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hunting
Posted: Fri Apr 04, 2014 11:48 am
by moggiethouable
Anybody remember the word "hunting"?
my 1098 is doing it.
Only uphill under load, or on the flat if pushed, if I drop from say 3rd to second and bring the revs up high it disappears, idle is good.
Condensor is 1,500 miles old, as are points and plugs.
Its like a slight misfire, but no backfire is present.
My first port of call will be the new condensor, then check the mixture?
if it was too lean would that cause it? I will check the plug colour,
anyone else got any ideas?
Thanks as always.
Dick.
Re: hunting
Posted: Fri Apr 04, 2014 12:11 pm
by bmcecosse
Condenser would be my #1 suspect.... But also check if the carb piston is free to rise - and falls with a nice clunk. Yes - weak mixture could cause this - and could burn holes in the pistons....
Re: hunting
Posted: Fri Apr 04, 2014 12:17 pm
by moggiethouable
Thanks BMC.
A nice job for the weekend.

Holy pistons Batman!
Re: hunting
Posted: Fri Apr 11, 2014 2:44 pm
by moggiethouable
Set to today and set the mix a little richer, as the plugs were a lighter shade of pale.
The hunt has gone, I shall carry a spare condenser regardless, just in case.
Thanks BMC she seems good now.
I think I was a little over exuberant when altering what was a very (black plug) rich mixture when I acquired her.
Tallyho.
Re: hunting
Posted: Fri Apr 11, 2014 3:55 pm
by bmcecosse
Little by little is the way to go!
Re: hunting
Posted: Fri Apr 11, 2014 5:39 pm
by Ufudu
A slightly different question:
My 948cc with HS2 carb has a small amount of "hunting" at idle and no load (is that called hunting?) where the speed varies in oscillation with a period of a few seconds, not a big change in RPM but audible.
Does that mean anything? Is there a variable amount of air and/or fuel getting in anywhere?
Re: hunting
Posted: Fri Apr 11, 2014 5:56 pm
by blues2rock
Sounds as though it is running weak at idle, try lowering the jet a bit at a time to see if it evens out.
Re: hunting
Posted: Fri Apr 11, 2014 6:16 pm
by Ufudu
Thanks, I have in fact been weakening the mixture (one "flat" at a time) over the last week after inspecting the plugs after a longish run every day.
However the "hunting" at idle has been persistent, whilst the plug colour shows it is still running slightly rich.
Otherwise the motor pulls like a train.

Re: hunting
Posted: Fri Apr 11, 2014 6:49 pm
by bmcecosse
" Pulls like a train " Excellent!! Have you tried swinging the dizzy at idle to see if there is a better setting?
Re: hunting
Posted: Fri Apr 11, 2014 6:57 pm
by Ufudu
No I have not, it's preliminary set to about 7 deg BTDC; I thought I would set the mixture first then do the "just not pinking" adjustment later!

Re: hunting
Posted: Fri Apr 11, 2014 7:16 pm
by bmcecosse
Aye - but the idling setting may not be right - so try swinging it back and forth a little.
Re: hunting
Posted: Fri Apr 11, 2014 7:24 pm
by Ufudu
OK will do that tomorrow thanks!

Re: hunting
Posted: Sat Apr 12, 2014 4:34 pm
by katy
However the "hunting" at idle has been persistent, whilst the plug colour shows it is still running slightly rich.
Rich mixture can cause hunting.