How do you clean a Mikuni BS28 CV carburetor USA model?
I bought a 2007 Kawasaki Eliminator 125 (BN125-A8) with 423 miles on it
that had been sitting garaged for 5 years.
I drained the carb and tank. I was amazed at how clean the effluent
was.
But it's running very lean and changing characteristics.
Needs to be cleaned.
This carb is 30 years newer than my previous experience
and has pollution control stuff on it.
Normally, I'd just disassemble it, shoot it full of B12 Chemtool
and stick it in the ultrasonic cleaner.
This carb has a plastic main jet piston and rubber diaphragms
on the piston and the coasting enricher.
The manual also mentions that there are non-removable plastic parts
inside and warns about harsh chemicals with no actual guidance
on where those parts are or what chemicals are permissible/safe.
B12 Chemtool contains all manner of chemicals including
Toluene and Acetone. I'm afraid to put that in this
carb.
I have to remove a bunch of stuff to get at the carb on this
bike. I don't want to do it more than once.
Yes, I did buy a fuel filter.
So, what chemicals and methods does one use to clean
this carb without destroying it?
Is there anything safe and effective to add to gas?
SeaFoam gets a lot of hype Mostly Naptha.
Just pouring something into the gas is a lot more
attractive than disassembly, if I could be confident
that it wouldn't hurt anything.
mike <ham789@netzero.net> wrote in news:okfar6$h54$1@dont-email.me:Interesting misspelling. I have the same problem with trippple. ;-)
How do you clean a Mikuni BS28 CV carburetor USA model?
I bought a 2007 Kawasaki Eliminator 125 (BN125-A8) with 423 miles on it
that had been sitting garaged for 5 years.
I drained the carb and tank. I was amazed at how clean the effluent
was.
But it's running very lean and changing characteristics.
Needs to be cleaned.
This carb is 30 years newer than my previous experience
and has pollution control stuff on it.
Normally, I'd just disassemble it, shoot it full of B12 Chemtool
and stick it in the ultrasonic cleaner.
This carb has a plastic main jet piston and rubber diaphragms
on the piston and the coasting enricher.
The manual also mentions that there are non-removable plastic parts
inside and warns about harsh chemicals with no actual guidance
on where those parts are or what chemicals are permissible/safe.
B12 Chemtool contains all manner of chemicals including
Toluene and Acetone. I'm afraid to put that in this
carb.
I have to remove a bunch of stuff to get at the carb on this
bike. I don't want to do it more than once.
Yes, I did buy a fuel filter.
So, what chemicals and methods does one use to clean
this carb without destroying it?
Is there anything safe and effective to add to gas?
SeaFoam gets a lot of hype Mostly Naptha.
Just pouring something into the gas is a lot more
attractive than disassembly, if I could be confident
that it wouldn't hurt anything.
sea foam won`t hurt anything in your carbs. I would put a doubble
strength dose of it in a tank and run it out first. Have had good luck getting that to free up the carbs. if that doesn`t work then you can try something more aggressive. Its very possible that those vv carbs will
loosen up and run better with some use. KB
Thanks, but the whole point of my post was to determine exactly what is
more aggressive and won't damage the carb.
Exactly what chemicals can I use?
So, what chemicals and methods does one use to clean
this carb without destroying it?
mike <ham789@netzero.net> wrote:
So, what chemicals and methods does one use to clean
this carb without destroying it?
Get an ultrasonic cleaner. You'll use it for a lot more than just
cleaning carbs, and they're surprisingly cheap. Amazing things.
But what about all those twisty passages inside of a massive object.
By the time the shock wave gets thru the tiny holes, down the narrow
passages and into the place that's gummed up, is there any energy left?
mike <ham789@netzero.net> wrote:
Thanks, but the whole point of my post was to determine exactly what is
more aggressive and won't damage the carb.
Exactly what chemicals can I use?
As always, YMMV, but I've had reasonable luck on SV650S carbs using
hot Pine-Sol. It's glycolic acid solution in water, so it won't do
much to plastic and rubber. It will etch zinc, so galvanized steel
and brass both get stripped and the brass turns pink. It doesn't seem
to etch carb body material too badly, but I'd watch closely during
the soak. I used the Pine-Sol on a hot plate, not quite simmering.
