kz750 ltd h2 1981 - will crank wont start fully?

If they made the ignition system I would follow their advice. I have been performing my own tuneups on my KZ650-C1 for 35 years and never have I even heard of using a separate battery; it certainly is not required when using Kawasaki the stock ignition on my bike. All the strobe does is sense the firing of the spark plug (using the inductive pickup clamped around a spark plug wire) and upon sensing that it completes the power circuit from the battery that triggers the strobe light. I guess it's possible that the Bransden electronic components are so sensitive that they are affected when the strobe pulls power from the bike's battery. I wonder if the timing gets squirrely when the turn signals are used?

SORRY ABOUT THE DOUBLE POSTING - I HAVE NO IDEA WHY IT HAPPENED. Ed

I agree, with a stock bike, no extra external battery should be needed for your timing light.
Now on a Dirt bike with no lighting, the voltage would be AC and no DC and the light may act funny or not work at all.
Angel I read you signature and it sounds like you will have a great bike to cherish those memories of your Dad.
Post up when "Eric" is running, or any other questions if you need more help. The KZR bunch will do their best as usual.

Steelhorseangel

3 days ago you said

all the wiring has been checked thoroughly.
the left coil is for 1 & 4 cyls. the right 2 & 3.on the boyer bransden ignition system
you've a link wire, to link the coils + -.
then a green to the coil, returned through inline 10a fuse.
the is a ground wire black. finally two wires
to the magnetic stator. i get 4 super white
sparks.


But your pictures clearly show left 2 & 3 and right 1 & 4

Could it be that you have things backwards ? Like ramtough_63 said ? Worth a double check on the wiring perhaps ?

hi motorhead!

thank you for lovely words, what a nice
guy you're!

*** yippee Eric runs! ***

the local mechanic alan was brought it.
he loved my bike. he trained on them in the
80's! i set the F stop, Alan adjusted the carbs.
they still continued to leak, bike cuts out.

i paid £300 for the carbs to be completely
serviced. ultrasonic cleaning, new parts, milled
out 3 idle screws. i even got a 5 page
report on them. in reality this bad welsh company
ripped me off, cleaned the outside and left
unserviced parts inside. alan and i took the
carbs apart, found floats at all levels. two lower bowls
leaked. also i'd the carb top lids chromed
and they polished nearly all the rivets off.
under load the inside of each lid, a small metal cup
dropped from each lid, resulting in no suction!
as eric started with the initial static timing.
alan connected up the carb balancers. at first we
didn't get any readings on the balancer?
as the carb top innards had all fell apart, the
carb diaphrams couldn't work correctly.

finally the bike was static timed, carbs balanced.
the mechanic couldn't get the bike to idle correctly.
told me, it was the most confusing bike
he has ever tried to get started.
suggested that the petcock is problematic.
he checked this, advised a pingel valve and pingel
hi flo everything.

eric is now shattered, he has now gone
to his garage. he has had his nuts reved for
about 5 hours!

the mechanic wants to use all of carb spares
and rebuild a better set of carbs. his said
this might solve the non idling consistantly problem!

i'll will keep you posted!

Yippee!

Angel

Did the mechanic test the carb holders to see if they are leaking (letting unwanted air in at idle)? They are easy to test. Set the idle as low as possible (the lower the better), spray carb cleaner at the joints where the carb holders mate with the cylinder head and where they mate with the carbs. If the carb holders are leaking they will permit some of the carb cleaner to be drawn into the engine which will affect the idle. (When mine were leaky the engine actually stopped running when the carb cleaner was sprayed). Leaky carb holders can have a terrible effect on idling even though they have practically no effect on the engine running at higher rpm. This is because with the throttle closed the engine vacuum can't draw much air through the airbox so it will tend to suck the air through the leaky carb holders. When this happens the idle becomes very erratic. If yours are leaking replace them; trying to seal them up with gook isn’t a very good substitute. Ed

