Two-stroke plug lifetime?

[stoo]

Bike (RG150) needs a new plug every 100-150 k's, but otherwise runs sweet and starts in one or two kicks.
The plugs I pull out look like so:

And work fine again for a while if I give them a bit of a scrub and gap check.
What's a likely cause for this in a 2stroke?
Manual says the oil pump is fine, but I spent ages trying to reproduce the carb tuning procedure from the manaul after I cleaned it.
Bike wouldn't play the game, but I eventually got it to roughly follow the rules and had it running/idling/starting nicely and thought I had it sorted.

[sootie]

Bike (RG150) needs a new plug every 100-150 k's, but otherwise runs sweet and starts in one or two kicks.
The plugs I pull out look like so:

And work fine again for a while if I give them a bit of a scrub and gap check.
What's a likely cause for this in a 2stroke?
Manual says the oil pump is fine, but I spent ages trying to reproduce the carb tuning procedure from the manaul after I cleaned it.
Bike wouldn't play the game, but I eventually got it to roughly follow the rules and had it running/idling/starting nicely and thought I had it sorted.

All my experience with many 2-stroke engine plug problems has been too much oil being burnt.
It is always a problem ensuring adequate lubrication without getting plug fouling.
A cheap multimeter will often show a reading across the plug on ohms range. This absolutely confirms fouling, but an infinite reading does not rule out the plug, because it is required to operate reliably in higher pressures, and at much higher voltages.

I can not view your photo very clearly, but if the plug looks black & sootie (yes thats me!) it is probably either a mixture which is too rich, or more likely too much oil in the combustion chamber. (It sounds like you are already on to this.)

I would check the spark external to the engine in a darker environment. It should be a clearly blue colour (It may not be that bright). If it is pure white (like a sparkler) the gap energy is low (even if it is quite bright). This would probably be due to fouling, and exchanging to a new plug outside the bike would prove this. (Another less likely possibility is a weak or otherwise faulty ignition system.)

Hope this helps.

[eelracing]

Your sparkplug is very wet and could be indicative of a lot of around town low rev stop start riding?
I don't mean to tell you to suck eggs but Two Strokes love a good caning and perform best at high revs.Keeps the plug dry too.
Try and avoid labouring the engine,so rev it out more through the gears,holding a lower gear/higher revs around town.
While it may not endear you to your fellow road users and pedestrians,who cares eh, just take the long way home.

[FJRider]

Take it for a ride that distance on the open road/motorway at (or above) the speed limit. I bet the plug will be fine at the end. But carry a few spare plugs anyway ... easier to replace and clean them later anyway.

The joys of 2-strokes ...

[paturoa]

You should get ~10 thousand ks out of a plug on a RG150 if it is running sweet and the bike is used for general road use.

It is always hard to tell, but they will foul really quickly when running too rich. Take it to someone who knows what they are doing, or even a reputable bike workshop.

[Asher]

Looks to be running too rich but we don't know what sort riding you were doing before hand. Go do a plug chop and see what it looks like then

[imdying]

How many kms on the engine? When was the last time you refreshed the top end? Very easy and cheap to do before it goes bang. Afterwards, not so much. Two stroke maintenance is easy, just never neglect it... it's not a four stroke where the cam chain or whatever will rattle around for years before actually causing serious trouble.

[ellipsis]

...yes, if the cam chain on the RG is rattling around you certainly do have problems...

[stoo]

Finally had some time to look more closely.
Did the multimeter trick and it's definitely fouled, and I'm blaming my carb.

Pulled it off again, checked/cleaned jets, and now trying to set the float height but this has me confused:

Where exactly does distance distance (A) start and finish?
I assumed it would either be red or yellow:


Never really had to set float heights before so I'm confused.

[sootie]

Finally had some time to look more closely.
Did the multimeter trick and it's definitely fouled, and I'm blaming my carb..

I think you should check the carb jetting, float level, and lubrication levels of the bike & correct these and any other problems as necessary.
You might also like to consider an Irium or Platinum spark plug. They cost a bit nore, but they last longer, and they are great at reducing fouling problems.
[Try "spark plug" on Trademe under "Motorcycle Parts". You will have to check that you buy the right plug.

[stoo]

float level

But how?
None of the measurement options I've tried (see two of them in the previous post) are physically able to match the manual specs before the bendy tab comes into contact with the rest of the float hinge thingy.
As of now, the lowest I can get is 10 (manual says 8). And fucked if I can figure out where the manual says I'm supposed to measure from (also see previous post).

I'm fairly certain the jetting is standard, unsure on the oil pump but by eyeometer the smoke levels appear normal now.

Will also investigate tasty sparkplugs too, now that I've fouled all my spares.

[sootie]

But how?
None of the measurement options I've tried (see two of them in the previous post) are physically able to match the manual specs before the bendy tab comes into contact with the rest of the float hinge thingy.

Hmmm ... hard to be very helpful without an eyeful here.
Suggestion: Google "Suzuki (model no) adjust float level"
If you go through the replies this usually produces something which will help.

I once owned an early Honda which appeared to be factory standard, but which I became sure was over jetted.
In the end I put a piece of thin Cu wire (about half the jet hole size) through each carburettor main jet, and secured each with a bend around & through the jet inlet holes (hope you can follow that).
I ran the bike for years like that, and it was a different machine - absolutely better in every way. It did appear to be a design fault with that model.
(The bike involved here was a 4 stroke & had twin carburetors. It started cold with no choke, had difficulty revving, and hogged fuel before I reduced the jet sizing. Plug fouling was also an issue.)

Maybe something here will help.

[imdying]

I once owned an early Honda which appeared to be factory standard, but which I became sure was over jetted.
In the end I put a piece of thin Cu wire (about half the jet hole size) through each carburettor main jet, and secured each with a bend around & through the jet inlet holes (hope you can follow that).
I ran the bike for years like that, and it was a different machine - absolutely better in every way. It did appear to be a design fault with that model.
(The bike involved here was a 4 stroke & had twin carburetors. It started cold with no choke, had difficulty revving, and hogged fuel before I reduced the jet sizing. Plug fouling was also an issue.)

Well fuck me dead... I thought I was the only one crazy enough to have tried that... worked in my application too

[sootie]

Well fuck me dead... I thought I was the only one crazy enough to have tried that... worked in my application too

Good to know my way too! The bike was a Honda CB360 twin (which I was never that impressed with).
Other point of interest is that if the wire diameter is half that of the jet hole, then remaining jet area still working is 75% of the original (not 50%).
(Remember your old formulas for the area of a circle!)

Actually I currently own a 2009 Piaggio Fly scooter which also seems to run a bit rich. I am considering a re-run of the old script!

[imdying]

Ooooh, I have to dredge pretty hard in the old memory banks... but I think it was related to the pilot circuit on an Holley 600 vac/sec. Was suggested to me by an older, hideously experienced joker I worked with.