question about rotary valve...

[icemanOpie]

This Is probably a no brainer but I am new to 2-cycle engines using a rotary valve. I have become aware through many hours spent working on a 1990 xp, given to me via frustration of a friend, with the 587 yellow motor that the rotary valve gear is stripped on one side. It was given to me with the oil tank removed. I actually rode it for about 30 min. then abruptly died. Obviously if the rotary valve is not turning, It will not run. My question given all this info is.. Will it run with premix without the rotary valve plate as many other 2 cyl. 2 strokes that do not have reed valves or rotary valves? Or is the rotary valve critical to deliver the fuel to the right cylinder at the right time to this particular engine? Yellow 1990 587 btw. I also understand the other possibilities of twisted crank, wasted bearings, etc...junk motor...just wondering if the engine will run w/o the rotv.

 

[Dennis]

Rotary valve times the intake air/fuel charge. The engine will not run without it.

DAWG

 

[seadooya]

with the oil resivoir been removed. You starved the rv assy of oil. You can go premix all day long, but you still need the oil tank, to supply the oil to the rv assy.

Need to pull the assy out, and get anutha. No need replacing just the brass gear, the shaft is bent. You'll keep blast'n the new gears, if shaft aint replaced.

 

[icemanOpie]

that's what I gathered. I rode the machine as it was when it belonged to my friend that gave it to me. He got pissed at it when it quit running. What I've found wrong with it since...is he replaced the flywheel with the wrong one due to a bad ring gear. He drilled out the fuel return banjo bolt, I replaced with correct new unit, 0.8. And the needle and seat was not properly regulating at popoff pressure, was not seating at all, now is. now I find probably the most major problem...Bad rv gear. Where does one end with pi$$ing money into the hole in the water? Also just bought a new starter, old one magnets let loose, probably due to him trying to start with no rv assy, working properly. think I'll tick to 4 strokes from now on. Thanks for the info guys, I'll work on plucking the motor tomorrow.

 

[seadooya]

check it out, bud. SBT offers that replacement motor, with 1yr warranty for 495 buks. The rv assy alone, will cost 100 buks, plus time..etc get'n damn thing out, cleaned of its housing...etc. Just anutha ave.