Tuesday, April 17, 2012

The engine!

     Today is the day the engine arrived.  How do I know, because the dog always looks this smug after trying to eat the Fex Ex lady.

     But of course the sight of the box made Jason quite happy, if not a bit derp and speechless as you can see.

     Enough of all this, how bout we just get down to the good stuff.  Like the box, and the engine it's self.

     Now I have to tell you what it is.  Well it is a Lifan 125cc with a full blown 4 speed gearbox in the traditional 1 down 3 up configuration.  Full real clutch, no automatic clutch here.  Of course we had to test fit things.

     Now she looks mean huh.  But the thing is, I am having problems getting EPA/CARB certs for this engine, even though it is used in other bikes that happen to be sold in the US and even in California.  But I am sure we will persevere, because once I have those documents it can be registered.  Not sure how we are going to do that, but it is on the list.

     I have done some calculations as for gear ratios, with the sprockets we have now the thing will do 38.2 MPH at 7500 RPM's.  But that is boring, I want these ratios.

17 tooth front, 26 tooth rear ..


7500 RPM's  to primary gears  2015 RPM's

2015 RPM's  to final drive.   Sprocket speed is  2103

1.529  sprocket ratio  really  ... remember it is not over drive...

1375 RPM's at the wheel.  one rotation of tire is 4 feet....

5500 feet per minute.. =   62.4 MPH...

1st gear..

2015 to primary 

1st gear is 2.833 = 711 RPM at front sprocket

465 RPM's at rear wheel

1860 feet per minute  = 21 MPH


1.706 ratio..  =  1181 RPM front sprocket

772 real wheel RPM's 

3088 feet per minute = 35 MPH

3rd gear

1.238 ratio = 1627 at front sprocket

1064 rear wheel RPM's

4256 feet per second =  48 mph

     Enough said on that right.  And really the thing will wind out to about 9000 RPM's so I have heard on the net.  So that is just that much faster.  Right now the decision has been made to stick with our old sprockets since we happen to have them on hand and we really do not want to order more.

     Cash for us both is getting a touch tight, I mean I dropped cash on getting real Internet here.  (But I have a 15 gig a month cap, bastards)  And we happen to both be out of work as well.  So we are on a no cash budget, but not like that has stopped us so far.  Just made things a bit slow.  If you want to see my Resume, please just leave a comment.  I could use the work.   Ok that is it for this week, see you all next week.

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