Will a low battry keep an XS11 from starting?

[crazy steve]

...So next I suppose is to check the grounds and get a new solenoid...

One other thing to look for before you spring for a new solenoid; do carefully check/clean all your connections, but if that still doesn't fix it, check for 'hot spots' on your cables. The factory wire lugs are crimped on, and sometimes corrosion can get inside the wire insulation and eat enough of the wire away that it won't have enough cross-section left to carry full current. The wire will check fine for continuity and may look ok, but when you pull a heavy load on it, it will get warm at the bad point. The wires will heat under a heavy load anyway, but the bad spot will be hotter. If you find evidence of semi-melted insulation on any of the cable ends, that's another sure sign of a bad cable.

'78E original owner

[crazy steve]

Oh yeah.... one more thing. To do a 'farmer check' on the solenoid (to see if it's internal contacts are bad), just take a pair of pliers and use them to 'grip' the two big bolts. You don't even have to turn the key on. If the starter spins good, bad solenoid....

And don't use a real good pair of pliers, as there will be a few sparks. You could even use one of your jumper cables.

'78E original owner

[Larrym]

Old McDonald had Wisdom

Oh yeah.... one more thing. To do a 'farmer check' on the solenoid (to see if it's internal contacts are bad), just take a pair of pliers and use them to 'grip' the two big bolts. You don't even have to turn the key on. If the starter spins good, bad solenoid....

And don't use a real good pair of pliers, as there will be a few sparks. You could even use one of your jumper cables.

'78E original owner

That's a good technique, Crazy steve. I've seen it done before but I've never been able to bring myself to do it. All that arcin' and a-sparkin' always startles me: I Just can't get past the flinch reflex.

I've never tested a 9-volt battery by sticking it on my tongue either. I just can't man-up and do it.

I think I'm over-compensating for that by riding/owning a superbike....(sigh.)

.

[clcorbin]

Sorry, but you're one of the many. If you understand electrical theory, what the system is on makes no difference. As Cy said, current is always (with one exception) controlled by voltage and resistance. No matter how many amps are available, the circuit will only draw what it needs.

I = V/R. Pretty simple equation, isn't it?

The one exception? Motor loads; as voltage goes down (and load doesn't), the motor will draw more current in an attempt to do the same work. If you've ever burned up an electric weedeater with a too small/long extension cord, this is why....

This only applies to an AC induction motor, aka "Synchronous" motor. They have a slip angle between the AC voltage coming in and the rotation speed of the rotor. As the voltage drops and the load stays too high, the slip angle increases. Due to the induction of the motor, this causes the current draw to increase and this extra power gets dumped in the windings as heat instead of turning the rotor. Slip it enough long enough and the insulation burns off the windings and they short out and/or catch on fire.

A DC motor just slows down. It is a pure resistive motor, so current follows the I=V/R. The winding resistance is fixed, so as the voltage drops, so does the current. As the current drops, so does the motor speed. This is exactly how you control the motor speed on a mechanically commutated DC motor.

Does this make any difference here? Not a bit to anything other than the starting circuit. You could damage that, but only if you run it contiunously for too long. Even the smaller bike battery has enough current to do this, it'll just start a smaller fire. We all know better than to do that, right?

Exactly. About the only other thing I would worry about when jumping a bike with a very dead battery is that you CAN damage that battery if you jump it with a much larger battery as the larger battery will be able to charge the small one faster than the small one should be charged. Usually, this will only be an issue if the bike's battery is really dead and you manage to get a REALLY good electrical connection to the battery. (aka: very low resistance) Normally, this more time than you spend jump starting a bike.

Of course, the fact that you ARE jump starting it indicates that you might have a problem with the battery in the first place (general case, not necessarily this case!), so damaging the battery (more than it already is) isn't that big an issue for me.

[Mashermoto]

Lots of good advise out there. I want you guys to know that I'm listening to all of it...and I am keeping a good attitude. In fact, I'm home from work today due to a bit of a cold, and I'm really bored. So this would be a good time to take a short break from the trouble shooting and run off down a rabbit trail. Why not...we have already had some Alice in Wonderland metaphor about rabbits from Larry And...after some ramblings...I'll get back to some XS question. So hold on...this is going to be a long post

Here is a little background on 'ol Masher.



