Hi all,

I've got an NSR that for some reason seams to start up on 1 cylinder.
The back pressure in 1 exhaust seems fine but the other exhaust has hardly any.
I took it to a mechanic and he said carby problems because it was coating brand new spark plugs black after a 5 min warm up....
Anyway this seemed to fix the problem and the bike was running fine ( i think) up until I went to start it up one morning to go to work and presto, the - 1 cylinder problem had reappeared.

Does anyone know what the problem could be.

This is my first bike and I brought it for $2000, and have spent $1500 on it and i cant even ride it.....People tell me to sell it but when it was running fine i really enjoyed the ride so I am reluctant and would rather try to fix it.

What did your mechanic do to fix it the first time ? Have you tried a fresh plug in that cylinder ?
_________________

You might try taking a good look at the coil to the duff cylinder - look in particular at the blades to see if there is any evidence of pitting/charring, as a poor (loose) connection to the female connector of the wiring harness can cause the intermittent sypmtoms you describe. Make sure that connection is clean and snug - mine was just loose enough that sometimes the bike would run fine, and other times go on one cylinder. Drove me completely nuts as I had this going on with both cylinders intermittently. When I finally thought to replace the female connectors with new ones, problem solved. Hope that helps.
_________________
-Jim
'93 MC21

I have a 21 that does this, will run fine and then will cut onto one every now and then. I think today i traced it down to the ign trigger pick up connector. Have a look there.
_________________
If I have to take the carbs off once more...

Ah yes they can act bad once they heat-up and seem fine when cold I have seen this on some Honda Magna's. Usally you can Ohm test, need spec ?
_________________

The mechanic i took it to said he will pull of the carby, clean and reset the screws, floats and stuff.

Anyways the same mechanic said i replace the spark plug and this fixed the problem.

He said he thinks the problem is my fuel tap is dripping fuel even when set to off and this will cause it to flood and foul the plug.

Strangely enough this happened to the bottom cylinder.

Now this cylinder is really blowing smoke, more than before and continously.
Is it possible the rings on the cylinder could have been damaged by this flooding.
I had to drive the bike nearly 10kms on 1 cylinder to get it home.

Or should i just let the bike run to clean / burn of excess fuel / oil?

I had that problem with my mc-18 if it sat for a while. The lower cylinder would flood out. It is the lowest point on the motor. Pull the lower cylinder plug. With the ignition off kick it over a few times. Reinstall the plug and see if it gets any better.
_________________

Since the fix the bike was sitting for not more than 48hours without a startup. I even run the motor a bit in off position befor shutting of.
Last shutdown a run in off until it doesn't have enough fuel to keep running.
Then took me nearly 15 kicks to fire it up
Anyway i have pulled the plug now after starting and testing.
It seems kind of strange but, I pull up to work shut of the motor and start pulling out the cylinder plug , people will think I have a 'gone mad anti theft device syndrome', but at $15 a plug for 2 weeks of use thats too much for me.


Anyway does anyone have any ideas on why this cylinder is smoking a lot now.
When I rev both exhausts shoot straight out about 2-3mtrs behind the bike , so back pressure seems fine but the bottom cylinder, left hand exhaust has a nice blue colour smoke to it. Right hand side has not nearly as much smoke.

hi im having the same problem ive gone through 2 sets of plugs already at $15 a plug its very expensive if im standing behind the bike my left exhaust is missing and skipping, this is the top cylinder right? when i replaced the plugs it went sweet for about a month then i pulled em out and sam as you ther fouled, black adn full of fuel, i also run it dry off the fuel and never use the choke as fear of fouling plugs? any solution to the problem would be great.. i think there must be some sort of fuel leakage or running to rich on one cylinder ,.. any ideas how to adjust this .. these plugs are costing me more than petrol!!