hey guys i have a question for ya.. my neighbor has a 04.5 600, and at about 4300rpms the thing starts to pop and back fire, it also idles realy ruff and is VERY cxold blooded..i have replaced the plugs they were a month old and fouled i have replaced the fuel filter and cleaned the pcv systemstill no change , i have not had ANY running problems w/ my lil 400.. can you gust help us out it is de-thawing up here in michigan and time to ride...........thanks ahead of time


savage

oh ya, the intake boot is ok -- checked for air leaks

 

So it runs good and smooth up to that point? Plug wires ok and in good contact? Check and make sure the air filter is installed correct. Make sure the gray foam that fits around the snorkal is not getting sucked in to it and causing it to have an air resrtiction. Make sure the airbox lid is on correct, the drain plug for it is in place and the air box is connected to the carb ok and the carb to the intake ok. You said you replaced the plugs. Were they white or black? It sounds like it could be an air box restriction based on the rpms you described. They are bad for getting that foam that is around the snorkal or the foam that some have up around the gastank where the snorkal goes up under the plastic getting sucked into the snorkal tube. If this is the case, the plugs would havve been black. No, it will not run correct withe airbox lid off so you can't remove it and try it. Check this first and give us a reponse.

 

yep plugs are black... no restrictions that i can find...

 

sendori , can ya help us out!!!!!PLEASE!!!!!!!!!!!!!!!!!!

 

well its getting too much gas for sure. did you pull the carb off to make sure things were all set and the float level and needle and seat were all good. another thing is the valves adjusted right, cam not worn out. this causes backfiring sometimes when lobs get worn off. like was mentiioned make sure theres no restrictions and vent tubes arent blocked or crimped. best i can thing of right now.

 

yea i am going to pull the carb and go through it and do a good cleaning and adjusteing ,, not till next weekend though....as always thanks stendori