the bad reviews.


Having owned the 07 and now the 08, the bottom end is stronger on the 08.
I have ridden both bikes back to back and the 08 450 wins. It feels more eger to get on with the job, but it is very quiet.
With the WHITE BROS CARBON PRO (full system) it packs even more punch of the bottom and through the mid,throttle responce is improved also.All of which is to be exspected
I have only ridden around a S X tack with this exhaust. as i wanted to see the difference between stock, and i have not put the carbon pro on since as i like the new stock delivery better.:thumbsup:

  • polarbear

Posted September 05, 2007 - 05:25 PM

#39

hopefully....shortly...someone will get on here who has the 08 and has tried it now with a different exhaust system. I am dying to know how much it helps. After reading what TWMX said I am beginning to wonder about their staff and test riders. I have lost lots of respect for them and their bike testing.





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