Glad to hear the bike is going, but not hearing that the carb work was so poor. Its a bad problem having things done incorrectly but still paying.
Hopefully this other mechanic you are using now will get "Eric" all set up and be fair on the price. Just being able to listen to the engine run has to give you a emotional high. The spring/ summer is not far off now.
Post up a video of the Bike when you get a chance.

steelhorseangel wrote: finally the bike was static timed, carbs balanced.
the mechanic couldn't get the bike to idle correctly.
told me, it was the most confusing bike
he has ever tried to get started.
suggested that the petcock is problematic.
he checked this, advised a pingel valve and pingel
hi flo everything.

the mechanic wants to use all of carb spares
and rebuild a better set of carbs. his said
this might solve the non idling consistantly problem!

Well... No offence to anybody, but your new mechanic is not totally competent with these bikes.

You DO NOT perform a vacuum balance syncronization until all other problems have ben ruled out.
The bike when setup bench synced and static/stock settings will start and purr like a kitten. Often hardly needing any vacuum sync at all.

These bikes are fairly basic and straight forward to get cleaned up, started and idling fine. Vacuum syncing before things are setup correctly, only makes problems worse and masks other issues.

As long as the stock petcock doesnt piss gas everywhere, and flows gas correctly when on, there is NO reason to replace it with anything! Dont waste your money.

Sorry about your bad luck finding a decent mechanic, but it is difficult to find people as familiar with these bikes as you will find right here.

PS - Petcock has nothing to do with idling... You can have the gas off and as long as the carbs have filled to thier stops (all level at correct fuel amount), the bike will start up and run fine for several seconds before it starts to lean out as fuel is consumed from the bowls.

MFOLKS, please post your carb cleaning 101 -or just search for it.

THE BEST MECHANIC FOR THIS BIKE IS YOU! Your work looks great. You have the time. Just grab a service manual - and ask questions here. You will be riding in no time.

hi ed

thank you for your message.

i've changed all of the carb rubber boots
on both sides of the carb. the carb has been
tested for leaks.

when i bought the exhaust system 2 into 1 x 2!
i was advised not to use assembly paste.
i bought new everything for sealing the exhaust
ports, new brass gaskets. again i was advise
not to seal the ports with 'fire putty'. this came
from the exhaust company! however when eric
started i saw gases seeping out.
this is todays job!

sadly i didn't have a choice of mechanics.
i live on the west coast of the uk. there
is an expensive yamaha bike shop, that told
me to buy a new bike. wouldn't give me
any advice without paying high $!

the local cheap mechanic doesn't concentrate
very well at all. the bike started, he tweaked the timing,
after 6 hours of trial and error,the bike started and
stopped, no popping etc. the fuel/air mix
is wrong. the new standard plugs are black, dry and
sooty. the mechanic said he doesn't like
the plugs, buy some ngk b6's not b8?
my grandfather always said 'a poor workman
always blames his tools!'
the mechanic is now blaming the carb
float heights, the jets seem wrong he said.
is this guy struggling or creating a problem
that is not there?
as a rookie bike builder, the air/gas mix is wrong.
the evidence is the sooty black plugs. should be
mid brown,
the bike started first time, next day, no throttle.

the fast idling and the mixture is the wrong.
he blames the needle valves or is this again
a case of creative accounting?

regards and thanks kzr's

Angel

steelhorseangel wrote: hi ed

thank you for your message.

i've changed all of the carb rubber boots
on both sides of the carb. the carb has been
tested for leaks.

when i bought the exhaust system 2 into 1 x 2!
i was advised not to use assembly paste.
i bought new everything for sealing the exhaust
ports, new brass gaskets. again i was advise
not to seal the ports with 'fire putty'. this came
from the exhaust company! however when eric
started i saw gases seeping out.
this is todays job!

sadly i didn't have a choice of mechanics.
i live on the west coast of the uk. there
is an expensive yamaha bike shop, that told
me to buy a new bike. wouldn't give me
any advice without paying high $!

