Hard starting, trouble idling, boyer failing?

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StephenP

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Oct 23, 2021
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Long winded post, forgive me.

I’ve got a 73 850 that i’ve had for almost four years, it’s got a boyer of some sort on it. Normally it’s fairly easy to start (for me) tickle fuel till you see it, ignition off roll it to compression, ignition on stand on the kicker, and it usually goes first or second kick. Well i picked up a 69 one owner stock S model, so I’ve been ignoring the 850 a little, but i guess about 6 weeks ago i went on a ride was 2 hours each way at 70 mph, which is as hard as i have ran continuously, it seemed to be ok with it. When i got back i saw the right carb was flooding so i shut the fuel off and ignored it. Rode it around the block two weeks later just to keep it from wet sumping, sat for another 3 weeks or so, and i cranked it i think it had wet sumped by this time, it took a good effort to get it running, i let it get to temp ran it a few mins shut it down.


Today i pop the bowl off the right carb and clean the trash out out of the needle and seat and decided i would ride today. Well i did my usual starting ritual, kicked and kicked and kicked the most i could get was one cyl would fire but never fully light off. So i resorted to the last ditch effort which is flood it with the ticklers hold the throttle open, and kick it several times. Same deal. Borrowed the plugs out of my S model no real difference, both sets of plugs looked decent i kicked it plugs out with one plug hooked up to see the spark, it looked weak but it was also daylight and also i was literally seeing stars from kicking this damn thing. Put the plugs in kick it until i literally puke. Finally i get it lit off and jump on, tear out get about a half mile away pull the clutch in, goes dead. Pop the clutch get it running, pull clutch in and it dies again, so i turn back around get to my house goes dead in my driveway. i am done. This bike has always been pretty reliable

I am wondering if maybe the ignition box is going dead.. maybe i got it hot on the trip, it’s old… i don’t know what my voltage is at my battery but i turned the headlight on with it not running, it was bright. I just dont know what the symptoms of a failing boyer is. But this bike has never cared it always runs

Oh i jumped on the 750 S, with the plugs out of the 850 and it lit off first kick.
 
The Boyer black box will either work or it won't .
Here are some far more likely issues .
Failing battery . Oxidized kill switch . Oxidized or worn out ignition switch . Battery terminals not tight or oxidized . Ground(s) not tight or oxidized . Clogged pilot jets from sitting a long time . Boyer wires at the point plate entry starting to separate from vibration . Gas tap clogged with crud .
Investigate those and have new spark plugs handy .
 
Torontonian said:
The Boyer black box will either work or it won't .
Here are some far more likely issues .
Failing battery . Oxidized kill switch . Oxidized or worn out ignition switch . Battery terminals not tight or oxidized . Ground(s) not tight or oxidized . Clogged pilot jets from sitting a long time . Boyer wires at the point plate entry starting to separate from vibration . Gas tap clogged with crud .
Investigate those and have new spark plugs handy .
Click to expand...
I definitely think its an ignition issue. At least with the hard starting. But those are all good things to check, and the box is black for sure
 
Try this , it's simple .
Run a ( hot ) wire from the negative battery terminal directly to the Boyer black box . It has a white wire that you will connect to . This bypasses all other electrical circuits . If it fires up then the problem is in the other circuits . Trace backwards .
 
StephenP said:
Long winded post, forgive me.

I’ve got a 73 850 that i’ve had for almost four years, it’s got a boyer of some sort on it. Normally it’s fairly easy to start (for me) tickle fuel till you see it, ignition off roll it to compression, ignition on stand on the kicker, and it usually goes first or second kick. Well i picked up a 69 one owner stock S model, so I’ve been ignoring the 850 a little, but i guess about 6 weeks ago i went on a ride was 2 hours each way at 70 mph, which is as hard as i have ran continuously, it seemed to be ok with it. When i got back i saw the right carb was flooding so i shut the fuel off and ignored it. Rode it around the block two weeks later just to keep it from wet sumping, sat for another 3 weeks or so, and i cranked it i think it had wet sumped by this time, it took a good effort to get it running, i let it get to temp ran it a few mins shut it down.


Today i pop the bowl off the right carb and clean the trash out out of the needle and seat and decided i would ride today. Well i did my usual starting ritual, kicked and kicked and kicked the most i could get was one cyl would fire but never fully light off. So i resorted to the last ditch effort which is flood it with the ticklers hold the throttle open, and kick it several times. Same deal. Borrowed the plugs out of my S model no real difference, both sets of plugs looked decent i kicked it plugs out with one plug hooked up to see the spark, it looked weak but it was also daylight and also i was literally seeing stars from kicking this damn thing. Put the plugs in kick it until i literally puke. Finally i get it lit off and jump on, tear out get about a half mile away pull the clutch in, goes dead. Pop the clutch get it running, pull clutch in and it dies again, so i turn back around get to my house goes dead in my driveway. i am done. This bike has always been pretty reliable

I am wondering if maybe the ignition box is going dead.. maybe i got it hot on the trip, it’s old… i don’t know what my voltage is at my battery but i turned the headlight on with it not running, it was bright. I just dont know what the symptoms of a failing boyer is. But this bike has never cared it always runs

Oh i jumped on the 750 S, with the plugs out of the 850 and it lit off first kick.
Click to expand...
Clogged pilot circuit.
The carbs told you so.
 
