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Read my piston please

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Hay guys had oil coming from under where the pipe connects to the head. Replaced the seals it wasn't that so today decided to replace the head gasket to see if that cures it.

While taking the head off noticed my piston

Could someone tell me what's going on is it lean or rich. Jetting totally confuses me I can't work out how to do itimage.jpgimage.jpg

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Please explained to me. Like I say I'm useless at jetting. Do you think I need bring out the air screw a bit more. Don't want be messing with jets ATM. Plus when I practice I want ride not plug chop. Only get 4 hours to ride there

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Agree with arnego2 very rich piston wash. How you attempt to lean your jetting depends on where you spend most of your time with respect to throttle position. If you just trail/play ride at lower rpm's,  A leaner pilot jet change might make all the difference in the world.

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I ride mx and not fast but a do rev a lot mostley 3 pinned.

I did order a new jet kit from the USA but they wanted £15 get it throw customs it's a joke.

Could it be that the jets are worn.

When you say rich does that mean it's getting to much fuel or oil? I've always run at 32:1

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Just had a read of a dummy's guide. Going raise the clip one and see how it goes

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I ride mx and not fast but a do rev a lot mostley 3 pinned.

I did order a new jet kit from the USA but they wanted £15 get it throw customs it's a joke.

Could it be that the jets are worn.

When you say rich does that mean it's getting to much fuel or oil? I've always run at 32:1

32:1 is fine. It's your end jetting that's too rich and causing spooge. So if you truly spend most of the throttle in the midrange, then you are correct a needle clip adjustment will be the most impactive. I also suggest starting your jetting process with fine tuning the pilot jet, then moving to the needle. No matter how "fast" you are, correct pilot jet selection is critical for 250's and 500cc bikes to pull crisp right from idle.  

Edited by Polar_Bus

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Should all the jets have a number on them??

Jetting will have to wait till next month now had a crap wage.

Try the clip in the meantime. Like I say I don't have anywhere or time to do plug chops.

I have to pay to go a track

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Jets don't wear. If it was running good, dont worry about it. A two stroke wont gernade for being rich. The rings can eventually stick from carbon, but the rest of the engine likes the extra oil. Are you fouling plugs? I wouldn't do too many changes unless you know what you are doing.

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H there. Had the carb apart today gave it a good clean. The clip was in the middle so moved it up one.

It also has a 178 main and 50 pilot I'm sure 48 if factory not 100% sure tho

Never foul plugs just once when for sum reason the air screw was only 1 turn out.

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178/50 seems rich, unless you're riding in a cold climate at sea level. You could do several things - you can drop the size by one on each, and get a much crisper response. As far as the needle, if you drop the jets, you could probably leave it in the middle. With the air screw, just mess around till you get the best result, but it should be 1-1.75 turns out.

You could even go to 40:1 oil ratio, depending on the oil you run (high quality synthetic). This will of course make the bike a little richer, but it might help in the log run with spooge and such.

 

All this information assumes you have a well maintained bike, clean air filter, good gas etc...

Of course, check the plug anytime you make changes, it'll tell you if you're doing better or worse.

Good luck, keep us updated.

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H there. Had the carb apart today gave it a good clean. The clip was in the middle so moved it up one.

It also has a 178 main and 50 pilot I'm sure 48 if factory not 100% sure tho

Never foul plugs just once when for sum reason the air screw was only 1 turn out.

Don't beat yourself up over rich jetting. Remember this key comment : "it's better to foul a $8 plug, than melt a $400 top end" (and you're not even fouling plugs at this point) . Some visible spooge is no big deal, just messy. Yamaha YZ's come jetted pretty darn ideal for summer use right from the factory, and many times I see too lean OEM jetting as soon as the cooler fall temps arrive. It's up to you if you decide to lean down, me personally at this time of year leave the jetting alone. I would think more about leaning down next summer.

Edited by Polar_Bus

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I'd pick up a few sizes leaner pilot and main jets from your local dealer, usually $5 max each, your at 178/50 now so pick up a 175 and 172 also a 48 and even a 45 pilot. You likely will end at 175 and a 48 pilot and still be safe. What altitude are you at and what are the temps your running at now?

Also what is your air screw setting? That will tell you where to go for your pilot.

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Haha you guys have never been the UK then. We are at 350ft to 1000ft here. I'd say at my house I'm 450ft from sea level.

Also at the mo it's a roasting 9'c haha

Been raining for the past 48hrs

I think I will get myself some lower jets when I get some money together.

My bike is always maintained to the highest. Oil every 2 rides and filter after ever moto

Also use fully synth. 2 stroke

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Well if your in the uk you should be good. Your at stock jetting 178 & 50, stock needle at 2nd clip. Your at sea level and cold temperatures. Jets only costs a few bucks for new jets.

Sounds like worn jets to me.

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I knew jets could ware out. Will order some new ones. Thanks guys

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 Oil every 2 rides and filter after ever moto

Also use fully synth. 2 stroke

Your just wasting money changing trans fluid after only 2 rides.   Cleaning your air filter after each moto is prudent but really unnecessary unless conditions are extremely dry and dusty.

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Your just wasting money changing trans fluid after only 2 rides.   Cleaning your air filter after each moto is prudent but really unnecessary unless conditions are extremely dry and dusty.

I use ATF had 15L given to me. I don't see no harm in changing it after 2 meetings. Also changing to a clean filter after I moto I don't see no harm. It's ither dry and dusty here or pure slop. That's what I like to do

I've worked my hardest over a few years to get a bike after 12 years off. My rents made me sell up when I was 18.

So changing oil and filter regular is sumthing I like to do. I've got nothing else in my life that I really enjoy

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