If everything checks out, good compression, good spark, fuel getting through the carburetor, good ignition coil, good throttle safety electronics, the only thing left is the crank seals. And they do make a difference. They are inexpensive, easy to replace, worth doing if you have no idea if they have been done. Here's my video on doing the seals. kzfaq.info/get/bejne/oteHe89pur3XhIk.html

Any progress? I just posted a couple of new videos about this model. Another fix to get it started...

I have one with the same problem, Good Spark, rebuilt carb, good compression plenty fuel but just pops and wont run. Almost wants to start but falls off to nothing. Thanks for the info, checking seals this weekend.

The spark it was getting might not be strong enough. Because once you put the spark plug inside the hole, the amount of compression can reduce the spark within the cylinder. So it needs to be pretty significant spark, not just a little bit. If that makes sense. So you can try a different coil, or a different stator or even a new spark plug. Let us know what you find out.

Something else we noticed, if you get "shocked" by grabbing the spark plug wire when you are trying to crank it, that is also definitely a problem. (Even if there are no bare or damaged areas to the spark plug wire). This means the voltage going through the spark plug wire is being lost. So you have to replace the spark plug wire as well. But you can usually purchase the coil with the wire. Just make sure you get a good one. And not the cheap Chinese one.

Here is the playlist thus far with this bike. The project has been on hold for a little while. But here is what we have done so far. kzfaq.info/sun/PLVsdJzatTm_VySzQES7XBCxJFakTUHTbY

What is it doing?

In another one of my videos - after this one, I show the exact fix I did. Which was nothing more than spraying some contact cleaner into the combustion chamber. Or you could use starting fluid. Whatever you prefer. This thing started right up after that (and has ever since.) And I changed nothing else. No, I don't know why. All I know is it happened and it worked. So remove the spark plug, spray some contact cleaner or brake cleaner, or starting fluid down into the cylinder, install the spark plug, and see if it fires right up. Also, if you say you have spark, how much spark do you have? A little bit of spark may not be good enough under compression and load. But if it is a very bright Brilliant Blue spark, you should be okay. There is a difference between just 'spark' and sufficient spark. If that makes sense. So make sure you have sufficient Spark.

And what do you consider a 'good' compression?

I also noticed that it makes a difference if the air filter is installed, as well as the airbox is installed with the lid. I know that doesn't make any sense either. But it is what it is. Many other people will tell you the same.

If it's not getting fuel it's obviously carburetor related. Make sure fuel flows though.

Make sure the petcock valve inside the fuel tank is not dirty or malfunctioning

Oh, I sprayed starting fluid in the intake, and this quad started right up and ran perfectly from then-on. But did not want to start before that. And I checked EVERYTHING.

Wheres the crank seal at

@@wildernesslife8600 on the crankshaft. Of course....

@@HorsepowerHouse brain fart. How can you tell if that's what's causing it? Just replace it.

@@wildernesslife8600 because it's a common issue on a 2-stroke that won't start - if you have checked everything else.

@@wildernesslife8600 With 2-stroke motors, if the crank seals are worn - the compression will be decreased, vacuum will also be decreased - and no motor can run with low-ish compression & vacuum. So, if it's not the top-end, piston, rings, gaskets, carburetor, electronics, etc - it's the crank seals. And depending on the model you have - it CAN be a difficult just to replace both seals. As they say "your mileage may vary..."

Read all of the comments.

What all have you replaced? And what year is the quad?

@@HorsepowerHouse was able to save piston and cylinder at the moment I just noticed the spark plug has spark but very little I appreciate your help and it's a 2001 tb250 two stroke

@@mycagonzalez9716 Yes, if it only has little spark, you might need to replace all - CDI, Coil, Stator. It is probably a good idea to go ahead and replace all of them. I had to do the same on this ATV. After more than 15 years, the electrics begin to fail. You can get "generic" ones on eBay. Not very expensive. Just make sure you get the exact ones that look like your original parts.

@@HorsepowerHouse thank you for your help it was the stator and coil

@@mycagonzalez9716 Great! I have learned when working with vehicles like this - older than 15 years - just go ahead and replace all the electrics and be done with it. Otherwise you will struggle and fight with it. Been there. lol

Read the title and description

Spray contact cleaner in the cylinder. Made mine fire right up after I checked (replaced) everything under the sun. And ran perfectly from then on.

Otherwise, simply find a mobile mechanic. Let someone else solve it.