What are the tricks to starting this 99 YZ 400 f

[Mr.Selfdestruct]

I've got this 99 Yz 400 f. I'm new to dirt bikes, and kick starting.

I've litterally destroyed my right leg and foot trying to kick start this beast, it has fired up a few times, and once its on it runs great, but geez i must be doing something wrong.


I've searched all kinds of tips on GOOGLE, all the stuff about priming the motor by holding in the compression release and then giving it throttle while i kick the pedal 5-6 times, then taking my hand off the throttle setting the kick at TDC backing off about an inch and kicking it through smoothly, but i rarely have success.

It still takes me 20-30 kicks to get the thing to fire. I've had friends over and they've had the same trouble with the thing.

And once im able to get the thing to fire up and warm up, when i finally kill the motor and try to fire it back up warm it doesnt want to start AT ALL ! Even with the hot start button, hell i thought this bike was supposed to turn over easier once warmed up.

Im starting to think there is something mechanically wrong with the bike that is preventing it from firing up.

Is there anything i can check on the bike that might help me start this SOB easier ?

I'm getting pretty frustrated with it.

 

[sixds]

make sure your valve clearances are good.

 

[Jaybird]

I don't think the priming advise was much good.
It's probably why you aren't able to start the beast. (shrug)

If the bike hasn't started in awhile, I would maybe blip the throttle one time.
Then find TDC. After that use the comp release to push the piston just a hair past TDC. Then let the kickstarter all the way back up, let off the comp release, and kick forcefully all the way through. (just like in golf or horeshoes, follow through is important)
Keep your hand off of the throttle during all this. Try holding the brake assembly instead.

Also, check your valve clearances like 6ds suggested. Valves out of spec will cause a hard start.

Now, once you figure this out, you will be fine.
But, once you also get tired of this, you would really enjoy how the bike acts once you put an auto-decompression cam in. You will then remove the decompression lever, and any angst you have about starting the engine. It WILL be a different animal from then on and you, as well as your sore legs, will love it.

 

[Mr.Selfdestruct]

Thanks for the suggestions. This is great information.


I've read several times about kick starting the bike without using the comp release, with this bike when i find TDC and try to kick it through i can litteraly stand on the kick starter.

I actually have to blip the comp release at the sametime i kick, otherwise the kick starter wont budge, at all . This is what the previous owner told me to do as well.

Is this normal ?

I was under the impression the comp release was only used to find top dead center, but with this bike i have to blip the comp release just to start my kick!

 

[XRpredator]

you use the compression release to get just past TDC, then let the kickstarter back up, then go with a nice healthy full kick.

Also, along with valve clearances, a fresh spark plug will do wonders.

I know a lot of guys who have been all kinds of frustrated with starting the YZ-Fs, but then I look at my brother, who hardly ever did any maintenance (until his boy started racing the pee wee class), and he could start any YZ-F within 3 kicks.

 

[Mr.Selfdestruct]

So, i should be able to kick the sucker without tapping the comp release huh ?



I'll check the plug, i havent done that yet.

After that, i think im gonna have to take this thing to a shop and see if they can figure it out.

 

[XRpredator]

So, i should be able to kick the sucker without tapping the comp release huh ?

no

You run the kickstarter until you meet resistance. This is TDC.

Then, you use the compression release to nudge it just past.

Then, you allow the kickstarter to come all the way back up in it's stroke.

Then YES, you should be able to kick the sucker without tapping the compression release lever.

 

[Ol'89r]

And once im able to get the thing to fire up and warm up, when i finally kill the motor and try to fire it back up warm it doesnt want to start AT ALL ! Even with the hot start button, hell i thought this bike was supposed to turn over easier once warmed up.
QUOTE]


THIS is an indication of tight valves. As others have suggested, check your valve clearance.

 

[Mr.Selfdestruct]

Ok, i will have to get some specs on what my valves should be at, then i'll adjust them as needed.

 

[Mr.Selfdestruct]

WOO HOOOO !! I figured it out!


After reading what you guys posted on the site, and waiting for my poor leg and foot to heal up, I FIGURED OUT HOW TO START THE BEAST !!

I was able to kick start it 5 different times with a total of 10 kicks, FINALLY !

Cant wait to report how the sucker does out on the trails.


Thanks for the help, i'm now patiently awaiting a new hub so i can get this thing on the trails.

 

[granthamtm]

I am really glad to have found these posts. We bought my husband, 6'3" 200lbs, a 99YZ400f about 6 months ago. After watching him struggle every time he tried to start it, I had no desire to try. We just bought him a RMZ450 and now the YZ is mine, I am 5'8" 130, so you see my concern. The carburetor is being rebuilt right now; but I am already pissed off about have to try to start the beast. I love riding the RMZ and can start it with in a kick or two. I will let you know how it goes on the beast once I have the carburetor back. Wish me luck.

 

[rmk_racer]

LoL!!! I bought a 2000 WR400F a few months ago and it took me awhile to get the hang of starting that beast. Got it figured out now though, usually only 2 or 3 kicks. About kicked my leg of at first!

 

[Jaybird]

granthamtm,
I highly suggest you look into changing your exhaust cam out with a new auto-decompression type.
It will completely change the character of the bike and how it starts.
The decompression lever is removed, and the starting ritual is a thing of the past.

If I'm not mistaken, you can use a new cam from a YZ450, or do like I did and chose an after market component. I went with the HotCams model. It is a bit pricey, and may have an ever-so-slightly different lobe than the stock auto-decomp for the 450. But these guys put out top shelf work. (IMO)
http://www.hotcamsinc.com/index.cfm?fuseaction=cProducts.view&productid=488

The change-out (done properly) involves having to re-shim the exhaust valves, and checking and/or changing the intake valve shims, which the bike is more than likely due for anyway. But don't let shimming valves scare you off...Nikki provides a good tutorial here (somewhere) that describes the procedure, and she swears it no big job for her.
It will be money well spent. You and the old man will not regret it.