D
Deleted member 12676
Guest
to all parts sellers;
My challenge to all of you is to stop just serving yourselves and start serving the needs of your customers. Owners of the Grubee engine desperately need more power and reliability. Bad reliability comes from ****ty cheap chinese carburetors and too much vibration (from too heavy wrist pins and overly advanced ignition). Bad power comes from weak cylinder compression, bad carburetion, overly advanced ignition, and the lack of an extended intake track. So unless you offer the following items you classify yourselves as nothing more than a self server:
name brand carburetor (Mikuni, Dellorto, etc) 14mm to 16mm for 48cc, 16mm to 18mm for 69cc
lighter wrist pin
higher compression cylinder head (to have around 130psi)
long offset intake manifold with 2.5" long 3/4" I.D. hose and carburetor adaptor
(The Jaguar CDI is available only from JNMotors since they have exclusive distributorship as long as they continue to deal honestly with me.)
I think it is a shameful disgrace that the only expansion chambers available are those made for high rpm peaky powered pocket bikes. They are good for top rpm power but they lose a lot of mid range power as a result of the too-strong baffle return wave which fights against delivery ratio at mid range rpm. But that can be fixed by lowering the return waves strength by extending the baffle wave. Just cut the baffle in half and weld in the right sized steel tubing that is 2" long. Tubes of various sizes are available online such as this one:
35mm x 1.2mm $4.30/ft onlinemetals.com
Exactly how to do the modification is explained on my web site. Why don't the main parts sellers do the mod and offer pipes that are more expensive to cover their extra time and cost? Because it is easier to let the public remain with the illusion that their expansion chambers are adequate and keep selling them. If they offered a "torque pipe" they would temporarily have less cheap and easy sales until it became more public knowledge that a torque pipe is what these engines need. But that is all just a matter of education which they can easily help do.
My challenge to all of you is to stop just serving yourselves and start serving the needs of your customers. Owners of the Grubee engine desperately need more power and reliability. Bad reliability comes from ****ty cheap chinese carburetors and too much vibration (from too heavy wrist pins and overly advanced ignition). Bad power comes from weak cylinder compression, bad carburetion, overly advanced ignition, and the lack of an extended intake track. So unless you offer the following items you classify yourselves as nothing more than a self server:
name brand carburetor (Mikuni, Dellorto, etc) 14mm to 16mm for 48cc, 16mm to 18mm for 69cc
lighter wrist pin
higher compression cylinder head (to have around 130psi)
long offset intake manifold with 2.5" long 3/4" I.D. hose and carburetor adaptor
(The Jaguar CDI is available only from JNMotors since they have exclusive distributorship as long as they continue to deal honestly with me.)
I think it is a shameful disgrace that the only expansion chambers available are those made for high rpm peaky powered pocket bikes. They are good for top rpm power but they lose a lot of mid range power as a result of the too-strong baffle return wave which fights against delivery ratio at mid range rpm. But that can be fixed by lowering the return waves strength by extending the baffle wave. Just cut the baffle in half and weld in the right sized steel tubing that is 2" long. Tubes of various sizes are available online such as this one:
35mm x 1.2mm $4.30/ft onlinemetals.com
Exactly how to do the modification is explained on my web site. Why don't the main parts sellers do the mod and offer pipes that are more expensive to cover their extra time and cost? Because it is easier to let the public remain with the illusion that their expansion chambers are adequate and keep selling them. If they offered a "torque pipe" they would temporarily have less cheap and easy sales until it became more public knowledge that a torque pipe is what these engines need. But that is all just a matter of education which they can easily help do.