IIRC it took around an hour. Rinse with clean water, dry and assemble.
Before doing anything else, I'd put good quality gas in the bike
and ride it some. It might clean up on its own. Emission controlled
carbs are lean, a small tweak of the idle mixture could do what you
want.
If you do take the carb apart, check for welch plugs over the idle and
low speed fuel ports to the carb throat. If they're present, and the
carb won't improve with immersion in cleaner, it might pay to remove
them, clean the chambers underneath and install new plugs. Hopefully
less drastic measures will suffice.
hth,
bob prohaska
Seems to be only one plug over the pilot adjustment.That's probably the anti-tamper plug. It'll have to go.
The actual jet seems to be accessible inside the bowl.
I put a colder plug in it,
Poured some seafoam in the gas,
Backed the pilot adjustment way out.
Been running it intermittently to keep the seafoam distributed.
Seems to be helping a lot.
Put the pilot adjustment back where it was and it's mostly running.
I'm optimistic.
Thanks, mike
As I stated in my original post,
mike <ham789@netzero.net> wrote:Somebody suggested it.
That's probably the anti-tamper plug. It'll have to go.
Seems to be only one plug over the pilot adjustment.
The welch plug I'm talking about (which you may not have)
was over the series of hair-fine drillings in the carb
throat where the rising edge of the throttle butterfly
passes.
The actual jet seems to be accessible inside the bowl.
I put a colder plug in it,
That's a surprise, what motivated a colder plug?
Everything I looked at was clean, clean, clean.Poured some seafoam in the gas,
Backed the pilot adjustment way out.
Did you take it out and look? There was junk on the end of
one pilot needle on my SV.
Been running it intermittently to keep the seafoam distributed.
Seems to be helping a lot.
Put the pilot adjustment back where it was and it's mostly running.
I'm optimistic.
Thanks, mike
You're welcome, good luck!
bob prohaska
mike <ham789@netzero.net> wrote:
That's probably the anti-tamper plug. It'll have to go.
Seems to be only one plug over the pilot adjustment.
The welch plug I'm talking about (which you may not have)
was over the series of hair-fine drillings in the carb
throat where the rising edge of the throttle butterfly
passes.
The actual jet seems to be accessible inside the bowl.
I put a colder plug in it,
That's a surprise, what motivated a colder plug?
Poured some seafoam in the gas,
Backed the pilot adjustment way out.
Did you take it out and look? There was junk on the end of
one pilot needle on my SV.
Been running it intermittently to keep the seafoam distributed.
Seems to be helping a lot.
Put the pilot adjustment back where it was and it's mostly running.
I'm optimistic.
Thanks, mike
You're welcome, good luck!
bob prohaska
I'm operating on the assumption that any detonation is a serious issue.
Am I worrying too much?
Advice?
Thanks, mike
mike <ham789@netzero.net> wrote:
I'm operating on the assumption that any detonation is a serious issue.
Am I worrying too much?
Not until you know why.
Advice?
Check the timing and TPS if it has one.
What's a TPS?Thanks, mike
HTH,
bob prohaska
What's a TPS?Throttle position sensor. It's a surrogate for the "vacuum advance" unit
The article I read was general, not related to this particular bike.
It suggested that timing was fixed for the low RPM range, then advanced
a LOT over some narrow midrange, then stayed at that level for the
remainder of the speed range.
I could infer that the advance is starting too early.
I'm not convinced that fits with the symptoms.
Say that I took the cover off and measured the advance.You need the manual to identify the timing marks.
How do I know whether that is good or bad?
What would I do about
it if I decided it was wrong?
The thing doesn't have a tach, so I'd have to build one.
I have a Snap-On automotive scope, but the spark pulse width is
too short. By the time I set the sweep speed low enough to see
two sparks, the sampling interval is too coarse to catch them all.
I realize that it's not conclusive, but many of the posts regarding
this bike are about it running too lean. Making it richer seems to be heading in the right direction, I just need more of it.
