I have a 77 GL1000 with about 30k miles on the clock. The carbs were cleaned and rebuilt last year plus electronic ignition was installed. Usually it starts well when cold but about every third or fourth start I’m getting a backfire. The plugs appear almost new. Have not checked the timing. Any suggestions other than timing?
Thanks in advance!
Backfire (sometimes)
Moderators: CYBORG, Oldewing, robin1731, Forum Moderators
-
- Zinc Member
- Posts: 42
- Joined: Tue Apr 26, 2016 9:16 pm
- Location: Sarasota, FL
Backfire (sometimes)
1980 GL1100 (Sold)
1977 GL1000 (Sold)
1977 GL1000 (Sold)
-
- Zinc Member
- Posts: 42
- Joined: Tue Apr 26, 2016 9:16 pm
- Location: Sarasota, FL
Re: Backfire (sometimes)
More information: The plugs are actually quite dark, especially 1 & 4. So, should I assume that the carbs are adjusted too rich?
1980 GL1100 (Sold)
1977 GL1000 (Sold)
1977 GL1000 (Sold)
- jdvorchak
- Honored Life Member
- Posts: 5238
- Joined: Mon May 25, 2009 8:01 pm
- Location: East Alton, IL
Re: Backfire (sometimes)
I think at the very least hook up your sync gauges and verify/correct sync. Then perform idle drop and sync again if needed. Swap the plugs fore and aft and ride it some more to see if the 1&4 are still loading up on you.
New users please visit our "Shop Talk" for common tips and help:
http://ngwclub.com/forum/page/ST
Don't fix it 'til it's broke...
The person with the most toys wins!
If it has wheels or a skirt you can't afford it.
Amateur Radio Station WW9L
71 CL350 with Bingham side car
2021 HD Triglide
2008 HD Dyna Low Rider
83 KZ1100L1 Son totaled it
83 KZ550LTD Shaft sold
Previous bikes: 84 GL1200 STD, 83 KZ550LTD, 83 CB1000, 78 CB400A, 82 CB900F, 79 CB750K, 2001 GL1800, 2000 Dyna Super Glide, 1972 CB350 K4, 1985 GL1200A, 1997 1200 Sportster, 84 GL1200I, 82 Honda CM400E, 81 Suzuki GS650L, 72 Triumph Bonneville 750, 72 Honda CB350, 66(?) Honda 305 Scrambler, 6? Yamaha yz250, 62 650 Matchless (Norton-Villers).
John
http://ngwclub.com/forum/page/ST
Don't fix it 'til it's broke...
The person with the most toys wins!
If it has wheels or a skirt you can't afford it.
Amateur Radio Station WW9L
71 CL350 with Bingham side car
2021 HD Triglide
2008 HD Dyna Low Rider
83 KZ1100L1 Son totaled it
83 KZ550LTD Shaft sold
Previous bikes: 84 GL1200 STD, 83 KZ550LTD, 83 CB1000, 78 CB400A, 82 CB900F, 79 CB750K, 2001 GL1800, 2000 Dyna Super Glide, 1972 CB350 K4, 1985 GL1200A, 1997 1200 Sportster, 84 GL1200I, 82 Honda CM400E, 81 Suzuki GS650L, 72 Triumph Bonneville 750, 72 Honda CB350, 66(?) Honda 305 Scrambler, 6? Yamaha yz250, 62 650 Matchless (Norton-Villers).
John
-
- Zinc Member
- Posts: 42
- Joined: Tue Apr 26, 2016 9:16 pm
- Location: Sarasota, FL
- salukispeed
- Platinum Member
- Posts: 1951
- Joined: Sun Feb 21, 2010 10:08 am
- Location: Oak Forest Illinois US
Re: Backfire (sometimes)
Just thinking and Just to be sure I assume the back fire is on initial attempt to crank and the back fire is from the muffler. Is it stock exhaust and is the idle speed unusally high? which can load the exhaust with fuel and air at shutdown which pops with the next start. I wonder if an extra rich idle mixture can do the same.
Honda 72 CL100 sold
74 CB750 K4 nice driver
1966 CA77/305 Dream nostalgic driver
84 GL1200I work in progress
1970 CT 70
1982 GL500 Interstate
74 CB750 K4 nice driver
1966 CA77/305 Dream nostalgic driver
84 GL1200I work in progress
1970 CT 70
1982 GL500 Interstate
-
- Zinc Member
- Posts: 42
- Joined: Tue Apr 26, 2016 9:16 pm
- Location: Sarasota, FL
Re: Backfire (sometimes)
It’s on the initial start up and immediately after the engine is started. Always out the stock exhaust. I am using the choke on start up. Could that alone be causing a overly rich fuel mix?
1980 GL1100 (Sold)
1977 GL1000 (Sold)
1977 GL1000 (Sold)
-
- Zinc Member
- Posts: 42
- Joined: Tue Apr 26, 2016 9:16 pm
- Location: Sarasota, FL
Re: Backfire (sometimes)
Well, as some of you may have suspected , the backfire apparently was caused by overuse of the choke when starting the engine. Today I started it just using a half twist of the throttle and no backfire. Seems like I always imagine the worst possible problem rather than just focusing on the simple stuff.
1980 GL1100 (Sold)
1977 GL1000 (Sold)
1977 GL1000 (Sold)
- Rat
- Photo Gallery Admin
- Posts: 15480
- Joined: Fri Oct 21, 2005 9:59 pm
- My Album: https://www.ngwclub.com/gallery/v/wingmans/rat/
- RIP: cookie
- Location: Toronto .... Canada
Re: Backfire (sometimes)
Well .... you do live in Florida .... the choke is probably not required ??
Gord (looks warm from here) Jones
Gord (looks warm from here) Jones
"I'd rather Ride than Shine"
‘14 KLR650 ... not a rat ... yet
‘84 GL1200i ‘R2B6' (Rat to Be 6, the last, adopted by twowings)
My Original 'RAT' was a hybrid '82 CB900/1100F
‘14 KLR650 ... not a rat ... yet
‘84 GL1200i ‘R2B6' (Rat to Be 6, the last, adopted by twowings)
My Original 'RAT' was a hybrid '82 CB900/1100F
-
- Zinc Member
- Posts: 42
- Joined: Tue Apr 26, 2016 9:16 pm
- Location: Sarasota, FL
Re: Backfire (sometimes)
Yes, I live in Florida but there are times when the bike has been difficult to start and the choke seemed to help. As the engine gets more frequent use, it appears that it’s now unnecessary.
1980 GL1100 (Sold)
1977 GL1000 (Sold)
1977 GL1000 (Sold)
-
- Similar Topics
- Replies
- Views
- Last post
-
- 22 Replies
- 644 Views
-
Last post by CHUCK HAHN
-
- 25 Replies
- 831 Views
-
Last post by Sidecar Bob
-
- 5 Replies
- 630 Views
-
Last post by gltriker