I'm still tweaking this Kawasaki Eliminator 125
to get rid of the detonation.
Somewhere in the attic, I have an ancient exhaust gas analyzer.
IIRC, it works by passing an infrared light thru the exhaust
and divines air/fuel ratio from that.
Was made back when there was lead in the gas.
Does that method have any value with current engine/fuel
designs?
mike <ham789@netzero.net> wrote:
I'm still tweaking this Kawasaki Eliminator 125
to get rid of the detonation.
Somewhere in the attic, I have an ancient exhaust gas analyzer.
IIRC, it works by passing an infrared light thru the exhaust
and divines air/fuel ratio from that.
Was made back when there was lead in the gas.
Does that method have any value with current engine/fuel
designs?
Sure. Assuming it still works, it has no way of knowing whether you
are using a carb or fuel injection.
Are you sure your detonation problem is definitely down to the mixture
being too lean? Ignition timing would be the first thing I would
check. And before anyone says if the timing is right at idle it must
be OK at higher RPMs, I would not assume that.
I had a weird issue with a 1995 Kawasaki EX500 ignition module (K calls
it the "IC Igniter") that had a timing problem between cylinders (one
was OK the other one was advanced by 6 degrees) even though the engine
only has a single ignition trigger coil, and the magnetic reluctor
pole pieces on the rotor were exactly as they should have been.
Replacing the IC Igniter did in fact fix the problem (verified with
an O-scope).
If this was my bike I would be checking ignition timing at various
RPMs to make sure it's correct.
On 8/14/2017 10:45 AM, Mark Olson wrote:
mike <ham789@netzero.net> wrote:
I'm still tweaking this Kawasaki Eliminator 125
to get rid of the detonation.
Somewhere in the attic, I have an ancient exhaust gas analyzer.
IIRC, it works by passing an infrared light thru the exhaust
and divines air/fuel ratio from that.
Was made back when there was lead in the gas.
Does that method have any value with current engine/fuel
designs?
Sure. Assuming it still works, it has no way of knowing whether you
are using a carb or fuel injection.
Are you sure your detonation problem is definitely down to the mixture
being too lean? Ignition timing would be the first thing I would
check. And before anyone says if the timing is right at idle it must
be OK at higher RPMs, I would not assume that.
I had a weird issue with a 1995 Kawasaki EX500 ignition module (K calls
it the "IC Igniter") that had a timing problem between cylinders (one
was OK the other one was advanced by 6 degrees) even though the engine
only has a single ignition trigger coil, and the magnetic reluctor
pole pieces on the rotor were exactly as they should have been.
Replacing the IC Igniter did in fact fix the problem (verified with
an O-scope).
Can you give more details on how you set up the scope to make that measurement?
I have an inductive pickup that clamps on the spark plug wire to
read the spark. How did you determine the TDC position?
I could intercept the crank position sensor, but that doesn't
tell me whether that signal is in the correct relationship to TDC.
If the timing light says the spark is at the T position on the
cam sprocket, there isn't much one can do.
The service manual has a detailed write-up on how the ignition works.
Has a nice graph of the advance curve, but it has no numbers about
the RPM of each inflection point. I'll take a crack at the timing
this afternoon.
And the bike has no tach. I have a timing light with a tach, but
it's for 4-8 cylinders and the resolution is useless for one cylinder.
If this was my bike I would be checking ignition timing at variousThanks, I'll take all the advice I can get.
RPMs to make sure it's correct.
I've concentrated on carburetor because:
There's little written about this bike, but most of what exists
complains about it running dangerously lean.
The spark plug insulator was bone-chilling white.
It was detonating at speed ranges much above idle under acceleration. Cruising was not a problem for detonation, but surging at high speed
was an issue.
It's a 2007 model with 423 miles on it. Apparently been in
storage for 5 years.
A treatment with SeaFoam and backing out the pilot screw fixed
the hanging idle, but it still detonates. Cranked the pilot screw
out 4 turns and still not much improvement in ping, but it feels/sounds rich just off idle.
I cleaned the carb best I could. There was no gunk in it at all.
I was amazed at how clean it looked.
I wasn't too aggressive because
the manual warns about non-removable internal plastic parts.
They don't say where, but I decided not to use carb cleaner with
acetone or toluene. Stuck with simple green and water in an ultrasonic cleaner.
I couldn't get the pilot jet out. Twisted as hard as I dared and decided
to come back another day. Low speed was ok.
I did hook up a vacuum pump and sucked fluid back thru the jets.
All the tiny holes in the venturi seemed to be open.
