Club 80-90 Forums

kevtherev wrote:

Bigfootedboarder wrote:Hi
CO and hydro carbons are a little different, the CO may be less than one but and hydrocarbons are unburnt fuel emitted from the exhaust in parts per million, so you may only have 0.81% but .0.80% could be contributing to the HC's, could be an air leak as previously mentioned but that normally manifests in a poor lambda reading....

what he said...
that CO reading is way too low..
2.5 - 3% is preferable
That's where your high reading is coming from.
My money is on a leak through the carb.

close the airbleed screw to increase the CO

If it stock then CO should be 0.6% +/- 0.3
You really need to retest with fresh oil the crankcase first and a clean air filter a partially blocked air filter pulls more through the crankcase breather, if it is still high then check with the crankcase breather disconnected to see any difference in readings. The carbs need adjusting now anyway you are buggering around with the screws that don't effect the idle emissions, these engines have three carbs, two for running and a central idling carb. All carb adjustments are done with the crankcase breather disconnected.

oops I shall retract that.
Forgot that this is an Aircooled engine.
apologies

Thanks for sharing your knowledge guys.

Just waiting for the call.

I've spoken to a local guy who has experience setting up carbs and has all the gizmos to do it so will speak to him again if it fails this time. After further checks for air leaks and other ignition problems of course!

Cheers

It passed

Hydrocarbons down to 837

I'm gonna go do a dance.

For future reference I reset the volume mixture screws to 2.5 turns, removed the air filter from the box, disconnected the oil breather and tightened the manifold nuts as they were a little loose. Also took it for a good drive.

Reset the carbs and put the filter/breather back and it's idling ok again