School boy error

SIM

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Hi,
I went for a spin around the dales last night only for the bike to cut out half a mile from home, I managed to get home after it restarted a little time after. The bike was turning over but not firing.

I think my school boy error was to put in some high octane fuel thinking it would clear out any crap. Does it seem plausible it was running too rich and has led to it cutting out.

My 100gs has never cut out before and I have also never put in premium juice.

All cables and fuses are in order

Cheers Simon
 
I wouldn't think it was that. I've never had any problem using different petrol.

I used to have a problem where my bike would just cut out until it cooled down, then it would start again. Mine was some sort of electrical problem somewhere which was never totally right until it was re-wired.
 
It wont be the upward change in octane rating. Its something else.
 
What did you check at the roadside? - if both cylinders died at the same time, it suggests sparks/ignition system.

Anyway, why not PM/chat one of our resident experts, say 'mikeyboy' who has just picked up yet another project I see, a somewhat tired R80/100GS.
 
Kill switch is my guess. Possibly ICU overheating.
 
Cheers guys, will have look and hopefully report back with good news and a simple job

Once started again it did sound like only one cylinder was working properly
 
I had a similar problem, it was poor contacts in the ignition switch.

Which of course was the last thing I checked.

Part of the problem was that for some reason someone had moved the wires around on the relays so everything was going through the switch instead of the relay circuit.
Didn't find that until I replaced the harness and relays.

Best way of removing crap is to first remove the float bowls,drain and clean then remove the tank and taps, drain and flush the tank and clean the taps and filter.
Then fit new inline filters in there are any and new fuel hose if you haven't done so recently - hose to current standard J30 /R12 will stand up to anything you put in the tank so the odd tank of jungle juice will not dissolve the hoses and block carbs with a black goo - DAHIK
 
Thanks,

I suppose I was lucky I wasn’t stuck up in the dales when it decided to just cut out, it was running great until then, opened it up on the bypass, down through gears to get round the roundabout then stopped.

Always a job with an airhead.

Cheers fellas 👍
 
to get round the roundabout then stopped.

Check your wiring around the headstock, and the wiring plugs attached to the frame which serve the harness into the binnacle/headlight/handlebar switchgear. Known problem with chafing, and with the plugs pulling apart. Extra handlebar movement (such as going round a roundabout, esp. if its a tight one) can be the last straw giving intermittent contact....and also, just to be extra tricky to detect, the wires can break inside (work hardening) but the external plastic insulation can be undamaged......
 
The fault with my switch was that the black plastic infill on the back which appears to be crimped in had slackened off a little and was being moved around by the cable, so when making the checks SS has suggested might pay to have a look there too.
 
Thanks for all the info guys, finally managed to get round to sorting. I binned old fuel, replaced inline filters and spark plugs and cleaned carb bowls and now all running well.

I still feel a little paranoid though given I will be off to Belgium in a few weeks. I did not see any crap in the fuel or filters, but the plugs seemed a little coked up on end, when I earthed it sparked orange.

Do I need to worry about the coil or leccy as mentioned above, it just seemed odd that it just cut out.

Will be off for a bimble tomorrow evening to see how the old bird runs.

Once again thanks for your input in helping a mechanically inept biker 👍
 
a bit of dirt or water in old fuel could easily make it cut out. Give it a teat ride and if all is well relax.
 
Make sure your tank breather is free flowing and as said previously electric plug connections under the tank ,my r 100 gs used to chuck it occasionally and that was the problem bad connections in the terminal blocks
 
Every car sold today has a inline filter and they seem to work just fine on them.
But they are a service item, and should be replaced / cleaned regularly, depending on the type.
If you buy cheap and nasty no name filters you get what you pay for, but water has no effect on the medium in a quality brand name filter.
I have been using inline filters for as long as I have been riding bikes, and have never had a problem with them.
Unless you call doing the job they were installed to do a problem!
 
Every car sold today has a inline filter and they seem to work just fine on them.


Unless you call doing the job they were installed to do a problem!

Very true. Cars and trucks (and for many many decades specifically diesels) have had inline fuel filters, the difference here is that nearly all of these are under positive, sometimes very significant positive, pressure or vacuum. Our feeble wheezy asthmatic dinosaur airheads rely on the Newtonian principle of gravity feed and small bore pipes with a relatively slow flow rate and no bypass return which can lead to loss of filter performance (aka become blocked).

But as BB correctly points out, if a filter is blocked and causes "problems" then its actually done its job. The disease and the cure, at the same time.

I would rather have a few filter problems (remove, throw away, fit new ones) than have to re-build 4 inline carbs a couple of times in a row if the tank/fuel supply was contaminated, say....
 
Thanks for all info. Running like a dream 2 good run out in the dales this week and bob on :beerjug:
 


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