Gday all,

my 76 clubman has always run, sometimes better than others and as of late I've started running into some misfire issues more and more.
Long story short, unless I very, very gently squeeze the throttle on when it's not choked, it misses horribly and kind of farts it's way along until it clears its throat.
It's got a 1.5" SU on it and as far as I am aware that was what it came with. I've done the usual things like K&N filter, new inlet and exhaust and I recently had the head reconditioned.

I've checked the timing and as far as I am aware with a frustrating lack of timing marks and a disappointingly non-functional timing light, it's as close as it needs to be. I don't think it is an ignition timing issue as it doesn't cough and fart when it's choked.

I've also tried leaning it out and richening it up but to no prevail. Perhaps there is an air leak somewhere in the carb? I am not sure. Has anyone had any similar issues/throw some suggestions my way?
Thanks team.
Joe

_________________
-----Better is the enemy of good-----
-1976 Yellow Devil Leyland Clubman-
-1970 Morris Mini Van - Work in progress-

If you fitted a sports filter it needs a richer needle. One guy here had this problem, I suggested a CP4 needle and that fixed it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

If it is backfiring out the carby then its leaning out. After swapping out the intake and exhaust for a more free flowing system it now requires more fuel. Definitly swap the needle as Doc has suggested. Also check the dashpot oil. No or low dashpot oil will cause the piston to rise quickly giving too much airflow and giving a weaker mixture.

I have also fiddled around with different needles too in an attempt to richen it up with the more air flow. It did seem to be precariously low on dashpot oil when I checked it just before. I topped it up and will give it a go tomorrow morning. I'll let you know how we go. thanks for the comments so far

_________________
-----Better is the enemy of good-----
-1976 Yellow Devil Leyland Clubman-
-1970 Morris Mini Van - Work in progress-

Went for a spin out to blackwood for cars and coffee this morning. After topping up the dashpot oil and richening it up 1.5 flats, she ran pretty well. However, it was misbehaving up until the point it warmed up and it took a very long time to get there. Was a pretty chilly morning though. Once she was warmed up though it was a really good run.

_________________
-----Better is the enemy of good-----
-1976 Yellow Devil Leyland Clubman-
-1970 Morris Mini Van - Work in progress-

Richen it a bit more, 1.5 flats is nothing.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Seems to be alright how it is. Spark plugs are a good colour on the current tune. Looking forward to the weather warming up so I can take it out a bit more!! (And not get frostbite on my nose and ears) Thanks for your help team!

joe

_________________
-----Better is the enemy of good-----
-1976 Yellow Devil Leyland Clubman-
-1970 Morris Mini Van - Work in progress-