My R100R has 14K miles. It suddenly started idling on one cylinder a couple of days ago. When I roll on the throttle a bit the left cylinder starts firing and above 2000 RPM the bike runs great.
I removed the left idle jet and blew it out with compressed air - no change.
Last night after dark I was running the bike in the driveway and I noticed that the left exhaust pipe was red hot!
Any assistance would be greatly appreciated.
In the past, I've seen idle jets that were plugged, but was cleared using a weldor's tip cleaner or guitar string.
This last is, of course, a "California thing". In the South we greatly prefer the use of a banjo string.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Thanks for the help! Here's what I did so far:
I replaced the idle jet and idle mixture screw on the left carb. Swapped spark plugs R to L. Visually inspected the L spark plug wire. No difference, left cylinder does not fire when idling but starts firing as soon as the throttle is advanced. Seems fine above 2000 rpm.
Best,
Paul
Visually inspected the L spark plug wire.
Paul -
You can't see the issue with ignition parts. If the parts are over 5 years old, then replace the wires with METAL CORE wires (not modern car wires), NGK 5K Ohm plug caps, and 2 new BP7ES plugs. You can get all this at any good LAPS for under $20.
Try that.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
I swapped plug wires, still not idling on L cylinder... ?
Best,
Paul
I swapped plug wires, still not idling on L cylinder... ?
Best,
Paul
And the spark plug ?
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Yes I also swapped plugs, L to R - no change
If you swapped the wires and plugs from one side to the other by re-routing the wires but leaving them in the coils as they were, and the problem stayed exactly as it was, we can deduce the following;
1) The "dead side" (L)secondary ignition assembly will support the cylinder at idle on the right side.
2) The "good side" (R)secondary ignition assembly will not support the cylinder at idle on the left side.
3) The trouble probably does not lie in the ignition system.
former Airmarshal, IL.
Same 3 rules apply: Fire. Gas. Compression.
When was the last time you adjusted your valves ? Because tight valves will have this effect.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
You can also swap the carbs from side to side with a little careful cable routing. That would certainly answer your questions.
Did you recently wash the bike and possibly introduce water into the carb in question?
If this just started happening and all was well before, wondering if you can go back and retrace anything that may have lead to this?
A more detailed cleaning of the carb maybe in order?
Problem solved - I had both carbs rebuilt by the Bing Agency, synced them with a Carbmaster instrument. Bike runs great!!!
Thanks for all the helpful suggestions.
Best,
Paul
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