kz750 ltd h2 1981 - will crank wont start fully?

hi all

here is a technical challenge for you!

my project bike is complete. the battery
is fully charge. the petcock now works,
i put the new diaphragm on the wrong way!
soon found out, it leaked.

good sparks!

fuel was put the tank, about 3 litres.
switched on, pulled in clutch, pressed starter button.
twisted throttle, the engine cranked fast and good.
the engine has only done 6,600 on a 1981.
popped and banged, still wouldn't fully start?

i've not done engine timing before.
the electronic ignition is brand new and all
parts fully tested.

could it be the timing?

i live miles away from any bike shop
and being a timing rookie, i've just
bought an inductive timing light from amazon.

is the timing easy or very technical to do please?
the timing has never been done on this engine.
it was stored in plastic shrink for years.

many thanks ya all, for helping me!

kind regards

angel

steelhorseangel wrote: hi all

here is a technical challenge for you!

my project bike is complete. the battery
is fully charge. the petcock now works,
i put the new diaphragm on the wrong way!
soon found out, it leaked.

good sparks!

fuel was put the tank, about 3 litres.
switched on, pulled in clutch, pressed starter button.
twisted throttle , the engine cranked fast and good.
the engine has only done 6,600 on a 1981.
popped and banged, still wouldn't fully start?

i've not done engine timing before.
the electronic ignition is brand new and all
parts fully tested.

could it be the timing?

i live miles away from any bike shop
and being a timing rookie, i've just
bought an inductive timing light from amazon.

is the timing easy or very technical to do please?
the timing has never been done on this engine.
it was stored in plastic shrink for years.

many thanks ya all, for helping me!

kind regards

angel

Don't touch the throttle when starting a KZ. Choke on / key on / petcock on / pull in clutch lever / hand off the throttle / push starter button / listen to engine start and smile. Ed

hi ed

thanks your message!

i believe you, i really do. i will try your method
tomorrow. is this standard starting procedure
on all kz's or just the kz750 ltd?

q) as the timing has ever never been set, does this
contribute to my starting fully problem?

q) why does it bang, cough and splut?
is it trying to clear its tubes?

we accidentally left the choke on and try to fire
it up, an hour later. there was a small pool of gas.
then i noticed the gas in the overflows.

she banged like a bomb going off, still wouldn't
start. flooded maybe!

many thanks for your advice matey!

angel

Can you post a Video link of the bike trying to start?
It could be that the Ignition timing is to far off. Or that the wiring from the electronic Ignition is incorrect, firing the coils wrong. 1&4 2&3 grouped, but each needs to spark at the correct time. Could be that its 180 degree out here. Easy to swap the primary wires at the coils to check if its that. Or you could use a timing light and see if the #1 cylinder is firing when the 1/4 mark is aligned.

hi motorhead

many thanks for your message!

do you like motorhead, the metal group then?
i love all metal bands. my fave tune
is by the scorpians 'rock me like a hurricane!'

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.

the only thing that i've not done is adjust
the timing. i've never done this. just sent off
for an inducting timing light from amazon.
i will have a good read of boyer's timing spec.
and the kz workshop manual. this is the only
adjustment that i've not done. a learning curve
for me!

is timing adjustment hard to do?

many thanks for helping me motor!

regards

Angel

hi all

other than stock or dyna has anyone installed
a boyer bransden electronic ignition?
they're based the uk. please follow this link:-

www.boyerbransden.com

5 year guarantee!

.

hi csr!

thank you for your message!

the vacuum petcock is a stock item!
we've just rebuilt this. the fix kit was new.
however the assembly can be rebuilt two
ways. on the little white square of plastic.
there is. small slot. not sure what this is for?

q) what position does the slot go in?
i've a oem workshop manual, doesn't say.
i then checked the parts diagram, nothing?

q2) as we initially got leaks from the petcock.
we found that i'd put the diaphragm in wrong.
this was corrected, no leaks. 3 litres of gas put in
to test. how much fuel is present on res?

another kzr kindly advised that you don't touch
the throttle at all. please see his previous posting!

turn on kill switch
turn on ignition
turn on choke, prime
pull in clutch switch
press starter
Dont twist throttle!!!!
engine starts
big smile

i will try it today and let ya all now!
fingers crossed!

regards

Angel

.

Did you time the pulse coils down by the crank shaft? You should time 1 and 4 first then 2 and 3.

As was mentioned before,check that the wires are not backward from the pulse coils to the ignition coils. Most eledtronic ignition uses the left pulse coil for 1 an4 and the right for 2 and 3.

steelhorseangel wrote:
q) why does it bang, cough and splut?
is it trying to clear its tubes?

we accidentally left the choke on and try to fire
it up, an hour later. there was a small pool of gas.
then i noticed the gas in the overflows.

she banged like a bomb going off, still wouldn't
start. flooded maybe!

many thanks for your advice matey!

angel

Small pool and fuel in the overflows suggests that one or more float valves are not doing their job. Bang also suggests this as raw fuel in the exhaust will ignite rather enthusiastically. Leaving the choke on when the engine is off has no effect, no worry there.
Check the engine oil level. If it is unusually high, or if there is a strong odor of gasoline in the crankcase, STOP! Change the oil before proceeding. A malfunctioning float valve can allow fuel to drain into its cylinder, which will then drain past the rings into the crankcase. Trying to start an engine in this condition can lead to bent rods or even a BANG several orders of magnitude larger than you have so far experienced. Think grenade.....
Any time the fuel tank has been off or the carbs taken apart, 10 or 15 seconds of PRI is needed to fill the carb bowls. After that, turn the petcock to RES or ON depending on the fuel level in the tank. The starting procedure mentioned above is right on and is good advice for any carburetted scoot.
Good luck. Oh yeah, setting the timing is not complicated, but to use the light, the engine will need to be running. You can get it in the ballpark using a static method. I would expect that method to be part of the instructions that came with the new ignition and in the shop manual.

hi roy

thanks for your message!

a boyer bransden ignition system has been fitted.
i don't know how to do the technical electrical
stuff.

i will contact boyer on monday, things
you know, things you don't know!

kind regards

Angel