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Ryan McLaughlin

My favorite YZ250x mods!

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So I have a 2019 yz250x and I have recently changed two parts that have made it so much better in the tight technical singletrack. First the heavier GYTR flywheel made a huge difference. But then I put on the new Lectron H-series carb. This combo has made the low end so much better. The torque is stronger and more linear. Far less like to stall or flame out. The power is so much smother I'm using about 25% of the clutch in the tight stuff then I was before. Highly recommend!

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Where did you get the H-series? There site doesn't say they're avalable for the yzx.

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Posted (edited)

    If we are talking engine, for me, the best mods in order from first to last was jetting( OEM was rich idle to wot), head mod(OEM squish of almost .110"), removing a .8mm pv washer, fww, dep pipe. 

    Now, if the throttle is even cracked a hair, it is impossible to stall. I can not even begin to put into words how much better it is. Stock the motor was very mellow and extremely rich. The only place it ran only half way right was wot.

     As far as the chassis goes, first, best mod to last was set up(sag, lowering triple clamp), a mt16 and m59 tires with tubliss, springs for my weight(200+), arc rc8 clutch perch and levers, hodgkins stator.....and skid plate/barkbusters.  

         I had a hard time getting the chassis to corner right. It is better now after setting the fork height at +8mm.

       

Edited by morrison250r
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7 minutes ago, Clutch44 said:

Where did you get the H-series? There site doesn't say they're avalable for the yzx.

From the site. I emailed them and they said all they have is the h series. If you look at the picture for the one listed its the h series even though the description says hv. Same price and everything. They changed the picture on the page to the h on the 8th.

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1 minute ago, Ryan McLaughlin said:

From the site. I emailed them and they said all they have is the h series. If you look at the picture for the one listed its the h series even though the description says hv. Same price and everything. They changed the picture on the page to the h on the 8th.

I'll have to send mine back for the upgrade then and see if they can get this turd to work.

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Just now, Clutch44 said:

I'll have to send mine back for the upgrade then and see if they can get this turd to work.

Mine was perfect out of the box.

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13 minutes ago, morrison250r said:

    For me, the best mods in order from first to last was jetting( one was rich idle to wot), head mod(OEM squish of almost .110"), removing a .8mm pv washer, fww, dep pipe. 

What was the head mod and what was it's impact on performance? How did removing the washer effect the bike? Oh and what is few? Lol thanks

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4 minutes ago, Ryan McLaughlin said:

Mine was perfect out of the box.

So did you just get yours a couple of days ago? If so can you report back after 20 hours? I only say this because mine worked great for about 5 and then was all over the place.

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4 minutes ago, Clutch44 said:

So did you just get yours a couple of days ago? If so can you report back after 20 hours? I only say this because mine worked great for about 5 and then was all over the place.

Yeah, I'll do that. I have about 5 hrs on it so far. Won't be riding this weekend, going to TKO hard enduro as a spectator.

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Yes, I would be shocked if the Lectron gives any more low end torque than a well-jetted stock carb. But glad it is working for you.

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23 minutes ago, Ryan McLaughlin said:

What was the head mod and what was it's impact on performance? How did removing the washer effect the bike? Oh and what is few? Lol thanks

       The head mod was done by rb mods. It is nothing special. He cut the squish band from approximately ,107" to .045" then opened the bowl back up have the same compression as factory. UCCR is now 13:14-1

    Combined with jetting the carb the results were dramatic. Improvement was greatest on the low end however mid and over rev was improved also. My estimation is 40% better low end, 20% better mid and 10% overrev. Sponge was eliminated. The I can now set the idle for 1300 rpm and it is more consistant also. I would rather have 25% of the gain of the head mod vs my dep pipe. It is literally 5x better.

      Removing the washer lessened the preload on the power valve. Stock it felt like the low-mid to mid-high was overly soft and.....prolonged. Jetting, head mod and the pv mod transformed this bike to the point I do not feel a fww is necessary. 

     Few probably means fww......

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3 minutes ago, morrison250r said:

       The head mod was done by rb mods. It is nothing special. He cut the squish band from approximately ,107" to .045" then opened the bowl back up have the same compression as factory. UCCR is now 13:14-1

    Combined with jetting the carb the results were dramatic. Improvement was greatest on the low end however mid and over rev was improved also. My estimation is 40% better low end, 20% better mid and 10% overrev. Sponge was eliminated. The I can now set the idle for 1300 rpm and it is more consistant also. I would rather have 25% of the gain of the head mod vs my dep pipe. It is literally 5x better.

      Removing the washer lessened the preload on the power valve. Stock it felt like the low-mid to mid-high was overly soft and.....prolonged. Jetting, head mod and the pv mod transformed this bike to the point I do not feel a fww is necessary. 

     Few probably means fww......

Got it. Thanks! That's a lot of good information to consider. I was considering an aftermarket head but if you've had that much of an improvement, I might go that route

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