1981 Honda CB 650 custom Starting issues

Rob Kleinschmidt wrote:

 > You do get oil circulation long before the engine has warmed up,
 > but again, oil as an aid to compression is only speculation.

It might be that the engine oil is still cold and thick and seals the
rings better than warm oil, regardless of whether a multigrade oil is
being used...

Why? Because lube oil is refined from crude, using heat, and every time
the engine is started it distills the oil some more...

That doesn't explain why professional drag racers try to make their
runs with cold engines though. Those guys can and do change their oil
after every few runs...
 >
 > I have observed that a warm engine can be harder for the starter
 > to turn than a cold one, but can't say for sure why this would
 > be.

I think it's probably pre-ignition. You don't hear loud pings, but the
spark is occurring a few degrees BTDC and it begins resisting
rotation...

Many years ago, motorcycles and cars had control levers to retard the
spark and operate the throttle or the choke (or all three) right there
where the operator could get at them...

One of the drills for starting my friend's 1931 Model A Ford included
retarding the spark. That made it possible to hand crank the engine...<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

krusty kritter wrote:
 > Rob Kleinschmidt wrote:
 >
  > > You do get oil circulation long before the engine has warmed up,
  > > but again, oil as an aid to compression is only speculation.
 >
 > It might be that the engine oil is still cold and thick and seals the
 > rings better than warm oil, regardless of whether a multigrade oil is
 > being used...
 >
 > Why? Because lube oil is refined from crude, using heat, and every
time
 > the engine is started it distills the oil some more...
 >
 > That doesn't explain why professional drag racers try to make their
 > runs with cold engines though. Those guys can and do change their oil
 > after every few runs...
  > >
  > > I have observed that a warm engine can be harder for the starter
  > > to turn than a cold one, but can't say for sure why this would
  > > be.
 >
 > I think it's probably pre-ignition. You don't hear loud pings, but
the
 > spark is occurring a few degrees BTDC and it begins resisting
 > rotation...

Likewise, I have observed that an engine that can't quite be cranked
with the throttle shut will crank more readily with it open. Hence
the speculation about compression (vacuum).

 > Many years ago, motorcycles and cars had control levers to retard the
 > spark and operate the throttle or the choke (or all three) right
there
 > where the operator could get at them...
 >
 > One of the drills for starting my friend's 1931 Model A Ford included
 > retarding the spark. That made it possible to hand crank the
engine...

There's getting it to fire and then there's just getting it to
turn over.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

Rob Kleinschmidt wrote:
 > krusty kritter wrote:
  > > Rob Kleinschmidt wrote:

 > Likewise, I have observed that an engine that can't quite be cranked
 > with the throttle shut will crank more readily with it open. Hence
 > the speculation about compression (vacuum).
 > There's getting it to fire and then there's just getting it to
 > turn over.

Possibly, opening the throttle on a hot engine admits enough mixture to
cool off whatever hot spot has been causing the engine to preignite...<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

Rick Cortese wrote:
 > Rob Kleinschmidt wrote:
  > > Rick Cortese wrote:
 > <snip>
  > > The argument is that the compressed gasses give you a spring effect
  > > once you reach TDC while the vacuum stroke doesn't.
 >
 > Just went out and checked kicking over one of my bikes. Getting it
past
 > TDC with WOT seemed to be a little tougher then closed. I don't have
 > that much higher compression then a stock bike with it. Yes it will
 > rebound when it gets past TDC but the effort to get it past TDC seems

 > much greater.
 >
 > *BUT*: I don't know if you read everything in the newsgroup but a
while
 > back I posted I may get a LIFAN engine. Engine is here now and is
 > electric start. I will put a DVM on it and see what kind of current
it
 > draws under the two conditions. Nothing quite like an experiment.

Probably is tougher to get to TDC. You certainly see a difference
in a compression test. Not sure how a multi-cylinder engine with
staggered compression and intake strokes might affect the problem
either. My twin with cylinders firing 360 degrees apart definitely
cranks more happily with WOT. Looking forward to your experiment.
Might even try the same myself.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

Rob Kleinschmidt wrote:
 > Rick Cortese wrote:
<snip>
 > The argument is that the compressed gasses give you a spring effect
 > once you reach TDC while the vacuum stroke doesn't.

