Picked up an 85 650 today

[Option13]

There is a reason that the 650 doesnt charge unless it is @ 2500 RPM or better. My question again: what is that reason? That is an abnormal dynamic, and anything can be corrected. There must be a way to correct it so it charges at idle. It might take a lot of re-wiring, or a bigger magnito, or whatever...but what is the problem that mkes it discharge at idle? Anyone here know anything about electrics?

You can look at it in two ways:
     1. The alternator isn't big enough/doesn't have enough windings.
     2. The alternator doesn't spin fast enough.

I've heard of people, in their own home, rewinding alternators to produce more power. It's apparently pretty tricky though.

Why do you think it needs to be fixed? On cars using underdrive pulleys to reduce the speed of accessories (including the alternator) is a fairly common modification. This reduces electrical overhead by reducing the alternator speed, but frees up horsepower in the process.

Damn, the Japenese are supposed to be good at electrics. How could this of happened?

The engineers decided that they were willing to trade off having excess electrical power at low RPM's to free up some horsepower all across the board. It's only a problem when running lot's of accessories and low RPM. I guess they decided the '83 models went too far and they needed a bit more power. Also, this isn't an uncommon thing for older bikes - people adding a bunch of accessories other than lights is a fairly recent trend. Unless you are hell bent '83on turning an 80's 550/650/700S into a full on Goldwing style cruiser it simply isn't a problem. Everyone talks about it being an issue, but I have yet to hear anyone say "I got stuck on the side of the road" or "I had to jump my bike" and blame a normally functioning charging system on any of these bikes. Anyone who has, well, I'd like to hear about it.


My theory is that the when the 700S came out, they upgraded the 650 to the 700S charging system both as an upgrade and a way of simplifying production. The 700S, 650, and 750 all share fairly similar charging systems if I'm not mistaken. So the '83 650's and 550's (no one mentions the 550's for some reason, even though the engines are identical other than displacement) got the short stick. Barely.

[Option13]

The bike has a little cam chain noise.  Up around 2500-3000 RPM.  Noticeable, but not terrible.  I think I'll ride it for a season as is and if I like the bike enough next fall, I may tear into the engine.  I'm fairly mechanically inclined but have never done engine work.  I think it would be a good learning experience and I'm pretty sure I wouldn't mess something up     I'd be worried most about stripping things out.

Kirk

Unless you are seriously annoyed by it and feel it must be silenced, you really don't need to worry about the cam chain noise. Almost every 650 does it, and it doesn't hurt the engine. There is a fix involving an aftermarket spring. If I was diving into the engine anyway, I would consider it, but until that happens I'm content to live with it.



I know, double post, but I felt the issues comments were too unrelated to have in the same post.

[abigbadzebra]

I know, double post, but I felt the issues comments were too unrelated to have in the same post.

I appreciate the help!

I'd also be more interested in your HID setup if you have a link/info on it.

Thanks!

[Option13]

I actually wrote a fairly detailed install thread. If you have any questions about something I didn't cover about HID's, feel free to ask in that thread or by PM.

[abigbadzebra]

Right on!  Thanks again!

Richmond, VA, eh?  I used to get down in that direction when I lived in Alexandria.  Just for Kings Dominion, though :)

Bike in your avatar looks good.  Got bigger pics?

[Option13]

http://nighthawk-forums.com/index.php/topic,7014.msg104856.html#msg104856

http://nighthawk-forums.com/index.php/topic,7014.msg146682.html#msg146682

[TimmyJ]

The engineers decided that they were willing to trade off having excess electrical power at low RPM's to free up some horsepower all across the board.

How is trading off excess electricity at low RPM's help with horsepower? Ive never heard of such a thing. Horsepower is a creature of displacment, valve lift, and exaust. The spark is the spark, no? Enough to ignite fuel, thats it. I dont see how an increase in spark is going to do much in the horsepower catagory.

Everyone talks about it being an issue, but I have yet to hear anyone say "I got stuck on the side of the road" or "I had to jump my bike" and blame a normally functioning charging system on any of these bikes. Anyone who has, well, I'd like to hear about it.

With a dead battery you can push start it and exceeding 2500 RPM....but if the battery will not hold the charge, you would have to keep it above 2500 RPM at all times to keep it running. Theoretically.