Which keeps leading me back to the pilot jet as the most leverage.
mike <ham789@netzero.net> wrote:
What's a TPS?Throttle position sensor. It's a surrogate for the "vacuum advance" unit found on autos with Kettering (points and condenser) ignition.
Crudely put, timing needs to advance with speed and retard with
manifold absolute pressure. Absolute pressure measurements are sort
of a pain, but some bright fellow figured out that if you know the
throttle angle and engine speed manifold pressure can be worked out
for any given engine. It's usually a variable resistor mounted on the throttle butterfly shaft. If it's not working, it sends wrong information
to the ignition control which is apt to give wrong spark timing.
A TPS can be checked with an ohmmeter out of circuit, or a voltage measurement in-circuit if you can get at the terminals. You'll need
a manual to indicate the correct values, I don't think they're standardized.
It may not be the problem, but it's an easy test, relatively speaking.
The article I read was general, not related to this particular bike.
It suggested that timing was fixed for the low RPM range, then advanced
a LOT over some narrow midrange, then stayed at that level for the
remainder of the speed range.
I could infer that the advance is starting too early.
I'm not convinced that fits with the symptoms.
Say that I took the cover off and measured the advance.You need the manual to identify the timing marks.
How do I know whether that is good or bad?
What would I do aboutStart replacing parts, unless you can find a bad connection.
it if I decided it was wrong?
The thing doesn't have a tach, so I'd have to build one.
If it's wrong enough, you might not need a tach. Finding advanced
timing at dead slow idle would be a strong hint.
I have a Snap-On automotive scope, but the spark pulse width isI don't think an oscilloscope will tell you timing, generally.
too short. By the time I set the sweep speed low enough to see
two sparks, the sampling interval is too coarse to catch them all.
A timing strobe is more likely to help.
I realize that it's not conclusive, but many of the posts regarding
this bike are about it running too lean. Making it richer seems to be
heading in the right direction, I just need more of it.
Which keeps leading me back to the pilot jet as the most leverage.
Carb problems are common, ignition problems seem to be much rarer
and usually of the "no spark" variety. Your case might be one of
the exceptions. Both mixture and timing affect detonation tendencies
and one can compensate for the other to some degree.
HTH,
bob prohaska
On 8/1/2017 7:30 PM, bob prohaska wrote:
mike <ham789@netzero.net> wrote:Have the manual. Timing marks were easily identifiable
What's a TPS?Throttle position sensor. It's a surrogate for the "vacuum advance"
unit found on autos with Kettering (points and condenser) ignition.
Crudely put, timing needs to advance with speed and retard with
manifold absolute pressure. Absolute pressure measurements are sort
of a pain, but some bright fellow figured out that if you know the
throttle angle and engine speed manifold pressure can be worked out
for any given engine. It's usually a variable resistor mounted on the
throttle butterfly shaft. If it's not working, it sends wrong
information to the ignition control which is apt to give wrong spark
timing.
A TPS can be checked with an ohmmeter out of circuit, or a voltage
measurement in-circuit if you can get at the terminals. You'll need
a manual to indicate the correct values, I don't think they're
standardized.
It may not be the problem, but it's an easy test, relatively
The article I read was general, not related to this particular bike.
It suggested that timing was fixed for the low RPM range, then
advanced a LOT over some narrow midrange, then stayed at that level
for the remainder of the speed range.
I could infer that the advance is starting too early.
I'm not convinced that fits with the symptoms.
speaking.
Say that I took the cover off and measured the advance.You need the manual to identify the timing marks.
How do I know whether that is good or bad?
when I checked the valve settings.
What would I do aboutStart replacing parts, unless you can find a bad connection.
it if I decided it was wrong?
The thing doesn't have a tach, so I'd have to build one.
If it's wrong enough, you might not need a tach. Finding advanced
timing at dead slow idle would be a strong hint.
I have a Snap-On automotive scope, but the spark pulse width isI don't think an oscilloscope will tell you timing, generally.
too short. By the time I set the sweep speed low enough to see
two sparks, the sampling interval is too coarse to catch them all.
A timing strobe is more likely to help.
I was gonna use the scope as a tach. It has a frequency readout
if you can see 3 or more pulses. I was gonna use a clamp on
current probe around the plug wire.
