View Full Version : 73 atc70 w/ 88cc kit Questions

05-05-2007, 01:08 AM
I recently bought a 1973 atc 70. I love this thing... I Just purchased a 88cc head and a pro race cam from dratv.com using the stock head w/some port and polish. I ported intake, Intake tube and carberater, and upped the jet. NoW I also odered the high compression head gasket 52mm/.016"=.38mm. What kind of compression ratio am I looking at?What Kind of power Am i looking at?

Ps. Im having A grudge drag race against a friend. He has A stock 97 Z50...Who do you think will win !!!

05-05-2007, 10:45 AM
the 70..even stock would beat it

05-05-2007, 10:54 AM
When I first bought It I raced him about 6 time he beat me each time about 2-3 bikes. I dont know if the top end was hurting, or it was cause he's 150 lbs And im about 190. Im hoping to whoop on him Now....

05-05-2007, 11:18 AM
I also have an 88 cc kit from trail bikes .com only i installed it on a 78 z50 motor and
i used the stock 50 head i ported the head to match the intake and carb that came with the kit and it just oozes power at mid and top end now,i put this motor on my ct70.

05-05-2007, 11:33 AM
Besides it being a 88cc kit on a 50 is there a big differents in power??

05-05-2007, 11:46 AM
as far as power and torque it feels like it has almost twice as much but it also had
a microscopic carb stock . i would say it has around 8hp now .

05-05-2007, 12:38 PM
NICE.. I cant wait for it to be finished.... Im going to race him this saturday.....Is it true that a xr50 exhaust will work on a atc 70.All you have to do is cut 2 inches off and reweld it togther??/

05-05-2007, 01:05 PM
good luck getting done soon and i think you will smoke him . as far as the exhaust
i am not completely sure but i bet you can work out something . i made the back half of my exhaust and welded it to the original header on my ct70 .

05-05-2007, 01:56 PM
Does anyone know if this head gasket isthe thinnest you can get?? 52mm/.016"=.38mm

05-22-2007, 07:09 PM
Most 50 exhausts you don't have to do anything but a little bending to fit on a 70.