I've already done a bit of testing by shimming the cylinder to raise all 3 ports (video out soon), and I have 3 new cylinders here for porting and testing.
Here’s my formula: 1) Levelled carb, perfectly straight engine, sprockets and chain 2) Completely gut the muffler and drill holes in the cap. Lengthen header to 9” by attaching a piece of handlebar with twisted wire and cuttings from a tuna can (or spend money and use rad hose and pipe clamps) 3) Port match all manifolds, trim top of exhaust port by 1.5mm and bottom of intake by 1mm 4) Tune carb accordingly - raise or lower float arms, needle up or down, air filter cover on or off, change it’s shape or remove entirely Right there you’re pushing out enough horsepower to hit 45mph+ with a 36 tooth sprocket, and zero dollars spent. But you never can tell with these engines, I built one for my friend a while ago that will go over 38mph and it’s completely bone stock, running a 44 tooth sprocket.... and he weighs 240lbs! Conversely, I’ve had a one that needed all kinds of tuning just to go 35mph.
We did test some porting, raised the exhaust 1mm, widened it 1.5mm on each side. We lost a lot of low end power, didn't gain any peak and only increased the max RPM by 200rpm or so. With how much it lost down low, It really wasn't worth porting. All engines will respond differently as you say. I'll be trying some porting on the new BT engine. I'm currently making a pipe for it
sorry for the very late reply! The HP carb results are on the motoredbicycle forum and I think maybe part2? either way, it performed terrible, soooo much worse than the stock carb.
There's a small amount of play in the magneto. Without grinding the keyway, you should be able to loosen the nut and turn the magneto either way a few degrees. Retarding usually benefits these unmodded sub 6k rpm motors, advancing is better for the highly modified motors that do 10-15k rpms. Please dyno both directions with your build, please.
Adjusting the magneto does nothing but placebo. The ignition system doesn't spark at a set crank angle Moreso at a inducter charge level. If you want to adjust timing then get a ecu!
First video ever to put a motorized bike on a dyno! Great job mate.
I think 2strokestuffing beat me to it by a few years, it was a custom made bike dyno and not a chassis dyno but it definitely inspired all this
Wow unbelievable I love this so glad your doing tests like this very rare to see and I love it!
Great video! Waiting for other parts !
Thanx fer da vids, mate...
Thanks for the video 😁👍
Awesome series subbed :)
Thanks!
You got a freaking dyno?! Thanks for sharing.
Another great vid....sheesh I'm going to have to subscribe....with notification bell turned on😎
Ow bout some cylinder to engine block porting, mate? Just match it up to even out flow...
I've already done a bit of testing by shimming the cylinder to raise all 3 ports (video out soon), and I have 3 new cylinders here for porting and testing.
That chain...
😮🤦
Thanks for the research!
Here’s my formula:
1) Levelled carb, perfectly straight engine, sprockets and chain
2) Completely gut the muffler and drill holes in the cap. Lengthen header to 9” by attaching a piece of handlebar with twisted wire and cuttings from a tuna can (or spend money and use rad hose and pipe clamps)
3) Port match all manifolds, trim top of exhaust port by 1.5mm and bottom of intake by 1mm
4) Tune carb accordingly - raise or lower float arms, needle up or down, air filter cover on or off, change it’s shape or remove entirely
Right there you’re pushing out enough horsepower to hit 45mph+ with a 36 tooth sprocket, and zero dollars spent. But you never can tell with these engines, I built one for my friend a while ago that will go over 38mph and it’s completely bone stock, running a 44 tooth sprocket.... and he weighs 240lbs! Conversely, I’ve had a one that needed all kinds of tuning just to go 35mph.
We did test some porting, raised the exhaust 1mm, widened it 1.5mm on each side. We lost a lot of low end power, didn't gain any peak and only increased the max RPM by 200rpm or so. With how much it lost down low, It really wasn't worth porting. All engines will respond differently as you say. I'll be trying some porting on the new BT engine. I'm currently making a pipe for it
Just got one my self
You gonna love AND hate it at the same time.
@@leonardarola I already do. I can't get chain guidance right bc I have a weird frame. So the chain pops all the time
👽👍🏻✨
Whoooooa. Ya didn’t port match the intake gasket.
I cant find the video that you tested those parts im curious about the hp carburetor
sorry for the very late reply! The HP carb results are on the motoredbicycle forum and I think maybe part2? either way, it performed terrible, soooo much worse than the stock carb.
Chain needs a way better tensioner!
There's a small amount of play in the magneto. Without grinding the keyway, you should be able to loosen the nut and turn the magneto either way a few degrees.
Retarding usually benefits these unmodded sub 6k rpm motors, advancing is better for the highly modified motors that do 10-15k rpms.
Please dyno both directions with your build, please.
Great idea! Should I do the test with the stock carb and exhaust?
Adjusting the magneto does nothing but placebo. The ignition system doesn't spark at a set crank angle Moreso at a inducter charge level. If you want to adjust timing then get a ecu!