Hard hot start

[Rydrhard]

I have an 09 K1300GT that won't turn over when the weather is hot and the engine is hot. The cure is to install an additional battery and starter relay harness P# 1241 8532 735 my problem is I have to take the air silencing box out to install the harness. There are 4 clamps holding the box to the throttle bodies and 2 clamps holding vent hoses. I don't know how to remove these clamps. Are they cut off and replaced with aviation type? Is there a pair of pliers to release them? Has anyone else done this fix?

[Dennis Andress]

My 09 K1300 S did that too. The fix for me was to replace the battery. The OEM battery sucked rotten beer soaked eggs. I was left on the side of the road a few times, waiting for the engine to cool down a bit. The battery died when it was about a year old and was replaced under warranty. The replacement battery still has trouble when the engine is hot. But if the starter stalls on the first try it always works on the second. Keeping the battery fully charged makes the problem go away.

 

Hacking up the airbox is just going to make the bike run poorly. Shop for a battery with more cranking amps, yet one that will still fit. Shorai will likely be my next battery.

[Rydrhard]

I am not cutting the air box just the clamps if I can't find a way to release them. My battery was tested and checked out fine. The voltage drop on the starter relay wire and battery cable is too high when this occurs. The dealership got this bulletin from BMW.

[Dennis Andress]

Without looking at the clamps themselves, my experience on past bikes has been that they need to be cut. You could replace them with just about any clamp, but I prefer the OEM clamp as they are best sized to the diameter of the intake tubes. And any other design of clamp tends take up too much space. The OEM clamps require a special tool to install, but the tool is available and cheap at most auto parts stores.

 

What you said about the voltage drop across the cables and starter relay is interesting. Someday I'll take a close look at mine to make sure the terminations are clean and tight. Yet, that kind of voltage drop is probably present in any starter circuit, and shouldn't matter as long as the battery has enough volts to begin with. I know that when my starter stalls my radar detector resets. I take that to mean battery voltage dropped to some absurdly low value - because the battery ran out of amps.

 

 

[Rydrhard]

You are right , if the GPS resets you ran out of power. That's a battery. I don't have anyway to see if the power runs out at the time it stalls the starter..if the battery can produce for example 100 amps. The starter say draws 50 amps on a normal start. On a hard start the starter draws 80 amp but the cables can only allow 70 amps then the starter can't force the engine past the stall condition. If the cables can easily carry 120 amp then the engine can't stall the starter. That is my thought on how to solve this.. I hope?

[Dennis Andress]

The cables can drop voltage, not restrict current flow. If there were, say, just .5 ohms resistance in the cables, then 80 amps (I) across .5 ohms is a 40 volt drop (80 * .5). More than the battery puts out. Which can't be right. But assuming 20 amps, across the same .5 ohms, gives us a 10 volt drop (20 * .5), leaving just 2 volts at the starter. I think a more realistic resistance would be .1, or at most .2 ohms. Minor and insignificant BS if you ask me. Reality is: the battery doesn't have enough moxie to overcome the engine's 13:1 compression ratio.

 

A DC motor will draw maximum current at zero RPM. That's when my Radar detector resets. Maybe you could see if your's does the same thing by duplicating the problem with the battery cover off. Then hook up a volt meter, or even a 12v test light, across the battery terminals and see what happens when the starter stalls.

 

Dennis

 

 

Ohm's Law

[racer7]

BMW uses light gauge wires in a lot of the bike but have the really used such a low gauge in your K1300 that it can't carry starter juice acceptably.

I don't have any such problem ith my K1200 but then it also has an Odyssey, not BMWs marginal stock batteries

I own an RT which uses the same battery. In that bike, the BM stock battery is infamous for barely being able to crank the bike if it has dino juice in the sump and the weather is cold....

[Dennis Andress]

BMW uses light gauge wires in a lot of the bike but have the really used such a low gauge in your K1300 that it can't carry starter juice acceptably. ....

 

I don't think so. At least in the case of both mine and Laney's K1300 Ss. Both of our bikes had the stalling starter problem almost from day one. And the problem went away on both bikes when the OEM batteries were replaced. My bike sits a lot, working at home has really reduced my ridding time, because of that my starter will stall if I don't plug in the battery tender every couple of weeks. Laney commutes about 40 miles a day and never has the problem.

[Rydrhard]

I took my bike from Calgary to Santa Monica pier via Route 66 in September. When I got into the southern states the weather got into the 80F then I would have to hit the starter 3-4 time after a hot soak of 15 - 25 minutes before the engine would start. As soon as I got back into Oregon, B C and Alberta no problems starting anytime. I parked it October 15/12 and never started it again until March 7/13. Cranked 2-5 seconds and it was running.. That battery seems pretty strong to me. BMW says cables are the cause of the hard start hot, I'm changing the cables from the battery to alternator/starter and starter relay. I will be going have hot weather this summer if it hard starts then.. If it does then the battery goes.. A waste of time and money changing the cables. You guys are right, BMW wrong, I'm out $160.00

[Dennis Andress]

Now you gave me something to think about. Laney's bike had an electrical fire last year. While it's best that I don't discuss what, how and why on this forum, the result is her bike has a brand new wiring harness. I wonder if that came with higher gauge cables for the start...

 

Please check back here after your trip and let us know if the problem is solved.

 

Dennis