Popping & Backfiring, won't idle after new top end

[Shee_Rookie]

O.K. Just rebult the top end with Wiseco 0.20 pistons, the rest of the bike is completely stock. Tried to start it for the 1st time and it would not fire. Put new plugs, made sure there was spark still no dice. Then pulled the plugs and poured some gas down the cylinders and put plugs back in and bingo and fired right up, but when i hit the trottle it would bog and die and would not restart. Pulled the carbs and made sure nothing was plugged or gummed up put everything back together and same thing. After performing this a few times the bike would start with the choke pulled out but after letting it run for a bit then hitting the throttle it would backfire (Only out the right side) and sound like it wanted to die at low rpms. Changed the needle clip position to all the way out to try and lean it out and then bike will now start on it's own, idle and run with the choke pulled out one notch without backfiring, but if I put the choke all the way in I am back to backfiring , no idle, no starting and over all running like shit. Sorry for the long post but I am going a little nutty. I am at 4300 elevation, stock bike except for .20 over bore and new pistons and ANY help would be appreciated. Could it be mains or something???

[richybanshee]

Okay ... it sounds like lean jetting.

 

You mentioned two specific things attributed to lean jetting, backfiring and running better with choke out.

You need to make sure that the top end is torqued correctly and that there are no air leaks or problems with the gaskets, specially the head gasket. Also check if air is not leaking near the reeds, or boots. make sure carbs are not dirty. One more thing, very important, check if the tube that goes between both carbs is connected, else it will not start and if it does it will die.

 

 

If everything is okay, then put the needle on the middle, the 3rd notch, stock position. The shee is supposed to start, if it is rich on fuel it will not run without bogging but it will start.

 

I think you probably did not connected the rubber tube that goes between both carbs.

[stclark816]

Is your choke tube deal in between the two carbs connected?

[Shee_Rookie]

Will check those things when I get home. I am pretty sure that everything is connected, but I will check again to make sure. Any specific tips on checking for leaks?

[stclark816]

When you put everything back together, did you use all new gaskets? Make sure everything around the carb area is tight. Sometimes things come loose.

[Shee_Rookie]

Yes, I did use all new gaskets and I will check again to make sure everything is tight.

[lincster]

Sounds like an air leak.

Spray carb cleaner around the intake boots, head... everywhere.

If the idle changes, there is your leak.

You probably need to go up 1 size on the pilots and a couple on the mains.

After you get the air leak checks done.

[Shee_Rookie]

Is your choke tube deal

Edited March 22, 2005 by Shee_Rookie

[stclark816]

Yay!! One of my posts was actually a contribution to the site!!!

[locogato11283]

Yay!! One of my posts was actually a contribution to the site!!!

343229[/snapback]

thats a first...maybe ill sticky this one so everyone can see

[ledofthezep]

LOL

[sredish]

You know... this place has gone to hell since I haven't been able to be around much anymore....

[Ducman]

Damb, the choke tube strikes again! The only symptom that seems to be a sure tell sign is backfires out of the right side and runs like shit. Some say it bogs like its rich, some say it will start up and rev to the moon like an air leak. Its probably the easiet fix that causes people to lose the most time trouble shooting carbs.