FOAK:Honda CB 250 RS

dave eades wrote:
 > were they any good?
 > Thinking of buying one for the 20 mile round trip daily commute.
 > anything to look out for?
 >
 >
 > Dave
I had 2 and ran them for 20000 miles apiece. The only breakdown I had
was a broken throttle cable.

My last one is still going with 32000 miles on the clock and present
owner is still happy : -)

If over 20000 miles:
Apart from the usual checks for oil leaks, smoky exhaust and suspension\
wheels, etc
Camshaft lobe wear and rattly valvegear
Cam chain rattle
Try to find out if the oil has been changed very regularly (every 1000 -
1200 miles is good)
Cam bearings
Engine balance chain

If the engine sounds "clacky" at anything over a tickover speed, suspect
the worst.

Tends to eat chains and sprockets
Corrosion inside of swing arm bracing if high miles and regular winter use
If electric start version, make sure starter gear engages cleanly
otherwise it chews the teeth off the starter gears. (You can retrofit
the kickstart if the electric start is naff)

Dead easy to work on, light for a 4 stroke, huge fun for a 250 4 stroke
that was quite quick in it's time and handled well. You can fit a Honda
XL500 motor in the frame ; - )

Steve


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dave eades says...
 > were they any good?
 > Thinking of buying one for the 20 mile round trip daily commute.
 > anything to look out for?

I used a 170,000 mile one for a 100 mile a day flat out commute down the
M1, M25 and M4. It wasn't happy doing it, but it managed it. I then
retired it to a 50 mile a day commute, which it was a little happier
with.

As long as the cam and camchain don't rattle, it's had very frequent oil
changes and the mileage looks right then buy it. Other than that, check
the condition of the rear sprocket cush drives. They have a habit of
wearing out and wrecking the rear wheel hub. As does the large circlip
that holds the rear sprocket in place. If the rear sprocket has sideways
moevement then you'll have trouble repairing the groove it sits in and
the chain will wear like buggery. Everything else is straightforward and
the type of things you'd check on any used bike. Just bear in mind that
the CB250Rs doesn't have an oil filter as such, so frequent oil changes
are very important.

--
Lozzo
ZX-9R
"As know it all cunts go he actually has half a clue"
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Steve Dixey says...

 > Try to find out if the oil has been changed very regularly (every 1000 -
 > 1200 miles is good)
 > Cam bearings

What bearings? The cam sits direct in the head.

--
Lozzo
ZX-9R
"As know it all cunts go he actually has half a clue"
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Lozzo wrote:

  > > Cam bearings
 >
 > What bearings? The cam sits direct in the head.

Perhaps he missed a "a lack of" in the sentence.

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"Lozzo" <lozzo RemoveThis @speedyspic.co.uk> wrote in message
news:MPG.1c8075fe29138eaf989bd5@news.individual.net...
 > dave eades says...
  >> were they any good?
  >> Thinking of buying one for the 20 mile round trip daily commute.
  >> anything to look out for?
 >
 > I used a 170,000 mile one for a 100 mile a day flat out commute down the
 > M1, M25 and M4. It wasn't happy doing it, but it managed it. I then
 > retired it to a 50 mile a day commute, which it was a little happier
 > with.
 >
 > As long as the cam and camchain don't rattle, it's had very frequent oil
 > changes and the mileage looks right then buy it. Other than that, check
 > the condition of the rear sprocket cush drives. They have a habit of
 > wearing out and wrecking the rear wheel hub. As does the large circlip
 > that holds the rear sprocket in place. If the rear sprocket has sideways
 > moevement then you'll have trouble repairing the groove it sits in and
 > the chain will wear like buggery. Everything else is straightforward and
 > the type of things you'd check on any used bike. Just bear in mind that
 > the CB250Rs doesn't have an oil filter as such, so frequent oil changes
 > are very important.

The cam running directly in the head is common to all the models and clearly
a weakness in the design. Cheap oil, infrequent changes or low level can
cause permanent damage.

The cush drive and chain wear problem was solved with the RS-D, along with a
few other niggles. Only issue was they took off the kickstart and added an
electric start with a poor engagement mechanism (sounds like an old Ford
Cortina). Anyway the electric start is fine if the bike is used everyday
and the battery is in good condition - otherwise it's trouble.