the local cheap mechanic doesn't concentrate
very well at all. the bike started, he tweaked the timing,
after 6 hours of trial and error,the bike started and
stopped, no popping etc. the fuel/air mix
is wrong. the new standard plugs are black, dry and
sooty. the mechanic said he doesn't like
the plugs, buy some ngk b6's not b8?
my grandfather always said 'a poor workman
always blames his tools!'
the mechanic is now blaming the carb
float heights, the jets seem wrong he said.
is this guy struggling or creating a problem
that is not there?
as a rookie bike builder, the air/gas mix is wrong.
the evidence is the sooty black plugs. should be
mid brown,
the bike started first time, next day, no throttle.

the fast idling and the mixture is the wrong.
he blames the needle valves or is this again
a case of creative accounting?

regards and thanks kzr's

Angel

Angel I am not a mechanic but being brought up with every member of my family being highly skilled in the art I have picked up alot by osmosis

first you got it running without popping back firing etc... you cant let performance machines sit and idle alot and read the plugs they will either be black and wet or black and dry or white and new looking no real read. from idling and reving.

get the exhaust leak fixed get it buttoned up and put some miles on it. it will either settle in or develope new issues within a few possibly 2-500 miles then take it for a short ride then another little longer ride then then a little longer ride. dont condemn anything til you actually have a problem. just my .02 keep up the good work

Angel, do your carbs look like this?



This is the Stock CV Mikuni from your year and model. If this looks correct, #16014 is the Slow speed Idle mixture screw. Turing these clockwise, until lightly seated, then backed back out to 2 turns. This should be what your manual says, or close, it may say 1-1/2 turns out. 2 should be better for the colder weather.
Then #92009 is the float bowl drain screw. There is a small hose, or attachment, here that is for the drain. Turn your Pet-Cock to "Prime" and then with the Bowl drain open, and a clear piece of tubing attached to the bowl drain and held up along side of the carb. This will be a sight gauge to show the fuel level. Patton has an excellent picture/ tutorial, and the service manual also covers this. The fuel level is very important, you need to verify that it is set correctly, before you can go and do any carb jetting etc. Check this next/ First Angel.
Also stay with the B8ES Spark plugs, or what they Cross reference to. Do Not put the 6 heat range in the bike. That is way to hot and can cause engine damage, ie a holed piston.

Motor Head wrote: Angel, do your carbs look like this?

This is the Stock CV Mikuni from your year and model. If this looks correct, #16014 is the Slow speed Idle mixture screw. Turing these clockwise, until lightly seated, then backed back out to 2 turns. This should be what your manual says, or close, it may say 1-1/2 turns out. 2 should be better for the colder weather.
Then #92009 is the float bowl drain screw. There is a small hose, or attachment, here that is for the drain. Turn your Pet-Cock to "Prime" and then with the Bowl drain open, and a clear piece of tubing attached to the bowl drain and held up along side of the carb. This will be a sight gauge to show the fuel level. Patton has an excellent picture/ tutorial, and the service manual also covers this. The fuel level is very important, you need to verify that it is set correctly, before you can go and do any carb jetting etc. Check this next/ First Angel.
Also stay with the B8ES Spark plugs, or what they Cross reference to. Do Not put the 6 heat range in the bike. That is way to hot and can cause engine damage, ie a holed piston.

Good advice! If the bike wont idle well/smoothly off choke, you may want to spray/mist some water onto the header pipes. After just a few seconds of idling, the water should instantly vaporize. If the water collects on the pipe, that cylinder is not firing correctly.
You may need to remove carbs and check that the pilot jets are infact clear, not clogged with some fresh debris that was missed.

Checking for air leaks (as Ed mentioned I think), is a good thing too. rely on yourself, cause no-one else is more competent!

Cheers.

- Dont listen to that mechanic! Your suspicions are correct!

By the way - I found a candid photo of the guy who serviced your carbs for 300 quid (see first pic) and of his own motorcycle after he fine tuned its carbs (see second pic):