2 questions

[YAMAHA711]

mk my first question
is it possible to retap the oil drain on the case to a 7/16-20 because i decided to be stupid one day and tighten it ALOT or do i have to get new engine cases

and my second question
my brother just did a complete rebuild torqued everything to specs new everything and it is running very tight i will not start will the electric start u have to pull start it and it starts and u hit the gas and it drags it self down and kills its self is it possable that we put the crank bearings in backwards ? would that even create drag we have tried everthing new oil pump torquewd to specs everything so just need some help thanks

[nicker71]

First question helicoil it. My brother did the same thing on his new KFX450R and he had the shop helicoil it. It worked fine so far and that was about a year ago.

Second question, Not sure maybe timing?? or valves need adjusting??

[Ride1Rob]

Did he replace the timing chain. If it is the slightest bit stiff or binding it can make the bike do this as well. No links should feel kinked when you move them.

[YAMAHA711]

ok thanks for ur help can i get a few more opinions thanks for ur help rob and mr nicker lol ill be sure to try and check on both