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Lectron Tuning Question for YZ250 with EG295 Kit

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Hey all.  Haven't posted in a while.   I am trying to tune out a stubborn lean spot on my bike, and I am having an issue.

Bike details:

 

YZ250 with Eric Gorr 295 "Mo Betta" pump gas build

Squish adjusted to .067 and head modified for lower octane gas

Timing retarded 2 degrees from stock 

FMF Gnarly pipe

Lectron 38mm Shorty Carb with 3-2xl metering rod

40:1 Motul 710 Synthetic with 91 Pump

 

Settings were originally set by Kelly at Motosportz based on the above and supposedly intentionally a touch rich for a fresh motor break in.  

 

Here is my problem.   at around 1/8 throttle, i start getting detonation as the RPM starts to rise.  This should be remedied by turning the metering rod in to richen.  the low mid.   I am under the impression that 1/4 turns should make a big difference.   I am currently 1 and 1/4 more rich, and I am still having significant partial throttle detonation showing.   WFO, I have adjusted the power jet and the thing is dialed with no detonation whatsoever.  

 

Should I keep richening the metering rod, or am I nuts here?  

 

Also, how would I check baseline on this from a measurement perspective?   If someone has a similar setup, any tips would be appreciated greatly!

 

Cheers,

 

-Paul 

yz.jpg

Edited by pentaxis

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^Thanks!

 

Just gave Lectron a call directly.   I think it was David I spoke to?  Very helpful!    He agreed that it sounded like a fine tuning issue, and that I should just keep going richer on the metering rod.  If I can't get it dialed in with this particular rod, they have a 3-3xl that would fatten up the bottom end even more and should get things dialed in.  I will give it a spin (literally), and post back.

Edited by pentaxis
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Not a big bore.

If I raise mine to far the idle goes away. Only takes a quarter turn to go from awesome to poo.

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So I spent some time this evening trying to get this sorted.   I was at 1-1/4 richer than delivered.   I tried 2 full turns, still had some noise, and now 3 full turns.  I can tell the bike is running rich, because kit kinda chugs now at low rpm low throttle openings.  I am still getting transition rattle at lower-mid RPM, when I roll the throttle on from 0 opening to 1/16 or 1/8 throttle.    Beginning to wonder if this isn't a detonation thing, but it sure sounds like it.    Motor is completely fresh with less than 2 hours on it.    Any ideas?  

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Eric likes a big squish. Some will disagree.

I can't comment on a 295. Only a stock 250. You can't jet away a squish issue.

David told me a 3.2m was good for 300s.

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I have a 3-2XL in my Lectron, it worked very well on my 295. What is your kicking compression? Have you thought about a 50/50 mix with race gas? I agree with seer, turn that needle to far and it doesn't idle.

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I dont have a compression tester. Race gas to see if it is detonation was my next step. At 3 turns in, I still have an idle. You can tell it is rich by how it is running at low rpm small throttle position. Only time it makes odd noise is in the saying, seer. as described above. thanks for your feedback. I'll see about testing compression as well.

 

 

 

everyone that run 295 kits seem to agree that .060 - .070 is the optimal squish and usually help with letting stuff. I had mine recut to hit this as it was wide at first like you were saykng

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I had my pump gas head cut to .060 and after talking to my local guy that just built my 285 I wouldn't hesitate to cut your head to .045. My 285 is set at .045.

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Thats interesting for sure, and maybe worth looking into in the future.   There are lots of bikes that are doing well with a .060 -.070 though, even if optimal is lower.   I don't think that would be causing the issue.  

 

I will report back after I get some race gas in the beast, and see if anything changes.

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Is it possible that some of that could be piston noise because the bike isn't broken in yet?    I originally had this build done earlier this year, but was trying to diagnose noise that turned out to be a broken powervalve actuator.  6 heat cycles, and about 30 miles of trails total while trying to dial this in since the last rebuild.  Any ideas?

Edited by pentaxis

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Make sure your manifold clamp is tight. I had issues on my cr.

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Will check this tonight.   Picked up a 5 gal barrel of VP 110 for some testing.   Also spoke to Kevin at Lectron.   He mentioned that they have seen 295 guys run 2-3XL metering rods with good success as the taper helps with some finicky part throttle tuning.  Might be just the ticket, so I ordered one up that will be here next week.

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Kinda on topic.

I rode cr 250 tonight with the 3.2xl. Diffently lean on the bottom. If I go in a quarter turn it's horrible at idle to 1/16.

I tried the 3.3xl. Fluffy.

Might have to try my 3.2 m again.

I'm having trouble finding perfection. It does hook out on root filled hill climbs better than ever. Slight bog is great for traction but needs extra clutch work.

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Sniper racing sells a air screw kit. I'm ordering one . The I can run a richer needle setting for midrange and adjust the idle.

You can get Lectron to install one too.

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Interesting.   Let me know about the air screw.  I will let you know about the 2-3XL   Richer bottom with a leaner top should do the trick, since the 3-2XL is at about 3/4 out right now anyhow on the main jet, it should be perfect with 1-1/4 out with the new rod, and a better taper.

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Mine was tuned on the Dyno. It's been spot on.

 

Just wanted to checkout how it alll worked. Like pulling TV's apart when I was a kid. "Curiosity killed the Cat"  :lol: .

 

Here's a 1/4 turn richer on the metering rod. "Went fom Choclate to boilled lollies". Was better on the 2nd track but still no fun to ride. I just wanted to go home  :facepalm: . (Don't carry tools).

 

RM144

https://www.youtube.com/watch?v=RzJu3OwVmPA

Edited by AddictedToBling

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I am very happy with my 2-3XL. Not running it on a YZ 295, on a KX 250. I went back and forth from the 3-2XL to the 2-3 and settled on the 2-3.

I ride the bike from 5k to 11k, didn't get up any higher at the end of the season due to hunters but I am really happy with the performance on the tight single track.

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Interesting. Let me know about the air screw. I will let you know about the 2-3XL Richer bottom with a leaner top should do the trick, since the 3-2XL is at about 3/4 out right now anyhow on the main jet, it should be perfect with 1-1/4 out with the new rod, and a better taper.

David afford another needle but I didn't get the code. It's so close to perfection. ...

I brought my keihen on my ride -cation. One week RVING and riding. Can't decide if I want it's mid or the Lectron smooooooothness.

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Do you know how to adjust the needle or power jet? It's simple but I wonder.

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