250-500cc Can't cure lean machine.

Since I installed lectron throttle is hanging after been on the gas & pinging a lot too. (on closed throttle.) To cure needs 1 3/4 turns out on PJ & 2 1/2 turns richer on rod(than recomnd -2.058"), which leaves it blubbering then fouls plug. Same result with 3-2M & 2-3xl rods.
If that wasn't enough, now has developed mid-range lean bog when cracking throttle.
Thought it had airleak ,but didn't show up with leak-down or spray test. Replaced intake boots (double gaskets with silastic) & crankseals anyway.
Been thru everything i can think of & out of ideas,maybe one of you blokes on here can suggest something i've overlooked.

Heres what else I checked-
Strong spark, good voltage from magneto,right ohms from coil,plug lead & cap.Also good when hot.New plug.
Compression 175psi. Recent new piston.
Not losing coolant.
Fuel tap & breather not blocked.
Carb sealed up & float ok.
Reeds look alright ,new ones coming anyway.
Powervalve working properly.
Repacked silencer.
Tomorrow I might stick stock pipe back on in place of DEP,see what that does.
As you can see I've been reading plenty of threads. Any suggestions appreciated.

Have you stuffed the old carb back on too rule all that out. Or did you buy lectron to cure the lean issue?

Good point.Forgot to mention that I tried Keihen back on.Don't notice it as bad,probably because runs rougher with this carb, but still doing it.

Sounds like a definite air leak somewhere between the carby slide and combustion chamber. Intake manifold, reed block, crank seals, base gasket, crank case centre gasket or exhaust flange are the usual suspects. With the engine running try spraying wd40 or similar in these areas, any change to the engines note or speed indicates a leak.

Did this occurre immediately after any changes made eg. top end rebuild? Poss piston in backwards??

Mine does a similar thing with mikuni

I recently put the pro circuit pipe on and noticed it was running more lean - quite a white plug even after going back from 4 to number 2 on needle and one up on main jet
Pipes do make a big difference

When I tried pilot screw in further it was fluffy

I will try going back to richer slide and pilot on mine but cant help you with yours - sounds like its a very similar issue and may not really be an issue . Might have to put up with hanging idle

Sure sounds like an air leak No cracks in the cases or manifold? I would go back to square 1/stock and add a mod at a time. Lectron cures probs usually, not causes them.
Is there a lot of spooge? Bad fuel? Water somewhere?

Random but couldn't be plug not tight enough or dodgy plug thread lettin air in? Sounds like uve covered(checked/replaced) everything. Bsse gaskets where case halves join? Crank seals in right way? Pipe orings/exhaust manifold gasket area? Head orings? Sum unlikely jus tryin to spur sum1 more cleverer than me into action!

perform a leakdown test, not just replace things

He did n spray test but got nuthin

Smarty pants lol.

leak down is different to air leak test - checking rings -

Thanks for all the replies,helpful bunch on here.
As I mentioned,pressurised crankcase, sprayed soap & only air escaping was tiny amount from powervalve.Also sprayed carb cleaner at all usual suspects.No detectable air leak anywhere.
Crankseals in right way-same with old ones.
New rings -175psi compression,is that about right with race-head?
Good seal @ pipe.
Piston in backwards,thats a new one.Would it run? Has arrow on top,sure i got that right. But did start immediately after new top-end Oldscool.
Don't think I can just put up with it,will probably seize at some point.
Used 2 different fuels,might try some premium(95),but never made difference before.
Think will take your advice NCSteve, start from scratch & add new bits one at time.Can check that arse-about piston while I'm at it!

Hope ya get it sorted mate

Wonder if worth a call or email to someone like Dave at Two Stroke Performance? Buy sumthn off him for his time if he cums up with a solution!

If u on DBW Nutty is pretty onto his 2t engine building too

Yakka, I've seen seals leak one direction but not the other (some crank seals are double sided). Pressurising the engine doesn't fully test a crank seal against allowing air to be drawn INTO the engine. Not a common situation I know but it is a possibility.

If you removed the carby and exhaust to plug those areas for the pressure test and had no leak anywhere then I'd start at those areas. Perhaps manifold not sealing around carby.

Good point. Hard to do vacuum test with powervalves though,near impossible to fully seal. Did replace c/seals after problem arose & crank surface looked good.
New rubber boot that seats well on carb & clamp tight.Spray tested around it too.

Just going to put this out there, your lectron choke is screwed on fully and not loose, also have you pulled the float bowl to see if there is any debris in it as some have had small plastic pieces blocking it up

Cheers,may do that before i chuck it in the dam.

Yeah,had good look in bowl,nice & clean. Will check the choke later.Thanks.

It does sound more fuel related seeing as how much work you've gone to seeing if everything sealed.
I must admit I've never done a leak down test, have done the spray carb cleaner when running.

Your meeting rod is is the correct way round? I did that stupidly cus I was holding the carb back to front.. shhh don't tell anyone.

Easy mistake jp,might even give it a try!
I think you're right in being fuel related.