'81 KZ440 problems.....big ones.

Iknow this is probably against group ettiquette, but I've already
posted about this in rec.motorcycles and I think it might get some more
views here. Plus, this being a more tech oriented board, I thought
there would be more advice.

I bought it last month, it was sitting a long time. Long story short,
I had a leaky carb problem that I just can't solve, and some really
strange engine behavior.

Well, originally, I could not get gas to flow through the carbs, now I
can get it to start and run reasonably consistently--

I took the carbs off again and gave them another once over, and made
sure things like the diaphragms were good, and made sure the jets are
good and whatnot. I already replaced the float needle, and the floats
still, well, FLOAT, but...they still leak. I think part of the problem
is the petcock, though.

I'd replace the needle seat if I could, but it doesn't seem to be
removable. I'll check the manual and confirm, though.

I got a new pilot screw when I bought the rebuild kit, but I can't find
the mother to replace it. I checked the exploded parts view in the
repair manual I have, and it's apparently up near the diaphragms, and
should have a plastic cap covering it. I only see a metal peg at that
spot. I checked it against the other set of carbs I have, and the same
thing. So if I'm supposed to replace it, it's a mystery how to get to
it....

But the problem I'm having right now is it will only run with the choke
closed. It runs reasonably well for a minute or so, I don't even need
starting fluid now. But then it starts to struggle and pop. It seems
like it's popping back through the carb on the right side. If I run it
for long enough, the exhaust gets really smoky on that side, and the
pipe will start to turn red hot near the head.

I'm no expert, but it seems to me that I'm getting early detonation,
which causes the pop back through the carb, and I'm also getting some
fuel burning in the exhaust gasses. But I don't know. This is the
first time I've dealt with this kind of thing. I'm thinking bad valves
on that side? Perhaps the timing is borked.

Interestingly, when I first fired it up today, BOTH pipes were getting
extremely hot, but now it appear to be only the right one. Still, to
start with, only the right pipe had really smoky exhaust.

I'm stumped, and I'm.......disinclined to crack in to the head to see
for myself (i have a history for those kinds of things...A bad one)

It may be possible that the exhaust valve is exceedingly worn, so the
exhaust gasses aren't escaping fast enough, causing excessive heat in
the cylinder which would cause the detonation, but that wouldn't
explain the super hot exhaust pipe. I think. But hey, it may not even
be a valve issue.

Any advice would truly be helpful.
Thanks
Tokay

 

It sounds like you are starving for fuel..
Not enough fuel is getting from the fuel tank through the carb.
Problem could be any on, or a combination of:
1.tank not venting
2.petcock and/or fuel filter clogged
3.float valve in carb stuck, and not opening properly
4.pilot jet clogged.
5. etc.

 

At least you didn't crosspost your message to both groups. Then this
thread would
be endless and every Stumpbroke Texas KY Jelly Butt and their San
Francisco Cheerleader and every Dry Stick Canadian in Reekie would feel
they had to answer.

Yeah, right. Strange behavior. Like nobody ever experienced a gummed up
set of carburetors before. ;-)

Well, if you suspect the petcock isn't holding gasoline, just
disconnect the fuel hose and let it drip into a container. If it fills
the container you have a leaky petcock. Automatic vacuum operated
petcocks have a diaphragm to pull the cone shaped valve on the back
side of the petcock open, then a spring pushes the valve closed.

There might be crud on the valve seat in the petcock, or maybe
corrosion that needs to be scrubbed away with a gentle abrasive
material.

Petcocks sometimes leak around the 4-hole grommet, too. They can leak
from the PRI hole to the outlet hose even if the lever isn't in the PRI
position, if there is a groove
eroded between two holes.

Sometimes you can just remove the expensive grommet
(they cost around $20 if you have to mail order one separately) and
flip it over, or rotate it 90 or 180 degrees to get the grommet holes
to line up in a position where the
unwanted groove isn't allowing gasoline to pass from the PRI port to
the outlet.

Kawasucki has bought dozens, if not hundreds of different part number
petcocks for their ever-changing models, but the grommets are probably
very generic. One grommet probably fits 20 different petcocks. Problem
is, you call up your local Kawasucki, and you talk to a Certified
Nosepicker behind the parts counter, he won't be able to help to find
the right part. He finds a basic part number and it's followed by a
dash number, and that blows his feeble mind.

So you have to learn to go through the parts diagrams yourself to get
the simple parts you need. Sometimes you have to tell the Parts Retard
that you have some later model Kawasucki to get the creep to find the
part you need.

Or, you can order petcock rebuilt kits from www.oldbikebarn.com and get
a more generic aftermarket kit.

I have a mail order envelope sitting on my desk right now. It has the
$10 grommet for a 1985 Kawasucki in it, but it cost me $20 to special
order it when three local Kawasucki Retards couldn't find the right
part.