Back in the day I once did a bit of racing. Some speedway, road racing, very little motorcross, but mostly flat track. This is a picture of my oldest brother David on his Trackmaster Triumph 750. His nick name is now D.L. McSwain...don't ask why...I think there was alcohol involved I'm not sure where this picture was taken. I thought it was the Oklahoma City state fairground, but the background doesn't look right. My avatar is actually a sketch from a picture of DL on this same bike. The avatar picture is from the Louisville mile track. From what I understand, Louisville was such a large and smooth track that the riders wouldn't fully shut off the throttle going into the turns. Rather they would roll it back, set up into a slide, and get back on it again. Had to be a cool feeling DL followed the circuit back then, which was about 40 years ago. Just before the oil embargo Flat track was a fairly big motorcycle sport. DL made it up to national numbers 89, 78 and about 50 when he quit half way through a season on an Yamaha 750 twin.



Here is a picture of brother Jay that was taken in the summer of 2009 somewhere at a short track in Kansas. Jay raced the AMA circuit back in the day also. In this picture he is riding the old fart class Don't ask me why someone in their mid-50's takes up flat tracking again...that's just my brother

As for me...well I did OK in the sand lot league But never made it to the big time...I'm the one that crashed and broke bones

Here is some of my recent projects.



This is a 1978 XS650 that I bought from a guy in Kansas and converted it into a street tracker. Guys...this bike was way cool I put every trick you could find on the XS650 Garage USA forum into this bike. That's a sportbike monoshock swing arm. The engine is a 750cc big bore, 277 re-phased crank, ported head, Webcam 59 grind cam, modified rocker arms, 34mm Mikuni carbs, right side exit reverse cone mufflers and a whole lot more. This is a mocked up picture showing the paint scheme I was going to use. Unfortunately some crack heads stole this bike while I was in the garage spraying paint



I did get to ride it a little around the neighborhood before it was stolen...wow was that bike awesome Notice the XS1100 Special front end



Speaking of electronics...here is the ignition system that Pamcopete on the XS650 forum designed for me. Pete is kinda like some of you guys here that when he gets cut he bleeds electrons Pete told me through the forum what components to get and I put them together. This system uses a Mallory automotive ignition module that is triggered by an optical sensor. That copper disk is what triggers the ignition fire. Pete used a Gerber baby bottle lid for his original design, I found a copper end cap used for plumbing and cut it down to specs. Because I had a 277 re-phase engine and I also wanted to eliminate the wasted spark, Pete designed a converter for me that used some diodes and other stuff I don't even remember now to achieve that goal. Otherwise, for a normal engine, what you see is the complete ignition. No TCI or anything. The really cool thing is that it only cost somewhere around $70. MikesXS.com now sells a more commercial model of the Pamcopete units on his web site for a very reasonable price.



Then I ran across this 1978 XS750 triple in a garage sale not far from my house. I really wasn't looking for a bike like this, but I owned a new one back in the day and put a 900cc big bore in it. Ran really good This one was in pretty good shape. I just had to clean the varnish out of the carbs and brake system. I actually hadn't rode a street bike since I sold my original 78 XS750 triple. So I used this one to get my motorcycle licenses again. I think this one is also the only bike I EVER sold for a profit



This is a 1980 or 1981 XS650 that I bought on Ebay and drove to Salina, Colorado to pick up. That's a small town at the base of the Rockies. In fact, the guys back door view was the Rockies I made this one to just be a sexed up street bike. The engine is about the same as the street tracker except it wasn't re-phased and used the stock electronic ignition. I also used one of those new MikesXS.com big bore kits that came with a pre-bored cylinder. Notice the extra large cylinder fins?



I kept it feed and watered for a few months. It now has a new home in Kansas. I kinda miss the old girl



So now I'm down to one This is the 78 XS1100 we are working now. I got it with the engine out of the bike, but most everything else still bolted on. It also came with some spares from a crashed 1981 Special that the PO was going to use as parts.

So there you go...that's my projects from the last couple of years. Like I said a few hundred words ago, I'm keeping a good attitude about this bike build...but I do yearn for the day when I could just go to the bike shop and get a new part slid across the counter Seems like with these old bikes you either have to order online and wait or stumble into that thing at Home Depot that just happened to fit perfect

During lunch, I'll go have that battery checked at a different auto parts store and see if I get the same answer.

Later

[crazy steve]

This only applies to an AC induction motor....
A DC motor just slows down. It is a pure resistive motor, so current follows the I=V/R. The winding resistance is fixed, so as the voltage drops, so does the current. As the current drops, so does the motor speed. This is exactly how you control the motor speed on a mechanically commutated DC motor.

Sorry, not true. Any electric motor, whether it's AC or DC, operates on the same basic principles. If you calculate current draw for the Yammy starter assuming it's 'purely resistive' using the service manual figures, what you'll come up with is this:

It's series wound, so you add the field and armature numbers: .007 + .01 = .017 ohms. Plug this into the equation and you get I=12/.017. This comes out to over 700 amps! I don't think that little battery and skimpy wiring can deliver that....

