Honda pcx crankshaft locks under throttle?

My friends pcx blew and the crankshaft seized we un seized it with a breaker bar to find out it spins smoothly but when you open the throttle it cuts out and the crankshaft locks up straight away?? Is there a throttle activated oil pump in these or what could it be.. I'm used to working on 2t bikes done plenty of rebuilds & as far as 4t bikes I've only done dirt bike engines which aren't fuel injected... does anyone know ??? Thanks


Seized means bearings and journals burned / galled / trashed. I thought everyone knew this. When aircraft have a prop strike (similar to seizing) the engine must be torn down, all moving parts carefully inspected, the crankshaft checked for runout, the journals mic'd, and everything magnafluxed. Look up the words you don't know.


Just keep doing this until you destroy all rotating parts in the engine. It is already likely trashed pretty bad. Why not go for broke and see if you can shoot a rod through the crankcase (actually, this is exactly what you are doing right now). Make sure you take video. Or... pull the engine, get a shop manual and proper tools, identify which bearings you have fried/siezed multiple times and fix what is wrong?


We told you already. The bearings are likely shot and the connecting rod could be bent. It is hard to destroy the bearings on these bikes as they have roller bearings but the bike was clearly starved of oil. Open the crankcase and start inspecting. The oil pump is a rotary vane pump and is driven by the crankshaft. They are very robust and they are almost bullet proof.