Starting!

Helpful information and requests for assitance and advice
Big Pete
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Joined: Wed Mar 21, 2018 5:11 pm
Location: Highland UK

Starting!

Post by Big Pete »

Hi been through the forum and not seen a problem quite like this.
500 g80 with fresh wound mag and new plug will start first or second kick.
Leave it for 2 weeks and there's no chance it starts till it gets a new plug and then boom first or second kick. It has auto A/R and rebuilt monobloc carb. I've tried with air valve open and closed, mix screw turn and 3/4 out. I've taken the plug out and there is what seems a good spark but the plug is wet, I suspect wet dumping but after 2 weeks? Maybe just needs a good run? Weather up here is dire just now.. maybe just carry a box of plugs!
Highlander, "There can be only one"…
Mick D
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Location: Aberdeenshire

Re: Starting!

Post by Mick D »

Hi

Is the bike garaged? it could be damp related.

Regards Mick
Big Pete
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Joined: Wed Mar 21, 2018 5:11 pm
Location: Highland UK

Re: Starting!

Post by Big Pete »

Yep it's garaged every night and a heater left on, maybe I'm spoiling it! :D
Highlander, "There can be only one"…
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griffin
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Location: NOTTINGHAMSHIRE UK

Re: Starting!

Post by griffin »

Are the plugs good quality original ones and not cheap copys off of ebay ?.
I had similar trouble with plugs fouling, got my new plugs from the Green spark plug company and now they are always a consistent coffee colour.
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spookefoote1956
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Re: Starting!

Post by spookefoote1956 »

Are the points set right and are you getting a healthy spark without the plug cap on?
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oldandsmelly
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Location: DEVON UK

Re: Starting!

Post by oldandsmelly »

I had a similar problem starting my G80 after fitting a new BTH mag (chuffing brilliant thing!) and a new Burlen Amal monobloc. I did have lots of problems with the new carb, but once I had sussed those, I still had intermittent starting problems.

After much frustration and bad language, It turned out to be the spark plug. As mentioned above, There seems to be a lot of duff plugs on ebay at the mo and I had bought a batch of 'Champion' N5's thinking I was saving money. I went along to my local motor factor shop and bought a real Champion N9 and now it starts second kick hot or cold. It could be that running the slightly hotter plug also helps if its burning a little oil like mine does. My G80 rarely gets left more than a week without use but I've not noticed any difference how long its left.
Big Pete
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Joined: Wed Mar 21, 2018 5:11 pm
Location: Highland UK

Re: Starting!

Post by Big Pete »

You could have hit the nail on the head lads I bought a box of champion N-5's of e blag and it wasn't from the green plug co. I'll try going to a 9 from a reputable supplier and report back. Great fat spark at the cap.
Highlander, "There can be only one"…
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GOLDSTAR
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Location: KENT UK

Re: Starting!

Post by GOLDSTAR »

not the AMC but on another old nail using short reach plugs, I have had 2 NGK's go down without any reason and both purchased from a reputable dealer at £4.50 each! purchased a number of Champion's from Green spark plug co appear to work well and much cheaper. Someone has suggested elsewhere there are a number of 'scnide' plugs about. kind regards
Big Pete
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Joined: Wed Mar 21, 2018 5:11 pm
Location: Highland UK

Re: Starting!

Post by Big Pete »

Well(touchwood!), the old girl has started last 3 times ive tried. Found out it was a resistor cap so replaced it with a crimp terminal just now.
Next problem is the idle , its all over the place. Feels like the slide is sticking but i know its not. Suspect its weak but adjusting the mixture screw doesnt make a huge difference to revs till i ride and stop. Then its either racing or dies!
Any thoughts appreciated.
Cheers Pete
Highlander, "There can be only one"…
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clive
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Re: Starting!

Post by clive »

Sounds like an air leak between carb and the tufnol spacer or between the spacer and barrel. Other possibility is there is air leaking round the throttle slide.
clive
if it ain't broke don't fix
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