In Search of Predator 420cc Torque Camshaft

Colemanman

Colemanman

Member
#1
#1
Hello everyone

Im looking for a torquey camshaft for a predator 420cc engine. I have a bone stock one laying around as i speak without a unit to put it on. I plan on getting the stage one kit and doing a governor delete as well as rejetting the main and pilot jet.i wanna keep the stock flywheel to keep my electric start and charging system. I know a billet rod will be most likely be needed, maybe springs? Id like to purchase a high torque, wide powerband camshaft. From about 2000 to 5000. I dont have a need to spin higher than that. Not nothing too radical, but something i can put in the motor and toss it in a 450lbs go kart buggy with a converter and have gobs torque to climb hills, sand,and ride in the DNR ORV trails in the upper part of the lower penninsula of Michigan.
 
delray

delray

Well-Known Member
#3
#3
Stock cam will work fine. You just need to advance the timing little,billet rod a must,little stiffer springs then stock,rejet the carb,good k&n style air cleaner,good header.
Mikuni carb might work also but lowend response might drop off just little. Depends on the carb size? If you want to go little more with it? Maybe clean up ports little into the bowl areas only and mill the head and run 91non/eth gas.
Don't need to go crazy. Big blocks have ton of lowend torque.....:scooter:
 
Colemanman

Colemanman

Member
#4
#4
I got the stage one kit on it already. Id like to polish and clean the ports but have never done that before. Is that something that would be easy for a beginner.
 
delray

delray

Well-Known Member
#5
#5
Colemanman said:
I got the stage one kit on it already. Id like to polish and clean the ports but have never done that before. Is that something that would be easy for a beginner.
Click to expand...
yes and no. i just don't know your personally skills at this? so it would be good for you to do some research on this. like i said earlier don't go crazy on this. just need to clean up the casting inside little bit so things can flow little better. tape is you friend when it comes to cleaning up the ports in the bowl area. don't want to damage the seats. like i said earlier too timing is a must and good header is a must. not some home made header either. i see you want to ride it on DNR ORV trails . a RLV muffler won't kill the power so bad like a stock lawnmower muffler will and rlv muffler help keep the noise down too for the DNR guys...lol if you skip on one of this mod's it can effect the performance of this engine very easy. stock cam with the correct mod's should pull very easy from 2500-5000rpm's max all day......:scooter:
 
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65ShelbyClone

65ShelbyClone

Well-Known Member
#6
#6
Could also adapt the silencer from a 150-250cc 4-stroke dirt bike if you don't need a spark arrester like we do out in the southwest.

Colemanman said:
I got the stage one kit on it already. Id like to polish and clean the ports but have never done that before. Is that something that would be easy for a beginner.
Click to expand...
Easy to do, sort-of to not really. Easy to do well, no.
 
Colemanman

Colemanman

Member
#7
#7
Right on right on thanks for the info. I might try having my dad help me polish the head. Hes got experience with some big block mopars so im sure.he could help me put. Yea i just got into the dnr trails this summer. Was riding in kalkaska michigan. It was a blast riding in the woods and trails. It sucks tho bc i have to travel 3 to 4 hours to get remotely close to the trails.
 
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