Hello everybody! I have recently purchased a mc16,and I'm having a little trouble with it! It starts easily and idles fine! But it seems to be only running on the top cylinder! I have searched through the forums and have tried everything I can manage,cleaned carbies,new plugs,swapped coils,checked reeds! I haven't done a compression test yet! When running I can pull the lower plug lead and makes no difference! I can put my hand over ther lower silencer and it has no effect on the engine! I'm fairly new to these bikes but I'm going to assume I have a bad piston and rings! I'm just trying to eliminate everything first before I pull the heads! Any help would be great!
Thank
Tim

Well I ran it again! Still only top cylinder firing! Cleaned all the cool cdi connectors! Battery is over 13 volts! Pulled the spark plug on lower cylinder and it appears dry! So I have the carbies off again and it seems clearly visible that one carbie is dry by just looking at the Venturi! Both float bowls are full! Have pulled the slow jet and main jet and everything seems good! Not sure where to go from here! Thanks
Tim

Well I'm back! I managed to get hold of a compression tester! I checked both cylinders cold,as the carbies are off and could get them back on in time! Both cylinders have come back at 76 psi! This sounds low! But is this figure ok for a cold engine! I think that both cylinders coming back the same,seems to be turning me back to carbs! The local mechanic suggests putting the carbies back on and trying a little start aid in the cold cylinder! Any ideas?
Thanks
Tim

Ok I'm back again! Carbies on! Air box off! Sprayed some start aid,but no difference! I did blip the throttle and the cylinder did heat up! Noticed a fair amount of blowback through the cold cylinder!
I'm lost as to where to go! Have checked reeds and cages and they appear in good condition!
I'm running out of ideas!
Thanks
Tim

Hello again! I forgot to mention when I shut the bike down! I could see what looked like smoke returning through the cold cylinder carb
Tim

Hello Tim, and welcome to NSR-WORLD.

Have you tried swapping the CDIs? The MC16 uses two, and it's becoming common to see at least one fail as they age.
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Hello Andy
Yep have tried swapping cdi aswell no difference! Have the lower exhaust off looking through the port, piston seems ok! But there are a few score marks on the transfer ports just above the port bridges! I'm starting to think I may have a damaged skirt on that piston! I'm not sure but this could be causing the blowback through the carb and making the carby look dry! I have also put my hand over the cold exhaust while running and it won't stall the engine,hand on the good cylinder exhaust I can stall the engine if I hold it there! To me this would suggest the transfer ports are leaking back to crankcaseThe engine from 3-4K up seems to heat that cylinder and visible smoke!but from idle to 3-4K it blows back and coughs! Does this sound like I might be heading the right way? I'm hesitant in pulling the barrel until I can get hold of some gaskets and rebuild kit!
Thanks
Tim

Hello
Well I'm back at work for 7 days! So no more testing! But have sourced a rebuild kit! Pistons,rings,small ends etc! I thought while I'm taking barrels off might aswell update to the better mc 18 barrels and heads! So I'm also replacing barrels and rc valves! Have been researching a leak down fest to check the dreaded center seal and outer seals! I have a terrible feeling it will be seals! But I'm in no rush so if I have to i will be rebuilding the bottom end aswell!
Leak down test should verify this!

Hello
Well I think I have found my drama! Taco did a lil dance and then down to 1 cylinder! Swap Cdi and problem moved! Anybody know of some mc16 cdis or suitable equivalent in Australia
Thanks
Tim

Best bet is prob to search on yahoo Jp then use a deputy bidder

Hello
Just wondering if there is a circuit diagram around for these early cdis or does anybody know the advance curve?
Thanks
Tim

Hello
Ok so I'm finding it really hard to get a hold on mc16 cdis! Can anybody tell me if a mc 18 Cdi be retro fitted to these early engines?
Thanks