MOT - CO emissions

[thekettleson]

Morning,

Having only managed to do 1,000 miles since last March and with the car pretty much sat in the lock-up going nowhere for a few weeks now, other than a pre-MOT blast, I had my 1850HL MoT'd at the weekend and only failed on the CO emissions, which at about 6.5% at 3,000rpm, and slightly higher at 2,500rpm, are a little too high (!) - quite pleased that there was nothing else . I've got the electronic ignition kit to fit, and new plugs, air filters etc, so I guess that plus a few hours with Jon's SU wiki by my side should see a pass on the retest.

James

[Jon Tilson]

I'd be looking at the choke return, which gets lazy as they get oldr. Try pressing the jets up after you have wamred up and pushed the choke in.
If the jets move up a tad there is the reason for your failure.

Present the car fully warmed up and press the jets up by hand and it should pass. Bit of lubrication will help on this, but simetimes its just tred retirn springs on the choke linkage. The rubber mounts can sag a tad too and make the cross shafts bind a bit, which also doesnt help.

Jonners

[Toledo Man]

A good service followed by a tune up (do the ignition side first) should bring down the emissions.

[thekettleson]

Thanks for the tips. Have got Sunday set aside to have a play and get everything right.

James

[thekettleson]

Morning. Pleased to say my 1850 passed the retest yesterday after an afternoon of resetting (playing with) the carbs on Sunday. I've not quite got the set-up right (my first time setting up twin SUs) and so need to spend a bit more time fettling but 3.8% CO was a good result and gets me the necessary 12 months

Very useful guide - thanks Jon.

James

[thekettleson]

Had another play today and as a result my 1850 is smoother and pulls along happily through the revs. It's probably not perfect but I'm definitely happy

James