I do have several timing strobes. One has a tach, but it's designed
for 6-8 cylinders. With only one cylinder, you end up multiplying
a very small number at idle. Then there's the issue of the waste
spark.
I realize that it's not conclusive, but many of the posts regarding
this bike are about it running too lean. Making it richer seems to
be heading in the right direction, I just need more of it.
Which keeps leading me back to the pilot jet as the most leverage.
Carb problems are common, ignition problems seem to be much rarer
and usually of the "no spark" variety. Your case might be one of
the exceptions. Both mixture and timing affect detonation tendencies
and one can compensate for the other to some degree.
Ok, but if I can't change the timing, all I can tell if it's working
or not working. The angle doesn't seem to be variable at all.
Compensation does not seem to be an option.
I tried a different experiment. I covered about 40% of the air filter element with plastic sheet.
HTH,
bob prohaska
I didn't even get out of the driveway.
Changed it to about 15%. Still HORRIBLY rich...not drivable.
I expected it to get richer, but this degree surprised me.
You could get 15% variation from the kind of oil you put
on the filter element.
I've had several bikes over the years from 50cc to 550cc.
I don't remember any of them being anywhere near this temperamental.
mike <ham789@netzero.net> wrote in news:olrslo$rru$1@dont-email.me:
On 8/1/2017 7:30 PM, bob prohaska wrote:
mike <ham789@netzero.net> wrote:Have the manual. Timing marks were easily identifiable
What's a TPS?Throttle position sensor. It's a surrogate for the "vacuum advance"
unit found on autos with Kettering (points and condenser) ignition.
Crudely put, timing needs to advance with speed and retard with
manifold absolute pressure. Absolute pressure measurements are sort
of a pain, but some bright fellow figured out that if you know the
throttle angle and engine speed manifold pressure can be worked out
for any given engine. It's usually a variable resistor mounted on the
throttle butterfly shaft. If it's not working, it sends wrong
information to the ignition control which is apt to give wrong spark
timing.
A TPS can be checked with an ohmmeter out of circuit, or a voltage
measurement in-circuit if you can get at the terminals. You'll need
a manual to indicate the correct values, I don't think they're
standardized.
It may not be the problem, but it's an easy test, relatively
The article I read was general, not related to this particular bike.
It suggested that timing was fixed for the low RPM range, then
advanced a LOT over some narrow midrange, then stayed at that level
for the remainder of the speed range.
I could infer that the advance is starting too early.
I'm not convinced that fits with the symptoms.
speaking.
Say that I took the cover off and measured the advance.You need the manual to identify the timing marks.
How do I know whether that is good or bad?
when I checked the valve settings.
What would I do aboutStart replacing parts, unless you can find a bad connection.
it if I decided it was wrong?
The thing doesn't have a tach, so I'd have to build one.
If it's wrong enough, you might not need a tach. Finding advanced
timing at dead slow idle would be a strong hint.
I have a Snap-On automotive scope, but the spark pulse width isI don't think an oscilloscope will tell you timing, generally.
too short. By the time I set the sweep speed low enough to see
two sparks, the sampling interval is too coarse to catch them all.
A timing strobe is more likely to help.
I was gonna use the scope as a tach. It has a frequency readout
if you can see 3 or more pulses. I was gonna use a clamp on
current probe around the plug wire.
I do have several timing strobes. One has a tach, but it's designed
for 6-8 cylinders. With only one cylinder, you end up multiplying
a very small number at idle. Then there's the issue of the waste
spark.
I realize that it's not conclusive, but many of the posts regarding
this bike are about it running too lean. Making it richer seems to
be heading in the right direction, I just need more of it.
Which keeps leading me back to the pilot jet as the most leverage.
Carb problems are common, ignition problems seem to be much rarer
and usually of the "no spark" variety. Your case might be one of
the exceptions. Both mixture and timing affect detonation tendencies
and one can compensate for the other to some degree.
Ok, but if I can't change the timing, all I can tell if it's working
or not working. The angle doesn't seem to be variable at all.
Compensation does not seem to be an option.
I tried a different experiment. I covered about 40% of the air filter
HTH,
bob prohaska
element with plastic sheet.
