Gk71b starting

[WeeChris]

Got bike home from garage after re-commissioning.

Mot'd,serviced,carbs sonic cleaned.

Started good at garage, started not bad 1week later then cut out.

Couldn't get it started.

Changed plugs, choke full on ( I think, lever fully towards grip). I'm new to bikes, used to vespa's.

Bike started ran for a bit, half choke ran for 30 secs then cut out. Wouldn't start again.

Left it over night , fuel switch off went to start it and engine turning but not even trying to fire up.

Fuel there & spark.

Any ideas??

Any pointer appreciated.

Guy at garage says take it back & look. Difficulty is 8 miles away and no access to a van or trailer.

[dobbslc]

Sounds like it might be flooding.
Did it turn over slowly on the first couple of revolutions like a lat battery then speed up?
Try cleaning or replacing the plugs, turn the engine over with the plugs out then refit and try to start it with no choke.
The carbs on these bikes cause a lot of trouble, they are over 20 years old now! The seals and O rings fail causing flooding.
Lite tekl Blair on the forum does seal kits for the later bikes not sure about the 71's though.

Dobbs

[WeeChris]

Bike turns over at good speed.

Will clean plugs but were brand new and only been ran in engine for max of 5 minutes.

Will give the turn over with no plugs etc as you say.

The guy who cleaned & rebuilt carbs said they wer in good condition.

Will see if I can find a seal kit

Thanks for your advice. Will update tomorrow.

[slabbygk71b]

If you've not fixed the problem yet, try looking at your ignition coils.

I've had a lot of problems with the coils in the past, they still show a spark with the plug out and earthed against the head but the engine heat fries the coils and the spark breaks down under load.

I got a spare set of coils and fitted one at a time, the coil for 2&3 solved the starting and running issues straight away.

You could spend hours fiddling with the carbs and get no further, try the coils and see what happens. My bike starts first time every time now as I've fitted stick coils of each cylinder.

Hope this helps.

[WeeChris]

Hi

Bikes starting and running now. Found a short in a wire going to one coil.

Issue I have now once I run for 30 mins or so it doesn't like to idle. In fact cuts out, but I can restart straight away and hold revs up.

Could this be the coils under heat breaking down?

Where did you get stuck coils from?

Cheers

Chris

[slabbygk71b]

Sounds like the coil or coils are on their way out. I found that the bike would not re-start when hot, would cut out without warning and falter giving the feeling that the carbs were out.

I bought a set of 954 fireblade stick coils with sub-loom from a bike breakers. I think they were £45.00, if you check the standard GK71B coils I think the resistance is 3 ohms, you need to choose your stick coils with a similar rating when paired.

Practical Sportsbike magazine did a feature on this about 2 years ago, contact Bauer Media to get a back issue or have a look on the internet as well, it is a common upgrade and will get rid of the gremlins (unless you get a dodgy set of sticks!)

If you need any more info I'll try and help.