Engine Modifications

[SwissArmyKnife]

Who has split the crank case and really modified their engine? Not just put on a air filter and exhaust.


Cams?

Valvetrain?

Piston and/or connecting rod?

Flywheel?

Carb work or carb swap?



I am building a "kart racing" engine for my winch right now and was just wondering how many guys really modify their motors?

[supermanotorious]

I always remove the govenor, if you do that, replace valve springs, carb jet, intake, and header, your little 6.5 will put out 9! Check out these links:

http://www.wakeboarding-winch.com/viewtopic.php?t=54&postdays=0&postorder=asc&start=0

http://www.affordablegokarts.com/mm5/merchant.mvc?Screen=PROD&Store_Code=A&Product_Code=BK1&Category_Code=BOK1

[SwissArmyKnife]

yeah this is the 3rd winch i am building.

original motor was a honda 6.5 from a generator

first thing i did was swap the crank shaft for a non-tapered shaft and removed the govorner while i had the case split.

have both the stock carb and i just ordered a gx390 (13hp) carb... built a custom intake to match the ported head.

i bought 2 cams one is from N-R racing for "marine winch boarding" .252 lift and the other is from affordablegokarts the .265 mod cam "for large carbs"... gonna see which one i like best

i have both 18 and 26lb springs... i'll prolly run the 18's untill i get some stronger rocker arms.

i can't really run an aluminum flywheel because of the starter (i removed the pull start) and batt charging coil, but i am going to reinforce the blower housing JUST INCASE the flywheel decides to come apart at high rpm

[supermanotorious]

my customer wanted a black engine so I thought I would try the new Harbor Freight Predator line, they look reverse engineered but there are some differences from the blue Lifan engines, some changes for the better!


the mounting diagram with measurements is a nice touch







notice the engine provides 2 wire swivels for your throttle!

the wire swivels are attached by axle style retaining clips

the gas tank bolts from the bottom instead of the back

this should be familiar

this should be familiar

[SwissArmyKnife]

that plastic gear on the cam makes me nervous, especially if your not running a govorner.

i like the throttle linkage setup.

[supermanotorious]

Good point, I didn't even notice the plastic cam