'78 GL1000 backfiring

Information and questions on GL1000 Goldwings (1975-1979)
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Posts: 1
Joined: Wed Aug 25, 2010 3:49 pm
Location: Boston, Massachusetts
Motorcycle: 1978 GL1000

'78 GL1000 backfiring

Post by djgamari » Wed Aug 25, 2010 4:32 pm

I've just become the proud owner of a 1978 GL1000 in good condition except for one issue. Roughly 1 min and 30 secs. after a cold or warm start, she begins to pop (or backfire) out the tail pipe. This just occurs on the left side. All cylinders are firing. She is still rideable, as when the engine is under a load power delivery is smooth, but there is still popping when under no load or coasting. The carbs were supposedly rebuilt before I bought the bike. Being a novice at carb issues my next step will be to bring it to a honda mechanic. Could it be a vacuum leak or perhaps the fuel mixture is too lean on one carb. Any ideas?

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Re: '78 GL1000 backfiring

Post by dingdong » Thu Aug 26, 2010 8:41 am

The popping is usually an indication of a lean condition in one or more of the carbs. If it is only happening at idle you most likely have the idle pilot screws set too lean or who ever did the rebuild didn't get the idle circuits cleaned properly. A vacuum leak could also cause a lean condition. You might check for leaks by using an unlit propane torch all around the carbs. If the idle changes with the propane then you have found a leak.
When a previous owner says that the carbs have been rebuilt that doesn't mean they were done properly. Not many mechanics know or care how to do it properly on an older Goldwing.

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