Hello all, My r100 with bean can cuts out every now and then, just for a second when it is cold or hot usually at speed except yesterday as I pulled off my street with motor cold it stopped, backfired and I had to restart it and it fired right up. I'm about to dive into it and was wondering if anyone had any ideas? Headed for control module first, I do not think there is any gel on it. Thanks
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Airhead cuts out
- Thread starter arptra
- Start date
I read about heat sink but I thought that was when motor was hot
manicmechanic
ABC,AMA(LIFE),MOA,RA,IBMW
Ceck the connections to/around the starter relay. Also your ground connection to the transmission for snug.
Mine did that and I traced it to the connections just under the front left side of the tank. I cleaned them all (relays, etc) and then made a "shield" out of an old milk gallon jug (plastic) and have never had the problem since. On mine, at one time there must have been a brake cylinder leak under tank and these connections are right near the brake cylinder.
Last edited:
lowndes
New member
Arptra,
My brother had a very similar problem with his '79 R100RT for MONTHS. And he is an old MC mechanic from way back, still works for an antique MC racer part time doing engine rebuilds and restorations, so he "knows a thing or two" about bikes. Cold or hot, at least once every ride, it woud just die, riding down the road or still in the parking lot. Drove us nuts, me because I'd be behind him and it would die, he'd switch it OFF then ON again and it would be the biggest, loudest backfire you ever saw with yellow flames shooting out 10 feet. Scare the bejeebers out of me. It was most definitely a safety issue, too, loosing power when passing, etc. Most of the time it would restart immediately, sometimes it would take a minute or two, but always restarted.
He replaced or swapped out everything, ignition switches, relays, handle bar controls, coils, wires, plugs, boots, even sections of the wiring harness. Turns out it was the neg battery cable that was corroded INSIDE the insulation from battery acid, and not visible from the outside. It was almost completely severed. Not sure exactly the electrical/mechanical problem resulted in these symptoms, but it did.
He finally found it by process of elimination, installing temporary bypasses around the existing switches, relays, connectors, etc. Bad "grounds" are always a very difficult prob to sort out and the last thing we think about. He rebuilt the ground cable with new lugs and sealed the ends of the insulation with heat shrink and silicone about 6 weeks ago and problem solved.
GOOD LUCK with this, and please LET US KNOW what you find when you do find it!!
My brother had a very similar problem with his '79 R100RT for MONTHS. And he is an old MC mechanic from way back, still works for an antique MC racer part time doing engine rebuilds and restorations, so he "knows a thing or two" about bikes. Cold or hot, at least once every ride, it woud just die, riding down the road or still in the parking lot. Drove us nuts, me because I'd be behind him and it would die, he'd switch it OFF then ON again and it would be the biggest, loudest backfire you ever saw with yellow flames shooting out 10 feet. Scare the bejeebers out of me. It was most definitely a safety issue, too, loosing power when passing, etc. Most of the time it would restart immediately, sometimes it would take a minute or two, but always restarted.
He replaced or swapped out everything, ignition switches, relays, handle bar controls, coils, wires, plugs, boots, even sections of the wiring harness. Turns out it was the neg battery cable that was corroded INSIDE the insulation from battery acid, and not visible from the outside. It was almost completely severed. Not sure exactly the electrical/mechanical problem resulted in these symptoms, but it did.
He finally found it by process of elimination, installing temporary bypasses around the existing switches, relays, connectors, etc. Bad "grounds" are always a very difficult prob to sort out and the last thing we think about. He rebuilt the ground cable with new lugs and sealed the ends of the insulation with heat shrink and silicone about 6 weeks ago and problem solved.
GOOD LUCK with this, and please LET US KNOW what you find when you do find it!!
Well I installed new switches with headlight switch, (was planning on that anyway), another control module, checked grounds , cleaned relay and it was pretty dirty and I believe that may have been the issue, runs great now well it ran great before just that hiccup now and then, time will tell. Thanks guys!
stevenrankin
Active member
I had the same problem
Hello, I had the same problem. cleaned a lot of connections, grounds, and so far the problem has gone away. At least I think the gremlins have jumped off. St.
Hello, I had the same problem. cleaned a lot of connections, grounds, and so far the problem has gone away. At least I think the gremlins have jumped off. St.
beemerguru
Member
If it starts happening again..take a quick glance at the tach..if it immediately goes to 0, a good part of the time it's the bean can.
stevenrankin
Active member
The problem most likely is not the bean can or the module
I had the same problem. Changed the bean can, the module, ignition switch to no avail. Turns out the problem was either a bad wiring ground (most likely) or a bad connection in the wiring harness. Went crazy, cleaned a lot of connections and now (I hope) the problem is gone.
Fell foolish replacing a lot of expensive stuff just for a bad connection. Should have started with cleaning grounds and connections first before replacing parts. I don't remember who in either the MOA forum or Airhead forum told me that. A very wise man. St.
I had the same problem. Changed the bean can, the module, ignition switch to no avail. Turns out the problem was either a bad wiring ground (most likely) or a bad connection in the wiring harness. Went crazy, cleaned a lot of connections and now (I hope) the problem is gone.
Fell foolish replacing a lot of expensive stuff just for a bad connection. Should have started with cleaning grounds and connections first before replacing parts. I don't remember who in either the MOA forum or Airhead forum told me that. A very wise man. St.
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