Top Speed

#6
44 mph right now. Geared it one time to see how fast it could go but once it hit 50 and was still pulling I knew that was fast enough for me. Found myself rarely going over 40 so I lowered the gearing.
 
#8
I think massacre was talking about top speed for his Tecumseh engine. this is under the Tecumseh thread.....:rolleyes:
Well I was talking about my Hs50, but I don't mind others chiming in with their top speeds either.
my top speed was attained with a 72 tooth rear sprocket. I do have a 60 tooth that I could put on it but I like the torque and acceleration with the 72.

So I noticed that the highest RPM that my engine runs is actually when I am braking.
Is this because the driver is closed and the driven is overdriving the crank?
 
#9
My “Roadster” is completely stock, Tecumseh Hs-40, diaphragm carb, governor untouched. Can’t wait to finish my Black Widow replica, then we’ll see how fast it’ll be. BW has an HS50, ARC rod, governor completely removed, Dellorto UA16S carb, 1” straight pipe exhaust. Massacre, what are your HS50’s specs?
 
#11
My “Roadster” is completely stock, Tecumseh Hs-40, diaphragm carb, governor untouched. Can’t wait to finish my Black Widow replica, then we’ll see how fast it’ll be. BW has an HS50, ARC rod, governor completely removed, Dellorto UA16S carb, 1” straight pipe exhaust. Massacre, what are your HS50’s specs?
Pretty much same as yours:
No governor, billet rod, dyno 245 cam, 18lb valve springs and aluminum retainers, lighting coil and flywheel, Chikuni 22mm carb, Robertson header. Bike pulls hard and revs high lol
 
#12
Pretty much same as yours:
No governor, billet rod, dyno 245 cam, 18lb valve springs and aluminum retainers, lighting coil and flywheel, Chikuni 22mm carb, Robertson header. Bike pulls hard and revs high lol
at about what rpm does your motor pull REAL GOOD and what jet are you running and when do you feel rpm's flattens out on top end. may not know if your gearing isn't low enough? or run out of travel space....lol are you running a memory tach?
 
#13
My “Roadster” is completely stock, Tecumseh Hs-40, diaphragm carb, governor untouched. Can’t wait to finish my Black Widow replica, then we’ll see how fast it’ll be. BW has an HS50, ARC rod, governor completely removed, Dellorto UA16S carb, 1” straight pipe exhaust. Massacre, what are your HS50’s specs?
on a hs-50 your running a big bore and a big intake bore. the dellorto 16mm will work,not the best,but better then a stock bowl carb, you really should go with a 22mm carb and a 16 pound animal spring and dyno retainers and keepers. it will pull hard up to 4700+ rpm's with no problems. with that stock cam.
 
#16
So high RPM on the memory tach says 8250. That is what I saw under heavy braking.
Bike seems to come in at 3000-4000 and at top speed I see about 5900-5950 in overdrive.

My concern is that the TAV is over diving the crank which makes sense since at slow drivetrain speed, the driven is closed and the driven is open which is kinda like reverse overdrive.
I don’t want to hurt the motor by over-revving it, obviously.

I bought some lighter weights but is there a way to tune the TAV to not be so brutal under braking?
Almost feel like lighter weights might make it worse
 
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