Stupid (?) carb question

[showtime]

Ok so I know the float bowl stores gas for the carb to draw on to feed the cylinder. Now if your float level is to low you will starve the motor at high rpm's. And if it's set to high the bowl overflows ?? causing a rich condition....but...as long as the float keeps enough gas in the bowl to supply your needs but not so much that it overflows...why is the level so critical ? Why do you lean/ enrichen the mixture if the bowl is just a ..holding tank so to speak, for the carb to draw on? (I looked for an icon of a blockhead but couldn't find one
Yes I'm cleaning/rebuilding mine and after all the talk about float levels I started wondering. And while I'm here I had one needle so full of rust and gunk I could hardly get it out. and for the price of new needles and gaskets (and I have an '80 with the o-rings around the seats) it seems I might just as well buy the rebuild kit for each and start with all good stuff for not to many more pennies. Any thoughts on that and where the best place to get the kits is ?

[randy]

Showtime,

No such thing as a stupid question.


The only thing 'allowing' the gas to mix with the air is the negative atmospheric pressure at the nozzle tube as the intake air passes by. The higher the gas level, the more gas gets sucked onto the air stream.

If the float is set too high the carb will flow more gas than is necessary causing a rich condition, regardless of whether the float needle is closed or open.


Try parts n more for the kits. $12.00 each

Parts n more

[DiverRay]

Showtime,
If the carbs are that bad, get kits. I bought the needle/seat & bowl gasket from Partsnmore, if I remember correctly. On your machine, the seat should come with a new "O" ring. Don't dip the carbs, just use a spray ond a brush to clean them out. IF you get a "complete" rebuild kit, BE CAREFULL!! Some of the kits, K&N, have the wrong size jets in them. Your jets should be fine, so all you really need is the needle/seat assembly with a bowl gasket.
The float hight needs to be the same across all the floats, so the carbs all feed the same mixture. If the level is too low, you can starve the engine. Too high, and the plugs will all be black and the bike will run poorly. Each bike is just a little different, so it's best to start at the factory setting. check the "Tech Tips" on the left side for more carb information
Ray

[stevo]

partsnmore carb kits with gasket.....gaskets wouldn't fit my float bowls properly..same basic size same basic shape ...just poorly cut pieces of crap ...i used the needle and seats ...but re-used my bowl gaskets..i had been super careful pulling bowls to save old gaskets (just in case)........if i hadn't had any other way,, i probably could have soaked and softened and butcherd on partsnmore gaskets to make them fit....fortunatly i didn't have to

[knewsom]

mine didn't fit perfectly either, but a little bit of quick work with a sharp knife and no problemo.

I think a small hole punch would've done the job nicely as well.

-Kris

[showtime]

Thanks for the info. And the tips about the rebuild kits and gaskets. I didn't break mine taking them off but their dried hard as a rock so I don't trust them. I'll have to..er...adjust the new ones I guess.
One more question if you don't mind...when fine tuning the carbs like adjusting idle, removing them again to re-adjust floats etc., do iI need to put the entire airbox and filter back on each time I test run it so I'm working off a consistant air intake or doesn't it effect it that much ?

[DiverRay]

The air box or filters WILL effect the tune. If you do the float level correctly the first time, the carbs should NOT have to come off again. As I didn't take the carbs off the rack, I didn't try to sync the carbs before the first start. They were off a little, but it would start and run. The rest of the adjustments can be done with just the seat off and the tank on backwards, in place of the seat.
Ray