Question about the height of a 5hp Briggs flathead.

#1
Does anyone know offhand the general dimensions of a 5hp Briggs Flathead? (Or know a place I can find them?)

The space in my frame from the plate to bolt the engine on, to the bottom of the bar that runs from the back to the front handlebar mounting tube, is 12-5/8" high. Would this provide me with enough clearance to mount a 5hp Briggs if I should decide to at a later time?

After finding that a 7hp Briggs was too big last fall, and not wanting to run into that problem again, I got the 3hp Briggs which gives me around 1.5" or so to spare. But I am finding the 3hp, while good on flat ground, isn't so go for hilly areas.

At the moment I have a 12 tooth centrifugal clutch and a 60 tooth rear sprocket setup, so I guess it's 5:1 gear ratio?
 

buckeye

Well-Known Member
#2
Which air filter? And carb. I can measure a 1985 to give ya a idea if that would help. From the base to the highest point ,which would be the spark plug on mine. Let me know if that would help.
 
#3
Buckeye- Thanks! I don't have a 5hp engine yet, so I don't know which air filter and carburetor it would have, but I am hoping to find something with a Pulsa-Jet carb and a fairly flat or low clearance air filter. A flo-jet would be cool because then I could make more adjustments but since space might be a problem, I don't think it would fit.
 

DZLBIKE

New Member
#4
I have a 1970 5hp Briggs here on the workbench and it measures exactly 12 1/8" from the base to the top of the pulsa jet air cleaner. 13 1/8" from the base to the top of the spark plug. It is 11 3/8" from the base to the top of the head bolts. I don't know if that helps you or not.
 
#5
DZLBIKE- Thanks! That does help. I guess the question now would be whether or not the spark plug lines up with that upper bar or if it's off-center from it. If it's off-centered, then it sounds like a 5hp engine would work fine for me, otherwise, the sparkplug wouldn't fit beneath the frame.

On second thought, I think I am gonna run out to the shed and measure the frame again. Gotta find a flashlight.
 
#6
Yep, 12-5/8". You would have thought that there would be blueprints or drawings available online for the purpose of measuring the physical size of these engines, haha.

DZLBIKE, do you know what the space from the front mounting bolt holes to the middle of the center of the sparkplug hole is? I wonder if the sparkplug would be offset to my frame.
 

DZLBIKE

New Member
#7
Its hard to get an accurate measurement, but it appears that from the center of the front mounting hole on the recoil side of the motor to the center of the spark plug is about 1 1/4" to 1 3/8".(Sitting on the bike, this would be from right to left) From the same mounting hole back to the center of the plug,(running fore and aft) it's about 4 1/4". I hope this makes sense.
 
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