Go Back   Harley Davidson Forums > Harley Davidson Motorcycles > Classic > Shovelhead
Sign in using an external account
Register Forgot Password?
Search


Shovelhead A place to talk about Shovelheads.

Reply
 
 
 
P
 
Thread Tools Search this Thread
  #1  
Old 05-10-2011, 05:18 PM
shovelhead716 shovelhead716 is offline
Hang Around
Join Date: Sep 2008
Posts: 39
Default backfire through carb.....timing to advanced?

1200cc with electronic ignition and s+s super "e". Bike runs strong. Kick starts o.k. When idling down to slow down, upon twisting throttle I get a cough through carb on returning to acceleration. Wondering if timing is to advanced or too retarded. Motor runs 200 degree oil temp when warmed up. Would this also be due to ignition being too advanced?
Reply With Quote
  #2  
Old 05-10-2011, 06:17 PM
ROTTEN ROB ROTTEN ROB is offline
One Of The Regulars
Join Date: Jun 2010
Location: POZO, CAL.
Posts: 234
Default

Could be a intake leak, check the bands and clamps on carb. That will make her run lean and heat things up. My 76 with an oil cooler, runs around 185. What do you mean by kick starts ok? The 73 I had ,3 prime strokes, turn ign. on, fired on first kick. If it's a bear to kick it could very well be out of time.
Reply With Quote
  #3  
Old 05-10-2011, 06:32 PM
shovelhead716 shovelhead716 is offline
Hang Around
Join Date: Sep 2008
Posts: 39
Default

Thanx for feedback Rotten! No oil cooler here. Plugs are tan. If she's warmed up she fires on first kick but when she cools down it takes a few kicks. Bike runs like a bear other than that lo-idle cough. I'll have to check out intake. If its o.k. you think timing is too advanced or retarded?
Reply With Quote
  #4  
Old 05-10-2011, 06:50 PM
ROTTEN ROB ROTTEN ROB is offline
One Of The Regulars
Join Date: Jun 2010
Location: POZO, CAL.
Posts: 234
Default

If she runs great and the plugs look good,I don't think it's a timing issue. Check for air leaks.I also run a S&S SUPER E. Love it!
Reply With Quote
  #5  
Old 05-23-2011, 10:14 AM
superp superp is offline
Hang Around
Join Date: Mar 2006
Location: Detroit, MI
Posts: 16
Default

I am with Rotten. Check for air leaks. I had the same issue with mine, same carb. It would sneeze through the carb going down the road.
I used a can of carb cleaner with the straw to pinpoint the leak. It was the intake gaskets, they just needed to be reset and tightened.
Reply With Quote
  #6  
Old 05-23-2011, 06:07 PM
FL84FXWG FL84FXWG is offline
Hang Around
Join Date: May 2011
Location: Florida
Posts: 6
Cool

Intake leak until proven otherwise.
Reply With Quote
  #7  
Old 05-23-2011, 06:39 PM
shovelhead716 shovelhead716 is offline
Hang Around
Join Date: Sep 2008
Posts: 39
Default

when sprayed with carb-clean will motor idle up if there is intake leak? Also there is no sneeze(cough) until engine is up to temp. Which is considerably hot! 210 degrees. Would this hi-temp also be a result of intake leak. (I have no oil-cooler, and cylinders have been punched out 60 over) Thanx again fellas for the input.
Reply With Quote
Old 05-23-2011, 06:39 PM
 
 
 
P
Reply


Tags
1976, accel, advanced, back, backfire, backfires, carb, carburator, davidson, firing, harley, light, shovelhead, ss, throu, timing


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Join HDForums

Advertising
Featured Sponsors
Vendor Directory
Sponsors

All times are GMT -5. The time now is 08:57 PM.


Internet Brands, Inc.