1985 BMW K100rs Won’t turn over - BMW Luxury Touring Community
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post #1 of 5 Old Jul 22nd, 2019, 1:45 am Thread Starter
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1985 BMW K100rs Won’t turn over

Hi I bought a 1985 bmw k100rs in the spring. I will admit I haven’t been riding it as much as I should but up until yesterday it was running great. It sat for a week due to inclement weather and I attempted to start it yesterday morning and it just cranks will not turn over. Thought maybe the battery needed a boost and had the tender on it all day still no start. Battery is brand new as of last month I just did the spark plugs at that time as well was wondering where to go from here.. Any help would be most appreciated
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post #2 of 5 Old Jul 23rd, 2019, 6:41 am
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Re: 1985 BMW K100rs Won’t turn over

Do you hear your fuel pump running when you turn key on before pushing starter button

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post #3 of 5 Old Jul 23rd, 2019, 3:05 pm
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Re: 1985 BMW K100rs Won’t turn over

They are don't like you to give them any gas. They flood easy. My '86 would not start if you gave it any gas..But , sometimes ...

Patric Blackman
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post #4 of 5 Old Jul 24th, 2019, 12:06 am
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Re: 1985 BMW K100rs Won’t turn over

More information needed, any little work done. Even though you have a new battery, have you done a load test? Volt meter on the battery, hit the starter and volts should stay at 9.6 or above. New battery is good but not to be eliminated right away, there can be problems or failures with a new battery. What kind of maintenance charger are you using. A modern smart charger? Good. Old Battery Tender from the back shelf, bad (1985). This is a 30 year old bike, lots of possibilities. A huge amount of maintenance would be needed to make it dependable, much less safe to ride.

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post #5 of 5 Old Jul 24th, 2019, 12:01 pm
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Re: 1985 BMW K100rs Won’t turn over

If your '85 is like mine, the pump doesn't start until you push the start button and should be heard running a second or two after releasing the start button. Check the fuse if you don't hear it.

Always check the 4 pin under the tank and that the jetronic plug are fully seated and locked. The ignition switch can also give problems and need a cleaning. A starter backspin couldn't hurt either.

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Kim Thomson
Motorcycle Cigar Smoker
05 K1200LT - The Golden Rocket Ship
91 K100RS - The White Stallion
85 K100 Standard - Big Red
79 R65 - "The Bee" is a buzzin' again!
06 525i - Premium, Sport, Comfort, Xenons

Gone, but not forgotten...
02 K1200LTC - Big Blue (accident at 40k)
88 K100RT - Chocolate (it was brown, melted - fire)
85 K100RT - (wore out)
82 Yamaha Vision - (electrics)
72 Yamaha R5C 350 - (broke trans)

Last edited by alabrew; Jul 24th, 2019 at 3:16 pm.
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