09 yz450 won't start in gear

31 replies to this topic
  • Wr822

Posted April 27, 2015 - 09:44 AM


Hey guys, had a bit of an issue a month or so ago when I bought my 09 yz450 with jetting, but got that figured out and it runs great, only problem I have now is that I can't seem to get it to start when it is in gear. This is a problem since I race harescrambles in which we have dead engine starts, this puts me at a huge disadvantage, anybody know what causes this? Got my first race comin up on Sunday so would love to figure it out but don't even know where to start since I don't even know what causes it. My WR had this issue when I put it together with the timing one tooth off... But this bikes never been apart and has around 20-25 hrs on it

  • mikedabike

Posted April 27, 2015 - 12:03 PM


None of my YZs have ever liked to start in gear consistently. I dont even try anymore.

  • Wr822

Posted April 27, 2015 - 12:29 PM


My buddy's had some trouble but it usually started, and everybody else's on the line does so there has to be something I can do! I hate hittin the first corner in last place! Lol

  • AFelix

Posted April 27, 2015 - 03:41 PM


Check you clutch adj. Make sure the bike is good and warmed up prior to the start. Run a thinner oil.

  • Wr822

Posted April 27, 2015 - 04:38 PM


I thought about that being a possibility, that the clutch was out of adjustment enough to create too much drag for it to start. I do notice that with the clutch pulled in on a standing engine running gate start, with it in the revs, it wants to inch forward on me

  • stevethe

Posted April 27, 2015 - 04:45 PM


It is likely your clutch plates are dragging. They even do it stock as in when you pull the clutch in and push the bike not running it tries to turn the motor over. I had trouble on my WR450 with blued metal plates that were warped.

I switched to a Hinson clutch pack and it starts with the electric starter in gear now. The Hinson clutch pack seemed to work better than stock. However the spring pack it came with was too stiff so I used the stock springs.

You might have good luck with the Hinson clutch pack for a YZ.

  • stevethe

Posted April 27, 2015 - 04:48 PM


I thought about that being a possibility, that the clutch was out of adjustment enough to create too much drag for it to start. I do notice that with the clutch pulled in on a standing engine running gate start, with it in the revs, it wants to inch forward on me

If you don't buy the Hinson you likely just need to replace the metal plates.

  • Wr822

Posted April 27, 2015 - 05:00 PM


Replace my clutch plates with only 20hrs on the bike? I probly have 200hrs on my WR and it's still got the stock clutch!

  • stevethe

Posted April 27, 2015 - 05:14 PM


You could blue the metal plates in an hour. Easy enough to replace, check and repair!

  • ThumpMe

Posted April 28, 2015 - 06:02 AM


Some YZ's and WR's seem to do this others do not. Not sure exactly why. Probably a matter of tolerance buildup on different parts within each individual motor.

I have an '03 that was terrible. Would just want to take off when in gear and running. Would not EVER start if in gear. I went through the clutch about 12-13 times last year about this time and got it MUCH better. Did a write up with pics over in he WR area on all the things I found and addressed.

I have noticed lately it is getting hard to start in gear again....not as bad.....but a little. Needs an oil change though so hopefully new erl will put it back right.

Also I know my battery is getting pretty old and a battery not cranking the motor real good can have a lot to do with this type problem.

Also on my '03 I believe that Yamaha calls for a 10W-40 oil but THEN quit making it! The loco Yamaha shop said just run 10W-50 which is even thicker when warm and made my drag worse! I now am running just a basic 10w-40 Valvoline (Or Penzoil) but look/make sure on the API sticker there are no
modifiers as these are bad for motorcycle clutches.

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  • AFelix

Posted April 28, 2015 - 03:51 PM


Valvoline 4t 10w-40 here :thumbsup:

  • Wr822

Posted April 29, 2015 - 01:35 AM


Afelix, yours starts in gear?

  • grayracer513

Posted April 29, 2015 - 06:47 AM


I have pretty much always used a 10w-40 (20w-50 only when it's really hot out), and mine never liked to start in gear ever.  It would for a little while when I rebuilt the clutch the last time, but otherwise, the clutch drag on the bike is just too much.  If the bike runs right, and you practice, you can get off with the top 10-20 guys on a line 70 riders long pretty regularly. 

  • AFelix

Posted April 29, 2015 - 07:53 AM


I have a 99 400, and it will start in gear without much issue when warmed up. But when she is cold you may as well forget it. I have done it cold, but I pretty much wore myself out. 

I recently replaced my plug with a stock heat range iridium plug, and that seemed to help alot. Grayracer has mentioned plugs regularly in these starting issue discussions.

