Carburetor problems

I have a 1981 KZ 650 H1 that is heavily modified. It has a wieseco piston kit bored out to 700cc (necessary as the cylinders were rusted), pod filters(which i haven't installed yet, as i cant fix the carbs), and i believe i will need to get new jets for the carbs. my problem is that i have literally no idea what i'm doing anymore, and i'm at the end of my rope with this bike. it's been almost 4 years of tinkering and i am nearing the point of no return with my budget. i love my bike and want to be able to keep it. I'm not sure what size jets i need to get for this bored out engine, and it wont start until i get them. it is perfect, it kicks, and even starts with starter fluid, only one or two kicks, but it needs something i don't know how to do. my options are to either figure something out or get rid of it. it you need more information i can get it, but i don't know what is relevant to my problem. electronically, it's brand new and mechanically, it's almost perfect, minus carbs.

i know i sound pathetic, but i just need help fixing this, i'm kinda fed up with it and don't really want to develop this kind of association with my bike. sorry

What you think as a carb problem may be actually a weak spark or no spark due to bad coils/dirty electrical contacts.

Do some simple checks first:

Good compression? You'll need at least 125 psi to produce power. An engine might run at 100 psi but will have low power.

Valves been checked for proper clearance?

With a fully charged battery, check what the input/primary side of the ignition coils is, it should be almost the same.

To check it, get a multimeter(I'm assuming a Digital one here),set it on VDC (Volts, Direct Current)range of 20.

Put the RED probe where the RED wire goes to either ignition coil, and the BLACK probe on either the Negative battery terminal or a good chassis ground.

This test is for the input side of the ignition coils, not for the output side which is the spark.

Turn on the ignition and the run/stop switch to run. A helper might be needed to do this check.

If your bike has the older ignition points, they probably need replacement. Another thought is the ignition coils themselves may be weak/failed internally. www.z1enterprises.com sells replacement coils and sparkplug caps that may also have failed.

If the reading is down around 8-10 volts,your bike needs to have the many and various electrical contacts/connectors cleaned.

Cleaning Motorcycle Electrics

Get some of the De-Oxit electrical contact cleaner and figure on spending a good day going from the front of the bike to the back. It’s a plastic safe cleaner/preservative. www.deoxit.com is their website.

On the older Kawasaki's, a majority of electrical connectors are inside the headlight housing requiring removal of the headlight, then the fun begins.

Do one set of electrical connectors at a time to avoid mixing up what connects to where. Usually disconnecting, spraying with De-Oxit and reconnecting is about all you'll need.

However, when encountering the green crud of corrosion, a brass wire brush may be needed on the pins you can reach.
Some 400-600 grit wet and dry sandpaper strips rolled into a tube should reach the male and female pins in the more difficult to clean connectors.

Smoker’s pipe cleaners, cotton swabs and wooden toothpicks work as cleaning aids.

Really small electrical connectors may require the use of a welders tip cleaning tool assortment.

Most pins in the connectors are coated with a thin plating of tin, and others may be nothing more than copper or brass.

If moisture is added, the resulting corrosion lowers the voltage/current being carried causing dim lights, slow engine cranking, slow turn signal responce and lower input voltage to the ignition coils resulting in weak spark.

The left and right handlebar switch pods will need attention too as they have circuit functions like turn, horn, run/stop, and start.

Usually a spritz or two with actuation of the switch is about all needed for these switches unless corrosion is detected and then careful disassembly is required.

The ignition switch may or may be not sealed to allow spraying the internal contacts. I urge caution if attempting to open this up as springs, and ball bearings may fly out never to be seen again!

If your bike has the older style glass tubed fuses, I suggest replacing them as vibration can cause internal failure. AGX is the type used, and most auto parts stores can get them for you.

Clean the fuse holder clips, looking for signs of overheating(discolored insulation, signs of melting),
I use metal polish on a cotton swab, followed by spraying another clean swab with the De-Oxit and then rubbing the inside of the fuse clip.

Each "Bullet Connector" will have to be sprayed to ensure good connectivity, especially the ones going to the energizing coil of the starter solenoid.

The alternator output “Bullet Connectors” are usually behind the engine sprocket cover and will need inspecting and cleaning too.



The turn signal light sockets will benefit from a spritz from the contact cleaner along with the tail light/brake light socket.

Some brake light switches can be sprayed on the actuating rod, with the spray running down inside to the electrical contacts, others may be sealed requiring replacement if the switch is intermittent in operation.

I think I've covered about all of the electrical systems on the bike.........

Electrical Connectors, Wire, And supplies
www.easternbeaver.com
www.vintageconnections.com
www.z1enterprises.com/catalog.aspx?pid=KPEL1
www.vehicle-wiring-products.eu
www.electricalconnection.com
www.electricalconnection.com/electrical-components/hitachi.htm
www.pbase.com/mainecruising/wire_termination&page=1
www.crowbarelectricalparts.com/butt_connectors.htm
www.ratwell.com/technical/Terminals.html
www.economycycle.com/servlet/the-Bullet-...lectrical/Categories
www.surplussales.com/SolderlessTerminals/WireTerminals-3.html
www.findtape.com/shop/product.aspx?id=32...&width=1436&height=0






Why WD-40 Should Not Be Used On Motorcycle Electrical Items.

For many years, I was proponent of the use of WD-40 on fuse clips, fuses, switches and connectors. After hearing of other peoples experience with intermittent and sporadic activity, I shrugged it off as maybe they did something wrong in the application of the product.

It wasn’t until the time I rode my 1982 GPz1100 B2 model to downtown San Diego that I encountered the problems others had gone through.

After concluding my business downtown, I walked to where my bike was parked, turned the key to unlock the forks, and prepared to start the engine. The key was in the "On" position, yet I had no lights in the dash panel, the fuel pump was not running(I have FI), and the horn and tail light were not working.


