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G5 plugs

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PHIL H View Drop Down
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    Posted: 28 Feb 2019 at 11:55
Morning all.
Checked my plugs on my 1979 G5 yesterday and found half the plug is running ok and the other half looks like its running rich or too hot, its black and crusty.
I have K and N air filters and have tried different plugs 6 and 7
All valves have been lapped and tappets checked (numerous times)
The thing is my 78 SP has the same problem.
So my thinking is......
I'am doing something wrong
The carbs need rejetting because of the K and Ns
Or the obvious...they all do that !
I will try to put a photo on but have never been successful on this site

Many thanks in advance Phil

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c13pep View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote c13pep Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 12:41
Chokes `sticking` springs to mind or even as simple as balancing the carbs
The accepted starting point when fitting K&Ns or similar is a 10% increase in jet sizes
CHRIS
you can`t have any fun in a straight line

Monza project
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Dave P. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 12:44
Have you checked that the "choke pistons" are seated correctly and that there is free play in the cables or the lever mechanism if that's what you have?

Aha!! Beaten to it.
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PHIL H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHIL H Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 12:51
Thanks chaps
Both bikes have fairly new chokes, the lever type but will have a check.
There is free play in the cables around recommended 2mm
Carbs balanced to best of my ability with ebay vac gauges.
Will have a play and go through all the above.
Was thinking about carb overall kits jets mixture screws etc.

1978 SP 1000
1979 G5 1000
YAM XJ600 Street Tracker
1976 Honda CB 550 project
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c13pep View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote c13pep Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 13:27
Certainly on my v50s changing renewing jets and needles makes balancing a lot easier. Did you do a two stage balance ie. 3000rpm to balance slides and then at tickover to balance airscrews etc.
CHRIS
you can`t have any fun in a straight line

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PHIL H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHIL H Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 13:50
No Chris....but I will now Thanks
1978 SP 1000
1979 G5 1000
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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 15:10
In my experience, the needle/atomizer jets wear badly on these with the needle flapping about in them. Fitting new ones made a huge difference.
Brian.

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PHIL H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHIL H Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 17:10
Yes think that's the way to go Thanks Brian
1978 SP 1000
1979 G5 1000
YAM XJ600 Street Tracker
1976 Honda CB 550 project
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2019 at 21:22
Looking through the jets you could clearly see they were oval, not round.
Brian.

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Ken-Guzzibear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 01 Mar 2019 at 12:08
K&N eurocarb recommend up 10%  the jets are cheap enough , chokes even new ones will stick Reading your question is this the actual plug is half / half? or left plug fine right plug fouling? How far is it going? if short trips it is just not getting hot enough If different bikes show the same symptoms What fuel are you using? Try a shot of RedEx go for a good run 50 mls plus, give it some beans then check The old "plug" pictures as per Haynes manuals are no good now due to the Ethanol in fuel 
I commute 18mls each way on my 76 V1000 if I have a slow one. lots of traffic and filtering the plugs look awful, it worried me, till someone suggested checking them after a more spirited run, totally fine I run K&N with Le Mans Breather ....up jetted 10% from stock but with the round carbs as spares for the old PHB 30's were getting scarce ..... Dunno if these observations help at all
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PHIL H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHIL H Quote  Post ReplyReply Direct Link To This Post Posted: 02 Mar 2019 at 11:53
Cheers Ken
refurb kits to be ordered
decent runs of 50 to 120 miles at a time
petrol is usually jet bp or shell
its each plug 50/50 good and bad, don't know if its inlet or exhaust side that gets dirty


1978 SP 1000
1979 G5 1000
YAM XJ600 Street Tracker
1976 Honda CB 550 project
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