There is a way to put the kickstart back in an RS-D but it does require a
little engineering. My sister did it on her CL250 (same engine) with great
success. She was talking about putting some instructions together but, as
she's in the middle of moving house, this isn't likely to be top priority.


--
Dave
ex Motorcycle Maintenance Workshop
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Lozzo wrote:
 > Steve Dixey says...
 >
 >

  >>Cam bearings
 >
 >
 > What bearings? The cam sits direct in the head.
 >

The alloy holes that the camshaft sits in are the bearings...of sorts.....

Steve<!-- ~MESSAGE_AFTER~ -->
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Steve Dixey wrote:
 > Lozzo wrote:
 >
  >> Steve Dixey says...
  >>
  >>
 >
   >>> Cam bearings
  >>
  >>
  >>
  >> What bearings? The cam sits direct in the head.
  >>
 >
 > The alloy holes that the camshaft sits in are the bearings...of sorts.....
 >

Yep, same with my Bandit and my FZR.

--
Bandit 600; CG125; FZR250RR; DS#1 ; DOMO#1 ; SH#2 ; SKoGA#7 ; BOMB#16
"Less scary than Petrolcan."
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On Fri, 18 Feb 2005 21:36:27 +0000 (UTC), "dave eades"
<davegee2001.DeleteThis@btinternet.com> wrote:

 >were they any good?
 >Thinking of buying one for the 20 mile round trip daily commute.
 >anything to look out for?

I had an RS-A for a few year - did about 24K on it and sold it at
about 48-50K miles and the engine was still going strong.

I *think* I replaced the camchain early on but ISTR that this was a
precaution really as it was getting near the limit - I never really
trusted the odometer reading.

The alternator died once: replaced from a breakers. Rear wheel
bearings went; rear sprockets were always loose due to worn hub/clip.

It was not fast: it struggled to make seventy into a strong headwind
but it was economical.

The auto-decompressor never worked becaues the cable was seized and
the cam arm inside the RH case had broken off, but it was always easy
to start.

It was comfortable: I once rode with the then GF to Loch Lomond on a
camping trip, and several times commuted to Sheffield from Newmarket
on weekends.

Oil must be changed regularly because there's no proper filter.

I got through one pair of aftermarket shocks during the time I had it.
Oh, a couple of rear wheel spokes broke, but that could have just been
bad maintenance on my part.

The only other mechanical problem I can recall was when it started
fading and misfiring on cold damp days after about ten minutes on the
A14. It had never suffered this before. These days, people would shout
"carb icing!" but I'd never heard of the condition back then.

After much head scratching I found that the carb float chamber
breather was clogged. Once I'd taken it off and cleaned it, the
problem went away. To this day I don't know whether it was the
breather itself, or whether in cleaning it out I also cleared
something else, maybe the main jet feed.

Oh, yes, just remembered: I *think* I've still got a spare rear wheel
and possibly a LH engine cover (no alternator, though), if anyone
wants them.

--
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"Pip Luscher" <pip DeleteThis @spammers.foad.luscher.freeserve.co.uk> wrote in message
news:c31f111bn3o47h7a819qf0thrn5j2c5sma@4ax.com...
 > On Fri, 18 Feb 2005 21:36:27 +0000 (UTC), "dave eades"
 > <davegee2001 DeleteThis @btinternet.com> wrote:
 >
  >>were they any good?
  >>Thinking of buying one for the 20 mile round trip daily commute.
  >>anything to look out for?
 >
 > I had an RS-A for a few year - did about 24K on it and sold it at
 > about 48-50K miles and the engine was still going strong.
 >
 > The only other mechanical problem I can recall was when it started
 > fading and misfiring on cold damp days after about ten minutes on the
 > A14. It had never suffered this before. These days, people would shout
 > "carb icing!" but I'd never heard of the condition back then.
 >
 > After much head scratching I found that the carb float chamber
 > breather was clogged. Once I'd taken it off and cleaned it, the
 > problem went away. To this day I don't know whether it was the
 > breather itself, or whether in cleaning it out I also cleared
 > something else, maybe the main jet feed.

You probably had some water in the bottom of the float chamber that was
freezing in these conditions.


