Phazer PTO burndown need diagnostic help (pics)

8

80enticeryami

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May 30, 2006
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Kent, WA
Had a burndown on the pto side on my phazer II seized on four corners of the cylinder with minor pitting on the top. Mag side plug is golden brown looks to be running great at time of burndown. This was well into a ride probably 2-3 mile at least so i wouldn't think its a matter of not enough warm up.

Couple theories I have..
1.) oil injection pump has a leak around the diaphragm possibly starved of oil. but the bottom end looks to have stayed lubricated.
2.) Carb leaned out plugged jet or oil injector.
3.) crank seal on pto side.. Dont want that not sure if it would affect both cylinders or just one side.
4.) some one just doesn't want me to ride in the greatest snow I've ever seen.

Here is some pictures



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DSC00355.jpg



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not enough piston to cylinder wall clearance,main jet obstruction(too lean) did not let it warm up enough before blasting off!there,s a few answers.
 
Pic's are wayyyy bad,,,oil starvation kinda looks like...don't see any piston
melt from lean out..

was this motor rebuilt???
 
Sorry about the pics my camera is not very good at close up shots. Would the piston seize on the sides like that from oil starvation? while the bottom end looks to be in good condition. Cleaned the carbs last night and they did have a noticeable amount of stuff in the main jet and pilot jet but on both side equally.
 
by the looks on the top of the piston it,s not running lean, it looks like cold sezure are u sure u did,ent suck some snow in to the air box. if that was a crank seal u would burn down on the exhaust side from top of piston down, i would highly recommend u put 2 new piston,s and rings get ur pistons swan teched and the head 2. it will eliminate that kind of seizing, protec that heat build up and cold seize u have lots of snow that poor engine was not warm enough yet, just my 2 cents Al Larson
 
What does swan teched mean? Also does it matter that I was well into a ride 2-3 miles as I mentioned and did let it warm up prior to going.
 
No pitting on the exhaust side just four marks on the equal sides of the piston and the rings were pretty well seized in the ringlands
 
145 main jets in a phazer are not the least bit lean, if that was the first run of the year and u did not clean the carbs they will have a scummy green shit on the inside of the jet and that will lean it out. i have had 2 phazers in my time and u will not burn them down with those jets, thats stock jetting from yamaha and they allways jet rich.just my 2 cents Al Larson
 
How many miles are on that piston?
Did the engine sieze at the 2-3 miles?
A fan cooled sled will have a greater piston clearance which makes cold siezing unusual.

Check the other piston for signs of scoring if you have not.
Check the oil hose to the intake on that side. I had one come off the fitting for some unknown reason.
Mix oil with the gas before you run it again. Check for oil leaks. While the sled is running, remove the oil hose from the intake fitting and pull the oil pump cable wide open and check for oil flow from the hose. Make sure the oil tank level is dropping before you run straight gas in the fuel tank.
 
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I did have a leak at the oil pump from the tachometer inlet. Dont know why doesnt appear to be any sort of seal that can fail in that area. Bought the sled two years ago. The sled has 3500 miles motor no way of knowing. I put at least 1000 more after buying it. So no it was not a recent rebuild.

Pulled the oil injection off to check it via the manual and it is within spec. The plunger that is.

Checked the other piston in the intake and exhaust port just by visually inspecting and cannot see anything odd or troublesome. 125 PSI compression on the good side. Bad side was 40 psi.
 
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