2006 YZ450F Valve Adjustments?? Noob


10 replies to this topic
  • Justin Pearson

Posted February 21, 2007 - 09:49 PM

#1

How often are you guys adjusting the valves?? I noticed the Service Manual says you need to adjust them right after break in.

Im not new to engine building and maintenance (cars, street bikes) but this is my first thumper, and being a 2 stroke guy (CR500) I have a huge fear of these things from a reliability stand point. To add to that the first time I had the bike out (Dumont, last weekend) I broke the kick start after A minor back fire (my mistake cracking the throttle while kicking). That was a shockingly expensive mistake!!

I do hear a very slight valve tick now after putting about 5 gallons of 100 race in it over those 2 days (the motor now has about 3 or 4 hours). But I really dont want to pull this brand new motor apart for nothing, is it necessary?? (valve adjust)

Also, do you guys jet the motor richer for sand duning?? Not sure if this is general practice as it is with 2 smokes.

The bike is Showroom stock, anything you guys recommend doing first?? I plan on exhaust and a better air filter, and after reading the Zip Ty thread possibly that mod as well. I changed the oil every ride (Amsoil MCF 10-40w) and am putting an o-ring chain on as I dont trust the stock non-o-ringers...

Thanks

  • stock510

Posted February 21, 2007 - 10:06 PM

#2

A slight tick is usual, they do sound noisy, its when its not ticking that you tend to worry.

To check the valves isnt as big a job as it sounds. 20 mins max.

Tank off, Frame brace off x2, Pull out hot start by turning the end of the cable that sits on the carb, undo the 2 allen key headed screws on top of the cam cover, tricky bit - pull off cam cover, its a tight fit in their so be patient and remember how you manouvered it off so you can get it back on in no time.

Piston to TDC on compression stroke and being so young the valves will almost certainly be within spec.

Every 10 or so hours give them a check to see how its going.

Reliability, if you give it good fuel, change oil regularly (every ride not necassary if its only a couple of hours) and clean AIR they are almost bulletproof.

Make sure you keep the air filter clean. As soon as you get lazy doing this, thats when dirty air gets in and the coating on the valves wears down and then your up for new valves and so on.

Just good basic maintenance and it'll run fine for many a hour.

  • NorCal

Posted February 21, 2007 - 10:08 PM

#3

I bought my bike, 2006 YZ450, used from a guy who hardly rode it. He said he had a recent valve check done when he sold it to me. I just checked my hour meter and I have put 40 hours on it so far this season. It still runs like a champ and starts very easy. I would check your bike after break in.


Definitely get an o ring chain. That stock chain will stretch and ruin your sprockets.

Careful of the fuel mixture screw. I had one back out on me at the track. I'm still mad about it.

I think exhaust systems are pretty overrated. My brother has the exact same pipe with an FMF slip on. I can't tell a difference in power.

Hope that helps.

  • grayracer513

Posted February 21, 2007 - 10:22 PM

#4

Your manual says to check the valves right after break in. You only have to adjust them if they actually need it. Odds are that it won't.

IMO, Slip-On exhausts are overrated. However, there are a number of good full systems that make a tangible difference in power, particularly on the lower half of the curve.

  • Justin Pearson

Posted February 22, 2007 - 12:12 AM

#5

I have noticed that the hot start/compression release does very little. My buddies 426 was a MAJOR difference however. (felt like kicking a 125 when you hit the release)

Is something wrong with my 450?? Sometimes when you first flip the kickstarter out to start the bike it feeles like the engine is SEIZED and even the compression release does little to get the kicker to move. Is this normal??

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  • Kasjok

Posted February 22, 2007 - 02:09 AM

#6

I have noticed that the hot start/compression release does very little. My buddies 426 was a MAJOR difference however. (felt like kicking a 125 when you hit the release)

Is something wrong with my 450?? Sometimes when you first flip the kickstarter out to start the bike it feeles like the engine is SEIZED and even the compression release does little to get the kicker to move. Is this normal??


First of all compression release and hot start are not the same. Hot start gives the engine more cold air and decompression allows you to kick the engine over TDC. 2003+ Yamahas have an automatic decompression system. Old 400f and 426f series had it manual by pull this little lever on left handlebar. 450f series are having hot start lever on the same place.

  • Yamahafan

Posted February 22, 2007 - 07:35 AM

#7

Is something wrong with my 450?? Sometimes when you first flip the kickstarter out to start the bike it feeles like the engine is SEIZED and even the compression release does little to get the kicker to move. Is this normal??


This problem was explained exceptionally well and solved by grayracer513 on the following thread:

06 YZ450F won't kick over but not seized???

http://www.thumperta...ht=kick starter

Please learn how to you the TT search function - it is very poweful and 99%+ of all problems have already been discussed.:applause:

  • WB450

Posted February 22, 2007 - 08:22 AM

#8

This problem was explained exceptionally well and solved by grayracer513 on the following thread:

06 YZ450F won't kick over but not seized???

http://www.thumperta...ht=kick starter

Please learn how to you the TT search function - it is very poweful and 99%+ of all problems have already been discussed.:applause:




Isn't that grayracer513's job to say if he feels the need? Give the guy a break.:applause:

  • grayracer513

Posted February 22, 2007 - 09:31 AM

#9

I have noticed that the hot start/compression release does very little. My buddies 426 was a MAJOR difference however. (felt like kicking a 125 when you hit the release)

Is something wrong with my 450?? Sometimes when you first flip the kickstarter out to start the bike it feeles like the engine is SEIZED and even the compression release does little to get the kicker to move. Is this normal??

The bar lever on your bike is NOT a compression release. The CR is automatic, as has been pointed out. The bar lever you have is the Hot Start, which opens an air passage that feeds intake air to a point behind the carb slide. The purpose of this is to lean out the fuel mix when starting the bike when it's just been shut off, like in a stall or a crash, and has had no real time to cool down much at all.

Another thing that has been said by a credible source is this: The Auto Decompression system operates based on the speed of the engine. It is said to be effective at speeds below something like 500 rpm. At speeds higher than that, it deactivates itself as the flyweight is thrown outward. The thing is that if you really rip into the starter hard, you can kick the bike at 700 rpm or so, which would defeat the whole idea.

  • Justin Pearson

Posted February 22, 2007 - 09:53 AM

#10

Thanks for the help guys, even my service manual calls it a compression release so I was confused. As far as the search function, I figured a bike this new might not have had all the bugs figured out and I look through lots of the threads and didnt find anything, sorry.

  • grayracer513

Posted February 22, 2007 - 10:12 AM

#11

Look on page 1-11 and 1-16 of the '06 manual. At no time is the lever referred to as a compression release in the discussion of control functions or starting procedure. That nomenclature may have been carried over from '02 in some other section of the manual, or you have the wrong book out.





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