philschultz2157860002
New member
rebuilt carb but no change, runs ok when warmed up.
-
Welcome! You are currently logged out of the forum. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please LOG IN!If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the benefits of membership? If you click here, you have the opportunity to take us for a test ride at our expense. Enter the code 'FORUM25' in the activation code box to try the first year of the MOA on us!
left cylinder backfire through exhaust and intake when cold, 76 r75/6
- Thread starter philschultz2157860002
- Start date
pauls1150
MOA #24991, south of Los Angeles
IFF (not a misspelling) it is actually a "backfire" - they're typically caused by unburned fuel igniting in the exhaust header; you need to determine the Why ... ignition timing (early airheads can show different timing of each cylinder (due to wobbling of the cam that opens and closes the points), or you may have a return spring on the advance mechanism hanging up. Also double-check that the valves are properly set.
Even a bad spark plug or ignition wire may cause it (insufficient spark to properly ignite the fuel mix when it should).
Do you have the air injection system? Nuke it (how-to in other threads here). Air leaks elsewhere may also cause it.
If the symptom is a bang out of the carb's intake, that's a different issue.
Even a bad spark plug or ignition wire may cause it (insufficient spark to properly ignite the fuel mix when it should).
Do you have the air injection system? Nuke it (how-to in other threads here). Air leaks elsewhere may also cause it.
If the symptom is a bang out of the carb's intake, that's a different issue.
Last edited:
Similar threads