No such thing as luck . Take a banjo string or thinnest guitar string and after you spray into , with the pilot jet screws out , jab/spin it about as deep as you can feed it in. Let the carb cleaner spray work in a bit and afterwards . Re-insert screws 1 1/2 turns out . Try again .
 
Verify strong spark . Fuel off . Pull both plugs . Re - insert plug caps to plugs . Rest plugs on top fin , hold the threaded section ( S ) there with clips .
Your hot wire bypass to Boyer white wire provides the power . Battery must be strong . Voltmeter can tell you , should read 12.5 ish or more . Boyer needs a good battery and a good ground . Kick over the bike in a dark area and observe the spark plug electrode tips for a white-blue spark . Remove hot wire if so ( good ) , reconnect original fused wire at harness and try again , plugs out and clipped to upper fin. No good spark now tells you it's in the total electrical system .
As for fuel , the pilot jets are a known problem with clogging up if sitting a long time .
 
Torontonian said:
Verify strong spark . Fuel off . Pull both plugs . Re - insert plug caps to plugs . Rest plugs on top fin , hold the threaded section ( S ) there with clips .
Your hot wire bypass to Boyer white wire provides the power . Battery must be strong . Voltmeter can tell you , should read 12.5 ish or more . Boyer needs a good battery and a good ground . Kick over the bike in a dark area and observe the spark plug electrode tips for a white-blue spark . Remove hot wire if so ( good ) , reconnect original fused wire at harness and try again , plugs out and clipped to upper fin. No good spark now tells you it's in the total electrical system .
As for fuel , the pilot jets are a known problem with clogging up if sitting a long time .
Click to expand...
Thing is it hasn’t sat for any length of time. I have owned it nearly 4 years and has never gone over 3 weeks without being ran if not ridden. The gas has never had a chance to go bad. Not that i disagree with the rest
 
A clogged carburator passage doesn’t just occur all of a sudden. It builds up after multiple 3-week layovers, including layers of crud on the needle.
To avoid it, run the bike with fuel off until it dies. Drain the float bowl. Remove the air screw and squirt carb cleaner into the hole. Some disagree,
but I always add fuel treatment to the gas I use in all of my small engines. Not that fuel is your problem. I’d be looking at your battery. Just because the lights are bright and a voltage meter reads “full”, that doesn’t mean your bettery is good. Take it to a battery store and have it load tested.
 
lazyeye6 said:
A clogged carburator passage doesn’t just occur all of a sudden. It builds up after multiple 3-week layovers, including layers of crud on the needle.
To avoid it, run the bike with fuel off until it dies. Drain the float bowl. Remove the air screw and squirt carb cleaner into the hole. Some disagree,
but I always add fuel treatment to the gas I use in all of my small engines. Not that fuel is your problem. I’d be looking at your battery. Just because the lights are bright and a voltage meter reads “full”, that doesn’t mean your bettery is good. Take it to a battery store and have it load tested.
Click to expand...
That’s actually a habit I have had for years. I cut fuel off when i turn on my street and let the bike die. Or even when i pull in a parking lot to prevent fuel boil
 
1. Most likely clogged pilot. I've had so many issues I drain the carbs after every run, even If I'm going to ride the next day.
Because if i don't, it sit and it's an issue.
2. Low battery voltage. Check with multi meter.
3. Boyer connections do fail at the stator.
Inspect wires at stator.
4......
 
No need to be kicking it like you did. If no joy after 5-10 tries, gotta start troubleshooting/testing stuff.
A voltmeter can tell you if batt is low and it there is a connection issue. Good sparks at plugs can tell you boyer is working. Plug condition can tell you if lean or rich and thus if there is a carb issue.
Original wiring and poor connections can make for lots of trouble.
 
Tornado said:
No need to be kicking it like you did. If no joy after 5-10 tries, gotta start troubleshooting/testing stuff.
A voltmeter can tell you if batt is low and it there is a connection issue. Good sparks at plugs can tell you boyer is working. Plug condition can tell you if lean or rich and thus if there is a carb issue.
Original wiring and poor connections can make for lots of trouble.
Click to expand...
Well if it wet sumps it can be a hard start, also it kept barking like it wanted to start, I’m stubborn and my thinking was once it finally lit off and warmed up it would he smooth sailing.
 

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