The factor that makes it all work is impedance, or more specifically, inductive reactance. This is also measured in ohms, and would be added to the circuit resistance. This also increases with frequency (in this case, motor rpms), so the faster the motor spins, the more impedance i.e. 'resistance' you have. Larry got about 80-90 amps in his test, so using R=V/I, you get: 12/90=.133 ohms. This is almost 8 times the 'measured' amount, and the difference is the impedance. As a side note, this also limits maximum motor rpm, so you can't have a 'runaway' motor.

Another way to look at this is via the 'power' equations, and this will show why current goes up for a given load if voltage goes down. One HP = 746 watts. So to produce 1 hp with 12v; P/V=I, or 746/12=62.16 amps. Lower the voltage, amps go up; 746/9=82.88 amps. So good connections become very important if they're reducing the voltage to the load.

How much HP does the starter motor produce? Using Larry's numbers, just a bit less than 1.1KW, which is very typical of a big-bore bike starter.

I'm not trying to bust anybody's chops here, but a lot of you seem eager to spend Mashermoto's money before he's eliminated all the possibilities; I've never seen throwing money at a problem as being the best way to go about it...

'78E original owner

[cywelchjr]

Sorry, not true. Any electric motor, whether it's AC or DC, operates on the same basic principles. If you calculate current draw for the Yammy starter assuming it's 'purely resistive' using the service manual figures, what you'll come up with is this:

It's series wound, so you add the field and armature numbers: .007 + .01 = .017 ohms. Plug this into the equation and you get I=12/.017. This comes out to over 700 amps! I don't think that little battery and skimpy wiring can deliver that....

The factor that makes it all work is impedance, or more specifically, inductive reactance. This is also measured in ohms, and would be added to the circuit resistance. This also increases with frequency (in this case, motor rpms), so the faster the motor spins, the more impedance i.e. 'resistance' you have. Larry got about 80-90 amps in his test, so using R=V/I, you get: 12/90=.133 ohms. This is almost 8 times the 'measured' amount, and the difference is the impedance. As a side note, this also limits maximum motor rpm, so you can't have a 'runaway' motor.

Another way to look at this is via the 'power' equations, and this will show why current goes up for a given load if voltage goes down. One HP = 746 watts. So to produce 1 hp with 12v; P/V=I, or 746/12=62.16 amps. Lower the voltage, amps go up; 746/9=82.88 amps. So good connections become very important if they're reducing the voltage to the load.

How much HP does the starter motor produce? Using Larry's numbers, just a bit less than 1.1KW, which is very typical of a big-bore bike starter.

I'm not trying to bust anybody's chops here, but a lot of you seem eager to spend Mashermoto's money before he's eliminated all the possibilities; I've never seen throwing money at a problem as being the best way to go about it...

'78E original owner

+1 on the impedance. From the symptoms I have heard described, they match what mine was doing after I put the replacement engine in. I had NOT swapped any wires, and was using the same ignition parts from the old engine, and it would just backfire once in a while. After 2 weeks of fighting with it (and making sure I had a fully charged and good working battery) it was suggested that I swap the primary coil wires as someone else had run into the same problem. So I took the tank off, and swapped the wires. I didn't even put the tank back on because I didn't expect it to work. I pushed the starter button and it fired almost instantly. I don't know how it happened, but somehow the coils ended up electrically swapped. It's a 2 minute test, and costs nothing, and swapping the primary wires on the coils just might get it to start.

Give it a try, the symptoms sound exactly like what was happening with mine, and that was the fix.

[motoman]

Just kinda briefly reading these threads and Backing up a ways, I see Ivan diaganosed your problem. Trust what he says, you have a bad battery at the least. At the parts store, they try to be of help, but don't have a clue really when it comes to testing and load testing batteries. Noticed in one of Mashers's threads he said that voltage kept dropping while trying to start. This is a sure sign of a shorted cell, no matter what the static resting volts are. So, in effect he load tested the battery witout having a good carbon pile load tester. Not having a load tester other than the bike, what you can do for your own satisfaction is remove all the fill caps on the battery and watch the cells while cranking it over. If a cell has the least sign of bubbleing, that likely is a shorted cell. A PROPER load test, is hard to find someone who REALLY knows how it's done and what the results tell you. Just for example: an automotive type wet cell battery that is rated at say 800cca would be load tested at approx. 400amp for 15-20sec. Normal voltage drop under this load would down to 10.5-11volts. If it holds that for the load time, it is a good battery. When under that same load for the same approx. period of time, it drops to the 10.5-11volts then gradually keeps dropping with that battery being a known charged battery, it can be for the most part condeemed. There are three more test you can do for complete satisfaction that battery is bad, but for the most part, PROPER load testing will tell the tale. May be retired, but still remember most of this stuff, as I was certified in charging and starting systems on all types of equip. and autos. Also our shop foreman was anal to the point of wanting written documentation of test results, including load testing individual cells with written doc. before authorizing any parts replacement....and a load more stories as you could imagine! Hope something here can be of help so you will have a dependable scoot for the future!

