Hi all
After not starting my mc21 for over a year i fired it up only to find the upper cylinder not running at idle.it seems to run when a give it a few revs but runs cold on idle.i have cleaned the slow jet,the air screw and float valve,changed the spark plug,swapped the coils but nothing has worked.I have read on here that it could be the crank seals.So if that is the case i was wondering if anyone knows where in Australia i could get my crank rebuilt?

2 stroke performance down in Victoria

turn the tickover up a bit on that side and try that
or pressure test the engine then you know if it leaks or not
test it both ways though pressure and vacuum i wouldnt go more than 4-5psi though

thanks Simon_r i will contact them and eyrey1 i am not sure what you by turn the tickover up a bit on that side?

A guy called Link in Melbourne is supposed to be good, rebuilds a lot of strokers (I have not used him so I don't know what his quality is like):

Link o418383958

thanks nxrsr20,i have called him and had a chat.i am still diagnosing the issue,he seemed to think it would not be the crank center seal as both cylinders would be running bad not just the one

can you not pressure test it ?
does it kick in if you hold throttle open a tiny bit ?
set the idle /tickover till it runs that cylinder
but if you have doubts get a pressure test kit ,i do all my engines now its good to know they have no leaks
and if they have that youve found them and mended them . bikes run much better once done

Have you checked continuity in the wiring? Tested while wiggling the loom around? Don't forget we're now dealing with a 20 year old bike.

thanks for the replys
it does fire a bit when i give it a few revs but still does not seem as good as the front cylinder,i have done a top end compression test and got 90psi on the offending cylinder and 105 on the front cylinder.piston and rings only 900 km old so i am suprised compression is this low.going to remove cylinder and fill the crank with petrol to see if it leaks as i dont have the gear to do a proper leak test.i haved swapped the coils and put new plugs in but that is all i have done electricaly