2005 YZ250 Problem Starting

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4/22/2018 4:02 PM

Hello all, looking for some further insight on here on what exactly I should be looking to fix on my bike. All woods riding here in Ohio and love my 2 stroke. Lots of money invested to be where i am at. So problem is as follows, blowing through plugs like a mother, on kick start have a loud proofing noise every so often but doesn’t seem to want to let fuel through carb, even with a fresh plug it’s not normal. Bump started it yesterday and ran with ZERO bottom end (bike felt dead). I have never had an issue starting the bike before. Could this be carb related or worse engine. And also would it be worth buying an ALL BALLS carb rebuild kit or sending to a shop and paying for it that way. Any tips or similar problems would be most grateful. Have a trip up north in MI coming up for Memorial Day weekend and would like to mix gas and kick ass. Thank you for your time. Photo


4/22/2018 4:25 PM

I have a 2000 that was a bit of a basket car when I got it. Fouled plugs constantly and was hard to start. Finally traced it to a bad wet side crank seal. Replaced that and used the All Balls carb rebuild kit. Check your float level when you do it, mine was way off. Haven’t fouled a plug since and it starts much better. He carb rebuild is easy. The power jet is a bit hidden though, had to put my glasses on for that!


4/22/2018 4:29 PM

Thanks so much man. I’ll defienetly look into this. Need some clutch work done soon I might as well kill 2 birds. did you ever experience a loud ‘poof’ like sound when kick starting it as well?


4/22/2018 4:33 PM

Can’t say that I did. But it might be from oil in the cylinder building up from the crank seal. I also replaced the choke circuit while I was at it. Also made it much easier to start from cold.


5/4/2018 11:32 AM

jtmaster wrote:

Can’t say that I did. But it might be from oil in the cylinder building up from the crank seal. I also replaced the choke ...more

When you took the primary drive gear off do you remember which way loosened the bolt? Photo


5/4/2018 1:05 PM

I don’t off hand. I believe it was normally threaded. I believe I gave it a quick blast with an impact gun and it spun off easy. Reg wrench might not work as well as the quickness of an impact. I watched a you tube video on it while I was doing it.


5/5/2018 4:10 PM

DJ at Pro-Action in Beaver Falls could take a look at it.

The money spent on a pro mechanic is money well spent!


"Thank God my father wasn't rich."

"You wouldn't take clay to Southwick, so why take sand to Red Bud?"

"I ride a two-stroke because I am Weigandt-level cheap"

5/5/2018 4:38 PM

Check your reeds.


5/5/2018 5:13 PM

The poof sound is most likely loaded up fuel igniting out into the pipe.

Is it easier to kick thru the kickstart? Like no compression.

A oil side seal usually smokes a lot.

Buy you a compression gauge say at sears.

Put the spark plug back in boot and lay on head so coil doesn't overload. Hold throttle open and kick till gauge stops rising. You should be over 150 psi.

If it is a 100 psi you need to tear down see what is wrong.

Once it is good again check compression periodically to see how the engine is living then you know when to rebuild.