Probebly nobody mentions the 550 because it was only made one year?

[Option13]

The engineers decided that they were willing to trade off having excess electrical power at low RPM's to free up some horsepower all across the board.

How is trading off excess electricity at low RPM's help with horsepower? Ive never heard of such a thing. Horsepower is a creature of displacment, valve lift, and exaust. The spark is the spark, no? Enough to ignite fuel, thats it. I dont see how an increase in spark is going to do much in the horsepower catagory.

You can't make power without a source. The alternator converts some of the engines power into electricity. You would agree that there are more electrical devices on the bike than just the ignition, right? And you would also agree that in order to not violate the laws of physics the electricity that powers those devices has to be converted from some other form of energy and not just spontaneously created, would you not? This power comes from running the alternator off of the engine. The more engine power you convert into electricity, the less power that goes to the rear wheel to accelerate the bike.

With a dead battery you can push start it and exceeding 2500 RPM....but if the battery will not hold the charge, you would have to keep it above 2500 RPM at all times to keep it running. Theoretically.

Only until the battery recharged, and I still don't see why this is a problem. Who push starts their bike to just let it idle?

[TimmyJ]

You can't make power without a source. The alternator converts some of the engines power into electricity. You would agree that there are more electrical devices on the bike than just the ignition, right? And you would also agree that in order to not violate the laws of physics the electricity that powers those devices has to be converted from some other form of energy and not just spontaneously created, would you not?

Nope. The power that the accesories get all comes from the alt/battery. The alt should make enough power easily to power all accesories.

This power comes from running the alternator off of the engine. The more engine power you convert into electricity, the less power that goes to the rear wheel to accelerate the bike.

I dont agree with that at all. It takes little engine power to create more electricity, as long as you have gasoline powering the engine. That is why all modren bikes can put a ton of accessory load on the alt, with no loss of engine power. The key is the word "alt"...is the alt big enough? Does it have enough windings? Evendently not on the 650, that's all I was saying.

I hope this charging issue is not an issue on the 1992 CB 750.

Yeah and on the 550 I know it wasnt mentioned because it was only made one year. In Wiki, the modren UJM or "standard" started with the CB750 inline 4. Wiki had the Nighthawk inline 4 honda's listed as the 650, 700, and 750. They forgot about the 550, as it was the smallest inline 4. Sadley, because of it's one year production, the 550 is often overlooked.

I just want to add the 650 is a damn fine looking bike, and Im glad the charging issue isnt much of an issue.

[Option13]

Aaaanndd you don't have to charge a motorcycle battery, unlike every other battery powered device you own? Or are you saying you have to plug in your bike every night to recharge the battery? That electricity comes from the alternator, and the alternator draws power from the crankshaft.

The alternator isn't magic. It converts rotational energy from the crankshaft into electricity. Spin it faster or make it bigger, either way, you make more electricity. That energy, no matter how insignificant you may feel it is, comes from somewhere.

Any power that doesn't go to driving rear wheel is lost acceleration. A bigger alternator wasn't deemed necessary, and you know what? The bike works just fine without it.  If it makes enough energy to run the bike in all anticipated conditions, why make it bigger?

I dont agree with that at all. It takes little engine power to create more electricity, as long as you have gasoline powering the engine. That is why all modern bikes can put a ton of accessory load on the alt...

If it takes power, it takes power. And you can't just "throw more gas on it". The engine has a peak output. Any power spent doing anything else other than accelerating is lost performance. Not to mention that excess power generated by the alternator has to go somewhere, and that somewhere is into the atmosphere. The regulator dissipates the excess electricity as heat.

The keyword being modern. The 650 was designed almost 30 years ago. If you think the charging problems on the 650 are bad, then you should look into how little extra electrical overhead 70's bikes have. From the view of the designers, it didn't need to make more electricity. That would involve making a larger alternator and a larger rectifier to shed more heat. Why overbuild something that adequately fulfills it's forseen role? It was built for the world of 28 years ago, not today.

[abigbadzebra]

Aaaanndd you don't have to charge a motorcycle battery, unlike every other battery powered device you own? Or are you saying you have to plug in your bike every night to recharge the battery? That electricity comes from the alternator, and the alternator draws power from the crankshaft.

