Overheat: bike wont start?

[TurboMike]

If you want the whole funny story, its here:

http://www.katriders.com/forums/viewtopic.php?p=452574#452574

But just the technical question:

I'm in stop dead traffic maybe moving a few feet every minute or so, for miles, its a 90 degree day. I can feel the bike making the chugging weak sound low in 1st that I get when the bike is too hot/overheating. Finally get fetup and start lanesplitting to get to the next exit. At one point I didnt like the mirrors of two SUVs I was about to squeeze through and did a quick brake/clutch and the bike stalled. Hit the starter right away and the bike bearly turned over. Very slow and weak but restarted after a turn or two (luckily). Totally felt like a dead battery. Right around the next corner was the accident and traffic was non existant and I was at speed again.

20 min later same thing happens on another highway, stop dead traffic. This time I go to local streets and a cop pulls me over, and I'm sitting there (key out) for 20 min while he checks my paperwork. Get back on the bike, and it turns over a half a turn and is DEAD. Try again and it wont turn over at all. I had to get pushstarted, then the bike started fine. Only drove a few blocks and then parked the bike for hours. I assumed it would still be dead and came with a bunch of friends to pushstart me to get home, but surprisingly the battery was very strong and the bike started as if it had been on a charger all day. Very weird. Thats when I stopped assuming is was my battery or generator, and that maybe the overheat was keeping it from starting?

So the question here is, does the bike not want to turn over enough that the starter cant turn over the bike when its in an overheat condition? The only other explanation I can think of is when the bike wouldnt start I had heavy chains under the seat to chain the bike to a pole when I parked it, and its possible they could have been contacting the + on the battery and shorting it. Thats the only think I can even think of other than it not starting from overheating. Unless possibly the battery was hot and weak, then went back to power when it cooled down? Its a 99+ 750 which I think comes with a battery not effected by temp? Duno.

[steves]

Is your battery low on water? The heat might have cause some of it to evaporate...

[jgalar]

At idle speed I would doubt that your charging system is putting out enough amps to cover running, lights and charge the battery. At low engine speeds you may have drained the battery, but after running the rpms up a bit you could have charged the battery enough to get normal starting.

If the problem is from overheating it is most likely pistons starting to seize.

[TurboMike]

I was shocked that after getting push started, the bike ran maybe 5-10 min for a few blocks then was parked for hours, yet started up normally with an obviously well charged battery. Thats what really made me confused between it being a charging/battery problem or a symptom of overheating.

I'll check the battery for water, I think I remember it being sealed.

[evol]

when a bike i had would overheat it would take a couple of goes to get it running again, it wouldnt fire up right away, and the heat never affected the battery, so to me it sounds as if it could be something to do with the battery

[The CyberPoet]

(A) A really HOT-HOT battery produces less power. Unlike a cold battery that regains it's previous power when warmed, a hot battery won't have it's power level won't return to normal when the battery gets back to normal temp (it will have lost some of it's storage capacity). Oh, and Steve means well, but your battery is maintenance-free and has no option to add water.

(B) An hot engine will evaporate some (or all) of the fuel in the carbs when it's parked. When you go to start up again, there may not be sufficient fuel to actually get it started (easy solution: turn the petcock to PRIME for 15 seconds and then back to ON, then start the bike).

(C) You never mentioned whether you turned the bike to off or to park when the cop pulled you over -- it's possible that between the extra-hot battery and the bike being in park, you drained the battery down too low for it to start the bike.

(D) Overheating won't cause the heads to warp (unlike water cooled bikes), but ignoring overheating may cause something to seize. I highly recommend you stick to Mobil 1 VTwin 20w50 for at least the rest of the summer, and consider installing one of my oil temp gauges in your bike so you know exactly what's going on (i.e. - when you need to stop/find an alternative route/etc).

(E) General rule: if traffic isn't moving (or moving as slow as you'd walk), put it in neutral and kill the engine. When traffic moves slightly, you can walk it forward...

