No Tach and backfires


Technical information and Q&A applicable to all years and models of Goldwings
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sam18135
Posts: 2
Joined: Sat May 08, 2010 8:49 am
Location: Tallulah, LA
Motorcycle: 1985 GL1200 Aspencade, 1978 GL1000

No Tach and backfires

Postby sam18135 » Sun Apr 19, 2015 7:53 pm



Hi all, I have an 86 gl1200 A that I recently bought that has a running problem. I took the carbs off and cleaned all bowls and jets, the left side carbs were full of jelled gas. after that the bike started for the first time in 4 years it runs rough but I have added lots of seafoam to tank and am running that thru to try to clean the carbs out. my main problem is that sometimes the bike will not start it will just backfire I noticed that the digital tach does not show any RPM when I spin the engine, yesterday it would not start so I let it sit overnight and this morning I hit the starter it showed RPM and it fired up and I ran it until fan came on, this problem is intermittent so after this long explanation my question is what could cause no RPM indication and no start then next day show rpm and start>



User avatar
tom84std
Posts: 493
Joined: Fri Jul 13, 2012 7:40 am
Location: Arlington, Texas
Motorcycle: '84 STD 1200
2002 VTX1800
2007 Shadow 750
69 BSA Bitsa
2004 Virago
VW Trike

Re: No Tach and backfires

Postby tom84std » Sun Apr 19, 2015 9:27 pm

Sounds as if it's been sitting for a while and possibly in some moisture or humidity? I'd really want to take a look at, and treat just about every electrical connector on the bike. Go to Amazon.com and look for electrical contact cleaner. Take the seat, false tank, headlamp bucket and anything else you need to, to get to the electrical connectors. Unlatch, pull them apart, hold them in a rag and spray them down with the contact cleaner. Latch them back together tightly. Pay special attention to the ignition coil connectors, (push-on connectors are tight) lamp sockets and don't forget the handlebar switches. Instrument cluster connectors and just about every connection in the wiring harness. It'll probably take two cans of contact cleaner. Under the left side cover, look for the three yellow wires between the alternator and regulator/rectifier. Cut that plug out and solder/insulate the yellow wires. Search "Goldwing Alternator Failure" or some similar search string.
Really scrutinize the subframe, the part attached to the sidestand. Look for evidence of rust. Those gather moisture inside the tube and rust out. Make sure the little drain hole is clear.
I really like bring an old unloved motorcycle back to life but there's a lot of electrics on a Goldwing. Time and humidity are not kind to them.

sam18135
Posts: 2
Joined: Sat May 08, 2010 8:49 am
Location: Tallulah, LA
Motorcycle: 1985 GL1200 Aspencade, 1978 GL1000

Re: No Tach and backfires

Postby sam18135 » Sun Apr 19, 2015 10:42 pm

I have done that to some of the connectors and the 3 stator wires have already been soldered. The funny thing is when this thing decides it is going to run it does so with no problems.

User avatar
tom84std
Posts: 493
Joined: Fri Jul 13, 2012 7:40 am
Location: Arlington, Texas
Motorcycle: '84 STD 1200
2002 VTX1800
2007 Shadow 750
69 BSA Bitsa
2004 Virago
VW Trike

Re: No Tach and backfires

Postby tom84std » Sun Apr 19, 2015 11:19 pm

sam18135 wrote:I have done that to some of the connectors and the 3 stator wires have already been soldered. The funny thing is when this thing decides it is going to run it does so with no problems.

I spent nearly thirty years repairing the machinery that keeps our mail boxes full of junk mail and bills. The problem I hated to see the most was the intermittent one. It only failed when you weren't looking for it.
The tach is part of the negative pulse circuit which fires the ignition coils. The tach malfunctioning along with misfiring and backfiring would go together, and it makes sense that they would occur together. Sounds like a flakey connection or component in that part of the ignition circuit.




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