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after successfully completing the street drag builds of rx and the single cylinder 4 stroke,s it was time for the evergreen commuter scooter honda activa.
After removing the engine from the bay it was time to examine the engine dimensions mainly the crank dimensions,stroke length width length of crank because my idea was to install the piston of honda shine into activa cylinder.
the stroke length of activa is 55.5mm
the stroke length of honda shine is 58mm.
the challenge was to accommodate the shine crank and piston on activa for which we had to mil the engine casing.the crank was then successfully installed into activa engine bay after the activa cylinder was re-bored to install bigger piston of shine there fore making the engine 125cc was completed .
A larger engine is of no use untill r unless the breathing of engine is set right which led to next challenge porting and deciding the right valve's..
before porting the major decision to be taken was regarding with carburetor suits the best for such a setup.Initally thought of apache rtr carb but later did not fix up due to complications in the carb size also the vaccum response.
after thinking many options i finally rounded up on the RX 135 carb.Few of my friends suggested that it would lead to flooding ,but i was confident that it would do the job and well versed in tuning these carbs.
To accommodate the carb the manifold was altered and carb issue was solved by deciding on the simota air filter to provide superior air flow.
Well a 2 stroke carb,what else do you expect?An ossome vaccum response.next lies the tast of porting modifying the port layout to set the right port goemetry .
the cam shaft remained stock as there were no options left since manually high lifting the cam is most dufficult task in performance tuning.
Well all done ,the final part was the exhoust.
If members here are thinking the setup is complete:-) no not yet will be installing an imported cdi unit and an high lift cam shaft very soon.
But before installing these two imports the results we have gained out of this setup pays of all the hardwork.
its clocking amazing timings which even some 150cc bikes don.t even come closer.
also the head was milled 1mm to oncrease the compression ratio.
To compensate the loss of compression due to porting and headwork the head was milled.
After removing the engine from the bay it was time to examine the engine dimensions mainly the crank dimensions,stroke length width length of crank because my idea was to install the piston of honda shine into activa cylinder.
the stroke length of activa is 55.5mm
the stroke length of honda shine is 58mm.
the challenge was to accommodate the shine crank and piston on activa for which we had to mil the engine casing.the crank was then successfully installed into activa engine bay after the activa cylinder was re-bored to install bigger piston of shine there fore making the engine 125cc was completed .
A larger engine is of no use untill r unless the breathing of engine is set right which led to next challenge porting and deciding the right valve's..
before porting the major decision to be taken was regarding with carburetor suits the best for such a setup.Initally thought of apache rtr carb but later did not fix up due to complications in the carb size also the vaccum response.
after thinking many options i finally rounded up on the RX 135 carb.Few of my friends suggested that it would lead to flooding ,but i was confident that it would do the job and well versed in tuning these carbs.
To accommodate the carb the manifold was altered and carb issue was solved by deciding on the simota air filter to provide superior air flow.
Well a 2 stroke carb,what else do you expect?An ossome vaccum response.next lies the tast of porting modifying the port layout to set the right port goemetry .
the cam shaft remained stock as there were no options left since manually high lifting the cam is most dufficult task in performance tuning.
Well all done ,the final part was the exhoust.
If members here are thinking the setup is complete:-) no not yet will be installing an imported cdi unit and an high lift cam shaft very soon.
But before installing these two imports the results we have gained out of this setup pays of all the hardwork.
its clocking amazing timings which even some 150cc bikes don.t even come closer.
also the head was milled 1mm to oncrease the compression ratio.
To compensate the loss of compression due to porting and headwork the head was milled.
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