Can a failing battery make an '04 carbed Bonnie run bad?

[msc66]

About a month ago on a whim I bought an '04 Bonnie that had a bad mis-fire. The previous owner had the carbs rebuilt and replaced the igniter then gave up.

Since I've had it all I did was swap the coil over from my '01 which did not help. The bike would start right up and idle ok but after warming up a little it would start running rough and develop a bad pop back through the left carb. It would also just sputter when you tried to give it throttle.

Today I wanted to do a compression test as a matter of course so I went to start it to let it warm up a little first but it spun over slowly then died. I put the battery out of my '01 in it and fired it up. I let it warm up and it seemed to be running much better. It popped back very slightly a couple times but nothing like before. I twisted the throttle and it revved fine. I took it for a 5 mile ride with no issues. Came home and let it idle and no popping.

It doesn't make sense to me but could a failing battery cause this and if so how?

 

[BlueJ]

It's the good old charging circuit that's failing. Probably the regulator/rectifier. It's not charging your battery like it should and thus you're getting weak/intermittent spark. With the new battery, you're running on, well, a new battery, but the charging circuit won't keep it charged enough, so it will wear out faster.

That's assuming it's not something else like loose vacuum hoses or carb boots or some such.

 

[Bonafide]

Mike, not sure if you remember when you were here - but I commented on how dim your headlight was and I tested your battery while your bike was running. I'm suspecting your issues my be related to the stator or more so the rectifier which is a common issue with our bikes. It might be worth it to have someone test your stator and rectifier.

To answer your question, yes .. your bike will run like shit if your battery is failing and/or not putting out the proper voltage necessary to power the electronic ignition system.

 

[JimmyR]

Is the stator an issue with our bikes too? I am replacing the rectifier on mine but didn't know that the stator might become an issue too. I just replaced both items on a 30 year old Suzuki. The rectifier is easy but the stator can get messy. :-( Oh well... could be worse.

 

[Bonafide]

I dont think the stator is a common failure like the rectifier on our bikes. I had to replace the stator on the 03, but only after it the rectifier had a nuclear fail ..

 

[thearcticsea]

Definitely either a bad rectifier, or a loose wire.

When my bike did this everyone said "rectifier" so I replaced it. Didn't help. So I threw in the towel and took it to Triumph. Within 20 minutes they found a wire had come loose from its pin connector inside the headlight and away I went, $80 lighter.

 

[msc66]

Mike, not sure if you remember when you were here - but I commented on how dim your headlight was and I tested your battery while your bike was running. I'm suspecting your issues my be related to the stator or more so the rectifier which is a common issue with our bikes. It might be worth it to have someone test your stator and rectifier.

To answer your question, yes .. your bike will run like shit if your battery is failing and/or not putting out the proper voltage necessary to power the electronic ignition system.

Hey Bud, this is not the '01 that I brought out to your house. It's an '04 that I just recently bought. The battery is definitely junk so I'm heading out to get a new one and then start testing the charging system. it'll be great if this is all that's wrong with it.

 

[whyme]

You guys may have solved my issue... I was wondering if my battery was starting to go and that's why its running bad...I noticed when I turned it over without the tender connected it seemed a little slow.

 

[mikenva]

One other simple thing to look at is the main 30amp fuse some of us have had trouble with the fuse fitting loose in the box everything that goes from or to the battery goes throught that fuse.It can make then run like shit to.

 

[Bonafide]

Hey Bud, this is not the '01 that I brought out to your house. It's an '04 that I just recently bought. The battery is definitely junk so I'm heading out to get a new one and then start testing the charging system. it'll be great if this is all that's wrong with it.

Ahhh .. didnt realize you had two bikes. So the 01 is still running good after the new ignition box? BTW, forgot to PM you and let you know I got the borrowed one back in the mail.