Reply With QuoteI meant Throttle Body. I've just been working on my 72 Beemer which has two carbs
Like most of us I’ve had my share of issues, (mostly minor) with both TT’s. It appears that I’ve finally resolved the last one.
There are a lot of cool/cold damp drizzly and rainy days where I live in the Pacific Northwest, (generally from mid to late fall through July 5th. When riding on those days both bikes will stumble a little plus “pop” through the carburetor until thoroughly warmed up. Even warmed up there’ll still be an irritating pop through the carb and stumble every five to ten minutes or so. None of this happens on dry sunny days.
Looking at the wiring under the air box, the front cylinder spark plug wire is very close to the wire bundle that carries the fuel injector signal wires. After thinking about it a little I wondered if there was any “cross-talk” between the plug wire and injector signal wires. The bike has suppression spark plug wires and resistor plugs so initially I dismissed the possibility but could never eliminate the popping.
Long story short:
Purchased a roll of copper foil with a conductive adhesive on one side.
Ran a “Tinned” 16 AWG stripped, (bare) wire along the spark plug wire.
Ran a second stripped tinned wire along about 8 to 10 inches of the wire bundle.
Wrapped the plug wire, wire bundle and stripped wires in copper foil.
Soldered ring connectors to the 16 AWG wire ends.
Ran the coil’s front mounting bolt through the connectors, bonding the drain wires to the engine.
NOTE: The bare wire acts as shield drain. It gives interference electrons, (EMI) a free ride away from the injector signal wires.
Problem solved. Went for a 20 mile ride in cold damp heavy drizzle. The engine didn’t pop once even before it had fully warmed up.
I meant Throttle Body. I've just been working on my 72 Beemer which has two carbs
Nice!
What's your '72?
It’s an R75/5. I bought it new in 72 after getting out of the Army. It has 243,000 miles. About 40% of the miles are from long trips taken during the summer. After getting out I went to college for six years. I’d work part time all winter, save the money and hit the road for 5 or 6 weeks every summer but then I got married.
A couple weeks ago the centrifugal mechanical spark advance grenaded itself. When it let go it also damaged the spindle on the end of the cam shaft to which it was mounted. The cam itself is not damaged but the drive flat on the end of the spindle is not there anymore.
A company called Euro MotoElectric makes an aftermarket electronic ignition that uses an optical pickup that’s mounted to the crankshaft instead of the cam shaft. Timing curves are programmed into ignition eliminating the need for a mechanical spark advance using fly weights. Hopefully I’ll have her up and running by the 1st.
well done sire and good info for those suffering similar ailment. please post pic of this fix if and when you have time. would like to see it.
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