  • grayracer513

Posted April 29, 2015 - 08:14 AM


Grayracer has mentioned plugs regularly in these starting issue discussions.


Iridium plugs are beneficial for any bike, but in particular, the '02 and earlier 426 and 400 models, since they produce a weaker spark at cranking speeds.  They may or may not help a later CDI bike start in gear, but I've always run them, and I have the same staring in gear problems as most everyone else does.

  • ThumpMe

Posted May 02, 2015 - 08:35 PM


I checked my notes and Yamaha originally called for 20w-40 till they quit making it. NOW they say 20W-50 (NOT 10w-40/10w-50 as I mentioned in the previous post) and I tried and was running Yamaha brand 20W-50 oil since I did all the clutch work about a year ago. I just changed out to 10W-40 Valvoline a couple days ago and it did help some. Still is a little hesitant to fire up if in gear but as I mentioned I do think my battery is on its last leg.

I also have a '99 WR400 and it has the sweetest clutch on any dirt OR street bike I have ever ridden. Must have been a good day at the factory is all I can figure. It will fire up one kick hot or cold, in neutral OR in gear and the only time I have to kick it more than once is if it has been laying on it's side drooling while I am getting my schtuff back together.

I am terrible at replacing plugs! If it still works why spend the bucks? I do carry a spare with me at all times though! In fact my '99 has about 16-17K on it and I believe it is on about it's third plug! My '03 only has maybe 3500-4K and still on the stock one.

When I did all the work on my '03 clutch, it was more due to the fact that if placed in gear it was go time, even with the clutch in I could not hold it back unless using the brakes. That and neutral was impossible to find if not still rolling. I was hoping to get it to be able to re-light a LOT easier when in gear and although it is way better than it used to be it still is a crap shoot as to whether or not it will relight if not put back into neutral before hitting the button. It sure does have better feel as well as engage a lot better and I have a ton more clutch control when in the technical sections though.

I may try one of those new high dollar lithium batteries next time around as I hear great things about the power they have.

  • grayracer513

Posted May 03, 2015 - 06:24 AM


I checked my notes and Yamaha originally called for 20w-40 till they quit making it. NOW they say 20W-50 (NOT 10w-40/10w-50 as I mentioned in the previous post)


Where do you see that? 


From the manual for a '12:

Attached Thumbnails

  • oil.png

  • ThumpMe

Posted May 03, 2015 - 07:01 AM


It is out of the 2003 Yamaha shop manual. Page 3-15

Mine has that same graph as you have pictured in the first photo although mine only shows five different weights....my oil graph does not show the 10W-50.

On the same page at the top right it lists the Recommended oils for US and Canada as being 20W-40 type SG, for 5C (40F) or higher, and then 10W-30 type SG for 15C (60F) or lower.

When I was going through my clutch hell last year I figured the first thing I should try is running the stock Yamaha brand oil as if that worked I would not have to tear into it. I went to my local Yamaha shop and they informed me Yamaha had quit making the 20W-40 and said to just run the 20W-50 instead. I did and the results were worse than when I had the 10w-40 Valvoline in it. Grabby clutch and pulling ALL the time when in gear and motor running.

I left it in there and went through the clutch WAY to many times trying just about every conceivable thing I could think of. Drilling the additional three holes out more towards the front (outside edge) of that inner clutch boss made the biggest difference, even with that thick oil in it. I figured not much oil was getting out to the outermost 3-4 clutch plates in the pack, and that might be causing or adding to the drag on it.

Post #126 was probably the most clear. That write up with pics is located here:


It really made a huge improvement in clutch feel and engagement on that scooter.

Last week I changed back to 10W-40 and it is noticeably better....it will start up while in gear after a flame out or engine kill maybe 50% of the time while still in gear now. Am hoping a new battery might push it up to 90%?

  • grayracer513

Posted May 03, 2015 - 07:33 PM


Never mind the graph, look at the viscosities that are specifically recommended in the '12 manual.  10w-40 and 10w-50 are right there, so on what basis, that being the manual for a 2012 model, do you claim that Yamaha "now says 20W-50 (NOT 10w-40/10w-50" ?

  • ThumpMe

Posted May 04, 2015 - 06:23 AM


WHOOPS! I did not mean that those viscosity oils should not be used.

What I was referring to in the second post is that in the last paragraph of my first post I made the mistake of referring incorrectly to both the oil I was using and the oil the shop told me to use as 10W-40 and 10W50, when it should have read 20W-40 and 20W-50. (I tried to show that by the part in parenthesis, but it is easily read over.)

I can see now re-reading it how that did not come across as clear as I had intended.

Sorry about the confusion.

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