Planet Minis

tomsta204 · 10-12-2008, 04:08 AM

is the crf50 motor the same as the crf70 motor but has the crf70 motor just got a bigger bore on it or are they diffrent in the internal part to

RIDE~4~LIFE · 10-12-2008, 05:51 AM

i think the 70 has a stronger gear box but im not sure

TheCRKid · 10-12-2008, 06:24 AM

the 70 have bigger valves in the head ,and different gear ratios

gbunner · 10-12-2008, 06:25 AM

I think the clutch is different too.

firepower354 · 10-12-2008, 08:06 AM

Head has bigger ports, valves and combustion chamber, so you use a "race" head BBK. Primary drive ratio is different, 70 uses the same ratio as TB, Tak etc. about 10% taller overall, same as dropping 3 teeth on the back sprocket of a 50. Transmission gearing is the same, but the 70 has sturdier parts. 70 rod is stronger/heavier, clutch is beefier, oil pump pumps more oil. And yeah, the bore's 8mm bigger.

PitRacerVince · 10-12-2008, 02:32 PM

damn firepower u know ur stuff, but I rode my buddies stock crf70 and was very surprised at how timid and sluggish it was vs a stock crf50.

firepower354 · 10-12-2008, 03:07 PM

Heavier bike, taller gearing. Add some compression with a thin head gasket, jetting, baffle mod, filter, and really wake it up. Cheap

10-12-2008, 04:08 AM	#1 (permalink)
tomsta204 PM Newbie Join Date: Sep 2008 Posts: 90	!!!!motors!!!! is the crf50 motor the same as the crf70 motor but has the crf70 motor just got a bigger bore on it or are they diffrent in the internal part to

10-12-2008, 05:51 AM	#2 (permalink)
RIDE~4~LIFE 2nd Gear Member Join Date: Jun 2008 Location: S.A, Australia Posts: 885	Re: !!!!motors!!!! i think the 70 has a stronger gear box but im not sure

10-12-2008, 06:24 AM	#3 (permalink)
TheCRKid Advertiser Join Date: Jan 2005 Posts: 3,781	Re: !!!!motors!!!! the 70 have bigger valves in the head ,and different gear ratios __________________ T Bolt USA ALL top Pitbikes ,Engines and Parts for Pitbikes & Minis Website Contact THECRKID@TBOLTUSA.COM or Call 215-630-3554

10-12-2008, 06:25 AM	#4 (permalink)
gbunner 2nd Gear Member Join Date: Sep 2008 Location: Greensburg, Pa. Posts: 357	Re: !!!!motors!!!! I think the clutch is different too.

10-12-2008, 08:06 AM	#5 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 6,266	Re: !!!!motors!!!! Head has bigger ports, valves and combustion chamber, so you use a "race" head BBK. Primary drive ratio is different, 70 uses the same ratio as TB, Tak etc. about 10% taller overall, same as dropping 3 teeth on the back sprocket of a 50. Transmission gearing is the same, but the 70 has sturdier parts. 70 rod is stronger/heavier, clutch is beefier, oil pump pumps more oil. And yeah, the bore's 8mm bigger.

10-12-2008, 02:32 PM	#6 (permalink)
PitRacerVince 2nd Gear Member Join Date: Oct 2008 Location: Lancaster, CA Posts: 255	Re: !!!!motors!!!! damn firepower u know ur stuff, but I rode my buddies stock crf70 and was very surprised at how timid and sluggish it was vs a stock crf50.

10-12-2008, 03:07 PM	#7 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 6,266	Re: !!!!motors!!!! Heavier bike, taller gearing. Add some compression with a thin head gasket, jetting, baffle mod, filter, and really wake it up. Cheap

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