predator engine, easy way to remove governer

[Frankenstein]

this is what a typical dyno sheet looks like, in this case for a corvette Z06

notice how torque tops out around 4700 RPM while power keeps climbing all the way to around 6300

Yes, power will increase as more rpm is thrown in, but at what cost? More fuel, hotter engine, less life. If you are using more fuel than optimal torque are you really cruising? No probably not. If I were to build a transmission for that vehicle then I'd probably keep my cruising engine speed right where torque falls and hp climbs past. This would be a good spot to make my normal cruise rpm for my environment. On that graph its about 5500 rpm.

I would also like to point out the transition zone from max torque drop to the point where hp starts to max is where the fuel and air are least needed to generate that power. So a cooler burning engine will last longer, so I figure my powerband is in that 5 to 6k range since it starts to look shaky after that and so my transmission would cover most low and high speeds within that 1-1.5k range. Obviously more fuel and air at the same time give more power through the entire rpm range, but that changes the optimal rpm range, it also puts more stress on the motor and drivetrain.

Most people will not have a dyno to hook the bike up to, and will need to feel it out, we also already have an idea of what to expect from these motors what to use carb size-wise and what rpm to use it in. If I can get away with tuning low end rpm to be as good as it will be and base my drivetrain on that so I can get a lot of reliable power for a long time.

 

[Street Ryderz]

Based on the above graph IMO the best cruise range is at 4000-4500 for a fixed single gear so that it's fuel consumption is nominal, power is still available when needed and gearing allows it to still climb.But for a multi geared setup I would make my shift points at 5500-6000 to make use of the torque to pull thru the gearing,Then for cruise you could go as low as the torque will support in a lower gear for sufficient speed at lower rpm!

 

[Frankenstein]

Based on the above graph IMO the best cruise range is at 4000-4500 for a fixed single gear so that it's fuel consumption is nominal, power is still available when needed and gearing allows it to still climb.But for a multi geared setup I would make my shift points at 5500-6000 to make use of the torque to pull thru the gearing,Then for cruise you could go as low as the torque will support in a lower gear for sufficient speed at lower rpm!

500rpm is kinda a small window don't you think? Unless you have 9 gears

 

[Will'smotobikes19]

If you wanted to ungovern the engine properly you can't use the 79cc they don't make billet rods for them so the rod will probably break when your'e going down the road full throttle. Proper way to remove the governor is disconnect the brackets take out the arm and the washer, take out the plastic gear and tap the hole- insert bolt with red loctite then you have to make a new rod for the throttle or use something like a 19mm mikuni.

 

[Deleted member 25783]

Wish I had taken photos, read #8.

 

[Deleted member 25783]

Having not got there yet Will, what carb needle setting works for you?

 

[Will'smotobikes19]

Well I haven't rode the bike to tune it yet I had to order m6 connector nuts to extend my fuel tank studs then I'm planning on using m6 allen bolts to hold the straps onto the connector nuts. My frame is ovalled and larger diameter than a regular beach cruiser where the gas tank mounts (micargi predator) my setup is still using the gov. and I'm just going to see how it does with the stock carb just how it is.