Big block 4 cycles

john2364

New member
I have noticed that there are a number of big block 4 cycles like the GX390. Are there racing classes for these or are they just for fun?
 

mikelavite#72

Site Supporter
yes the 390 , 420 & the Tecumseh Stars are all still verry capable engines . never underestimate them devils they will lay the torque to the track :) and plenty of places to run them . and i have seen all 3 of the engines i have mentioned run with , and finish in front of some 450'z
 

john2364

New member
Sorry if this is a stupid question but

it seems like the 4 strokes found in dirt bikes have substantially more power than the ones used in most kart races. Karts and Dirt bikes seem to run the same 2 strokes, why don't people race dirt bike 4 strokes?
 

XXX#40

2A supporter
Sorry if this is a stupid question but

it seems like the 4 strokes found in dirt bikes have substantially more power than the ones used in most kart races. Karts and Dirt bikes seem to run the same 2 strokes, why don't people race high dirt bike 4 strokes?
They do, the UAS Unlimited All Star's are filled with 4 stroke 4wheeler/dirt bike engines, in fact i'd say there is more 450 engines in UAS than anything.
Plenty of threads on the 450's here
http://karting.4cycle.com/forumdisplay.php?45-UAS-Outlaw
There's a man in that forum that makes cases for a bunch of different dirt bike engines that eliminates the transmission
Here's a race with 450's in it
http://www.youtube.com/watch?v=rolcdz0vJMU
 

brad hinkelman

Curiosity killed the cat
Sorry if this is a stupid question but

it seems like the 4 strokes found in dirt bikes have substantially more power than the ones used in most kart races. Karts and Dirt bikes seem to run the same 2 strokes, why don't people race dirt bike 4 strokes?

i ran with honda crf 250 4strokes 9 years ago....
 

GeorgeHenry

New member
Just add a wedge body and big 4 stroke either leave the tranny on or remove it and do a jackshaft with 4 disc clutch
 
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