Hi, my 2001 315 has developed a strange intermittant fault. After starting and running normally it will suddenly start running really rough, no power and won't rev. If I stop the engine and immediately re start, the fault has gone and it will run perfectly again. This sometimes happens after an hour or so of riding, but has happened almost straight after starting. It may not re-occur again for another hour, or it may happen after 15 minutes, but again if I cut the engine and re start the engine runs perfectly again. I have stripped the carb but found nothing amiss, I have taken off the mag cover but everything was ok in there. Any suggestions?

Thanks,

Chippy.

I would guess at it being electrical and would check the resistances are in tolerance on the Coil and on the Stator (or Magneto or whatever it's called).

To me it sounds like a tiny droplet of water in your carb still. When you stripped it did you blow through all the jets and holes with compresed air or a can of carb cleaner?

Thanks guys, I will re check the carb as that is easiest and see how it runs on Sunday at ESTC.

The fact that your problem is so intermittent makes the electrics a prime suspect. Check the kill button/circuit. Possibly a problem in the button itself, which could be intermittently shorting out. When you kill the ignition by pressing the button, you may temporarily relieve the cause of short circuit (corrosion?)

Hi Chippy,

Did you ever get to the bottom of your intermittent running problem? I ask because I hand exactly the same problem on Sunday, mine ran fine 90% of the time then all of a sudden she ran flat, wouldn't accelerate, knocked and popped etc..

As soon as I stopped her and kicked her again she was fine? She did this about 5 times, usually during a section - very helpful!

Any info would be of great help.

Nick.

hi, was out practicing today on my '99 315 and had exactly the same problem, not running smooth, making the most awful noise and chucking smoke out the exhaust. turned it off, visual check over, nothing out of the ordinary, started up again and fine! did either of you guys (nick or chippy) get to the bottom of the problem so that i know where to start looking.

cheers, stuart.

Chippy, I would bet a large sum of money that you have a non-resistor spark plug in your Cota.

What plug are you running? Martin

Edited April 19, 200917 yr by Martin Belair

Stuart, I would bet a large sum of money that you have a non-resistor spark plug in your Cota.

What plug are you running? Martin

Hi Martin, I've only had the bike for a month and the spare time I've had has been spent riding (probably about 9 hours) and not maintaining. I know the basic principle of how a 2 stroke works but not the detail, do you know what spark plug I should have and what effect a non-resistor vs restistor spark plug would have.

Cheers, Stuart

Hi Martin, I've only had the bike for a month and the spare time I've had has been spent riding (probably about 9 hours) and not maintaining. I know the basic principle of how a 2 stroke works but not the detail, do you know what spark plug I should have and what effect a non-resistor vs restistor spark plug would have.

Cheers, Stuart

Stuart, the manual says NGK BR6ES. We also used the Bosch WR8DP. Both plugs have the "R" in the designation meaning Resistor. Some people will tell you that you don't need an R plug and that the R is for Automotive purposes, they are wrong. They symptoms described are exactly what happens when a non-resistor plug is used in the Monty.

I am sure one more knowledgeable than me can explain it better, but I think that a charge builds up in and then is disapated when the bike is shut off. Then it runs great for a bit 'till the charge builds up again and so on....

Martin

Stuart, the manual says NGK BR6ES. We also used the Bosch WR8DP. Both plugs have the "R" in the designation meaning Resistor. Some people will tell you that you don't need an R plug and that the R is for Automotive purposes, they are wrong. They symptoms described are exactly what happens when a non-resistor plug is used in the Monty.

I am sure one more knowledgeable than me can explain it better, but I think that a charge builds up in and then is disapated when the bike is shut off. Then it runs great for a bit 'till the charge builds up again and so on....

Martin

Martin,

I really agree with you. From my understanding, most of the newer CDI systems are "matched" to a resistor plug and the engines must use resistor plugs for a proper "talkback" to the electronic ignition. However, I'm not sure how the shut off/restart solves the problem, but I bet there's a MSEE or two out there on the forum that can explain it to us.

As an added example, in some marine CDI systems, the engines require a spark plug with a special inductive type resistor (such as the NGK Z-type plugs). These types of ignitions systems produces less voltage and use of non-inductive type plugs can cause misfires and poor performance, so you can see that it's really important to follow the manufactuers recommendation as to plug type.

Jon

Stuart, the manual says NGK BR6ES

Thanks for that Martin, had a look at mine this morning and as you predicted it is a non-resistor BP5ES. Have ordered correct plug this morning, I'll let you know how I get on.

Cheers, Stuart.

My 97 mont does this as well. It 'fourstrokes' and doesnt rev out. I was told it would be water and to put the choke on and run it as fast as it will go, this clears it (happened 3 times now)

. I have cleaned the carb twice inbetween and I suspect its electrical, reminds me of a coil fault I had on a fantic years ago.

It cost me a 3 yesterday, seems to kick in after heavy drop offs, maybe I should check for a loose wire?

be interesting if someone finds the answer.

My 97 mont does this as well. It 'fourstrokes' and doesnt rev out. I was told it would be water and to put the choke on and run it as fast as it will go, this clears it (happened 3 times now)

. I have cleaned the carb twice inbetween and I suspect its electrical, reminds me of a coil fault I had on a fantic years ago.

It cost me a 3 yesterday, seems to kick in after heavy drop offs, maybe I should check for a loose wire?

be interesting if someone finds the answer.

did you clean the choke slide?

no!

will do now though.