I didn't even get out of the driveway.
Changed it to about 15%. Still HORRIBLY rich...not drivable.
I expected it to get richer, but this degree surprised me.
You could get 15% variation from the kind of oil you put
on the filter element.
I've had several bikes over the years from 50cc to 550cc.
I don't remember any of them being anywhere near this temperamental.
thats because its messing with the vv carbs to much vacume where it
shouldnt be. its easy to increase the main jet needle. I just used a
small metric flat washer under it to raise it up for a richer cruse rpm.
wont affect the wide open throttle or idle. KB
PS if you need more than one washer you will need to sand the bottom of
the needle retainer plug so there is still a slight movement of the
needle when tight.
mike <ham789@netzero.net> wrote in news:olrslo$rru$1@dont-email.me:
On 8/1/2017 7:30 PM, bob prohaska wrote:
mike <ham789@netzero.net> wrote:Have the manual. Timing marks were easily identifiable
What's a TPS?Throttle position sensor. It's a surrogate for the "vacuum advance"
unit found on autos with Kettering (points and condenser) ignition.
Crudely put, timing needs to advance with speed and retard with
manifold absolute pressure. Absolute pressure measurements are sort
of a pain, but some bright fellow figured out that if you know the
throttle angle and engine speed manifold pressure can be worked out
for any given engine. It's usually a variable resistor mounted on the
throttle butterfly shaft. If it's not working, it sends wrong
information to the ignition control which is apt to give wrong spark
timing.
A TPS can be checked with an ohmmeter out of circuit, or a voltage
measurement in-circuit if you can get at the terminals. You'll need
a manual to indicate the correct values, I don't think they're
standardized.
It may not be the problem, but it's an easy test, relatively
The article I read was general, not related to this particular bike.
It suggested that timing was fixed for the low RPM range, then
advanced a LOT over some narrow midrange, then stayed at that level
for the remainder of the speed range.
I could infer that the advance is starting too early.
I'm not convinced that fits with the symptoms.
speaking.
Say that I took the cover off and measured the advance.You need the manual to identify the timing marks.
How do I know whether that is good or bad?
when I checked the valve settings.
What would I do aboutStart replacing parts, unless you can find a bad connection.
it if I decided it was wrong?
The thing doesn't have a tach, so I'd have to build one.
If it's wrong enough, you might not need a tach. Finding advanced
timing at dead slow idle would be a strong hint.
I have a Snap-On automotive scope, but the spark pulse width isI don't think an oscilloscope will tell you timing, generally.
too short. By the time I set the sweep speed low enough to see
two sparks, the sampling interval is too coarse to catch them all.
A timing strobe is more likely to help.
I was gonna use the scope as a tach. It has a frequency readout
if you can see 3 or more pulses. I was gonna use a clamp on
current probe around the plug wire.
I do have several timing strobes. One has a tach, but it's designed
for 6-8 cylinders. With only one cylinder, you end up multiplying
a very small number at idle. Then there's the issue of the waste
spark.
I realize that it's not conclusive, but many of the posts regarding
this bike are about it running too lean. Making it richer seems to
be heading in the right direction, I just need more of it.
Which keeps leading me back to the pilot jet as the most leverage.
Carb problems are common, ignition problems seem to be much rarer
and usually of the "no spark" variety. Your case might be one of
the exceptions. Both mixture and timing affect detonation tendencies
and one can compensate for the other to some degree.
Ok, but if I can't change the timing, all I can tell if it's working
or not working. The angle doesn't seem to be variable at all.
Compensation does not seem to be an option.
I tried a different experiment. I covered about 40% of the air filter
HTH,
bob prohaska
element with plastic sheet.
I didn't even get out of the driveway.
Changed it to about 15%. Still HORRIBLY rich...not drivable.
I expected it to get richer, but this degree surprised me.
You could get 15% variation from the kind of oil you put
on the filter element.
I've had several bikes over the years from 50cc to 550cc.
