KZ-440?

When I blew air thru the carbs there was junk in one of the passage ways. The carbs are clean at this point.

Last season it ran and ran okay, but on one cylinder. Replacing the plugs fixed that problem.

I did not measure the fuel level in the bowls - I need to get a clean hose and will do that tomorrow.

Can this be a fuel mixture issue - To lean, perhaps?

Post edited by: bullitt00692, at: 2007/03/24 23:15

bullitt00692 wrote:

...Can this be a fuel mixture issue - To lean, perhaps?...

Well, yeah, it could be. The only weird thing is that it ran before...
If your bike was in unknown condition before, like you just bought it or something, I'd be swearing your problem was from clogged fuel filters, clogged pilot jets, bad float jets, or the floats set incorrectly. Basically, anything that stops nice fuel delivery to the pilot jet system.

However, since it ran before, it just keeps making me think that the only problem you could really have is dirt. I mean, carbs don't just jump out of adjustment, but they do just automatically get clogged over a winter with sediment and old fuel.

Oh well, it's a good thing to check your float levels whether it affects the problem or not. Proper float operation is IMERITIVE to a proper running engine. In my opinion, it should be one of the first things set/checked when troubleshooting the carbs, to set a good baseline.

okay - here are more bits of info.

I removed the boots from the carbs to the airbox and can now start it with chock closed (butterfly's closed) and bike will idle at 5000 - 6000rpm. I can open the choke to the half way point and RPM's lower to about 2000 RPM and if I open the choke much more, it will stall.

Any logic to this?
:silly:

bullitt00692 wrote:

okay - here are more bits of info.

I removed the boots from the carbs to the airbox and can now start it with chock closed (butterfly's closed) and bike will idle at 5000 - 6000rpm. I can open the choke to the half way point and RPM's lower to about 2000 RPM and if I open the choke much more, it will stall.

Any logic to this?
:silly:

Actually, with the choke, I would expect your bike to not be happy running on choke once warm. That's kinda normal.

In the first part, you mean you're holding the throttle open a bit to achieve the 5000rpm? If so, that got me thinking. There are two major things going on at that rpm range:
1 - you're using the main jet, not the pilot jet
2 - you're in a range where you the auto-advance is fully advanced
So for 1, it kinda suggests that your pilot system is still clogged or dirty or otherwise restricted. For 2, maybe you should give a good look at the autoadvancer and make sure it's returning to a rest state properly. I mean if it was frozen or rusted in a fully advanced state, it might also cause this....

What is an autoadvancer?

I am thinkign something is not 100% within the Carb - When the chock is open and the engine shouldn't the RPM's drop - Becuase they do.

But then when U twist the throtle, the bike dies.

This is starting to get beyond me - May need to pay the $$$ for a mecanic

I am having the exact same problem bike will run at 5000 with the choke on..this is after taking them apart twice to make sure all jets are clean, the left bowl is leaking (over flow) so I think the float pin is bad the new plugs i put in ..one fowled out right away (the left one) any one got a link to rebuilding carbs?

S!

Perhaps I need to understand how the carbs work so I can fix this problem.

Main jets are for higher RPM and I guess used with fully open.

Pilot jets are for lower RPM and used with choke closed.

Is this right?

bullitt00692 wrote:

Perhaps I need to understand how the carbs work so I can fix this problem.

Main jets are for higher RPM and I guess used with fully open.

Pilot jets are for lower RPM and used with choke closed.

Is this right?

thats my understanding,....I need to find a manual.

bullitt00692 wrote:

Perhaps I need to understand how the carbs work so I can fix this problem.

Main jets are for higher RPM and I guess used with fully open.

Pilot jets are for lower RPM and used with choke closed.

Is this right?

Well, kinda. The choke has it's own fuel and air passages that bypass both the pilot and main jet systems, so you could be choking no matter how much throttle is open.
The pilot jet system is in effect when the rpms are low and the main passage (main jets) aren't open yet. The pilot jet system also has it's own set of passages that let fuel and air around the main.
Once the engine picks up rpm, about 3000 rpm give or take, the main jet system is in use, allowing more fuel and air.
Hope that helps...

I have a 1980 KZ440A and i had the same problem. I thought it was the Carbs at first but it didn't work even after I Cleaned them out. I had to reset the points gap to get it to work. After I did that it worked fine.

I've had to of these lovely beasts. And the first i had the most trouble with the carbs.. i even went to the length of taking the hole top and bottom end out and re-doing valve seats ect... came down to it.. and the diaphram in the top was ripped. Also check your boots that they're not leaking.. (silicon them when you puttem back on even if they look good). To make sure your floats are working well. When the bowls are off... blow in the inlet of the gas tube.. and manually close the float nuts .. if it stops it great, if it dosn't its not working (clearly) and you need a new flow needle.. If it dosn't let air through when open then its clogged there ( im not sure if you tried this already ) THen like someone else said before CHECK and CHECK again the Petcock.. had soooo much trouble with the vacum valve in there... (first bike) ... These bikes are great once the carb scene is fixed! Don't Give UP!

440LTD wrote:

I have a 1980 KZ440A and i had the same problem. I thought it was the Carbs at first but it didn't work even after I Cleaned them out. I had to reset the points gap to get it to work. After I did that it worked fine.

I was working on a CB550 at the shop today and after manually restricting the airflow (airbox was off) and cleaning and readjusting the points it started right up.

It may be spark.Start up the bike and put your hands close to the end of the exhaust pipe.They should feel about the same temp, but you should be able to hear it running on one cylinder (especially since you said it was before so you know the sound). You can clean your points pretty well with a business card.If it is real corroded then use some sandpaper.