difference in engines?

dkon0450 · #1 05-31-2009, 08:03 PM

So i just purchased the JET engine kit for $119 for the 80cc 2 stroke engine. And i thought that it was a good deal.

now im looking around and notice alotta people have 4 stroke engines..but they are like $250 and im wondering what the better deal is?

I would like to go 40+mph when im all done moding the engine.

matt167 · #2 05-31-2009, 09:05 PM

keep in mind, bikes are lightweight and not really designed for consistant speeds over 25 MPH.. 35 MPH is really pushing your luck..

anyway. a 2 stroke will have more HP per CC, it's just there nature, but they have less torque and they have a smaller powerband than a 4 stroke.... a 2 stroke would greatly benefit from a SBP shift kit to keep it in the power band, but you would need a multi speed bike and an alloy hub

**Bikeguy Joe** · #3 05-31-2009, 09:13 PM

Two strokes can have as much or more torque than four strokes of the same cc's...
Two strokes are lighter and have less moving parts.
Four strokes don't require mixing gas and oil, but do require oil changes.
Four strokes are more tolerant of bad (lean) fuel air ratios.

dkon0450 · #4 05-31-2009, 09:25 PM

so if i have a stretch cruiser (similar to the one at the top of the screen) which one would be better if im trying to go for a max speed?

matt167 · #5 05-31-2009, 11:09 PM

2 stroke, with a SBP shift kit if you want speed, but you need at least 3 speeds to make it worth while.. actully a 3spd alloy hub with a coaster brake would be perfect IMO.

2 strokes don't have the torque needed to get out of the hole. they have powerbands in the upper RPM ranges and max torque will be in the powerband. hp will be in the same powerband.. so you need somthing that will get you in the powerband quick and keep it there. probably a 3,000 RPM powerband. probably starting around 5,000 RPM

Spunout · #6 06-01-2009, 09:02 AM

Quote:

Originally Posted by matt167

keep in mind, bikes are lightweight and not really designed for consistant speeds over 25 MPH.. 35 MPH is really pushing your luck..

anyway. a 2 stroke will have more HP per CC, it's just there nature, but they have less torque and they have a smaller powerband than a 4 stroke.... a 2 stroke would greatly benefit from a SBP shift kit to keep it in the power band, but you would need a multi speed bike and an alloy hub

stock 44-tooth sprockets will generally top out around 30mph, but thats keeping the revs high. you can throw a 36-tooth on, and cruise all day at 35.