88 650sx Carb

[jetracer800]

i have a question on my 88 650 carb ok looking at the front of the carb with the round body in my face, the adjuster on the right i think is the low speed adjust and the one on the left is the high speed adjust my question is there's a round bolt that is slotted on the bottom left side it's adjustable with a spring on it for tention, like i said it's a round bolt with a slotted head on it, what is that for,

i can't seem to get my carbs tuned right the low and high were out like 2 or 3 turns and the boat runs rich,

mind you it is ported and polished and has one rounded mikuni carb that has had some tapering done to it, modified, it also has a coffman pipe, and k&n air filter what do you think from a starting stand point were to adjust the set screws and what is the bottom slotted bolt for thanks alot

[Bill O'Neal2]

Re: 88 650sx Carb

Old round bodies have a third circuit, a primary circuit, besides the other two adjutment screws, some have a tee handle on the primary, yours has a slotted screw. The reason nobody uses that type carb anymore is that it will probably be about impossible to ever get it to work correctly.

You would be doing yourself a HUGE favor by swapping it out for a square body Mikuni 44mm carb.

I doubt anyone on this planet could tell you what you are asking even if they understood the workings of a round body carb.

[jetracer800]

Re: 88 650sx Carb

thanks Bill yeah i thought it was the water routing but i can't get this thing to get up on a plane, it seems that when the boat comes unhooked from the water it wants to scoot but bogs down a bit, so you think a square bodied mikuni would do the trick, im selling it to a buddy and i'll have him look into getting a new one or used thanks alot

Mike

[jetracer800]

Re: 88 650sx Carb

so Bill what would be a starting point turn them all the way in and out a turn and a 1/4? i don't know what to adjust on the round bolt maybe turn it in and out a bit just for a starting point,

i turned the low speed adjust in while it was running and it started to die and them i turned it out some to where it wouldn't bog anymore and it reved up pretty fast, i have to take it out to the lake tomorrow to test the high speed, so do you think a turn and a 1/4 on the high would be a safe start until i can get my hands on a 44

[Bill O'Neal2]

Re: 88 650sx Carb

I'd try two turns. Better rich than lean. Don't touch the primary adjuster.

[jetracer800]

Re: 88 650sx Carb

hey Bill does that carb have an internal fuel filter like the super bn's?

[Bill O'Neal1]

Re: 88 650sx Carb

No, ity has an inlet screen behing the inlet fitting.