2003 Warrior 350 Won't Start With Gas, Spark, and Compression

[dydot]

To start out I bought a cheap Warrior that is in great shape physically wise. It didn't start when I bought it. So I now have checked that I have a good blue spark, compression, and fuel. It doesn't even try to start with starting fluid. My compression is HIGH at 150 psi, so I can assume someone has put a high compression piston in I guess. Checked timing and it is perfect. What else would you guys advise me to check? This one should get pretty interesting!

After cranking a while it seems that it clunks pretty good but I hear that most of these do because of the starter clutch. Turn by hand and it sounds completely fine.

Tomorrow I will be checking Ignition coil, source coil, and pickup coil resistance. I will probably also try to pull start. I tried to pull start before cleaning the carb and it started but died right away. I would like to test as much as possible and not throw parts at it. Would appreciate any other suggestions.

 

[bones]

Start by downloading the manual here https://www.yfm350.com/threads/free-warrior-manual.20507/

 

[Kirk]

IF you have air/spark/fuel & compression that should start! If it doesn't, the easiest things to check are your fuel source (PLEASE don't use ETHER!!!) and then check that you have no exhaust restrictions, the valves are completely closed (valves adjusted too tight will hold valves open just enough to cause major starting issues)... the best thing to do next is a cylinder leakdown test, to see where your combustion pressure is escaping to. If you apply air pressure to the cylinder with the piston @ TDC (top dead center) with the valves closed (TDC/compression stroke) there should be only 2-5% leakage, and you won't hear that...if you hear air escaping out of the carburetor or exhaust then you just found a valve adjusted too tight or even worse...possibly bent/burned.....if you get a lot of air rushing our of the crankcase itself (remove the oil fill cap) then you have either a burned piston, failed rings etc etc etc...

Being you checked and got a compression reading of 150 (that's not "THAT" high....mine has 175, stock bottom end) THE ODDS OF YOU HAVING A BENT VALVE OR BURNED PISTON ARE LOW!

Let me know how you make out and if I can be of more help/.

Kirk Bonanny

 

[dydot]

Start by downloading the manual here https://www.yfm350.com/threads/free-warrior-manual.20507/

Thanks bones! I have the manual downloaded already.

 

[dydot]

IF you have air/spark/fuel & compression that should start! If it doesn't, the easiest things to check are your fuel source (PLEASE don't use ETHER!!!) and then check that you have no exhaust restrictions, the valves are completely closed (valves adjusted too tight will hold valves open just enough to cause major starting issues)... the best thing to do next is a cylinder leakdown test, to see where your combustion pressure is escaping to. If you apply air pressure to the cylinder with the piston @ TDC (top dead center) with the valves closed (TDC/compression stroke) there should be only 2-5% leakage, and you won't hear that...if you hear air escaping out of the carburetor or exhaust then you just found a valve adjusted too tight or even worse...possibly bent/burned.....if you get a lot of air rushing our of the crankcase itself (remove the oil fill cap) then you have either a burned piston, failed rings etc etc etc...

Being you checked and got a compression reading of 150 (that's not "THAT" high....mine has 175, stock bottom end) THE ODDS OF YOU HAVING A BENT VALVE OR BURNED PISTON ARE LOW!

Let me know how you make out and if I can be of more help/.

Kirk Bonanny

Thanks for the reply Kirk! I will get the valves adjusted this week. I will also perform a leak down test.

 

[dydot]

Alright today, I tested the source coil and the pickup coil. The source coil was way out of spec at 1200 to 1300 ohms. I tested that TDC was truly TDC by using a small screw driver in the spark plug hole thinking that I may have broken the fly wheel key way. TDC tested fine and it is truly TDC. I then decided to try to pull start by pulled with another quad and I got it to start and idle. I drove it around the yard a few times as well.

Is my issue the stator then?