Checking RV Clearance
Hard to tune or hard to start engine
You have to pull RV Cover assy w/carb, pull the rotary valve, use dots of grease in four
places on the rotary face to hold small pieces of .050 solder, reassemble the cover
on the motor with the valve out, torqe the cover bolts to spec, re-disassemble and
measure the squish on the solder, add all four measurements together and divide by
four, now measure the rotary valve thickness and subtract that number from the other
number, this will be your rotary valve clearance. Best is 0.012 = plus or minus 0.001.
0.010 the engine begins to overheat, 0.014is excessive clearance and hard starting,
difficulty in carb tuning, because it will steal the manifold pressure from the
adjacent cylinder, resulting in poor performance in accelleration & speed.
When water gets intruded into the manifold, say from theski flipped and the rider
failed to roll-over the watercraft in the direction he should see on the sticker
that is posted on the rear of the overturned watercraft, the water removes the
lubricating oils on the rv cover side of the rotary valve plate and wears away
the metal on the rv cover face. The next step is to have the cover re-machined
to original 0.012 spec. or replace with a new cover. Check this spec at final assy.
A good idea is to put paint on a shaft spline, and on the rv plate notch on engine
side before you slide the rv plate off the splined shaft, so as to make the valve
face toward the engine and retain the original timing and make this a "no Brainer"
to reassemble the rv plate. Use a non-acid solder if ya can find it.
Now is a good time to replace the two oil pump to rv cover spigot tubes 3/32"id tygon
lines. 6" & 8" long, use your drill as pictoralized in your shop manual, to prime.
Replace the Filter too, (every two years) as they get clogged.
Mount the carb(s), torque and sync the butterflies if dual carbed.
Install your rv cover assy as a unit, with a new o-ring.
Bills86e
Hard to tune or hard to start engine
You have to pull RV Cover assy w/carb, pull the rotary valve, use dots of grease in four
places on the rotary face to hold small pieces of .050 solder, reassemble the cover
on the motor with the valve out, torqe the cover bolts to spec, re-disassemble and
measure the squish on the solder, add all four measurements together and divide by
four, now measure the rotary valve thickness and subtract that number from the other
number, this will be your rotary valve clearance. Best is 0.012 = plus or minus 0.001.
0.010 the engine begins to overheat, 0.014is excessive clearance and hard starting,
difficulty in carb tuning, because it will steal the manifold pressure from the
adjacent cylinder, resulting in poor performance in accelleration & speed.
When water gets intruded into the manifold, say from theski flipped and the rider
failed to roll-over the watercraft in the direction he should see on the sticker
that is posted on the rear of the overturned watercraft, the water removes the
lubricating oils on the rv cover side of the rotary valve plate and wears away
the metal on the rv cover face. The next step is to have the cover re-machined
to original 0.012 spec. or replace with a new cover. Check this spec at final assy.
A good idea is to put paint on a shaft spline, and on the rv plate notch on engine
side before you slide the rv plate off the splined shaft, so as to make the valve
face toward the engine and retain the original timing and make this a "no Brainer"
to reassemble the rv plate. Use a non-acid solder if ya can find it.
Now is a good time to replace the two oil pump to rv cover spigot tubes 3/32"id tygon
lines. 6" & 8" long, use your drill as pictoralized in your shop manual, to prime.
Replace the Filter too, (every two years) as they get clogged.
Mount the carb(s), torque and sync the butterflies if dual carbed.
Install your rv cover assy as a unit, with a new o-ring.
Bills86e