The alternator isn't magic. It converts rotational energy from the crankshaft into electricity. Spin it faster or make it bigger, either way, you make more electricity. That energy, no matter how insignificant you may feel it is, comes from somewhere.

Any power that doesn't go to driving rear wheel is lost acceleration. A bigger alternator wasn't deemed necessary, and you know what? The bike works just fine without it.  If it makes enough energy to run the bike in all anticipated conditions, why make it bigger?

I dont agree with that at all. It takes little engine power to create more electricity, as long as you have gasoline powering the engine. That is why all modern bikes can put a ton of accessory load on the alt...

If it takes power, it takes power. And you can't just "throw more gas on it". The engine has a peak output. Any power spent doing anything else other than accelerating is lost performance. Not to mention that excess power generated by the alternator has to go somewhere, and that somewhere is into the atmosphere. The regulator dissipates the excess electricity as heat.

The keyword being modern. The 650 was designed almost 30 years ago. If you think the charging problems on the 650 are bad, then you should look into how little extra electrical overhead 70's bikes have. From the view of the designers, it didn't need to make more electricity. That would involve making a larger alternator and a larger rectifier to shed more heat. Why overbuild something that adequately fulfills it's forseen role? It was built for the world of 28 years ago, not today.

Hey, I'm 29.  What you trying to say   













 

[TimmyJ]

Any power that doesn't go to driving rear wheel is lost acceleration. A bigger alternator wasn't deemed necessary, and you know what? The bike works just fine without it.  If it makes enough energy to run the bike in all anticipated conditions, why make it bigger?

Absolutley not!!!!!! Any power not going to the rear wheel is lost power? It's so tiny, it's insignificant! What is it, 3 or 4 HP for a bigger alt? One that charges at idle? If they need to make up that 3 HP, just pop up the pistons a bit for better compression, or put a higher lift cam in or whatever. Why skimp on alt power which can be a dangerous move, espicially for people in cold weather climates? This is why I made the gasoline comment...as long as it has a supplement energy source (gas), then the engine can be made to make up the small HP loss.

The keyword being modern. The 650 was designed almost 30 years ago. If you think the charging problems on the 650 are bad, then you should look into how little extra electrical overhead 70's bikes have. From the view of the designers, it didn't need to make more electricity. That would involve making a larger alternator and a larger rectifier to shed more heat. Why overbuild something that adequately fulfills it's forseen role? It was built for the world of 28 years ago, not today.

So 28 years ago they didnt have the technology to make a strong enough alt? I was around 28 years ago...they did have that technology. Other bikes made plenty of power. I think Honda was trying to play it on the cheap for some reason, I dont know.

[Option13]

Absolutley not!!!!!! Any power not going to the rear wheel is lost power? It's so tiny, it's insignificant! What is it, 3 or 4 HP for a bigger alt? One that charges at idle? If they need to make up that 3 HP, just pop up the pistons a bit for better compression, or put a higher lift cam in or whatever. Why skimp on alt power which can be a dangerous move, espicially for people in cold weather climates? This is why I made the gasoline comment...as long as it has a supplement energy source (gas), then the engine can be made to make up the small HP loss.

68 / 72 = 0.944444444.

That's more than a 5% horsepower loss. Not insignificant at all.

If they could so easily make more power, why wouldn't they do it in the first place? Probably because it's not that simple. The 650 was considered to have quite a high specific output back in it's day, almost as good as the latest and greatest water cooled V4 bikes that were becoming the norm.

You still haven't told me why it needs to charge at idle. I've never heard of anyone being stranded. Continuous idling is not an anticipated condition for an air cooled motorcycle. I can't think of anyone that relies on their motorcycle as a source of transport in these climates that you speak of, nor anyone ever having suffered a terrible fate because of any motorcycle not having an alternator big enough to power a house.

So 28 years ago they didnt have the technology to make a strong enough alt? I was around 28 years ago...they did have that technology. Other bikes made plenty of power. I think Honda was trying to play it on the cheap for some reason, I dont know.

Or maybe they didn't have the technology that made people want to charge their cell phone and GPS while on the bike, or want to plug in grip heaters and other farkles that have become so common.