Just went out and checked kicking over one of my bikes. Getting it past
TDC with WOT seemed to be a little tougher then closed. I don't have
that much higher compression then a stock bike with it. Yes it will
rebound when it gets past TDC but the effort to get it past TDC seems
much greater.

*BUT*: I don't know if you read everything in the newsgroup but a while
back I posted I may get a LIFAN engine. Engine is here now and is
electric start. I will put a DVM on it and see what kind of current it
draws under the two conditions. Nothing quite like an experiment.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

Rick Cortese wrote:
 >
 > Enough happened to convince me to give up on looking further,
 >
 > The cranking amperage was higher then my meter goes i.e. 10 amps.

What you need is a measurement across a shunt.

I get a lot of mileage out of an old Sears engine analyzer from
eBay which includes a shunt and amp meter. Cost maybe $15.00

Lacking a genuine shunt, you can get a pretty decent idea just
by measuring voltage drop across the battery ground cable. Clip
one lead to each end of the negative cable. Crank at WOT and note
voltage drop, crank at closed throttle and note voltage drop.
Compare.

To get a rough idea of amps, you can use a known load on the
battery such as the headlight or tail light.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

Rob Kleinschmidt wrote:
 > Rick Cortese wrote:
 >
  >>Rob Kleinschmidt wrote:
  >>
   >>>Rick Cortese wrote:
  >>
  >><snip>
  >>
   >>>The argument is that the compressed gasses give you a spring effect
   >>>once you reach TDC while the vacuum stroke doesn't.
  >>
  >>Just went out and checked kicking over one of my bikes. Getting it
 >
 > past
 >
  >>TDC with WOT seemed to be a little tougher then closed. I don't have
  >>that much higher compression then a stock bike with it. Yes it will
  >>rebound when it gets past TDC but the effort to get it past TDC seems
 >
 >
  >>much greater.
  >>
  >>*BUT*: I don't know if you read everything in the newsgroup but a
 >
 > while
 >
  >>back I posted I may get a LIFAN engine. Engine is here now and is
  >>electric start. I will put a DVM on it and see what kind of current
 >
 > it
 >
  >>draws under the two conditions. Nothing quite like an experiment.
 >
 >
 > Probably is tougher to get to TDC. You certainly see a difference
 > in a compression test. Not sure how a multi-cylinder engine with
 > staggered compression and intake strokes might affect the problem
 > either. My twin with cylinders firing 360 degrees apart definitely
 > cranks more happily with WOT. Looking forward to your experiment.
 > Might even try the same myself.
 >

Enough happened to convince me to give up on looking further,

The cranking amperage was higher then my meter goes i.e. 10 amps.

This was kind of a surprise because the only lit I saw on LIFAN engines
said ~the starter needs a 12V 5 amp battery. They typically only write
one blurb for all their engines so this was probably written for their
50cc horizontal engine. This is their 200cc vertical Honda copy.

I found this out by hooking my 2/10/55 amp charger to it at the 10 amp
setting. Somehow "virtue is its own reward" doesn't seem to apply but I
am certainly glad I did this test before I ran out and bought a 5 amp
battery!

The engine didn't have the carb mounted but was with the factory tape
over the intake manifold to prevent stray packing from getting in.

Even trying it on the 55 amp setting wouldn't get it past TDC the first
cycle. Had to let some of the compression leak past the valves/rings.
Once it started spinning it went merrily on at something >15 amps. I
can't tell what it was because the chargers metter only goes to 15
amps.<sigh>

So I decides to listen for changes in RPM by poking a hole in the tape
*while* the engine is turning over with the starter. Kaabong! Engine
maybe made one revolution on shear momentum and stalls on the next
compression stroke. I pull the clips off before my battery charger
melts. At least dead stop is less subjective then "I think it changed RPM?"

