Hi folks need help, sherco 290 firstly its been running fine however fired it up Sunday and after a million kicks it fired up but was mis firing big time then started bellowing smoke that smells of burning rubber. It won't tick over and the engine isn't knocking or anything. 

Any ideas folks

3 hours ago, Backerlee said:

Hi folks need help, sherco 290 firstly its been running fine however fired it up Sunday and after a million kicks it fired up but was mis firing big time then started bellowing smoke that smells of burning rubber. It won't tick over and the engine isn't knocking or anything. 

Any ideas folks

Sound like the clutch side main bearing seal has failed and its sucking up gearbox oil and burning it. Take the carb and reed valve off and you will be able to tell if its sucking oil in.

Or the head gasket or bace gasket may have failed and your burning abit or antifreeze. 

A sheared key and rotated flywheel could alter timing and have a similar result.

Cheers gents I'll keep you informed,

An after thought probably unrelated but kicking it up there is a point in rotation that will literally take my weight all 13.5 stone, I've had loads of 2 strokes and never had one this hard to kick is that normal?

The sheared key looks the likely cause mate thanks 

I'm a bit heavier than you and a 290/300 will sometimes take my weight on the kicker at the right point. Normally either exactly TDC or the complete opposite at the base of the stroke.

 

if it's not the woodruff key, make sure the stator plate screws are all tight and the stator hasn't moved round a bit......

Edited December 14, 20205 yr by jonboy883

Wood ruff key definitely gone bud so stator could be anywhere on the shaft so its got to be that, I'm just relieved its not something drastic that I can do myself, thanks for the kick start info. It just means my son was right. I am a pussy

Why would a broken woodruff key make it smell like burning though?, shurly that would just affect the timeing and stop it from starting and running normally. I had a woodruff key snap on a yz125 and it just stopped it running starting, occasionally poped and spluttered. It Didn't make it smell like burning. 

It was pushing the fuel into the exhaust then firing it. Burning the oil build up in the pipe, that's my theory anyway. However got it all back together and it won't start at all now so £@?@ knows

Could be, I still think your head or bace gasket have gone, as burning fuel in the exhaust pipe or first muffler box will still usually only smell like 2 stroke, I cleaned my mid box with a blowtorch and it didn't smell like burning rubber, the acrid smell sounds like burning antifreeze.take the carb and reed valve off if it's sucking in enough antifreeze to stop it running you should be able to see little green droplets condensating on the con rod and back of the Piston (depending on the colour of your antifreeze). 

Thanks mate your probably right I'll have a look when I get chance and let you know 

Just to update, proper wood ruff key came today. ( I'd bodged one that nearly fit) now fitted with timing retarded 5mm and it started 2nd kick and runs a treat. As for dodgy smells I'm still no wiser but the bellowing smoke has gone so who knows what that was

13 hours ago, Backerlee said:

Just to update, proper wood ruff key came today. ( I'd bodged one that nearly fit) now fitted with timing retarded 5mm and it started 2nd kick and runs a treat. As for dodgy smells I'm still no wiser but the bellowing smoke has gone so who knows what that was

If the timing was very advanced the engine / exhaust would run at very high temperature, it could have been crap getting burnt out, hopefully !

Edited December 22, 20205 yr by b40rt

Hopefully mate