kz750 ltd h2 1981 - will crank wont start fully?

thanks ed!

i will change the #1 and #4 leads tomorrow,
fingers crossed!

i will let you know!

how many years have you been a mechanic?

i paint animals, i'm a wildlife artist!

regards

Angel

Personally, I wouldn't use NGK iridium plugs in a KZ750-H2. This is because NGK doesn't list an iridium plug for that model bike, they list the standard B8ES plug. Consequently, there is no way of knowing if the iridium plug is of the correct heat range and possibly even the length. Maybe NGK's European site shows different plugs? How did you select the plugs you are using?

Oh, I'm not a mechanic (just ask anyone on this site); I just like playing in grease. Ed

The cylinder that is not firing, maybe a vacuum leak or a Idle circuit in the carb plugged. Does the pipe get hot at a larger throttle opening? The Idle adjustment mixture screws you said were stuck, you now have them working? How many turns out from lightly seated, about 1-1/2 to 2 turns?
Maybe the cylinder is still not getting fuel, so what does that spark plug look like?

hi ed you're a Guru to me!

thank you for your help!

in the uk we've a company called wemoto
do a search on this company for
the two kinds of plugs.
i asked boyer bransden about
the plugs, they said upgraded
ignition could use ngk iridium
for a better spark. however they
cost over 3 times as much, but
are they any better? they say longer
lasting, more efficient spark etc
which is the best? electronically wise
things have moved on.

q) would a modern electronic ignition
system be better with a standard b8 plug
or a modern alternative the iridium?

regards

Angel

I believe Bransden is giving you a bunch of hype regarding their ignition system (keep in mind; they want to stay in business). You may not know it, but your bike already had an excellent Kawasaki electronic ignition the day it was built. So your ignition has not been upgraded; it has simply been swapped out for a different brand (which frankly may or may not be inferior to the original). Most folks who switch from points to electronic use Dyna ignition and coils; although in some cases they are able to find a Kawasaki electronic ignition to fit their bike which draws less current than the Dyna. I don’t know what the current draw difference is between the Bransden and the original.

Assuming you are using NGK BR8EIX plugs, they should work ok. I found a cross reference that says they are equivalent to the NGK B8ES, so the heat range and plug length should be the same. Whether or not they provide any advantage that makes them worth 3 times the price of a normal plug remains to be seen. Perhaps someone else on this site with hands-on experience using iridium plugs will chime in. Personally I use ND Hot-U plugs in my bike, but NGK make a quality plug too.

The only difference that you would be able to tell in those expensive IR plugs, is a lighter feel to your wallet/ purse. Unless you feel that you would get 100,000mi of riding on a set of plugs. Better to get the B8ES, or equivalent.
Is your cylinder firing now? Was it just that the plug was fouled with black wet carbon?

hi ed

thanks for your reply!

when i bought my bike, they're like hens teeth in the uk!
i've never seen another one. the whole bike looked ok, but frozen in time
with rust and decay. lots of parts missing, or the wrong parts fitted.
my clocks were 1980, the harness matched the bike. the harness didn't
match the bike. this became my quest to find parts to complete the bike.
i'd an oem ignition system fitted from factory, the coils had gone bad.
the cost over here for suitable coils were a lot. it was cheaper
to change the whole system over to one that they use on racing bikes here.
i understand what you mean about the oem parts. it's my location in the
world. no oem parts, you never see a kz here at all.

here is what boyer wrote to me:-

*************
Hi Angela,

Top dead centre (TDC) is the (0 deg) position when the piston right at the top of its stroke in the cylinder bore.
With your machine, the 4 pistons are arranged on a 180 degree crankshaft, therefore 2 of the pistons will be 180 degrees out of phase with the other 2 (for reasons of balance).
TDC of any piston can easily be found by carefully inserting a wooden dowl (pencil?) through the plughole of the cylinder concerned. The engine can be turned over more easily from the back wheel if all the plugs are loosened or removed to reduce compression in the cylinders.Using a dial gauge indicator is a more accurate method of determining the top of the stroke than a pencil. With any cylinder in its TDC position, the degree wheels 0 degree position can be referenced with a mark on a suitable part of the crankcase. If the engine is then rotated in the normal direction of rotation for 360-40 deg = 320deg (to reduce the effect of backlash), the MAX ADVANCE position (40 Degrees Before Top Dead Centre) can be marked. This will be the max advance strobe timing mark for 2 of the cylinders. The timing mark for the other 2 cylinders should be made 180 degrees around on the crankshaft.