I don't remember any of them being anywhere near this temperamental.
thats because its messing with the vv carbs to much vacume where it
shouldnt be. its easy to increase the main jet needle. I just used a
small metric flat washer under it to raise it up for a richer cruse rpm.
wont affect the wide open throttle or idle. KB
PS if you need more than one washer you will need to sand the bottom of
the needle retainer plug so there is still a slight movement of the
needle when tight.
On 8/3/2017 9:07 AM, Kevin Bottorff wrote:the
mike <ham789@netzero.net> wrote in news:olrslo$rru$1@dont-email.me:
On 8/1/2017 7:30 PM, bob prohaska wrote:
mike <ham789@netzero.net> wrote:
What's a TPS?Throttle position sensor. It's a surrogate for the "vacuum advance"
unit found on autos with Kettering (points and condenser) ignition.
Crudely put, timing needs to advance with speed and retard with
manifold absolute pressure. Absolute pressure measurements are sort
of a pain, but some bright fellow figured out that if you know the
throttle angle and engine speed manifold pressure can be worked out
for any given engine. It's usually a variable resistor mounted on
bike.throttle butterfly shaft. If it's not working, it sends wrong
information to the ignition control which is apt to give wrong spark
timing.
A TPS can be checked with an ohmmeter out of circuit, or a voltage
measurement in-circuit if you can get at the terminals. You'll need
a manual to indicate the correct values, I don't think they're
standardized.
The article I read was general, not related to this particular
filterHave the manual. Timing marks were easily identifiableIt suggested that timing was fixed for the low RPM range, thenIt may not be the problem, but it's an easy test, relatively
advanced a LOT over some narrow midrange, then stayed at that level
for the remainder of the speed range.
I could infer that the advance is starting too early.
I'm not convinced that fits with the symptoms.
speaking.
Say that I took the cover off and measured the advance.You need the manual to identify the timing marks.
How do I know whether that is good or bad?
when I checked the valve settings.
What would I do aboutStart replacing parts, unless you can find a bad connection.
it if I decided it was wrong?
The thing doesn't have a tach, so I'd have to build one.
If it's wrong enough, you might not need a tach. Finding advanced
timing at dead slow idle would be a strong hint.
I have a Snap-On automotive scope, but the spark pulse width isI don't think an oscilloscope will tell you timing, generally.
too short. By the time I set the sweep speed low enough to see
two sparks, the sampling interval is too coarse to catch them all.
A timing strobe is more likely to help.
I was gonna use the scope as a tach. It has a frequency readout
if you can see 3 or more pulses. I was gonna use a clamp on
current probe around the plug wire.
I do have several timing strobes. One has a tach, but it's designed
for 6-8 cylinders. With only one cylinder, you end up multiplying
a very small number at idle. Then there's the issue of the waste
spark.
I realize that it's not conclusive, but many of the posts regarding
this bike are about it running too lean. Making it richer seems to
be heading in the right direction, I just need more of it.
Which keeps leading me back to the pilot jet as the most leverage.
Carb problems are common, ignition problems seem to be much rarer
and usually of the "no spark" variety. Your case might be one of
the exceptions. Both mixture and timing affect detonation tendencies
and one can compensate for the other to some degree.
Ok, but if I can't change the timing, all I can tell if it's working
or not working. The angle doesn't seem to be variable at all.
Compensation does not seem to be an option.
I tried a different experiment. I covered about 40% of the air
HTH,
bob prohaska
rpm.element with plastic sheet.
I didn't even get out of the driveway.
Changed it to about 15%. Still HORRIBLY rich...not drivable.
I expected it to get richer, but this degree surprised me.
You could get 15% variation from the kind of oil you put
on the filter element.
I've had several bikes over the years from 50cc to 550cc.
I don't remember any of them being anywhere near this temperamental.
thats because its messing with the vv carbs to much vacume where it
shouldnt be. its easy to increase the main jet needle. I just used a
small metric flat washer under it to raise it up for a richer cruse
ofwont affect the wide open throttle or idle. KB
PS if you need more than one washer you will need to sand the bottom
the needle retainer plug so there is still a slight movement of the
needle when tight.
Can you recommend a thickness for this washer?
I'll give it a try.
Thanks, mike
<khakif@uci.edu> wrote:
<snip>
How old is the post to which you are replying?
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