I really need some help from any vetran Yamaha gear heads! I have a 2003 Warrior. All was well until I tried to start it and it sounded like something broke. Now it wont start. It has spark, and compression, but wont fire. I have changed plugs, and added starting fluid to cylinder, but still wont fire! Its a first for me. Motors always at least try to start for a sec. with starting fluid. I have no idea what to check. Could it be the timing chain? Please, anyone with ideas email me @ corbox1@aol.com I am trying to aviod a costly trip to the dealer. Thanks a lot.[img]i/expressions/face-icon-small-confused.gif[/img]

 

What was the compression PSI number?

 

I didnt do a real compression test yet. Due to the snowmobile tester not fitting in the smaller diameter yamaha ATV hole. But with finger over plug hole it seams normal. I will go get an adapter ASAP. What psi number would be normal? Thanks for the help.

 

Do a real compression test and get back with the numbers. The problem with a finger test is even 30 to 50 PSI seems like a lot. Under 50 and it's REAL hard the light the mixture. At 30 and under I can't get the mix to light.
Does it sound weird when it cranks?
What did it sound like when "something broke."
My experiance; when something sounds like it breaks, it's going to be valve gear or something bad. Sorry

 

how many hours are on the engine

My initial thought was the timing chain jumped a tooth or so... but get those compression #s -- remember wide open throttle while cranking it.

 

Has the carb become dislogdged from the intake boot?

 

I am looking all over to try to find an adapter for my compression tester. I cant find a 14mm to 12mm adapter for the Yamaha hole. I tried all of the auto stores in my area (Pepboys, NAPA..etc) I guess I will have to try to rig up a fitting using an old spark plug.
The carb. was just profesionally cleaned out and it is securely attached to the intake boot.

Thanks for the help so far guys, I will keep you updated later today if I can get an accurate pressure reading.

 

That throws up a red flag right there for me. Professionally cleaned probably means some punk at the local stealership probably jacked up your ride by not cleaning the carb correctly or reinstalling it wrong.

 

OK, bad news to report. I have no measureable compression. I can block plug hole with my finger and hit the start button and not get my finger blown off. I can feel a bit of psi, but not enough to make the guage read. Kinda like I feel a bit from the piston rising, than I feel the suction of it dropping. What is this sounding like to you? A bad valve, or worse?
What do you feel that I should do next?
It probally has a million hours on the motor. I bought it really cheap a few weeks ago ($400). I dont know the millage, but it has enough wear and tear to have bad swingarm bushings and wheel bearings and probally every other wearable part is sloppy.

I ran it for about 1/2 hour and it was fine. Final start attempt make a subtle breaking noise. Not a loud snap, just something metalic maybe binding or hitting. I need your opinion please. Try to get her going again, or part out on Ebay?

 

Take the valve cover off and turn it over and look at the valve action. More than likely it's going to be valve gear.

What? I have no idea. Could be timing chain, could be a stuck rocker or valve.......could be lots of things. The only way to find out is start to wrench on it until you find the problem.

One thing is for sure; the head is going to have to come off. Then go from there.