External fuel level measurement showed it to be at the low end of
the 4mm spec range. I moved it up to the top end. I was unable
to remove the float pin. It's pressed in and resisted careful
attempts to press it out.
At that point the performance was markedly improved. Spark plug
now has a little color. Still pinging
around 1/4-1/2 throttle accelerating thru the gears, but ok at cruise.
I raised the main jet needle .020", then .035". Both improved the
situation. I'll try one more increment to .050" before I give up.
Raised the main jet to 130. Improved the pinging. It's now
sounding rich at top end. Putting the fuel level back to
midrange might help that.
The performance of the 125 is crap, but probably the best I can
expect from a small engine. My concern is the pinging destroying
the engine. The pinging increases as the engine warms up.
I've been all over it with propane an detected no air leaks.
I experimented with blocking part of the air filter.
With 1/3 of it blocked, the bike would hardly run. Much greater
effect than I expected. I can't see how you'd ever keep the bike
in tune if it's that sensitive.
I'd agree that delaying the spark advance to a higher
RPM might fix the problem. I just don't think that's possible.
I'll take a timing light to it as soon as I get the tach built.
I'll drag out the gas analyzer and see what it tells me.
I have a Snap-ON automotive oscilloscope, but the screen resolution
is too low to see two sparks on screen to measure RPM. Probably
works great on an 8-cylinder car.
Probably time to twist on the pilot jet until it comes out or breaks.
I've tried a lot of stuff, but it should be obvious that I have no idea
what I'm doing. I've been driving the same Honda Shadow VT-500c for
over 30 years. Never had any issues with the CV carbs in that one.
Any additional advice welcome.
mike
mike <ham789@netzero.net> wrote:
On 8/14/2017 10:45 AM, Mark Olson wrote:
mike <ham789@netzero.net> wrote:
I'm still tweaking this Kawasaki Eliminator 125
to get rid of the detonation.
Somewhere in the attic, I have an ancient exhaust gas analyzer.
IIRC, it works by passing an infrared light thru the exhaust
and divines air/fuel ratio from that.
Was made back when there was lead in the gas.
Does that method have any value with current engine/fuel
designs?
Sure. Assuming it still works, it has no way of knowing whether you
are using a carb or fuel inject
Are you sure your detonation problem is definitely down to the mixture
being too lean? Ignition timing would be the first thing I would
check. And before anyone says if the timing is right at idle it must
be OK at higher RPMs, I would not assume that.
I had a weird issue with a 1995 Kawasaki EX500 ignition module (K calls
it the "IC Igniter") that had a timing problem between cylinders (one
was OK the other one was advanced by 6 degrees) even though the engine
only has a single ignition trigger coil, and the magnetic reluctor
pole pieces on the rotor were exactly as they should have been.
Replacing the IC Igniter did in fact fix the problem (verified with
an O-scope).
Can you give more details on how you set up the scope to make that
measurement?
I "made" a scope by constructing a resistive voltage divider network
and connected it to the primary side of the coil, running it into the
sound card of an old laptop. Recording the "sound" of the waveform let
me look at the relationship of the spark pulse vs. the pulse from the
trigger coil (stereo input of the sound card = 2 channel scope).
I knew the timing was off simply by looking at the timing marks with a inductive timing light from the 1980s, still works fine. I could see
the one cylinder was off by 6 degrees vs. the other one (accounting for
the fact that it's a 180 degree crank, naturally).
I have an inductive pickup that clamps on the spark plug wire to
read the spark. How did you determine the TDC position?
By shining the timing light on the timing marks. TDC is engraved on the alternator rotor which is visible through the timing access port. The
correct degree position for timing at low RPM is also marked for both cylinders.
I could intercept the crank position sensor, but that doesn't
tell me whether that signal is in the correct relationship to TDC.
I took a photo of the position of the timing marks when the timing
light fired and measured the angle graphically.
If the timing light says the spark is at the T position on the
cam sprocket, there isn't much one can do.
Sure- you can check to see how far the mark advances as you go up in
RPM. You might have to paint/engrave some of your own marks on the
flywheel to do this.
The service manual has a detailed write-up on how the ignition works.
Has a nice graph of the advance curve, but it has no numbers about
the RPM of each inflection point. I'll take a crack at the timing
this afternoon.
Yeah, without that info, or having some general knowledge about how
far timing should advance (I have a buddy who is an absolute expert
on this stuff) you're going to have to ask or do some research to
figure out what sort of numbers are reasonable.
