50 Hour Lectron 38mm Power Jet "Shorty" Carburetor Review

[NVarra]

I figured a quick update is due now that I've accumulated over 50 hours of riding time with the 38mm Lectron "Shorty" carb installed on my YZ250.


Fit and Finish
Please refer to this thread for the original fitment issues [resolved] on a YZ250 (https://www.thumpertalk.com/topic/1017683-38mm-lectron-carb-install/).

Once the carb was cut down to become the new "Shorty" version the fit was snug though acceptable, even with the reed spacer left in. After 50 hours of riding there is no visible wear on the air boot from the shock spring. The tight fit isn't a fault of the Lectron as the YZ250 is excessively tight between the intake and shock spring. Overall, it's a tighter fit than the OEM Keihin, but safe and usable.

After my first watery ride I discovered something alarming. The clear plastic float bowl wasn't sealing properly on the intake side of the carb which allowed a bunch of muddy water to enter. The fuel screen prevented anything too nasty from entering, but alarming nonetheless. A thin bead of Permatex gasket maker on the outer edge sealed it well and this hasn't happened since.


Installation
The installation of the Lectron is very easy and will take the average person 45 minutes to an hour. Remove the side panels, seat, fuel tank, rear shock, Keihin carb and stock throttle cable. Then route the new longer throttle cable, tie the TPS wiring up and away, mount the Lectron, install the rear shock, fuel tank, seat and side panels.

If you have a larger aftermarket fuel tank you'll become very familiar with this procedure (less the throttle cable and rear shock removal) as you cannot adjust the metering rod with the larger tank mounted. This seems terrible but it only took me 3 tries to get mine dialed in perfectly and it's fairly resistant to altitude, temperature and weather changes. An external adjustment like the APT Smartcarb has would be a very nice addition when the temp drops or you want on the fly adjustments for terrain.


Setup/Tuning
Out of the box the metering rod was lean and the power jet rich for my riding style and terrain. Keep in mind that I like my bikes on the rich side and that every bike will be slightly different.

My first adjustment was the metering rod 1/2 turn richer and 1/2 turn leaner on the power jet. This put the bike near spot on but a few sandy 1/2-5/8 throttle hill climbs had the bike too hot for my taste. The second adjustment I went 1/2 tun richer on the rod and 1/4 turn richer on the power jet. It started to hesitate a bit right off the bottom so I then went 1/4 turn leaner on the rod. This nailed it for my riding style and terrain. It is on the rich side as it can be started without the choke, but she purrs like a dream without any real symptoms of being rich. Throttle response is very crisp and there's minimal spooge after hours of single track. WFO plug chops are great too with a light golden brown on Chevron 94 octane pump.

 

I originally removed the reed spacer for clearance and posted that it didn't reduce the bottom end much. Unfortunately, I was wrong and ended up re-installing the spacer. With it removed the power was shifted to the top end more than I'd prefer. It wasn't necessarily a bad thing, it just wasn't for me.

 

 

For those that are interested, here's my setup:

 

YZ Year: 2008 YZ250X
YZ engine size: 250cc
Carb mods (PowerNow, Wings, JDJetting, ect.): Lectron 38mm Power Jet "Shorty" Carburetor
Air Filter: Twin Air
Main jet: N/A
Pilot Jet: N/A
Needle model/Clip position: N/A
Air screw: N/A
Altitude where you ride: 2000-5000'
Reeds: Stock reeds and cage with spacer block installed
Pipe/silencer: Pro Circuit Platinum 2 / FMF Q-Stealth
Head mod: Stock
Other mods(FWW, ect.): GYTR Off-Road Flywheel
Type of fuel: Chevron 94 pump
Type of Premix/Ratio: 32:1, Motul 710
Type of Trans oil: AMSOIL Formula 4-Stroke PowerSports 0W-40
Type of riding(MX, trails/technical, desert ect): General trails and technical single track
Where in the powerband do you ride (Lugger/Bottom End, or Wide Open - Top End): Mainly bottom to high midrange
Rear Tire: 120/100-18 Kenda Washougal Sticky
Gearing (sprokets): 14/51
Degree of satisfaction: She's darn near perfect for my riding style and terrain.
How much spooge 1) none, 2) little, 3) medium, 4) lots: 2 -  There's a very small amount of pipe wetting at the lip of the exhaust. I'm blaming this on the Q-Stealth though. ?


Performance
Amazing. It starts much easier and lugs much better than before then transitions very smoothly and crisply into a healthy mid and killer top end. The added over rev was a very pleasant surprise that allows you to hang on just that little bit longer. The bike is so much smoother and cleaner that at first it feels like you've lost power. That punch you in the face YZ powerband becomes, dare I say it, KTM like smoothness. A few log hops and sandy no approach hill climbs proved to me that all the power is definitely there, it's just much easier to use. Mud riding is so much nicer now too. The smoothness and ability to control throttle is really nice in slippery clay conditions. The other area I notice huge improvements in is fire road riding. You can roll the throttle on as slow as you want and it never hiccups or bobbles. You get a super smooth rise in RPM directly affected by how much you twist the throttle. I like it.


Appearance
Beauty is in the eye of the beholder, but I think it looks great. It's very clean with minimal venting/drain tubes and the clear float bowl gets tons of compliments, plus it's always nice to see you mixed your fuel.


Value
This product is worth the money. There is no way that you can jet the stock Keihin to be anywhere near as good as the Lectron. This is the best performance product, dollar to performance wise that I've bought to date.


