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Trimoto74
10-14-2018, 05:16 PM
So i picked up a pretty clean little 90. Its a '74. It runs but the carb leaks and its original. I'd like to just swap a carb on it for cheap. Been staring at ebay and found I find one that fits the original specs. The intake opening is 19mm and the air filter OD is 31mm with 48mm bolt spacing. I want it to just fit into the original air filter boot. Every one on Ebay says it fits 76-79 and seem to be mostly 22mm. It the 76-79 intake 22mm? Could I swap intake manifolds and open my options?

86125m
10-14-2018, 08:46 PM
well, the carb is probably leaking while the bike is stopped or does it leak all the times and around the bowl gasket. because if it's just leaking after it is stopped out of the overflow the needle valve is the culprit and the good news is that the needle seat on the 90s carb is replaceable The carburetor rebuild kit should come with everything needed. however if the carb can't be fixed this carb should be plug and play my 200x and 125m both run this brand carb the only thing you need to do is before installed the carbs choke flap screws need lock tight put on them. https://www.ebay.com/itm/Honda-ATC90-Carb-Carburetor-1972-1978-1976-1977-1978-THREE-WHEELER-NEW/123420177481?fits=Model%3AATC90&hash=item1cbc6a7449:g:D3MAAOSwPgxVNQzQ:rk:9:pf:0

coolpool
10-16-2018, 10:33 PM
Personally I've never had to replace a 90 carb ever for the 5 I've owned. I've cleaned them up and put them back in service just fine after each one being a train wreck. One culprit for leaking bowls is that people over tighten the 2 screws and distort the aluminum tabs. Take it apart, put a flat edge across the surface then carefully file the mating surface flat again. Then re-assemble and don't over tighten! As 86125 said, get a rebuild kit if necessary but please keep the original casting IMO.