I have a 1996 Magnum 425 that runs great except for some sporadic rough, missing. There does not really seem to be any rhyme or reason to when it acts up either. It typically seems to happen while just cruising down a trail at about 25mph or so (mid rpm) and just start missing. It acts like it suddenly got very rich mixture wise, or like the spark plug is fouling. It will do this for like maybe 10 minutes or so and then just clear up again. Once it decides to start missing, it does that at ALL RPMs. It will idle rough, and rev out slow and rough as if its almost flooded. I have pressed the override button on the handle bar to see if it has anything to do with the rev limiter, but that does not help. Not sure if there is a ground wire coming off somewhere, or if the rev limiter is deciding to kick in whenever it wants. Also, when it acts up, it smokes pretty bad too, as if its getting too much gas, or not burning what its getting. It is jetted correct for this altitude also.

Thanks for any suggestions you might have.

 

Try cleaning the ETC and adjusting your throttle cable first off.

 

Not sure exactly how much free play the throttle is supposed to have, but there is not very much. I will try cleaning the ETC though.

 

let me know if that helps

 

How do you clean the etc ? where is it located ?

 

I believe it's in the throttle housing on the handle bars. Just make sure there is no crud in there. I suppose there is some contacts that need to be cleaned, but I cannot be sure since I have not taken mine apart yet.

 

Took off the cover of the ETC / throttle area. It was perfectly clean in there and the micro switch seemed to be operating perfectly. So, the ETC is not the problem. I am going to go look at the carb again. Anyone know what the float level height should be set to?

 

checked my etc also. It is clean..Seems the bogging down and intermittant idle has now fouled the plug. I will have to wait until monday to get a new plug. Does anyone know if you can get the plug at advance auto or western auto ?

 

Try checking you fuel mixture adjustment on your Carb. I had same problem. There is a rubber washer that keeps it form backing out that wears-out. I fooled with it for 1 year before I figured it out. Replaced the washer and spring - runs great now

 

I will check, but I am 99% sure it's OK. There is plenty of resistance so that I don't think it is backing out. Also, the problem only occurs for a short then will usually go away. I would think if the mixture screw was backing out it would be bad until I tightened it again.