Whizzer Valve I.D.

T

tprjj49707

New Member
I bought a half dozen whizzer valves for my J engine. They are 3/4" dia.

I read somewhere the dangers of mixing them up as intake valve will burn up if used in the exhaust port. I think my J had them reversed (took apart twenty years ago) as the one with TP then some other marking is pristine, and the other valve looks like a rusty nail, literally.

My question is, what markings are on the exhaust valve? TP EX was one of the stampings, but I read somewhere there was another possible stamping.

I have a valve that is marked TP XB...is that exhaust? I imagine no harm would result in an engine with two exhaust valves.
 
Part #2218 exhaust valve was identified by TP and EX cast into the bottom of the valve head, however the replacement valves had TP & EX stapmed into the top of the valve head. Some of the original valves installed in the later "J" motors were marked TP and XP under the valve head [cast as part of the valve, not stamped]

Part #2226 intake valves had the TP and IN cast into the original valves, and the replacement had TP and IN stamped into the head.

Of course you can use the exhaust valve in either hole, but can't use the intake in the exhaust location.

I checked my NOS stock and valves removed from cylinders and all were marked. If it has "X" in the markings it is an exhaust valve and if it has "I" it is an intake. If it isn't marked it may not be an original Whizzer valve.

Have fun,
 
Thanks Quenton. Workload permitting, I will need my cylinder measured/honed/fitted for a piston, and valves done. Not sure about the guides, I will let someone wiser determine that. Your resume is very impressive if for no other reason than your experience with the XR-750.
 
If you want to add a little "punch" into your motor use a "300" series intake valve. The valve size was increased to 7/8" and it is easy to ream or mill the valve pocket for the larger valve. The "J" motor already has the larger carburetor used on the later motors with the 7/8" valves and the intake port is larger than the "H" motors. Increasing the intake valve size normally increases the top speed by about 3 MPH [to almost 39 MPH] on the "J" motor. Although you could also replace the exhaust valve with the larger "300" series, it doesn't help as the exhaust port is too small. The "J" cylinder doesn't have enough metal to open it up enough to match the larger exhaust valve. The later "300" cylinders had a much larger exhaust port but were cast with more metal at the port location.

Have fun,
 
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