First 4-stroke...... Help


13 replies to this topic
  • avbryce1

Posted February 06, 2007 - 07:38 PM

#1

Ok, The last bike I had was a 95 CR 125, that I sold in 2000 I havent had a bike since.

This weekend I bought a 98 yz400f for myself and a 2001 xr100r for my wife.

anyway, to the point.

The yz hadent ran in about 4 months. The guy I bought it from said it was "running lean and backfired a little."

I got it home and kicked it for a while with no luck so I pull-started it. I ran it for a while. after it was warmed up it started 1st kick no problem. I put it in the garage for about 48hrs. when I tried to start it, no go.

Now I'm totally ignorant to this bike so excuse my dumb questions. but what am I doing wrong?

The bike has a compression release. also what is the other thing that looks like a second choke?

  • gfmoto

Posted February 06, 2007 - 07:54 PM

#2

The dreaded starting drill. With the choke on give the bike one or two quick squirts of fuel with the throtle, Take your hand and place it on top of the throttle housing so you won't accidently give it any throttle. (4-strokes dont like throttle when starting) Then Kick the bike over once or twice with the compresion release pulled. Then kick the bike to top dead center (without the compresion release) once you find TDC you must use the compression release to go past TDC, BUT ONLY 1/2 A KICK, Then let the kickstarter come all the way back up and give it a good firm kick. 4-strokes take a firm kick not a fast kick like a 2-stroke. IF the bike won't start repeat process without touching the throttle. In time you will master the process, or you will sell it like the last guy and buy a 450 with automatic compression relase. Also if you tip over or flood it close the petcok and hold the throttle wide open and kick it with the compression relase pulled Good Luck, Next Bike CRF450 you will think you have died and gone to heaven.

  • avbryce1

Posted February 06, 2007 - 08:05 PM

#3

Thanks I will give that a try tomorrow

  • nopremix

Posted February 06, 2007 - 08:50 PM

#4

running lean and backfiring means, that when you chop the throttle when riding, it will pop and backfire. You can fix this by turning the fuel screw on the bottom of the carb out ( counter clockwise), or installing a bigger pilot jet. The max you should go out on the fuel screw is 2 1/2 turns, if more than that, then you need a bigger pilot jet.
That 98 bike was the grandfather of all of our modern Japanese 4stroke full blown mx bikes. I had one and it was great, but like mentioned before it is way more work to start and ride than anything newer. I am thinking however, someday that thing will be a collectors item. I sure remember seeing it kick butt while being ridden by pros that could take it to the limit.

  • King_Air

Posted February 07, 2007 - 04:45 AM

#5

[/QUOTE]
The bike has a compression release. also what is the other thing that looks like a second choke?[/QUOTE]

The other thing on the carb that looks like a second choke and has a red knob is the hot start. It is used for starting the bike when the engine is hot and after stalls, crashes,etc. It is pulled out until the bike is running and then is pushed back in. It leans the fuel/air mixture for easier starting when the engine is hot.

  • avbryce1

Posted February 07, 2007 - 06:30 AM

#6

Sorry, I wasent clear enough on the thing that looks like a second choke. The thing I'm talking about is connected to the airbox, and it has the exact same black sliding knob asd the choke.

  • TL426

Posted February 07, 2007 - 06:39 AM

#7

Sorry, I wasent clear enough on the thing that looks like a second choke. The thing I'm talking about is connected to the airbox, and it has the exact same black sliding knob asd the choke.


thats odd, i can think of the red hot start, black cold start(choke), and the idle adjustment knob, but nothing similar to the black choke knob.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • jayh300

Posted February 07, 2007 - 06:49 AM

#8

that's all my 99 yz400f has.... can you post a pix ????

  • King_Air

Posted February 07, 2007 - 06:50 AM

#9

Well, I am not sure what that is either. The parts fiche show something called a valve and it looks like it has a knob on it. It looks like it is associated with the airbox. I am sure someone will have the answer pretty soon. Now I am curious also.

  • avbryce1

Posted February 07, 2007 - 07:28 AM

#10

I'm at work right now so I cant post a pic right now. I go home for lunch at
12:30 I'll take a pic then and post it.

  • Florida_426

Posted February 07, 2007 - 08:29 AM

#11

Looking at an on-line parts fische I believe that is the 1999 version of the hot start, but I haven't seen a 99 to know for sure. Maybe Gray Racer will pick up on this one and help out.

Bill

  • XJBOB

Posted February 07, 2007 - 08:46 AM

#12

It's the hot start. My brother has a 98 YZ400 and the hot start knob is black and located between the airbox and the carb.

Bob

  • Smokeslider

Posted February 07, 2007 - 12:06 PM

#13

diddo with the hotstart, my 98 has the black knob for both the hotstart and choke, just in slightly different spots on the left side

  • avbryce1

Posted February 07, 2007 - 03:30 PM

#14

Thanks to you guys for all the help.

I'm about to go and try the starting method now





Related Content

Forums
Photo

100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies
Forums
Photo

Snake pit oct 30th by The Anvil


Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies
Forums
Photo

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F


Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.