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BlaineKaiser450
11-24-2007, 10:52 AM
If i were to put just a 13:1 piston, carb, and a cam on my 04 450, would the crank be ok or not? Would i need to do anything to the crank? thanks
the Z Man
11-24-2007, 10:58 AM
More compressoin = more torque on the already somewhat used crank bearings...
bloodmoney23
11-24-2007, 11:12 AM
you could def use new crank bearings or a new crank. Thats your call. Once again back to a previous statement on cranks. If it can hold a 480cc big bore bolt on kit it should def hold an upped compression piston. But if it does have a lot of hours on the engine then i would def replace at least the bearings so you dont throw the crank and destroy cases.
One_Bad_400
11-24-2007, 01:07 PM
to me 13:1 isnt that bad.. i think you'll be fine but you might as well put some new crank bearings in them just to be safe so 15 hours down the road you dont grenade your motor... i'm running 16.5:1 in my race bike with a stock crank so the stock crank is fine
tar
11-24-2007, 09:15 PM
Originally posted by One_Bad_400
... i'm running 16.5:1 in my race bike with a stock crank so the stock crank is fine

Holy shat is that legal I have never heard of that high of compression on a atv
bloodmoney23
11-25-2007, 06:04 AM
Originally posted by tar
Holy shat is that legal I have never heard of that high of compression on a atv

LOL!!! me neither man but you never know.
BOSTON GEORGE
11-26-2007, 06:38 AM
yeah its legal but just to let you know if you do go 13:1 with those few other things your gonna need tp replace your gonna need to run your bike with race fuel 110 octain and i think its also leaded insted of unleaded which isnt easy to come by but is definetly need because of the comp
400exrider707
11-26-2007, 07:29 AM
Originally posted by BOSTON GEORGE
yeah its legal but just to let you know if you do go 13:1 with those few other things your gonna need tp replace your gonna need to run your bike with race fuel 110 octain and i think its also leaded insted of unleaded which isnt easy to come by but is definetly need because of the comp


You can get it leaded, unleaded, oxygenated, however you want it from octanes rating of 99 - 110+


BlaineKaiser450 - I wouldn't even think twice about running that setup. Should be safe and reliable. Remember a motor is only reliable as its built.