Fit and Finish          6/10
Installation          7/10
Setup/Tuning          7/10
Performance          9/10
Appearance          9/10
Value               9/10
---
Overall               8/10

Edited August 22, 2013 by NVarra

[tim512]

Great review. I'd love it if you got your hands on a cast smart carb and did a comparison!

[RiderX]

Awesome review, I can't wait to get one of these for my 295.

[H-B-R]

NVarra - on the fuel bowl issue you had. Was any gas leaking out of the bowl? If water could get in I would expect some gas wold be getting out.

I've got a lectron and I am wondering if I should pull it off and check that seal.

[NVarra]

Great review. I'd love it if you got your hands on a cast smart carb and did a comparison!

 

Once they get the bugs worked out of the cast models I'd love to give one a try.

 

 

NVarra - on the fuel bowl issue you had. Was any gas leaking out of the bowl? If water could get in I would expect some gas wold be getting out.

I've got a lectron and I am wondering if I should pull it off and check that seal.

 

There must have been a small amount, but it was such a small gap that it would be difficult to see.

 

I saw the water beaded in the bottom of the bowl after riding through deep puddles. At first I assumed it entered through the filter, but my paranoia led me to pull the carb and sure enough the plastic bowl was slightly cupped.

 

If you've been in wet conditions and don't see water, it's probably a non issue but it's always better to be safe than sorry.

[smv ryder]

I have been reading a ton on the carb. They say if you ride single track/ enduro/ cross country the 36mm Lectron is a better way to go and if you ride MX and WFO all the time the 38mm is the way to go.

Did you think about going with the 36mm or did lectron suggest the 38mm?

Thanks for the awesome review!

[smv ryder]

Also where did you purchase the carb and PM price if you have time

[xxxbranham]

Every thing I've read seemed to indicate that there were no real differences between 36 and 38 - the 36 runs really good wfo and the 38 runs really good at part throttle - in my experience the 38 worked awesome at all revs and throttle openings on the yz250 - imho you're worrying too much about too little.

[smv ryder]

Every thing I've read seemed to indicate that there were no real differences between 36 and 38 - the 36 runs really good wfo and the 38 runs really good at part throttle - in my experience the 38 worked awesome at all revs and throttle openings on the yz250 - imho you're worrying too much about too little.

Awesome!! Thank you for the info!

I am wanting to put the lectron on my KX 250 just not a lot of info in the Kawi section.

Edited June 22, 2014 by smv ryder

[xxxbranham]

I got mine from Motosportz - Kelley has done a lot of real world field testing and helped develop the new needles.    Be prepared to answer: "what kind of riding do you do?" and "what are you hoping to achieve?"   The answers help him set the carb for your use - mine came pretty much perfect (dyno testing revealed I was a click rich on the power jet which lost 2hp and a click lean on the bottom which gave me a touch of 'ring-a-ding-a-ding' coming off the throttle but idled forever.   Don't forget that most applications require the longer (internal cable is longer) throttle cable so the slide  can close all the way.

[projectcxr]

I will also agree, had my 38 long body on the 325 for a while now, not being backwards at fuel/air adjustments on almost any infernal combustion engine, I will state the lectron is pure simplistic carburation in it's almost purest form, and it works much better than the multi-circuit metering devices...

[BRM]

Got the new motion pro cable yesterday, hope it solves the slide sticking issue in wet conditions.

[slo rider]

The Motion Pro cable that Lectron stocks and sells was over 5" too long on my bike (06 YZ250). So I ordered a custom cable instead, should be here this week.

Edited September 4, 2014 by slo rider

[BRM]

This is a new cable made by motion pro for Lectron.

[RiderX]

This is a new cable made by motion pro for Lectron.

  Can you post the part # if you have it?  Is it the one with the elbow on the carb end?  I think that's the one I have, just want to make sure I know what to replace it with when I need to.

[slo rider]

This is a new cable made by motion pro for Lectron.

 

I got my cable from them just a few weeks ago, so it should be the same cable (part# 07-1211).

 

I called Lectron about it and they told me they don't have cables for every make and model of bike, just the different throttle brands.

I called Motion Pro directly and ordered a 07-1211 that was 5.25" shorter. It showed up hyesterday so I installed it last night and it fits much better.

[BRM]

 

I got my cable from them just a few weeks ago, so it should be the same cable (part# 07-1211).

 

I called Lectron about it and they told me they don't have cables for every make and model of bike, just the different throttle brands.

I called Motion Pro directly and ordered a 07-1211 that was 5.25" shorter. It showed up hyesterday so I installed it last night and it fits much better.

No my cable # is 07-1340. I will fit it up today and give some feed back.

The long cable I ran down the inside of the radiator between the frame and utilised a cable tie as a ring support, that way it did not bend too sharply

[BRM]

Fitted the new cable, it has proper sized weather seals both ends, is 5 Inches shorter than the one with the brass elbow on the top of the carb and doesn't rub the frame.

Fit is perfect and throttle pull is so much easier and smoother, watch out for whisky throttle. It is so much easier to pull I could go to a stiffer spring no problem. 

Made my day. All it has to do now is keep the water out and not make the slide stick and perfecto.

[slo rider]

Fitted the new cable, it has proper sized weather seals both ends, is 5 Inches shorter than the one with the brass elbow on the top of the carb and doesn't rub the frame.

Fit is perfect and throttle pull is so much easier and smoother, watch out for whisky throttle. It is so much easier to pull I could go to a stiffer spring no problem. 

Made my day. All it has to do now is keep the water out and not make the slide stick and perfecto.

Good to know. I'll write down that part number for when I need a replacement.

[BRM]

Tested it last weekend, plenty of puddles but no rain. Flawless so far.