Hi, i rebuilt my yamaha aerox last year and has been working perfectly fine, however i changed the crank so it could handle the power better and now when i tighten the variator bolt the crank seems to lock up and not able to spin. any ideas? thanks, matt
What crank have you fitted and is the stroke length of it the same as the old crank? You might find that the piston is coming up against the cylinder head, preventing the engine from turning. Whip the cylinder head off and take a look, anything less than 1mm piston clearance from the head (the squish band) is a no-go, as the piston will hit the head under high revs.
hey, its a rms sports crank replaced a standerd crank, i will have to check the stroke length thanks for the info
Daft questions time. Does it turn over with the spark plug taken out? Have you used a locking pin or similar gadget to lock the variator while you tighten the nut?
Remove the cylinder head, keeping the piston and barrel in place, and turn the engine slowly by hand. If the sides of the piston are coming higher than the bore, then the length of the con-rod is wrong. It can be adjusted using different base gaskets, and i've seen multiple gaskets being used to correct the problem, but not something i would recommend. Question though.......if you remove the variator, does the engine turn freely? Or is it only when you fit and tighten the variator?
yeah it works with head on when the variator bolt is loose. when its tightened it locks up. im thinking possibly a missing washer somewhere? i think my best bet it take the casing aprt ans check all washers and bearing are in correctly...
Did this get solved? I’ve got same problem with same crank I have no barrel and as soon as I tighten variator it goes solid