--
Dave
ex Motorcycle Maintenance Workshop
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On Sat, 19 Feb 2005 18:57:37 -0000, "Dave Emerson"
<Dave_dot_Emerson.DeleteThis@LineOne.net> wrote:

  >> The only other mechanical problem I can recall was when it started
  >> fading and misfiring on cold damp days after about ten minutes on the
  >> A14. It had never suffered this before. These days, people would shout
  >> "carb icing!" but I'd never heard of the condition back then.
  >>
  >> After much head scratching I found that the carb float chamber
  >> breather was clogged. Once I'd taken it off and cleaned it, the
  >> problem went away. To this day I don't know whether it was the
  >> breather itself, or whether in cleaning it out I also cleared
  >> something else, maybe the main jet feed.
 >
 >You probably had some water in the bottom of the float chamber that was
 >freezing in these conditions.

If it was in a position to cause trouble, I'd expect it to be more
trouble as a liquid because it could then get sucked into the main
jet. As it was, I don't recall finding any water in the bowl.

--
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"Pip Luscher" <pip DeleteThis @spammers.foad.luscher.freeserve.co.uk> wrote in message
news:kf3f1112u6nrg5ccpb84sbdb8vrbpe1dcu@4ax.com...
 > On Sat, 19 Feb 2005 18:57:37 -0000, "Dave Emerson"
 > <Dave_dot_Emerson DeleteThis @LineOne.net> wrote:
 >
   >>> The only other mechanical problem I can recall was when it started
   >>> fading and misfiring on cold damp days after about ten minutes on the
   >>> A14. It had never suffered this before. These days, people would shout
   >>> "carb icing!" but I'd never heard of the condition back then.
   >>>
   >>> After much head scratching I found that the carb float chamber
   >>> breather was clogged. Once I'd taken it off and cleaned it, the
   >>> problem went away. To this day I don't know whether it was the
   >>> breather itself, or whether in cleaning it out I also cleared
   >>> something else, maybe the main jet feed.
  >>
  >>You probably had some water in the bottom of the float chamber that was
  >>freezing in these conditions.
 >
 > If it was in a position to cause trouble, I'd expect it to be more
 > trouble as a liquid because it could then get sucked into the main
 > jet. As it was, I don't recall finding any water in the bowl.

Not always obvious, it usually looks like a small orange/brown (rusty)
maggot swimming around the bottom of the bowl, if you take the time to look.


--
Dave
ex Motorcycle Maintenance Workshop
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On Sat, 19 Feb 2005 19:28:29 -0000, "Dave Emerson"
<Dave_dot_Emerson RemoveThis @LineOne.net> wrote:

 >
 >"Pip Luscher" <pip RemoveThis @spammers.foad.luscher.freeserve.co.uk> wrote in message
 >news:kf3f1112u6nrg5ccpb84sbdb8vrbpe1dcu@4ax.com...
  >> On Sat, 19 Feb 2005 18:57:37 -0000, "Dave Emerson"
  >> <Dave_dot_Emerson RemoveThis @LineOne.net> wrote:
  >>
   >>>> The only other mechanical problem I can recall was when it started
   >>>> fading and misfiring on cold damp days after about ten minutes on the
   >>>> A14. It had never suffered this before. These days, people would shout
   >>>> "carb icing!" but I'd never heard of the condition back then.
   >>>>
   >>>> After much head scratching I found that the carb float chamber
   >>>> breather was clogged. Once I'd taken it off and cleaned it, the
   >>>> problem went away. To this day I don't know whether it was the
   >>>> breather itself, or whether in cleaning it out I also cleared
   >>>> something else, maybe the main jet feed.
   >>>
   >>>You probably had some water in the bottom of the float chamber that was
   >>>freezing in these conditions.
  >>
  >> If it was in a position to cause trouble, I'd expect it to be more
  >> trouble as a liquid because it could then get sucked into the main
  >> jet. As it was, I don't recall finding any water in the bowl.
 >
 >Not always obvious, it usually looks like a small orange/brown (rusty)
 >maggot swimming around the bottom of the bowl, if you take the time to look.

I know what water in the float bowl looks like.

Like I said, if there's water in the float bowl then it'll cause
problems as soon as the petrol starts getting drawn in quantity into
the main jet, not several miles into the journey, so it's unlikely it
would've been coming in with the petrol because there would've been
water contamination from the start of the journey.

It's highly unlikely it would've got drawn up and in through nearly a
foot of breather pipe, especially as it was clogged.

