Miss On Left Cylinder then Back Fires

[ZRD1221]

Ok so here's the deal. I just rebuilt my top end and finally got the thing all back together, when i fired it up with the aid of starting fluid i noticed that the left carb was leaking like crazy out of the float drain nipple. Now these were the stock carbs with tors still on them so i just went ahead and bought a set of carbs with tors removed off of ebay. Got them in and fired it up with the aid of starting fluid again arggghh. However, it ran alot better but now it back fires out of the left pipe so bad it makes everybody around me jump. tried new spark plugs still back firing i can ride it but once i come to a stop it pops and spits, backfires once or twice then stalls out. Any help would be great.

[SAVAGE420]

Sounds like your lean man. First take the carb bowls off and see what mains and pilots are in there. Then jet according to your mods temp and elevation. Who knows what jets are in the carbs you just bought, you NEED to take the time and look. Second do a leak down test to see if your motor is sucking air some place. Simple, easy, and effective way to find out if your motor is 100% sealed up properly.

 

You don't want to melt a new rebuild down over a few dollars in jets and 15 minutes of your time

[98_shee]

Check your intake boots for cracks also, its not a good idea to ride it, if its lean you will blow it up.

 

 

Welcome to BHQ!!

Edited October 15, 2009 by 98_shee

[pr0blumz]

Are the carbs synced, did you put the slides in correctly and did you connect the choketube between the two carbs?

[ZRD1221]

Thanks for the advice men. So I now know that the carbs are jetted for the pipes im running. There jetted for sea level and im sitting at 355 above sea level. Choke tube is there no cracks in intake boots either. I wasnt getting a consitent spark and i checked out my ignition coil and it was bad so I went ahead and got another one. What im thinking is the left cylinder was missing and air/fuel was building up in the header then when the spark would fire it would ignite everything. I Still want to run the leak down test on it. Thanks again ill keep you posted when i get the new ignition coil.