backfiring problems


Information and questions on GL1200 Goldwings (1984-1987)
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Denny69
Posts: 6
Joined: Wed Apr 07, 2010 9:45 pm
Location: Newcastle, ontario,Canada
Motorcycle: 1985 GL 1200 Interstae

backfiring problems

Postby Denny69 » Wed Apr 07, 2010 9:55 pm



hello fellow wing owners.
I am having a problem with my 85 Interstate. it runs good for about 10 min, backfires and shuts down and will not start back up unless it sits for 10 min or so.Is this a simple fuel filter problem, or fuel pump, or something a little more tricky like carbs are out of sync or timing? Can someone please tell me what is going on with it.I am reluctanat to ride it to a mechanic, but don`t have a trailer to get it there. Is it safe to ride it the 15 km to the dealer or should I look for a buddy witha trailer?



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WingAdmin
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Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
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Re: backfiring problems

Postby WingAdmin » Thu Apr 08, 2010 9:58 am

This could very well be your master fuse. Is the battery being drawn down when this is happening? Something to check, anyway - have a look at this thread for more information.

k1w1t1m
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Motorcycle: 1980 GL1100 Interstate. 105,000miles and still going strong.(sold)
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Re: backfiring problems

Postby k1w1t1m » Thu Apr 08, 2010 11:24 am

It could be the pulse generators. I suggest you check the manual for procedures on how to test them. Reports are that they break down when hot which is as you describe.

Denny69
Posts: 6
Joined: Wed Apr 07, 2010 9:45 pm
Location: Newcastle, ontario,Canada
Motorcycle: 1985 GL 1200 Interstae

Re: backfiring problems

Postby Denny69 » Thu Apr 08, 2010 11:36 am

If it were the master fuse or dog bone fuse, would I still have power? It still rolls over fine and tries to fire, but usually ends in an ear splitting backfire. Another question is should the fuel filter be full all the time? I have just put a new filter on it and it seems to only have a trickle of fuel coming into it. The bike runs fine untill the filter dries up and starves the system of fuel. Once the bike sits for awhile, the filter seems to get half full of fuel again,and the bike will start right up.

k1w1t1m
Posts: 68
Joined: Thu Apr 08, 2010 11:07 am
Location: Centerton AR USA
Motorcycle: 1980 GL1100 Interstate. 105,000miles and still going strong.(sold)
2001 BMW R1150 GS (possibly for sale soon)
1997 Gl1500 SE in pearl sapphire black.

Re: backfiring problems

Postby k1w1t1m » Thu Apr 08, 2010 11:54 am

If the master fuse was blown you'd have no electrical at all.

From what you've said it definitely sounds like a fuel issue. First off I'd check the tank for crud and junk. I used a syphon to "vacuum" mine out. Disconnect the fuel lines and blow/clean them out. Can you hear the fuel pump running? If yes I'm pretty sure you'll find volume and pressure specs in the manual. If no the pump or wiring could be the problem. It could also be the vent in the gas tank cap. Some people have had luck with soaking the cap in Seafoam or they have drilled a 1/8th" hole for venting.

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tricky
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Re: backfiring problems

Postby tricky » Thu Apr 08, 2010 12:22 pm

Pulse Generators. Sounds like it could be.

Denny69
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Location: Newcastle, ontario,Canada
Motorcycle: 1985 GL 1200 Interstae

Re: backfiring problems

Postby Denny69 » Thu Apr 08, 2010 3:13 pm

k1w1t1m wrote:If the master fuse was blown you'd have no electrical at all.

From what you've said it definitely sounds like a fuel issue. First off I'd check the tank for crud and junk. I used a syphon to "vacuum" mine out. Disconnect the fuel lines and blow/clean them out. Can you hear the fuel pump running? If yes I'm pretty sure you'll find volume and pressure specs in the manual. If no the pump or wiring could be the problem. It could also be the vent in the gas tank cap. Some people have had luck with soaking the cap in Seafoam or they have drilled a 1/8th" hole for venting.



I have tried it with the gas cap off and it still does the same thing. I have also tries the seafoam on the cap and have also poured some into the tank as well. I am leaning towards a faulty pump at this stage. Any idea as to how I would check to see if it is the pump? I have listened for the pump , but not really sure if it is running or not.
Thanks for the help just the same.

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tricky
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Re: backfiring problems

Postby tricky » Thu Apr 08, 2010 3:28 pm

Here ya go..................................................
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WingAdmin
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1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: backfiring problems

Postby WingAdmin » Thu Apr 08, 2010 3:30 pm

Denny69 wrote:If it were the master fuse or dog bone fuse, would I still have power? It still rolls over fine and tries to fire, but usually ends in an ear splitting backfire. Another question is should the fuel filter be full all the time? I have just put a new filter on it and it seems to only have a trickle of fuel coming into it. The bike runs fine untill the filter dries up and starves the system of fuel. Once the bike sits for awhile, the filter seems to get half full of fuel again,and the bike will start right up.


