Darkwolf
New Member
- Local time
- 6:19 AM
- Joined
- Oct 16, 2018
- Messages
- 17
I'm sure everyone has experienced the higher rpm issue on the generic and stock 2 stroke engine kits when you're riding at full throttle, the engine goes from a whine to a power losing putter and acceleration pretty much halts, capping your top end speed at what feels like a lower rpm than what it's truly capable of.
Well that's because it IS capping off your top end at a lower rpm than what it's truly capable of! Why? Well come to find out these carburetors have a main jet that is a bit too big for these stock motors and dumps more fuel into the motor than the motor can ignite at higher rpm every combustion cycle so instead of firing every time it starts to fire every other, essentially killing power and your rpm range.
Now normally the solution is to buy a new smaller jet, adjust the clip height for the needle and so on, reducing the fuel amount that is sprayed into the motor at wide open throttle and thus helping eliminate the higherrpm four stroke issue... but if you're like me you don't want to buy or replace anything that isn't broken and have a bit of ingenuity and fabrication skills. If you do, then I propose the alternative way to eliminate four stroking all together and unlock your stock motors true potential!
Instead of reducing the amount of fuel your motor gets, allowing for a more ideal air fuel ratio but limiting performance in the process you can keep the oversized stock jet, not have to rip your carburetor apart and fix the rich air fuel ratio by feeding more air into your system with a RAM AIR set up! These motors have the carburetor behind the motor so air first passes over the hot motor before it can be scavenged up by the vacuum of your carburetor. As a mechanic for 15 years now I can assure you that not only is that a recipe for poor performance, but that also means the engine is working harder to suck air in than it really has to.
I decided to get creative, using two pieces from an old vacuum I had lying around (you can use pvc pipe elbows or whatever floats your boat) and made my own intake tube, shaped in a way where it scoops the colder air passing above the motor and funnels it down to the carburetor, and just like that my four stroking problem vanished! The engine pulls harder and hits a much higher rpm than it was ever able to before... so much higher my 80cc generic China girl which I've only backyard tweaked by shaving the head, swapping a bosch platinum 2 plug from my old impreza which intrudes into the combustion chamber upping compression and allowing for better spark and deleting the baffle in the stock exhaust, to propel my 170lb body over 40mph! Seriously! I couldn't believe it! I was skeptical at first figuring it might help a little, but the difference is astonishing! So if you wanna have a little fun I implore you to try and make a ram air system for your motorized bicycle, i guarantee you won't be disappointed!
Well that's because it IS capping off your top end at a lower rpm than what it's truly capable of! Why? Well come to find out these carburetors have a main jet that is a bit too big for these stock motors and dumps more fuel into the motor than the motor can ignite at higher rpm every combustion cycle so instead of firing every time it starts to fire every other, essentially killing power and your rpm range.
Now normally the solution is to buy a new smaller jet, adjust the clip height for the needle and so on, reducing the fuel amount that is sprayed into the motor at wide open throttle and thus helping eliminate the higherrpm four stroke issue... but if you're like me you don't want to buy or replace anything that isn't broken and have a bit of ingenuity and fabrication skills. If you do, then I propose the alternative way to eliminate four stroking all together and unlock your stock motors true potential!
Instead of reducing the amount of fuel your motor gets, allowing for a more ideal air fuel ratio but limiting performance in the process you can keep the oversized stock jet, not have to rip your carburetor apart and fix the rich air fuel ratio by feeding more air into your system with a RAM AIR set up! These motors have the carburetor behind the motor so air first passes over the hot motor before it can be scavenged up by the vacuum of your carburetor. As a mechanic for 15 years now I can assure you that not only is that a recipe for poor performance, but that also means the engine is working harder to suck air in than it really has to.
I decided to get creative, using two pieces from an old vacuum I had lying around (you can use pvc pipe elbows or whatever floats your boat) and made my own intake tube, shaped in a way where it scoops the colder air passing above the motor and funnels it down to the carburetor, and just like that my four stroking problem vanished! The engine pulls harder and hits a much higher rpm than it was ever able to before... so much higher my 80cc generic China girl which I've only backyard tweaked by shaving the head, swapping a bosch platinum 2 plug from my old impreza which intrudes into the combustion chamber upping compression and allowing for better spark and deleting the baffle in the stock exhaust, to propel my 170lb body over 40mph! Seriously! I couldn't believe it! I was skeptical at first figuring it might help a little, but the difference is astonishing! So if you wanna have a little fun I implore you to try and make a ram air system for your motorized bicycle, i guarantee you won't be disappointed!