So I got a pretty clean set of carbs from a 1990 F1 - real cheap on eBay.

Took them apart, replaced some gaskets, cleaned the jets and I think they look good to go, and best of all the internals all seem to be OEM. My problem now is how to get these onto my 1989 with all the mess of tubing that is hanging off ;-)

I read in this forum how the 1990 carbs, even though they are 34MM not 32MM, will fit fine on the 87 to 89 bikes... but the fuel hookup and the various breather hoses look different. Has anyone done this and can advise me what to do so that they will work on the earlier bike? My plan was to take most of the tubing off and where there are T fittings, just put a straight connector to cap them off.. there is also a little charcoal canister or filter that is inline with the center air tube, plus the fuel feed looks to be a one into 2 setup so that the fuel goes to the area between carbs 1 and 2, and then also between carbs 3 and 4.. not the single central hookup like on the earlier bikes.

Any help is appreciated!

 

Followup - since I had so much trouble finding information on this swap I decided to take the non-drilled slides & stock needles, and the main jets from the 90 donor carbs and put those into my 89 carbs... so now I am running all "stock" honda jets and needles without slides drilled. I sealed up the airbox and have factory air filter and it has never run better... as a bonus i discovered that one can turn the pilot screws even with the caps on while the float bowls are off the carbs.. so getting them all at exactly 2.5 turns out has helped with starting and with idle :-)

 

Sweet. Good job!