Stumped as to why nothing electrical was happening, I remember my earlier conversations about how WD-40 will over time become a non-conductor(more like an insulator). I had some pieces of 400 and 600 grit sandpaper in my tool kit and with them was able to scratch away the coating from the WD-40 on the fuses and clips.

After removing the insulating film, the bike started and ran like it should. Since that time, I’ve told people about the problem with WD-40. If you must use a contact cleaner, I recommend getting some "De-oxit" from Radio Shack Stores or any good electronic supply store.

Emberblade wrote:

I have a 1981 KZ 650 H1 that is heavily modified. It has a wieseco piston kit bored out to 700cc (necessary as the cylinders were rusted), pod filters(which i haven't installed yet, as i cant fix the carbs), and i believe i will need to get new jets for the carbs. my problem is that i have literally no idea what i'm doing anymore, and i'm at the end of my rope with this bike. it's been almost 4 years of tinkering and i am nearing the point of no return with my budget. i love my bike and want to be able to keep it. I'm not sure what size jets i need to get for this bored out engine, and it wont start until i get them. it is perfect, it kicks, and even starts with starter fluid, only one or two kicks, but it needs something i don't know how to do. my options are to either figure something out or get rid of it. it you need more information i can get it, but i don't know what is relevant to my problem. electronically, it's brand new and mechanically, it's almost perfect, minus carbs.

get a baseline setting for the carbs......research what is stock and go up one size on the pilot and two up on the mains if running pods and a pipe......whats in the motor as far as cams, ignition, etc,etc..?

dont start or try to run it without filters on for one thing, sure way to clog what jets u do have and maybe get crap in the slides as well

For an engine to run you need compression,spark and fuel.

If you rebuilt the engine you can rebuild the carbs.
Read your manual,start with the stock settings and work from there.
Make sure all the little passages are clean.

How is the tank,fuel filter and petcock?

Check the filebase lots of usefull info thier also.

The stock jetting is 92.5 mains & 15 pilots. But who knows what in there.
Does the bike have the stock exhaust?

Someone installed a kick starter? You lucky bastard. I miss having that.

Suffice it to say, we need more information here.

Do you have a service manual? ...and all the tools available to perform the entire maintenence chapter? Compression guage, feeler guages, etc.

#1 Compression/Operating condition
#2 Spark
#3 Timing (Cams and Ignition) & Valve lash
#4 Carbs

Those engine checks need to be done first, without assumptions. Mechanics with assumptions work on things for weeks, those who know get things done in hours.

All the information given so far is good, and DEFFINATELY get those filters on there, as they do provide necessary vauum for the carbs to work for the jetting you will need.

The bike should be able to start and idle fine, even with the stock pilot jets, so long as the fuel height (in bowls) is correct and the mixture screw is set extra rich for the pods.

Set idle up higher, pull choke full, and DO NOT use the throttle to attempt to start the bike. DONT TOUCH IT! It actually defeats the starting circuit and makes tuning for starting procedure frustrating.

Run starter/turn it over for about 5 ACTUAL whole seconds, these bikes need to be very highly tuned to start imediately (its possible), but is unlikely in your situation.

If it doesnt start - pull the plugs and look -- wet with gas? needs more air, dry as a bone? needs more gas.
Adjust mixture screw as necessary to add requirement - if it goes beyond 4 turns from loghtly seated, then you need to go with larger pilot.

Depending on your pods/intake tract size/vacuum/compression/cam timing, lift, etc!>!>! you will require X pilot jet - get it You may need to be 2 sizes larger or 3...

Hope you get this worked out...
Keep us posted and we can help.

Cams and ignition are stock for the bike. electrical is almost completely new, i replaced most of the wiring where it was worst, and what is left is new or untouched and working. I know that the generator functions, and so does the electric ignition. Tests from the factory service manual and the Haynes manual show this to be true.

The tank is freshly cleaned and the petcock was rebuilt. the fuel lines are new and the filter is also.

The exhaust is a stock one, a little rusty but nothing that should effect the back pressure and whatnot. Only strange thing is that someone cut off the crosspiece between the two pipes that runs underneath the bike, and the holes were filled. It actually doesn't have a kick starter, but one day... you know what, i have so many problems with it, i'm not even gonna go there.

I mostly use my factory service manual for specs and tests. every tool is at my disposal, i know a guy who has basically every tool i've ever needed. I really wont be able to do any work this weekend on the bike, so I can't run these diagnostics until next weekend at the earliest, and that's the new york bike show... yeah nothings getting done around here until two weeks from now. That'll be my next update.

I do understand that it takes time for the bike to kick over, and I usually keep kicking it until it floods. Not the best practice, but i'm desperate to fix the thing. After a compression test, I may be taking the engine apart again to possibly work on the valves, which would be where the cylinders leak from. The pistons fit perfectly, and were fit by a pro into the cylinders way before i ever got my hands on them.


Thanks for all the positive ideas everyone. really means alot to me.

sorry picture is a little dark

"Stock" carbs?? (manual slide with side located pilot air adjustment screws)

If so, this cleaning method might help:

[Click on image to enhance view.]



Good Fortune!

yeah thats what i have, air adjustment screws. Thanks, I'll give that a try.

Okay, so a quick update. I did a compression test. Unfortunately, the 4th cylinder gets to just about 40psi, while the rest peak at 145psi. After doing the tests recommended to me, putting oil in the cylinder to rule out bad piston compression or ring problems. That leaves the valves and their seats, which i believe to be the problem as they were the only thing that I neglected to replace. I probably will need to send the head out to be machined back into the correct size, or greater, but i'm unsure if that is neccessary. I'm going to move this post to the correct forum so that anyone with similar problems can find it.