Yes you would still have power, the master fuse is used only to get power from the stator (alternator) into the battery for charging it. You can remove it and the bike will still run, until the battery dies, at which point the spark will be insufficient, and it will start to sputter and backfire.

However, if the fuel filter is drying up and the engine is dying, it certainly sounds like a fuel delivery problem.

Try the test described above by tricky and see if you get the correct volume.

Have you tried replacing the fuel filter?

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tricky
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Re: backfiring problems

Postby tricky » Thu Apr 08, 2010 3:45 pm

I had an elusive backfire/quit/wouldnt run/backfire..... Some times it would run all day, one day after riding it quit on me with the back firing etc, we trailered it home. The following day it started right up again, I was ready to tear my hair out.... if I had any :)

I suspected a fuel problem, siphoned out the gas, fresh gas, new filter, new plugs, changed fuel lines, I was not going to mess with the carbs, the bike ran perfect the previous season, I knew the pump was fine. But it just sounded like a fuel problem.

Guess what...... Pulse generators. I had the old ones out, on the bench, measured them... fine.... heated them up with a heat gun.. measured again, they still came within spec's.

I figured, they were 25 years old, lots of miles, If I bought new ones and it wasn't them then I would have a spare set... put the new ones in, bingo, running like a charm again.

Before stripping carbs etc, if it was running fine then this started and you have done the simple stuff, lines, fresh fuel, check fuel pump etc.

Give them a shot, if it isn't them at least you will have a spare set, they will go eventually :)

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tricky
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Re: backfiring problems

Postby tricky » Thu Apr 08, 2010 4:13 pm

I just re-read you post again, if the fuel is drying up prior to reaching the filter, testing the pump wont accomplish anything, the filter is before the fuel pump. The fuel is gravity fed, maybe there is a blockage in the tank.
Only when you have an unrestricted fuel flow, remove the line going from tank to the filter, and allow it to drain into a container, you will tell if there is a restriction in the tank.

Denny69
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Motorcycle: 1985 GL 1200 Interstae

Re: backfiring problems

Postby Denny69 » Sun Apr 11, 2010 8:00 pm

tricky wrote:I just re-read you post again, if the fuel is drying up prior to reaching the filter, testing the pump wont accomplish anything, the filter is before the fuel pump. The fuel is gravity fed, maybe there is a blockage in the tank.
Only when you have an unrestricted fuel flow, remove the line going from tank to the filter, and allow it to drain into a container, you will tell if there is a restriction in the tank.




The filter always a little fuel left in it. but it is never full either.
According to the manual, the pulse generators are a bit tricky to replace. Is there any easier way to change thses without having to basically split the bike in half( take the swing arm off)?

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tricky
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Re: backfiring problems

Postby tricky » Sun Apr 11, 2010 9:35 pm

You have an 85 Interstate, the manual your reading must be for an 84. It is the 84 that are at the back of the engine

The pulse generators are at the front of the engine where the timing belts are located on 85 and up
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Denny69
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Location: Newcastle, ontario,Canada
Motorcycle: 1985 GL 1200 Interstae

Re: backfiring problems

Postby Denny69 » Wed Apr 14, 2010 6:54 pm

tricky wrote:You have an 85 Interstate, the manual your reading must be for an 84. It is the 84 that are at the back of the engine

The pulse generators are at the front of the engine where the timing belts are located on 85 and up

Thanks Tricky. You nailed right on. the pulse generators where gone, be back on the road soon.
Thanks again for all your help

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tricky
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Re: backfiring problems

Postby tricky » Wed Apr 14, 2010 6:58 pm

Good, you will be riding shortly, have a good season.

It's nice to see feed back

Thanks

axle133
Posts: 2
Joined: Sat Nov 14, 2009 12:26 pm
Location: Victoria, BC
Motorcycle: 1985 GL1200

Re: backfiring problems

Postby axle133 » Sun May 02, 2010 6:22 pm

For Denny69.....Where'd you end up finding a pulse generator from? I'm having the same issues with my fathers bike and am pulling my hair out!!

Cheers

Denny69
Posts: 6
Joined: Wed Apr 07, 2010 9:45 pm
Location: Newcastle, ontario,Canada
Motorcycle: 1985 GL 1200 Interstae

Re: backfiring problems

Postby Denny69 » Mon May 03, 2010 2:17 pm

axle133 wrote:For Denny69.....Where'd you end up finding a pulse generator from? I'm having the same issues with my fathers bike and am pulling my hair out!!

Cheers

Clairington cycle in Bowmanville did the work for me. I`m not sure where he got the parts from, I do know that they were new parts. I will get his email address and post it here for you.

axle133
Posts: 2
Joined: Sat Nov 14, 2009 12:26 pm
Location: Victoria, BC
Motorcycle: 1985 GL1200

Re: backfiring problems

Postby axle133 » Mon May 03, 2010 2:20 pm

Clairington cycle in Bowmanville did the work for me. I`m not sure where he got the parts from, I do know that they were new parts. I will get his email address and post it here for you.


That would be great, thanks.




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