Topic: Emissions equipment - deletion

[Faust]

It occurs to me that 1978 was the year emissions regulations began to apply to bikes. As it happens, that is the year of my project 550K. What I am wondering, is there anything I should "retrofit" from an earlier model? Vehicles older than 1984 are not "smelled" here, nor is equipment inspected.

[TwoTired]

The carburetors were "lean Burn" types to reduce hydrocarbon emissions.  I think the exhaust system was a bit more restrictive, too.  But, I don't know that for sure.

They work pretty much in the same maner as the earlier carbs.  However, the slow jets are pressed in to reduce tampering with idle mixtures.  The pilot jets meter fuel and have very limited range of effect.
There is only one needle taper profile I am aware of for the 78 carbs,  But, I think the selection of main jets could be more plentiful. 

Earlier carbs had "sloppier" mixture adjustments, which allow them to pollute more, but seem to be more forgiving of exhaust and air filtration modifications.

If you decide on earlier carbs, get the intake manifolds and rubber couplers that mate with them, too.
Cheers,