R 100RT - No spark from spark plugs

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rory100rt

R 100RT - No spark from spark plugs

Postby rory100rt » Wed Sep 16, 2015 5:19 pm

Hi,

I have just replaced the battery, given the carbs a clean and replaced the spark plugs in my '81 R 100 rt. It is turning over but doesn't want to start up. I tested the spark plugs with them grounded against the cylinder heads and found they aren't producing a spark, would I be right in assuming its an electrical problem - something to do with the plug caps/ht wires/coils?

I have a set of NKG caps in the post, just wondering if these can be put onto the existing (original BMW) HT wires easily, or will I need to replace the HT wires also (assuming it's not the coils)?

If so, is it an easy install - any tips would be appreciated!

Cheers,
Rory

Mike D
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Re: R 100RT - No spark from spark plugs

Postby Mike D » Wed Sep 16, 2015 5:41 pm

Were you getting a spark before you did the work?

If so then why would you suspect the HT leads?

Mike

rory100rt

Re: R 100RT - No spark from spark plugs

Postby rory100rt » Wed Sep 16, 2015 5:54 pm

Yes, it was starting before I changed the battery and spark plugs. I'm just working upwards from the spark plugs really - could it be a fuse perhaps? Is it possible to blow a fuse when changing over a battery?
I have read elsewhere that the plug caps can be a problem, the ones currently on the bike are looking a little corroded. I'm new to bikes so the Ht leads is an (un)educated guess!

rory100rt

Re: R 100RT - No spark from spark plugs

Postby rory100rt » Wed Sep 16, 2015 5:54 pm

I should also mention the last ime it was started was almost a year ago..

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Jaythro
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Re: R 100RT - No spark from spark plugs

Postby Jaythro » Wed Sep 16, 2015 6:57 pm

Twin coils?

or a Single coil with Dual output?

Check that the wire between the coils hasn;t been dislodged if twin coil

Or one of the coil wires broken or falling off a Dual output

If you get an 5w LED with a couple of fly leads you can link it into the coil wires and look to see it flashes when you turn over the motor on the starter

Also Check the Plug has not got pulled out of the ignition amplifier thingy under tank (Black plastic thing mounted with two small allen screws about 1 cm thick and 6cm long and 4cm wide
"Put your Ass on a motorcycle and ride with an attitude and the "Grim Reaper" will ride in your shadow!"

Islandmagee in case you're interested?

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george baker
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Re: R 100RT - No spark from spark plugs

Postby george baker » Sun Sep 20, 2015 6:29 pm

Hi
someone else has had a similar problem and some fault finding info was published there so have a look see and it may help

Good Luck
George
Member 21, R100R, and an under used K75

rory100rt

Re: R 100RT - No spark from spark plugs

Postby rory100rt » Mon Oct 05, 2015 5:54 pm

Thanks George,
I'll have read and let you know.

Rory


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