MonoRT
MonoRT
I am somewhat hesitant to write this because I know that many of you live in places where it actually gets cold. My 1985 R80RT is really difficult to start at or below 50 degrees Fahrenheit. These days, 50 degrees is about as cold as it gets a couple of miles from the ocean in SoCal. At 65 degrees and above, the bike starts with ease - even without the "choke". Once started, the bike runs just fine.
This behavior became noticeable last week. The starter seems to crank the motor over just fine (how thick could the oil be at 50 degrees?). I have a Datel digital meter wired directly to the battery (a 28 Ah WestCo) and I see the voltage go as low as 10.8 volts during prolonged cranking, but it pops back to somewhere between 12.8 and 13.1 volts when I take my finger off the starter button.
The motor spins and fires occasionally, but it is difficult to get enough consistent firing to start the engine running on its own. So far, I've been able to start the bike each morning, but it takes a lot of starter time to get the bike running and I know that can't be good for the starter.
Valve clearances look good; spark plugs look good and have about 2K miles on them. A couple of months ago, the bike was dying at idle and I purchased new plug wires, but I soon found out that the primary windings in my coil were failing (eventually, they went open and stranded me), so I left the wires alone and replaced the coil with a .7 ohm Dyna unit. This weekend, I put on the new wires, but that seemed to make no difference (old wires still seemed OK and measured 5K ohms each - new wires also measured 5K ohms each).
The starter is a Bosch and it has never been removed - original bushes and brushes for about 250K miles. I have Rick Jones' book on Boxer charging systems and he mentions that a badly worn starter could drive system voltage down to a point where it becomes difficult for the ignition system to fire the plugs.
How about the carbs? I've got the stock 32mm Bings and I believe that I have enough parts to rebuild them on-hand. A couple of months back when the bike was dying at idle due to the bum coil, I went through the carbs looking at the diaphragms, floats, jet stack etc? I did not pull the covers off the starting carburetors or enrichers or whatever you call them. I would not expect to have starting problems with two carbs at once - I'd think that the bike would fire and run (badly) on one cylinder, but I'm just guessing.
My bike lives in a nice, dry attached garage. I'm tempted to toss a 100w work light under it before I go to bed, just to see if the extra warmth makes it possible to start the bike without drama the next morning.
At all events, something is not operating correctly - 50 degrees should not make it hard to start the bike with full choke. Where do you-all think I ought to look?
This behavior became noticeable last week. The starter seems to crank the motor over just fine (how thick could the oil be at 50 degrees?). I have a Datel digital meter wired directly to the battery (a 28 Ah WestCo) and I see the voltage go as low as 10.8 volts during prolonged cranking, but it pops back to somewhere between 12.8 and 13.1 volts when I take my finger off the starter button.
The motor spins and fires occasionally, but it is difficult to get enough consistent firing to start the engine running on its own. So far, I've been able to start the bike each morning, but it takes a lot of starter time to get the bike running and I know that can't be good for the starter.
Valve clearances look good; spark plugs look good and have about 2K miles on them. A couple of months ago, the bike was dying at idle and I purchased new plug wires, but I soon found out that the primary windings in my coil were failing (eventually, they went open and stranded me), so I left the wires alone and replaced the coil with a .7 ohm Dyna unit. This weekend, I put on the new wires, but that seemed to make no difference (old wires still seemed OK and measured 5K ohms each - new wires also measured 5K ohms each).
The starter is a Bosch and it has never been removed - original bushes and brushes for about 250K miles. I have Rick Jones' book on Boxer charging systems and he mentions that a badly worn starter could drive system voltage down to a point where it becomes difficult for the ignition system to fire the plugs.
How about the carbs? I've got the stock 32mm Bings and I believe that I have enough parts to rebuild them on-hand. A couple of months back when the bike was dying at idle due to the bum coil, I went through the carbs looking at the diaphragms, floats, jet stack etc? I did not pull the covers off the starting carburetors or enrichers or whatever you call them. I would not expect to have starting problems with two carbs at once - I'd think that the bike would fire and run (badly) on one cylinder, but I'm just guessing.
My bike lives in a nice, dry attached garage. I'm tempted to toss a 100w work light under it before I go to bed, just to see if the extra warmth makes it possible to start the bike without drama the next morning.
At all events, something is not operating correctly - 50 degrees should not make it hard to start the bike with full choke. Where do you-all think I ought to look?
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