TOPIC:

Hi guys, i have a 1983 kz550 ltd, that is missing the choke flaps, any ideas on replacements? I searched but just found some posts about doing w/o them. If I can't find any, what is the best way to start it cold w/ no choke flaps? thanks

The choke flaps almost always fall off those things or at least on one or two of the carbs on each assembly. The ice thing is that they have a straight shot into the combustion chamber in that location... the flaps are really a poor design. You will need to buy another set of carbs off eBay to use or to steal the flaps from.

So how bad is it to not have the flaps on? I realize it will make the bike harder to start when cold, but I can compensate for that by covering the airbox hole during cold startups. Do I need to buy them? I really don't want to pay $50 for a set of trashed carbs, that the flaps may be okay on. thanks

I have the same problem on my 550. When i get to it I plan on trying to make some flaps. I am a machinist so i think i can come up with something that will work. Other than that i think wiredgeorge has the right idea of stealing them off another set of carbs. These engines are fairly cold blooded and are going to need a good choke system.

I have the same problem on my 550. When i get to it I plan on trying to make some flaps. I am a machinist so i think i can come up with something that will work. Other than that i think wiredgeorge has the right idea of stealing them off another set of carbs. These engines are fairly cold blooded and are going to need a good choke system.

what are the flaps, exactly?

The little Tekei round slide carbs have a different way of choking the system to provide a rich air/fuel mix at start up. Mikuni carbs typically use enrichment circuits with choke plungers. Keihin typically uses butterflys to choke the air flow. Tekei came up with a system that provides sort of a flat plate that drops down into the venturi when the choke lever is actuated. Sort of a "trap door" deal. Anyway, I suspect there isn't enough airflow through the pilot air jet and if this plate didn't have the flap, insufficient air would flow when on choke. They put a little flap; about 1 inch wide and 1/2" high in the middle of the plate and it is on a spring loaded pivot. When vacuum pulls at the plate, the flat opens just a tad (it is on inside of carb as I recall) and some air gets into the choke and pilot circuits. Unfortunately, the flap pivot breaks easily and the flap disappears SOMEWHERE (hehe) which I suspect means down the combustion chamber to be munched on my a piston. I have never heard of engine damage but I wonder... It is really a BAD idea especially when the part that joins the flap to the plate is sort of under-engineered.

If I owned a set of these minus the flaps I might also be tempted to put a piece of tape over the outside of the plate where the flat would cover. I would cover about 3/4 of the opening and see how effective starting the bike on choke would be. I would move the tape UP and DOWN to provide more or less air till I could start the bike on choke with the tape in the correct place. Then, I believe it would be just a matter of epoxying a piece of metal across the opening to allow a bit of air through but not as much as if the flap is just missing. Not sure how well this would work but it would be a lot easier than putting the flaps on the inside where they could fall into the engine again.

Post edited by: wiredgeorge, at: 2007/04/04 14:46

The choke is just the old-fashioned plate-over-the-opening type, with the trap-door flap as described. I think you can get the hand-over-the-intake effect by just making plates to cover the opening where the flaps were. That means you will have to play with the choke lever at startup.

Or you could actually try the hand-over-the-airbox-opening trick to get it started. Usually it just takes some playing around to get the right feel for starting reliably. At least, then you'll be the only one who can start it.



Post edited by: loudhvx, at: 2007/04/05 05:25

i think i will try to cover the gaps where the plates were, and just learn how to adjust the choke as needed to start the bike when cold

Make sure you use something that can't get sucked into the motor. You might want to just replace all 4 choke slides with 4 solid plates. That way they can't get loose.

Thats what i thought. Probably totally close off where the flaps would be and then use trial and error to figure out how much i need to adjust the choke to start it.

If you get it figured out, that would be great. I know some people who would love to have that info.