hunting

[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.

[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....

[moggiethouable]

Thanks BMC.
A nice job for the weekend. Holy pistons Batman!

[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.

[bmcecosse]

Little by little is the way to go!

[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?

[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.

[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.

[bmcecosse]

" Pulls like a train " Excellent!! Have you tried swinging the dizzy at idle to see if there is a better setting?

[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!

[bmcecosse]

Aye - but the idling setting may not be right - so try swinging it back and forth a little.

[Ufudu]

OK will do that tomorrow thanks!

[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.