Anyway, the icing effect occurs at the venturi and the emulsion/needle
jet, not the bottom of the float bowl because:

a) as the petrol is drawn into droplets, it will evaporate too and
that will have a major cooling effect;

b) the venturi's job is to lower the air pressure over the jets. It's
fundamental to a gas's behaviour that a drop in pressure will result
in a drop in temperature;

c) the float bowl gets a continuous supply of fresh petrol at ambient
or more likely just above ambient due to engine heat/ rider's knees
warming the tank, so even if there was water in the bowl, I'd be very
surprised if it managed to freeze. On the occasions it occurred,
ambient was above freezing.

HTH.

--
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"Pip Luscher" <pip DeleteThis @spammers.foad.luscher.freeserve.co.uk> wrote in message
news:keqg111gjq2o3r4m44tsvd5m54shprochv@4ax.com...
 > On Sat, 19 Feb 2005 19:28:29 -0000, "Dave Emerson"
 > <Dave_dot_Emerson DeleteThis @LineOne.net> wrote:
 >
  >>
  >>"Pip Luscher" <pip DeleteThis @spammers.foad.luscher.freeserve.co.uk> wrote in message
  >>news:kf3f1112u6nrg5ccpb84sbdb8vrbpe1dcu@4ax.com...
   >>> On Sat, 19 Feb 2005 18:57:37 -0000, "Dave Emerson"
   >>> <Dave_dot_Emerson DeleteThis @LineOne.net> wrote:
   >>>
   >>>>> The only other mechanical problem I can recall was when it started
   >>>>> fading and misfiring on cold damp days after about ten minutes on the
   >>>>> A14. It had never suffered this before. These days, people would shout
   >>>>> "carb icing!" but I'd never heard of the condition back then.
   >>>>>
   >>>>> After much head scratching I found that the carb float chamber
   >>>>> breather was clogged. Once I'd taken it off and cleaned it, the
   >>>>> problem went away. To this day I don't know whether it was the
   >>>>> breather itself, or whether in cleaning it out I also cleared
   >>>>> something else, maybe the main jet feed.
   >>>>
   >>>>You probably had some water in the bottom of the float chamber that was
   >>>>freezing in these conditions.
   >>>
   >>> If it was in a position to cause trouble, I'd expect it to be more
   >>> trouble as a liquid because it could then get sucked into the main
   >>> jet. As it was, I don't recall finding any water in the bowl.
  >>
  >>Not always obvious, it usually looks like a small orange/brown (rusty)
  >>maggot swimming around the bottom of the bowl, if you take the time to
  >>look.
 >
 > I know what water in the float bowl looks like.
 >
 > Like I said, if there's water in the float bowl then it'll cause
 > problems as soon as the petrol starts getting drawn in quantity into
 > the main jet, not several miles into the journey, so it's unlikely it
 > would've been coming in with the petrol because there would've been
 > water contamination from the start of the journey.
 >
 > It's highly unlikely it would've got drawn up and in through nearly a
 > foot of breather pipe, especially as it was clogged.
 >
 > Anyway, the icing effect occurs at the venturi and the emulsion/needle
 > jet, not the bottom of the float bowl because:
 >
 > a) as the petrol is drawn into droplets, it will evaporate too and
 > that will have a major cooling effect;
 >
 > b) the venturi's job is to lower the air pressure over the jets. It's
 > fundamental to a gas's behaviour that a drop in pressure will result
 > in a drop in temperature;
 >
 > c) the float bowl gets a continuous supply of fresh petrol at ambient
 > or more likely just above ambient due to engine heat/ rider's knees
 > warming the tank, so even if there was water in the bowl, I'd be very
 > surprised if it managed to freeze. On the occasions it occurred,
 > ambient was above freezing.

Agree with the physics of latent heat of evaporation but I've seen frost on
the outside of a floatbowl when the ambient was above freezing; particulary
on my Morini and a friends Ducati 450.

Any water in the float bowl can freeze to crystals that get drawn into and
block jets.

That's as well as any frost that forms directly in the venturi.

The best fix, on top of cleaning any water from the carb/tank, was an
additive sold by VW agents for Beetles, as these are alos known to suffer
from icing.

--
Dave
ex Motorcycle Maintenance Workshop
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