Regards,
Kevin - techl.

**********

i've not set the dynamic timing as i don't know how to do it correct for 1 & 4,
2 & 3. It's strange that 1 & 4 are warm pipes, yet 2 & 3 are hot.

i need to research the use of a strobe and to hopefully set the 2 pairs of cylinders.

Also pilot idle, air/fuel mixes, never ending, but a constant challenge!...

many thanks

Angel


Boyer Bransden Electronics Ltd
Frindsbury House
Cox Street
Detling
Maidstone
Kent
ME14 3HE

Tel: 0044 (0)1622 730939
Fax: 0044 (0)1622 730930
Website: www.BoyerBransden.com

hi motorhead

not had a chance to do anything today, some friends have called around!

back in the garage tomorrow. 2 pipes 2 & 3 are hot, 1 & 4 are warm?

i need to look at air/fuel mixture and pilot adjustments.
it's a voyage of discovery motor!..

i know that the bikes, starts and stops, sounds ok!..
i will post a movie as and when i work out why the other two cylinders are not
firing properly.

i personally think it's my lack of knowledge about all things mechanical!
the strobe hasn't been done. i tried to do this and i don't understand
about time setting for 1 $ 4, then 2 & 3. it's coincidental that
the cylinders that i'm having a problem with are 1 & 4, so is this a timing
problem?

ed disagree's with boyer about the timing degrees etc

thanks for your help, as always!

kind regards

Angel & 'Eric'

steelhorseangel wrote: "ed disagree's with boyer about the timing degrees etc"

I don't recall saying anything about boyer's timing degrees instructions? The only time I even mentioned the word timing in this entire thread was when I found it odd that the boyer folks said you needed a separate battery to use a strobe, and in that posting I recommended you follow their advice since they made the ignition system. Here's the posting:

650ed wrote: "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?"

Angel, does your timing light/gun, have an advance wheel/digital controls? (For settings degrees).

The Timing instructions from Boyer talks of having a degreeing wheel (which I am assuming you dont have...) for attaching to the crank and using to mark ignition cam.

This doesnt really help you that much for inital advance, which would be lining up your case mark with the "F" mark on the ignition cam.
They are talking about Full Advance, which happens after teh bike revs up past 3500rpm or so. The advancer changes the spark from around 10, to 40 degrees before TDC (in a smooth arc of progression) for proper operation.

To check your timing, you must first aquire a degreeing wheel.
Set TDC for 1-4 accurate as possible, install degreewing wheel, then advance motor 320degrees, and place a corrosponding mark on the ignition cam in direct relation to the case mark.
Then do the same for 2-3.
Then with engine running, and revving bike out to where full advance occurs. Look with timing light, and the mark you made should line up with the case mark (hence 40degrees full advance).

If it is to the left of the mark, you need to rotate your ignition plate counterclockwise slightly and retry, opposit for if its on the right of course.

I realize this is a bit crazy and complicated, but we can walk you thru it if you get a degreeing wheel.

Best of luck - you're almost there!

PS - the colder cylinders is "probly" not related to timing, and more so related to carb/air leak/etc.

hi tek.

thank you for your reply!

no my timing light is a simple one.
it has an inductive connector, croc clips.
it doesn't have a timing wheel.
i did download one in *.pdf format.
one was marked clockwise, the other is
anticlockwise.

i think i understand the mechanics, here
goes in rookie speak.

the engine is divided into two, each half
has two cylinders = 180 degrees. this
could be #1 & #4 or #2 & #3. as one half
goes up, the second half goes down.
each pair of cylinders have a different
timing mark.

q) are both timings marks for 1,4 & 2,3
marked on the stator engine casing?

boyer hasn't come back to me yet.
i sent them some more questions today.

boyer advise 40deg adjustment. that's
20degs per 180degs. so that equates
to 160 per rotation, clockwise or anticlockwise?
160*2=320
320+40=360

i wish that i could see one of you
guys adjust your timing!

clockwise or anticlockwise?

many thanks

Angel

hi tek
how can i see two timing
marks for 1&4, 2&3 when the stator plate
is covering up the timing plate and the magnetic
rotor wants rip your hand off!

could you do a simple drawing please!

do i turn the engine clockwise or anticlockwise?

what do the marks 1 l 4 mean on the
timing plate?

i can see why mechanics are always busy!

many thanks

Angel