Good Luck!
=-= The CyberPoet

[TurboMike]

A) I cant see the battery completely recharging in the 10 min ride from the cops to where I parked all day, so that would rule that out

B) Bike wasnt turning over, so I dont think that was the problem

C) I made sure the key was out

D) I keep telling myself to pick some up, since I'd have to go to a bike dealer (only thing local) I've been lazy about it

E) Ugh I cant see doing that in NYC traffic. At that point lane splitting in safer (IMO).

The more replies I read here, the more I think my chains I had under the seat were shorting the battery. Still wouldnt explain how it recovered so quickly. Weird car and bike mysteries are the story of my life tho.

[The CyberPoet]

C) I made sure the key was out

The key will come out in both the Park and the OFF positions, so removing the key does not gaurantee that you had the running lights off.

Q: Doesn't your positive terminal on the battery have a red rubber cover?

Cheers,
=-= The CyberPoet

[TurboMike]

My key has to be jiggled to get over to park, so I know thats was not an issue.

Yes it has a red rubber cap, which is permanetly in an up position because I have wires for my charger bolted right to the battery terminals. My list of things to do is to tape it down.

[bswasey]

These are small batteries, so the life expectancy is rather short when compared to a good car battery. Extreme that can drain a battery and I have seen times when a battery was almost completely drained, letting it sit for a couple minutes allowed gave it enough juice to turn over an engine (a 350 V8 in this case). 10 minutes is plenty of time for the battery to cool down. I'd recommend taking it to a parts store and having it tested. Also, I believe the Kat has a generator as opposed to an alternator so when the engine is idling, the generator isn't putting much power back into the bike so it sounds like a combo of the 2 thats causing it.

[ThAzKat]

C) I made sure the key was out

The key will come out in both the Park and the OFF positions, so removing the key does not gaurantee that you had the running lights off.

Q: Doesn't your positive terminal on the battery have a red rubber cover?

Cheers,
=-= The CyberPoet

did that once

OK, it is possible for a engine (oil/air cooled) to get so hot they will not start immediately. I was tuning on mine a while back and it quit running. Battery voltage was good but bike would hardly crank over. It did not seize or hurt anything. I was able to start the bike right up in a couple of hours or so. I have not done anything to the bike because of this since and that was 3 years ago. Bike runs great to this day.

[The CyberPoet]

OK, it is possible for a engine (oil/air cooled) to get so hot they will not start immediately. I was tuning on mine a while back and it quit running. Battery voltage was good but bike would hardly crank over. It did not seize or hurt anything. I was able to start the bike right up in a couple of hours or so. I have not done anything to the bike because of this since and that was 3 years ago. Bike runs great to this day.

In theory, it's possible that parts expanded to the point that they seized temporarily (such as the pistons in the cylinders or the cams in their journals), but it's very unlikely, since it wouldn't keep the starter from trying (you'd hear the difference). Much more likely is that the battery was simply really weak from the heat.

That's the good thing about an oil-cooled bike: let it cool down, and everything usually goes back to being as it should.

Cheers,
=-= The CyberPoet

[ThAzKat]

Yes, you are right CP, if it were a water cooled bike you would be replacing all kinds of crap.

[jgalar]

The aluminum piston expands at about twice the rate as the sleeve does. It is quite possible that the piston started to seize. I've overheated and seized engines before and have seen plenty of signs of piston seizing in engines that I have overhauled. You may not notice any change in performance after a heat seized engine has cooled off. I've torn down quite a few engines that had signs of pistons seizure, but gave the owner no indications of performance problems.

[TurboMike]

Ugh it happened again. Bike can sit in my garage for over a week then crank for 8-10 seconds before it starts (my bike has always been a slow starter) and the battery will be fine and crank it out fast. Today I went for my NY inspection and bike was sitting 15-20 min after a hot run, and it cranked for 2 seconds and was dead. Had to pushstart it again. Then a 10 min ride to work and it was sitting for hours, then started fine.

So my battery seems to be opposite normal. It holds power fine for a week and will start the cold bike fine. But a hot bike its dead and wont start it.

I know the battery is old anyway so I'm just going to replace it and see what happens.