79cc non-kit build

[Tony01]

I am not sure I buy all that. The force of compression is a fraction of the force of expansion, and exspasion force is what we want! Improved porting, better intake, exhaust, all serve to raise combustion pressure. Can,t say why your's broke, but I suspect it was not due to to much compression. The highest performance engines in the world use plain bearings on the rod. Yes, I know there is no oil pump, but it is film strength, not oil pressure that supports the rod.

Maybe so. But it did not yet break. still driving it 20mi round trip to work mostly WOT.

 

[daverouse93]

Not sure of my overall ratio, never sat down and figured it out. On my transmission it is 12 teeth on the clutch up to 29 teeth on the jack shaft. (I had to switch to the #35 chain on the transmission to use the manual clutch, original tooth count for 415 chain was 9 and 22) The other side of the jack shaft is 9 teeth and 44 teeth on the wheel sprocket, with the #415 chain. My bike also has 24 inch wheels, which I chose so it would be a little lower to the ground. My bike cruises good between 30 and 35 MPH at about 5000 to 5500 RPM which is about where I wanted it. For 26" wheels you would probably want to go with a bigger rear sprocket. My transmission plate is the one everyone is selling for the 79cc predator but I don't remember where I purchased it. OMB Warehouse sells different size sprockets that will fit the transmission. I hope this helps, sorry if it is a little bit convoluted.

 

[daverouse93]

How do you like the kit? Has it been reliable under pressure?

 

[malatious]

I have been very busy this summer and have not had a chance to do much riding. I did take the bike out and rode about 20 miles this week and it did great. Lost my air filter somewhere along the way, manage to adapt one from Auto Zone to fit. Made sure it was tight this time. Also, just got my California plate and registration. Plate is now mounted. Working on building turn signals, brake light, head light, and horn assembly to mount on the bike. During my ride I was able to get out where there were some longer stretches of road and was able to get the bike up to 40mph, lots of fun but feels a little fast for a bicycle.

 

[malatious]

Finally was able to get headlight, brake light, turn signals, and horn set up on the bike. Used one of those cheap China bicycle light kits and chopped it up so I could hook it into something that worked a little better but still keep the LEDs for longer battery life. Have everything wired to a motorcycle style control that can be operated by my thumb and put the rear components into a vintage bicycle turn signal case. Will see if it holds up, so far so good. Also added a cargo case, I love the look without it but need to have somewhere to carry things.