knock in engine help

[ltl666devil]

my 250r knocks between like half -3/4 throttle. its got a brand new top end in it. just wondering wut it might b. it sounds like the bottom end.

[XCredrider]

250r's are supposed to have piston slap pretty bad but that may be a ping from to little of octane. what compression are you running?

[ltl666devil]

im running 12:1

[Eddiesanders250]

what octane are you running?

[ltl666devil]

i runing 94 pump gas mixed with vp 110. it almost sounds like somthing is broke

[Tom TRX250R]

Mine has a slight knock from the engine even after rebuilding the complete lower end and top end. A little knock is normal from R motors. If it is really loud there might be a problem though, like your crank bearing going out!!

[wilkin250r]

Originally posted by Tom TRX250R
If it is really loud there might be a problem though, like your crank bearing going out!!

This was my problem, and it wasn't all that loud before it went.

[XCredrider]

mine did start making a tapping or almost a knock in the lower end it sounded like right before my crank went. there was nothing i could do but try to ge tback to the truck cause no dirtbikes could have towed me in te sand and if they had got the quads they wouldnt have been able to find me in the forest. lol needless to say it ruined my cylinder and piston and crank and jsut everything. Id take it apart and cheack it out if you are unsure. the most ti will cost is the price of gaskets. Mine was about $1000 :mad:

[ltl666devil]

ya i think im gonna have to rip it down and check it all over. prob replace all the bearings. thanks