[crazy steve]

Let's throw one more 'test' out there; Larry mentioned hooking the negative battery cable directly to the motor. Very good idea, but take it one more step and it should narrow where to look for the problem a bunch.

Using your 'jumper' vehicle, hook the negative cable directly to the motor case.

Now, without turning on the key, touch the positive cable to the solenoid connection that goes to the starter. Make sure you have good, bare-metal connections! If you have light-gauge cheapo jumper cables, borrow or buy a good set.

No change? Then the problem is in the solenoid-to-starter cable or it's connection at the starter, a bad starter, a poor ground between the starter case and the motor cases, or you have a mechanical problem in the engine causing it to drag (bummer, but you can't rule this out). To eliminate the cable, try connecting the jumper cable directly to the cable connection at the starter. Pull and check the starter for worn bushings, electrical shorts as per the manual. Clean all surfaces to clean bare metal where the starter attaches to the cases.

Spins fast and sounds like Larry's did in his video? Then the problem is the battery (very unlikely, as hooking a jumper battery to the bike should eliminate that as a cause), the solenoid, or the other cables/connections. By leaving the key off, that takes the ignition as a factor totally out of the equation. The starter should spin the motor properly whether the ignition is on or not (again, watch Larry's video; he disconnected/shorted all the spark plugs).

Do the 'farmer test' on the solenoid, and the results here will confirm/eliminate that as the problem. If you bypass the solenoid and get no change, then you have a problem in the cables/connections.

It's possible that you may have multiple problems, but until you methodically eliminate each possibility, it'll only drive you crazy....

'78E original owner

[Mashermoto]

Oh Man You guys aren't going to believe this...The referees in the replay booth have reviewed the tapes and the ruling on the field is REVERSED Winner winner chicken dinners for all...the battery is BAD

Ok, yesterday I took it to the O'Reilley auto parts store to have it checked. The clerk checked the battery with a hand held device programmed for 350 cca. His initial reading was it was bad. So the manager told him to hook it up on the stress test machine. After about ten minutes it's proclaimed good. So I reported to you that it was good.

Now then, yesterday it read 14 v when I brought it home. This morning it read 12.5 v. Hmmmm

So today I took it to a NAPA store and their hand held device reported it bad. Strike one. So I took it to a different O'Reilley store and they hooked it up on their stress test machine. It reported the battery as bad. Strike two. So I took it to an Autozone store. They used a hand held device that also reported it bad. So three strikes...time to throw this battery in the street.

Well, I really like the maintenance free batteries, but none are available without ordering one. So just to get by I went to Wal Mart and bought an acid fill battery for $45 and a battery maintainer for $20. At least they gave me $9 for my $70 AGM battery Anyway, I'm now only out $56 and should know within a couple of days what the next bottle neck is

Dang I hate messing with battery acid

I'll go charge this new battery up...in the meantime you guys keep hammering out those electronic equations...just don't hammer each other

[crazy steve]

HAH!

Well, that does me tell one last thing.... you need better jumper cables. If they had actually been delivering current, it would have started with a jump.

And make sure you properly activate that battery; charge it for at least 12 hours @ 2 amps, 14-16 hours would be better.

'78E original owner

[Mashermoto]

Steve,

Will do on the battery charge, and yes, my battery cables are old and cheap.

Don't go too far because I suspect I do have other issues. This may just be one in many.

Thanks to all for the help and great discussion. I'll report back when I know more.

BTW, just how did Larry post those videos That would be helpful if I could post something like that. Larry gets an extra chicken dinner for his video

[joceiphus]

I thought your avatar was a drawring of a wolf!
Shows how obsevant I am.

[DGXSER]

I thought your avatar was a drawring of a wolf!
Shows how obsevant I am.

ITs one of those trick pictures...If you look at ti oen way its an old lady...the other way its a vase....or soemthing like that.

[Montreux_Blue]

That's funny.... all this testing, cleaning, denying and it was just a bad battery.