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28mm OKO dumping fuel from overflow- Ideas?

Posted: Wed Apr 24, 2013 6:41 pm
by sleeperelite
Hey all,

Here's my deal, swapped an AF16 into my 89 SA50. Has a Polini Contessa BBK with said 28mm OKO carb on a chrome CT intake. Finally got my fuel delivery and spark issues solved. Motor will start and run, consistently but bogged down enough to where the clutch will not engage except for 1 lucky testing. However, it pours gas from the carb bowl's overflow. This carb has no screw to open and close the drain, my assumption is that this should be no issue if the carb and motor are functioning properly.

Took the carb apart twice and cleaned all the jets and assorted ports. Have gotten so results adjusting the tab on the carb's float but nothing ideal. The float assembly itself is starting to get a bit ragged from all my adjusting(bending) of the tab that manipulates the float needle/valve.

Was thinking maybe getting the rebuild kit for the carb, since its less than 20 bucks, and return the float to its stock positioning.

Any ideas if my problem may be more? Could my carb be just one of the bad ones and may need replacing altogether? My belief is that this BBK should accomodate this carb with no problems......

Re: 28mm OKO dumping fuel from overflow- Ideas?

Posted: Wed Apr 24, 2013 7:00 pm
by paulpauly7
your float level is messed up get the rebuild kit and readjust

Re: 28mm OKO dumping fuel from overflow- Ideas?

Posted: Wed Apr 24, 2013 10:28 pm
by patthesoundguy
Do you really need a rebuild kit, isn't the float frame steel in those carbs, can't you just bend it back. As long as the floats float and the float valve is good, I say just bend it so it sits right. But it sounds like the float valve is leaking now that I read more carefully. . Pull the carb with the bowl off and blow gently in the fuel line inlet on the carb while lightly lifting the float and you can see feel and hear where the floats stop the flow with the needle valve. Been adjusting floats like that for a loooongggg time. Yes a rebuild kit is cheap and that's great, but in the meantime waiting for it you may get it working without it.

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Re: 28mm OKO dumping fuel from overflow- Ideas?

Posted: Wed Apr 24, 2013 11:10 pm
by dun rite
while having the float needle out also do this just in case. http://hondaspree.net/wiki/index.php5?t ... Valve_Seat

Re: 28mm OKO dumping fuel from overflow- Ideas?

Posted: Thu Apr 25, 2013 10:13 am
by Mystic
i have adjusted my 21mm a million times and it still spits gas out the overflow. your float probably needs to be adjuated yes but these carbs are so cheaply made even the keihin pwk is the cheapest carb honda uses. i have gone to arreche myself the Oko is just a headache sometimes

Re: 28mm OKO dumping fuel from overflow- Ideas?

Posted: Fri Apr 26, 2013 9:48 am
by sleeperelite
When I pull the carb off again after the weekend, I will delve deeper into the float valve itself. I'll give it a more serious cleaning and polish.

The float frame is metal but I've definitely mangled it enough that its form is no longer true, or at least its bent to the point that my OCD is finished with it.

Thanks for the link to wheelman's breakdown. The wiki on here is solid!

The consensus I've been receiving about the OKO carb has been pretty similar to GY6 motors, you may be lucky to get a good one but don't be surprised at all when issues start to arise.

I've been eyeing up the Polini's 28mm carb. Anyone running this with their setup?

Re: 28mm OKO dumping fuel from overflow- Ideas?

Posted: Sun May 05, 2013 2:47 am
by sleeperelite
Time for closure- rebuilt and recleaned the OKO and its sterling again. I ended up grabbing the Polini carb as well and decided I'm gonna keep that one on the bike with a new black intake.

Soon to come- 28mm OKO carb and chrome CT intake for sale