I looked at the carburetor parts diagram on www.partsfish.com and it
doesn't show a removable valve seat, so it's probably cast into the
carb body.

If you have the carbs off the engine, turn them upside down and look at
the valve seat with a magnifying glass. You might find that there is a
tiny bit of varnish on the seat.
Carefully remove it with some fine emery paper on the end of a small
slot screwdriver, taking care not to remove metal.

Keep in mind that the rubber float bowl gaskets probably dried out, and
they will weep gasoline until the rubber soaks up enough gas to expand
and stop the weeping.

Part number 92066 is probably a thin metal plug. Use a small twist
drill, rolling it between your fingers to start a pilot hole. Maybe
roll some tape on the end to give your fingers some more leverage. A
machinist would have a tool called a "pin vise" to grip the drill. If
you have a set of jeweler's screwdrivers with interchangeable tips,
that might work.

Once you have, say, a 1/16th inch pilot hole drilled, enlargen it to
about 3/32nds or 1/8th of an inch, then screw a small sheetmetal screw
into the hole. Pull the screw and the plug out with a pair of pliers.

Then, before removing the screw, turn it all the way CLOCKWISE,
counting the turns until it stops turning. Write that number down. You
can then remove the screw. Don't lose the spring, tiny washer, and tiny
o-ring.

You can squirt Berryman's B-12 Chemtool Choke and Carburetor Cleaner
down the hole. Get it at Wal*Mart or any good auto parts store. $3.00
will get you an aerosol can or a 15-ounce can of the liquid B-12.

( If you live amongst English gentlemen and Yobs and you call gasoline
"petrol", you are advised to find a carburetor cleaner that contains
xylene, acetone, methyl alcohol, toluene, etc. Don't use a fuel system
cleaner containing "petroleum distillate", that's for fuel injector
lubrication.)

The spray will go down the hole and split 4 ways. One way will come out
the hole directly in line with the screw, so cover that hole with your
finger and keep spraying.
B-12 will then come out of the transition ports just downstream of the
throttle butterfly.

Cover those holes with your finger, too, and keep squirting B-12 into
the hole. The
B-12 will then come out through the idle jet and the pilot air jet,
which is probably in the carburetor inlet.

Cover the end of the idle jet and make the B-12 flow through the pilot
air jet. Cover the pilot air jet and make the B-12 flow through the
idle jet. When B-12 flows freely through all those holes, your idle
mixture circuit is clean enough to stop all those problems you imagine
you're having.

Do not lick your fingers when they are wet with B-12. Very, very bad
for the liver.

When you reinstall the idle mixture screw, assemble the spring, washer
and o-ring in the correct order and screw it all the way in until it
just barely stops. Then turn it back out the same number of turns you
write down and you're back to the factory setting.

You don't need a new metal plug, because the o-ring will stop leaking
gasoline.

That's because your idle mixture circuit is all plugged up.

Don't be silly. A detonation is a loud BANG! and it can break your
piston when it is contained inside the cylinder with the valves closed.

Except for a single backfire out the exhaust, or a backfire out the
carburetor mouth, you will never hear a 4-stroke engine detonating
unless you are actually riding the machine. And you will, by gawd
*KNOW* that your engine is detonating from the loud *clanking BANG!"
sound emanating from its oily guts.

The fuel in the exhaust pipe is coming through the choke starting
enrichener circuit.
Starting enricheners suck gasoline straight out of the float bowl.

Clean your carburetors until they are surgically clean. The tiny idle
mixture ports and the tiny idle jet causes more problems than you can
imagine. Newbie mechanics go through all the troubleshooting steps they
learned from working on cars, but don't know about the gum and varnish
buildup in the idle circuits that cause 90% of their problems.

Neither is probably the case.

The inlet valve guide seals were probably leaking oil into the
cylinders and that was burning out. And the alcohol additives in fresh
gasoline is cleaning your carburetors out.

The solution is to ride the motorcycle regularly, and put about 4
ounces of Berryman's B-12 into a full tank of gas every few months and
ride the carburetors clean.

You are definitely right about your decision not to open up the engine.
Leave the cylinder head right where it is, and, if you really feel that
the head should come off, get an experienced mechanic to do it for you.

But, I have faith in the B-12 process. Anybody can douche their
carburetors clean.

What a weird notion. Worn valves LEAK, they don't hold hot gasses worth
a damn.

See, it's like this. The crankshaft pulls the cam chain around. The cam
chain turns the camshaft. The cam lobe pushes the exhaust valve open.
The exhaust valve has no choice, it has to open, it cannot hold hot
gasses inside the engine if the camshaft pushes it open.

 

Check out the forums and archives at http://www.kzrider.com and if you
need parts, Z1 Enterprises has a good selection. Check them out at
http://www.z1enterprises.com

HTH,

- Nate >>

 

Remove the petcock and check the screen inside the tank.

- Nate >>