I'm sorry I didn't get any hard numbers but I think I have showed the
old thumper riders were right. It may be different with a multi cylinder
engine what with less problems with crankcase venting and having one
cylinder pushing while the other is draging. Only multi cylinder I have
avalable right now would by a Honda CB350 which is such an odd ball it
probably wouldn't prove anything other then Honda CB350 engines anyway.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

In article <ccrTd.5080$873.1206@newsread3.news.pas.earthlink.net>,
Rick Cortese <ricortes.RemoveThis@earthlink.net> wrote:

 > Rob Kleinschmidt wrote:
  > > Rick Cortese wrote:
  > >
   > >>Rob Kleinschmidt wrote:
   > >>
   > >>>Rick Cortese wrote:
   > >>
   > >><snip>
   > >>
   > >>>The argument is that the compressed gasses give you a spring effect
   > >>>once you reach TDC while the vacuum stroke doesn't.
   > >>
   > >>Just went out and checked kicking over one of my bikes. Getting it
  > >
  > > past
  > >
   > >>TDC with WOT seemed to be a little tougher then closed. I don't have
   > >>that much higher compression then a stock bike with it. Yes it will
   > >>rebound when it gets past TDC but the effort to get it past TDC seems
  > >
  > >
   > >>much greater.
   > >>
   > >>*BUT*: I don't know if you read everything in the newsgroup but a
  > >
  > > while
  > >
   > >>back I posted I may get a LIFAN engine. Engine is here now and is
   > >>electric start. I will put a DVM on it and see what kind of current
  > >
  > > it
  > >
   > >>draws under the two conditions. Nothing quite like an experiment.
  > >
  > >
  > > Probably is tougher to get to TDC. You certainly see a difference
  > > in a compression test. Not sure how a multi-cylinder engine with
  > > staggered compression and intake strokes might affect the problem
  > > either. My twin with cylinders firing 360 degrees apart definitely
  > > cranks more happily with WOT. Looking forward to your experiment.
  > > Might even try the same myself.
  > >
 >
 > Enough happened to convince me to give up on looking further,
 >
 > The cranking amperage was higher then my meter goes i.e. 10 amps.
 >
 > This was kind of a surprise because the only lit I saw on LIFAN engines
 > said ~the starter needs a 12V 5 amp battery. They typically only write
 > one blurb for all their engines so this was probably written for their
 > 50cc horizontal engine. This is their 200cc vertical Honda copy.
 >
 > I found this out by hooking my 2/10/55 amp charger to it at the 10 amp
 > setting. Somehow "virtue is its own reward" doesn't seem to apply but I
 > am certainly glad I did this test before I ran out and bought a 5 amp
 > battery!

Typically batteries are specified in Amp-hours, that is amperes per
hour. So a 5AH battery can nominally supply 5A for 1 hour, 1A for 5
hours, 50A for 6 min, etc.

I suspect that the 12V, 5AH battery, which is presumably what was
specified, would start the engine just fine. Mind, putting a
larger-capacity battery in the bike might be a good idea for other
reasons...

--
Later.
johajohn.RemoveThis@indianahoosiers.edu
Let 'indiana' be a 'noln', and 'hoosiers' be a 'solkk'.
Leave only the 'noln' and .edu after the @ to reply .<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

John Johnson wrote:

 > Typically batteries are specified in Amp-hours, that is amperes per
 > hour. So a 5AH battery can nominally supply 5A for 1 hour, 1A for 5
 > hours, 50A for 6 min, etc.

Ampere-hours != 'amperes per hour'.

Ampere-hours[1] are Amperes multiplied by hours, not divided by hours,
as you demonstrate with your examples.

The A-h rating of a battery is a measure of the total amount of charge
a battery can deliver with the unstated assumption that until that
total amount of charge has been delivered (at a sane current draw)
the voltage will remain close enough to nominal (again, at some normal
current draw) to be useful. IOW, there is some reciprocity failure,
you cannot necessarily draw 100A for 0.05 h, or 5 uA for 1 000 000 h, etc.

In SI units 1 Ampere-hour = 3 600 Coulomb. A 5A-h battery can deliver
18 000 Coulomb of useful charge.

