Winter's arrived...

.... and what's that noise I hear?

Ah, the delicate sound of a Kawasaki engine coughing and spluttering
with carb icing.

FFS, it's only October; I'm still wearing summer gloves, and I haven't
put the lining in my jacket yet. What's it going to be like when it does
get cold?

Maybe the full service it's getting this week will help: new air filter,
new plugs, carbs cleaned. We'll see.

If not, I'll have to source some snake oil to get the damn thing to
behave itself. Silkolene Pro-FST or something like that, isn't it?

 

Eddie wrote

Better. Doesn't this only happen when the temperature is low but not
yet below freezing and the weather on the damp side?

 

It's the damp that does it, yes. But it's going to be quite some time
before it gets properly cold and dry; there's an awful lot of unpleasant
dampness to get through first.

 

My SV did at this time of year, but only on the front pot.

 

1980's not 1990's ... I seem to recall GPZ900R's were the first to suffer
from it, and that it got reported on Watchdog after some unfortunate got run
over by a bus after the bike cut out and he fell off.

<snip>

 

<mode=Lynn Faulds Wood>
"This motorcycle exhibits symptoms of carb icing which means that it
could splutter to an extent that it *could* come to an unexpected halt,
killing a small child"
</mode>

 

Yes, yes, I know the theory. But the 9R didn't seem to suffer from it
last year, until some particularly horribly damp winter days. Now it's
started already.

"Shitty weather", you mean.

So, did your mate have any recommendations for avoiding it?

Others do, but they've got supposed fixes; carb heaters, and the like.

 

ITYM "potential death-trap."

 

your newsreader's doing that strange "double-indents become question
makes thing".

 

Freaky.

 

Eddie wrote:
snip all the other relevant stuff

<fx insert supposedly funny oneliner>
new bike with fuel injection, you know it makes sense.

Carbs are just so last year

 

Anyone remember the rip-up done by "Radio Active" yeeeeears ago, with "Lynn
Folds Over" pointing out the faults of increasingly absurb and outlandish
situations? Of a dead light-bulb: "A small child could easily fill a
bucket with water, take off its shoes and socks, carry the bucket to the top
of the step-ladder, climb into the bucket, take out the bulb and stick its
fingers in the unprotected light-socket. Don't you agree that would be
verra, verra deeeeeeeeengerous."

 

What no snake oil? Magnets? Gyroscopes? Pah!

Aye, that rings a bell... that'll be a job for my friendly mechanic
while it's in for its full service, then. Not that I couldn't do it, I
just haven't got the time.

 

What'll help more is the change by the petrol companies to
winter-grade petrol.

 

I've heard of winter grade diesel but not winter grade petrol?

 

<fx: raises one eyebrow to indicate suspicion>

 

http://www.hse.gov.uk/LAU/pelg/pelg27m.pdf

"Winter grade fuel is introduced at the beginning of September."

http://www.opsi.gov.uk/SI/si1994/Uksi_19942295_en_2.htm also makes
numerous references to winter grade petrol.

 

I can't work out why any change in petrol volatility would make ice
crystals less likely to form in the carb, but I'm sure our resident
Cambridgeshire town will explain.

 

ISTR that they put in extra quantities of lighter fractions in order
to help starting.

 

Here goes:

I'm sure the petrol mix is changed to give more of the lighter
(lower-boiling) fractions for easier starting, and that some
chemical(s) could be added to minimise or deter carb icing.

Have a look at this interesting article:

http://www.gasco.org.uk/upload/docs/GASCo paper final.doc

The reference to additives is near the bottom. What surprised me is
how little additive is needed.

If one has a motorcycle with carb icing problems, it might be worth
trying different brands of petrol; but to coincide each different
tankful with CI conditions might take all winter.

Does anyone have any views on which petrol brands might be best in
this context?