2009 vs. 2012 HT engine differences?

[Steve1990]

Hi all, haven't been on in quite awhile now mostly due to my HT being dead. I tore into it and found it needs a total rebuild, the motor mounts are sheared off and I discovered some scoring in the cylinder when I started tearing it down. I probably have only 2500 miles on it, but I'll admit to not breaking it in properly and beating on it pretty hard. The fact that I had my couple of years worth of fun with it makes it money well spent to me. I think I've decided that I want to start with a whole new kit and a different bike. Actually, I tore mine down and started the bike transplant when I was here last, believe I even started a build thread before I tore into the engine and made my discoveries about it and sort of abandoned the project.

Anyway, I see looking at the kits that most places are selling a 2012 version now, but I fail to see any differences between it and my 2009 version. Is there any notable difference? The only thing I see is that most seem to have a different carb on them than my old HT.

FWIW, I'm looking at the 48cc Grubee engine this time around, I hear that the 48cc run smoother than the 66cc. My old one was a 2009 flying horse "80cc".

Also, I apologize if this has been discussed before, I did search but couldn't find anything useful.

 

[V 35]

The theory is ... the 48cc engine has a shorter con rod, and a lighter piston allowing for higher revs. The ' big ' motor has a longer rod, and heavier piston. My Huffy has a 48cc Grubee and it revs smoothly right up to WOT My Worksman has an 80cc Power King, and it has a tingle at aprox 3/4 throttle. This was true on a couple ' other ' 80cc I've tried out. The 80cc does have more torque, and climbs steeper hills, but top end is about the same, due to revving the 48cc tighter.

 

[MotorBicycleRacing]

The theory is ... the 48cc engine has a shorter con rod, and a lighter piston allowing for higher revs. The ' big ' motor has a longer rod, and heavier piston. My Huffy has a 48cc Grubee and it revs smoothly right up to WOT My Worksman has an 80cc Power King, and it has a tingle at aprox 3/4 throttle. This was true on a couple ' other ' 80cc I've tried out. The 80cc does have more torque, and climbs steeper hills, but top end is about the same, due to revving the 48cc tighter.

The 48 cc, 55 cc and 66 cc all have the same length rod at 38 mm.

The difference in cc's is from the size of the bore.

Yes, a 50 cc piston is a lot smaller than a 66 cc.

 

[Fabian]

The 2012 engine will most likely have the updated crowded needle roller bearing assembly in the connecting rod big end, which has proven to be more durable and hence more reliable.