spark plugs

Has anyone ever improved a running 4 stroke engine by changing the plugs?

Just wondered like, because I haven't. [1]

I was fettling a little Honda engine today, of course I knew it was
shite in the carb, but because that was a pain to get at, I thought I'd
change the plug first.

No difference.

Crud in the main jet is what it was.

I've had 4 stroke engines that refused to start until I put new plugs
in, but once running changing plugs seem to make no difference whatsoever.

[1]Thinks, actually, I had a Beemer once that had the *tiniest* misfire
at idle, that new plugs fixed.[2]
[2]considers deleting post[3]
[3]I've written it now

 

I've improved the /starting/ of a 4 stroke by changing the plug[1], but
not the running.

[1] XL or XT 250, can't remember which.

 

Yes. Starting and running.

Some of the bangers I had (both racing and general PoS I had) quite
noticeable effects - one was a real shit to start and didn't run well at
full bore, new set of plugs (actually, IIRC, they were ones out of a
known good car) fixed it.

A couple of other cars had much better starting and pick up with new
plugs.

Fuel consumption usually improves too, certainly the Guzzi gets more
thirsty when it's in need of a service. Although that includes an oil
change but not air filters as it runs on open carbs.

 

Never noticed the difference new for old of the same standard plug type (eg:
B8ES), but I noticed a major improvement in engine response and high speed
running by changing the standard plugs to platinum type (eg: B8EV for my
Guzzis/B8EGV for the KX500). I doubt you'd see any improvement with a modern
4valve/cyl four though.

JB

 

Yes, but in association with stuff like oil and filters change.




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<Opens mouth>

<Thinks better of it>

<Exits stage left>

 

Christ, yes, plenty of times, but the removed plugs looked more like lumps
of coal than plugs.

 

In communiqué

It's a good trick if you can manage it. Bit tricky on a single I
suspect.
--
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| Pete Fisher at Home: |
| Voxan Roadster Yamaha WR250Z/Supermoto "Old Gimmer's Hillclimber" |
| Gilera GFR * 2 Moto Morini 2C/375 Morini 350 "Forgotten Error" |
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As others have said, certainly the reliability starting. Even more so if
changing grade (i.e. softer).

As a matter of course I now put NGK EV or EVX in bikes and cars.
Particularly ones where the plugs are a PITA to get at.

I have yet to have a proper look at the sulky McCullogh 436 chain saw I
bought home for TLC. After my ministrations with a rudimentary tool kit
in France it would start, but stop after a few minutes work. I suspect
the windings in the ignition thingy are breaking down when hot, but a
new plug made it easier to get going in the first place (but naturally
it's a stroker). Or it could be sawdust shite in what passes for a carb
I suppose.


--
+-------------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Yamaha WR250Z/Supermoto "Old Gimmer's Hillclimber" |
| Gilera GFR * 2 Moto Morini 2C/375 Morini 350 "Forgotten Error" |
+-------------------------------------------------------------------+