Is there an easy way to see if your bike is running rich or lean, apart from wiping the plug out and looking at the colour of it? Or using a rolling road and gas anilyser, basically i'm after a simple way to check the fuelling on my bike. Or even better do'es anybody know the standard jet size's for a CCM 644 DS (suzuki engine), it's got a race can on it at the moment (feckin loud) and has been re-jetted to suit, but i want to change it back to standard, along with the jet's, but i'm not sure about messing the fueling up on it. Also, assuming it was larger jet's that were fitted, to account for the race can, what effect would just putting the original can back on without re-jetting have on the engine performance and running, and could it do any damage? Any help or advice would be much appreciated, thank's

Shaun.

my mate had the same bike and when the dealer fitted his race can they didnt alter any fuelling at all so try just swapping to the original can food for thought did you know they suffer from freezing probs on the carb so when cold use super unleaded this stops it how don t know but suzuki told my mate this and it works

Even with a can and airbox mod (drilled holes or K&N) you'd only go from say 180 to 190 main jet. Manufacturers tend to run slightly rich out of the box, on the grounds that too rich is much safer than too lean, so it's possible that "end can only" would not necessarily need a rejet. Quick and simple way is to look at the sooty deposits on the end of the can. If it's thick black soot you're probably ok/too rich. If it's greyish or (gulp) whiteish - YOU"RE TOO LEAN. Too lean means overheating, pinking, blown piston.

The only way (for the lay person) to tell is with a plug chop. Clean the plug and run the bike flat out in third up a hill. Hit the kill switch andcoast to a stop. Examine the plug. Black and sooty, too rich, Light tan, perfect. Blistered white, lean.

Just putting the original can back on without rejetting should not cause any problems unless the bike was super lean on a race can, even then, the original can will be better. Worst case you might foul the plugs by running rich but there's bugger all in it really. Unless you are running a souped engine, these old plodders will put up with anything close to correct.

Screwd.

Even with a can and airbox mod (drilled holes or K&N) you'd only go from say 180 to 190 main jet. Manufacturers tend to run slightly rich out of the box, on the grounds that too rich is much safer than too lean, so it's possible that "end can only" would not necessarily need a rejet. Quick and simple way is to look at the sooty deposits on the end of the can. If it's thick black soot you're probably ok/too rich. If it's greyish or (gulp) whiteish - YOU"RE TOO LEAN. Too lean means overheating, pinking, blown piston.

The only way (for the lay person) to tell is with a plug chop. Clean the plug and run the bike flat out in third up a hill. Hit the kill switch andcoast to a stop. Examine the plug. Black and sooty, too rich, Light tan, perfect. Blistered white, lean.

Just putting the original can back on without rejetting should not cause any problems unless the bike was super lean on a race can, even then, the original can will be better. Worst case you might foul the plugs by running rich but there's bugger all in it really. Unless you are running a souped engine, these old plodders will put up with anything close to correct.

Screwd.

Thank's, that's what i thought, guess i just needed a bit of re-assurance, as i've had trouble before with engine's running lean and burning piston's out.