And the bike has no tach. I have a timing light with a tach, but
it's for 4-8 cylinders and the resolution is useless for one cylinder.
Tach is easy- just measure the time interval between trigger coil
pulses and take the inverse to get Hz, then divide by 60 to get RPM.
If this was my bike I would be checking ignition timing at variousThanks, I'll take all the advice I can get.
RPMs to make sure it's correct.
I've concentrated on carburetor because:
There's little written about this bike, but most of what exists
complains about it running dangerously lean.
The spark plug insulator was bone-chilling white.
It was detonating at speed ranges much above idle under acceleration.
Cruising was not a problem for detonation, but surging at high speed
was an issue.
Yep, sounds lean.
It's a 2007 model with 423 miles on it. Apparently been in
storage for 5 years.
A treatment with SeaFoam and backing out the pilot screw fixed
the hanging idle, but it still detonates. Cranked the pilot screw
out 4 turns and still not much improvement in ping, but it feels/sounds rich >> just off idle.
I cleaned the carb best I could. There was no gunk in it at all.
I was amazed at how clean it looked.
I wasn't too aggressive because
the manual warns about non-removable internal plastic parts.
They don't say where, but I decided not to use carb cleaner with
acetone or toluene. Stuck with simple green and water in an ultrasonic
cleaner.
I couldn't get the pilot jet out. Twisted as hard as I dared and decided
to come back another day. Low speed was ok.
I did hook up a vacuum pump and sucked fluid back thru the jets.
All the tiny holes in the venturi seemed to be open.
External fuel level measurement showed it to be at the low end of
the 4mm spec range. I moved it up to the top end. I was unable
to remove the float pin. It's pressed in and resisted careful
attempts to press it out.
In my experience, motorcycle carburetor float pins aren't pressed in,
they're a slide fit and only held in place by the carb bowl.
I'm thinking about lowering it back to the middle of the spec range,At that point the performance was markedly improved. Spark plug
now has a little color. Still pinging
around 1/4-1/2 throttle accelerating thru the gears, but ok at cruise.
Fuel level has a huge effect on mixture, as you found.
Agree. I did find an independent shop that suggested the .020.I raised the main jet needle .020", then .035". Both improved the
situation. I'll try one more increment to .050" before I give up.
That sounds like a lot.
Raised the main jet to 130. Improved the pinging. It's now
sounding rich at top end. Putting the fuel level back to
midrange might help that.
The performance of the 125 is crap, but probably the best I can
expect from a small engine. My concern is the pinging destroying
the engine. The pinging increases as the engine warms up.
I've been all over it with propane and detected no air leaks.
I experimented with blocking part of the air filter.
With 1/3 of it blocked, the bike would hardly run. Much greater
effect than I expected. I can't see how you'd ever keep the bike
in tune if it's that sensitive.
I'd agree that delaying the spark advance to a higher
RPM might fix the problem. I just don't think that's possible.
What I am saying is that it is possible for your ignition unit to
be defective, but still work. Once you get your head around that,
and check to see whether or not it is the case, you can rule it in
or out. When I say defective, I mean it has the wrong advance curve,
but it still happily produces sparks at the high tension side of the
coil. Just not necessarily at the right time.
I've had this discussion before with people who can't understand that
an electronic circuit can fail in unusual and unexpected ways, not just either working or dead. If you have timing controlled by capacitors,
and the capacitors lose capacitance over time (actually quite common)
you can have weird things happen.
I'm not even saying that bad spark advance is your problem- obviouslyI never run anything but premium gas. I did try three different brands.
the mixture was off quite a bit and you've sufficiently richened it
up so you might be getting to the rich side of things. If it's still
pinging, it might just be too much advance.
Does it get better with premium gas?
I'll take a timing light to it as soon as I get the tach built.
I'll drag out the gas analyzer and see what it tells me.
I have a Snap-ON automotive oscilloscope, but the screen resolution
is too low to see two sparks on screen to measure RPM. Probably
works great on an 8-cylinder car.
Probably time to twist on the pilot jet until it comes out or breaks.
I've tried a lot of stuff, but it should be obvious that I have no idea
what I'm doing. I've been driving the same Honda Shadow VT-500c for
over 30 years. Never had any issues with the CV carbs in that one.
Any additional advice welcome.
mike
I've pretty much exhausted what I can tell you at this point.
Good luck.
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 286 |
Nodes: | 16 (2 / 14) |
Uptime: | 89:07:50 |
Calls: | 6,496 |
Calls today: | 7 |
Files: | 12,100 |
Messages: | 5,277,442 |