05-07-2017, 11:40 PM
Anyone running these that familiar with the differences? I have two cylinders from saws. Both David Bradley, but different horsepower outputs. The one on left has exhaust opening cut down substantially compared to the other. Intake and exhaust ports are huge also.
[attachment=1267]
The one on left is rated at 5 horsepower the right one would be lucky to produce 3.
I/E Ports on left are 0.550" Right cylinder only 0.437"
[attachment=1265]
They both have same bore/stroke obviously, but the 5 hp model uses all of the external components as an AH-58 motor. Crankshaft and crankcase are different to accept the A-58 shroud ignition and flywheel.
[attachment=1266]
Internally are basically the same, except the 5 hp model uses a 1/2" piston pin instead of 3/8".
The piston on 5 hp model has pin located lower around 0.100"(guessing here) give or take making the combustion chamber almost 5 cc's smaller. Piston is high enough to top of combustion chamber, that its dimpled to clear spark plug electrode.
External differences also noticed the top fin on cylinder is cut off to clear the upper shroud.
These cross scavenged motors never really interested me since I had a garage full of decade obsolete PP58, 61, 64 and 82's to blow up when I was a teenager in jr high. But if these motors can pull nearly 5 hp in stock form, there is potential for a pair of them to make for a good ride.
[attachment=1267]
The one on left is rated at 5 horsepower the right one would be lucky to produce 3.
I/E Ports on left are 0.550" Right cylinder only 0.437"
[attachment=1265]
They both have same bore/stroke obviously, but the 5 hp model uses all of the external components as an AH-58 motor. Crankshaft and crankcase are different to accept the A-58 shroud ignition and flywheel.
[attachment=1266]
Internally are basically the same, except the 5 hp model uses a 1/2" piston pin instead of 3/8".
The piston on 5 hp model has pin located lower around 0.100"(guessing here) give or take making the combustion chamber almost 5 cc's smaller. Piston is high enough to top of combustion chamber, that its dimpled to clear spark plug electrode.
External differences also noticed the top fin on cylinder is cut off to clear the upper shroud.
These cross scavenged motors never really interested me since I had a garage full of decade obsolete PP58, 61, 64 and 82's to blow up when I was a teenager in jr high. But if these motors can pull nearly 5 hp in stock form, there is potential for a pair of them to make for a good ride.