Help with two-stroke tuning

[Skunk]

I've got one in mind...

[Skunk]

After a quick run (3rd gear, 60-70kph, 50% throttle, 1km long) this is the plug. Last photo shows colour best.

It wasn't running smoothly.

[Ixion]

Well, that's definately not lean!

I'd say quite rich, and rather oily. Probably dirty enough to cause misfiring which would not help.

[k14]

Yeah thats definately rich. Is that plug fairly new though? It could be a bit of a miss read if its an old plug that has been used whilst trying to diagnose the problem. Need to give it a good thrashing all through the revs to get a really good read.

Did you end up drilling out the main? If you give the throttle a quick rip from 0 to 100% whilst its idling does it rev up cleanly or does it bog? Does it fully rev out?

[Skunk]

Slow or fast twist with no load it revs clean
Slow with load it dies
Fast with load it starts to die then picks up.

I think it's rich with the wrong needle.

Ferk it; I think I'll just have to pay someone...

[k14]

Yep I reckon rich on the main.

[Skunk]

Hmmm, I'll go with than. It was a 137.5 that I drilled. It wasn't any good with the 137.5 either, so what would you suggest?

[k14]

Maybe you went from one extreme to the other? How much bigger did you drill it out by?

[Skunk]

It was a 1.4mm hole (Guessing thats 1.375mm). I drilled it with a 1.6mm

[k14]

Hmm, that seems like quite a big increase. Only going on rs experience here but going from say a 180 to a 172 in some cases can be from very very rich to dead on. Maybe want to solder it up and try 1.5mm?

[Skunk]

OK. (Goes to fine a 1.5mm drill bit...)

Thanks K14 for all your advise.

[Ivan]

have you had any luck with it? my standered carb is too rich as well went full noise down the road for about 2-3 Ks and killed it took plug out and it was black and oily and im running it at 30:1 Want to try it now tho now that I opened the reed stops up as it revs quite hard now


Need a way of transfering the video from my phone to my computer

[FilthyLuka]

blutoof is your friend... hehe. Go to dicksmith or an it store and get a blue tooth dongle ($15), that should sort out the phone to computer thing...

DENIS!

[geoffm]

Any reason you can't use "real" jets - it makes the job a lot easier. The problem with drilling them is the hole isn't smooth or consistant, nor is the hole necessarily in line, hence the flow won't necessarily as per the hole size. To mak elife more intersting, one of the Jap carb makers rated their jets by flow, the other by diameter. All very confusing. 137 ->160 is a big jump.
Don't forget number drills of you want a bigger range of sizes.
Don't forget to mark the jet with it's real size if you have drilled them, otherwise you will be very confused later on...
Geoff

[Skunk]

Cheers. I'm still looking for a 1.5mm drill (had to work today and it was too busy to get out).