my mate has 07 shero 250 that wont start now. last time we was out riding he had a good fall and the bike fell revving wide open he quickly killed it and had to walk back to the van with a bit of an injury.

next time went to ride the bike wouldn't start not even firing at all. check the plug and has a good spark and fuels getting through. after a bit of kicking there was a big backfire and still no joy. 

I am presuming its the woodruff key that's sheared so going to have a look at that for him. ie got the key and a flywheel puller coming tomorrow. 

anything to be wary of or tips to do it easier? thanks

Check flywheel key.

27 minutes ago, reggie said:

Check flywheel key.

I thought this so have a puller and woodruff key coming tomorrow

Get rid of any damage that the key has done to the tapers, ant high spots stop the taper taking the load properly which then puts the load through the key

Worse case will involve you needing to lap the tapers after filing off damage on the crank

Make sure the o-ring in the cover is in good condition when you reassemble it or use gasket forming silicon on it

 

cheers mate will do. whats the best way of holding the flywheel whilst torquing up

Flywheel holder, from memory the sort that is basically a large pair of vice grip with pins on 1 face work ok with the other side being ok for holding the clutch hub

woodruff key had sheared. 

ive changed that, cleaned the carb, new air filter and plug.

bike starts fine now and ticks over fine but just off idle is acting strange. air mixture screw doesn't stop or improve the problem.

with a tiny amount of throttle then let go the bike carries on to slightly rev more but in a lumpy way not clean revving then doesn't come back down to idle quickly or cleanly aswell. after this point it revs cleanly off the throttle and comes back down clean until this point then acts strange until decides to tick over.

any ideas what to check or could be? thanks

When you cleaned the carb, did you remove the pilot jet and clear it? Did you hook up any vents with hose?

Air leak ? Tighten jubilee clip on engine side of carb.

Edited December 16, 20178 yr by b40rt

carb was all clear and no blockages. there isn't an air leak around the carb checked when running with spray.

I was reading after the last post about stator failing symptoms and got the figures off splats websites for this stator. 

ive just been out and unplugged then dropped the meter on in diode setting. only 2 out of the 6 wires had a figure where they should be the rest were way off. 

 

Sorry late to the party on this but here is the flywheel holder I cobbled together for use on Betas. Actually I've made a few since they keep getting borrowed then disappear. Works like a charm. Piece of bar stock. One cut, three holes. Can even make a handle on the far end. Vitally important to not screw in the bolts on the flywheel deeper than the flywheel or you destroy the stator. Short bolts or washers/nuts as shims is a good idea.

1 hour ago, dan williams said:

Sorry late to the party on this but here is the flywheel holder I cobbled together for use on Betas. Actually I've made a few since they keep getting borrowed then disappear. Works like a charm. Piece of bar stock. One cut, three holes. Can even make a handle on the far end. Vitally important to not screw in the bolts on the flywheel deeper than the flywheel or you destroy the stator. Short bolts or washers/nuts as shims is a good idea.

cheers mate managed fine with a strap wrench. 

As long as you got it to the correct torque it’s all good. I was thinking about it and I would imagine you want it to move and shear the key under unusual loads rather than twist the crank.

fetching a stator for the bike Monday which should solve the strange hesitating etc

all sorted swapped the stator and did the crankshaft seal whilst there and all good now running like new,