[1] The use of the '-' sign to separate Amperes from hours is unfortunate,
it should be something to denote multiplication, but this is not unique,
e.g., ft-lbs and N-m are common usage.

--
Mark '01 SV650S '86 GL1200A '81 CM400T '99 EX250-F13<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

In article <421E6F15.A2A6FCBF.RemoveThis@visi.com>,
Mark Olson <olsonm.RemoveThis@tiny.invalid> wrote:

 > John Johnson wrote:
 >
  > > Typically batteries are specified in Amp-hours, that is amperes per
  > > hour. So a 5AH battery can nominally supply 5A for 1 hour, 1A for 5
  > > hours, 50A for 6 min, etc.
 >
 > Ampere-hours != 'amperes per hour'.

absolutely correct, sorry about that. I think the rest was correct, at
least it agrees with what you wrote. Thanks for the correction.

--
Later.
johajohn.RemoveThis@indianahoosiers.edu
Let 'indiana' be a 'noln', and 'hoosiers' be a 'solkk'.
Leave only the 'noln' and .edu after the @ to reply .<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

Rob Kleinschmidt wrote:
 > Rick Cortese wrote:
 >
  >>Enough happened to convince me to give up on looking further,
  >>
  >>The cranking amperage was higher then my meter goes i.e. 10 amps.
 >
 >
 > What you need is a measurement across a shunt.
 >
 > I get a lot of mileage out of an old Sears engine analyzer from
 > eBay which includes a shunt and amp meter. Cost maybe $15.00

I'll take this under consideration since it would be nice to have some
numbers. I think what it will need to characterize it will go beyond the
simple test set up I thought I could use originally. What it really
needs is a chart recorder or some kind of data logging. I'll grant you
after TDC the engine does freewheel a bit until the next compression
stroke. The time average amp profile may even be the same, it is just
that the peak amp draw exceeds the chargers ability to deliver. It would
make for an interesting graph.

The list of what I need to do it right is getting a little long. I'm
starting to question if the results could be generally applied. For
instance, same engine with a different flywheel will give different
steady state current profiles because of the flywheel's momentum. Beyond
you need more current to push a WOT past TDC then one with a closed
throttle I don't think I would be able to conclude much.

Kind of out of place in a motorcycle forum: Reminds me of a story from
the '60s. Used to be Super Modified races in my neck of the woods.
Friend of a friend spent what was then considered a record amount of
money building a car. IIRC there were some restrictions on engine and
carburetion but the track was next to an airfield<aviation fuel> so
compression was one of things people played with. The guy had so much
compression in the engine he needed to hook it up to two batteries and a
DC arc welder to get it started!

The first time he brought it to the track we were in the stands
watching. The track had just been resurfaced that week with what must of
been mashed up banana peels. He came out of the pits onto the track and
skidded to the right, over corrected and skidded left, BANG hit the wall
at the end of the first straight away and his day was over.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues 

Hello, I've got an 82 CB650, same engine and carbs. First adjust those valves or your going to burn a few of them. Easy to do (easier with the Honda tool) they are under those 3 covers on the top, you probably won't even need new seals for the covers, The starting procdure for the bike COLD is-- pull the choke all the way out and leave the throttle alone. The choke rotates the throttle the correct amount for you. Check to make sure the chokes are actually moving from full open to full closed, the choke cables are a problem on these bikes. A 9v draw when you turn the motor over is way too much, it would indicate a bad starter to me (new or not) but check and clean all your connections and grounds first. It may only have 10k miles but it's 20 something years old! Another thing to check is the advance weights, they are under the round cover on the right(as if your sitting on the bike) end of the crank. If they are stuck out when hot, the timing will be way to far advanced and the engine will drag as you indicate. Easy way to check that would be to turn the kill switch to OFF when the engine is hot and try to start the engine, if it turns over easily you've narrowed the problem to the ignition timing--static or advance. Stuck weights will also cause a cold starting problem but more likely the vacuum petcock is to blame if it won't start easy if you let the bike sit for a week or so. Good luck, Frank
 >> Stay informed about: 1981 Honda CB 650 custom Starting issues