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Does anyone have experience with both the 36mm and 38mm LECTRON?

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I have a 2015 KTM 250 EXC (XCW) for which I want to buy a lectron. The main reason is increased range, but I also like the idea of not having to fiddle with it too much once it's set. Still, range is my priority. 

I've done a ton of reading and thought that lectron recommended people on 250s to buy the 36mm and 300s would be recommended either a 36 or 38mm (if competing). If I'm not mistaken, pre-2017 KTM 250/300s BOTH had 36mm stock crbs, correct?  I think the Salvens site also recommends 36mm as well for both the 250/300 (pre2017). 

I contacted them yesterday and they now seem to recommend a 38mm (High velocity) for all KTM 250s, both modded and stock ones. He also mentioned it's compatible with 2017+ models as well. I don't plan on upgrading anytime soon (plus injection is the future, rendering them useless). Also, my bike isn't modded (yet). I MIGHT get an SX head and V-Force4 reed cage in the future, but not at the moment. When asked about the difference, the salesman seemed to say that the 38mm HV offers the same bottom end as the 36mm, but more topend. Best of both worlds and it's the best carb they make (and only $30 more so I wouldn't mind).. . I do like the idea of getting more topend (not that it's lacking), but wondering if going for something other than stock size is worth it.

Does anyone have any direct experience on the 36mm/38mm lectrons? Ideally back to back, but I doubt anyone has splurged twice for a lectron on the same bike... Is the 38mm worth it over the 36mm? Does it gobble more fuel? What are the different power characteristics? I had always assumed that I would get the 36mm since it's a 250, but now I'm wondering...

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I don't have any experience with the 38 on my 300.  That being said, I've never been riding it and thought to myself, "Gee, I wish this had some more power".  I'd guess you're in the same boat with the 250.  On top of that, the 38 will use more fuel, which is something you said you're trying to avoid.

I didn't really answer your question, but it's food for thought.

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I have had both 36 and 38 on 2 200sx's, one modded, one stock.  The modded 200 (head cut, port work) was intended for use on the track primarily which is why Lectron reccemmended the 38, the other stock engine was supposed to be a woods race bike, and they reccomended the 36.

 

As it turns out I sold the woods 200 since I like the track bike so much.  In my opinion the 38 pulled just as well off bottom, and complimented the head work that was done.  The 36 felt the same on bottom, but certainly didn't wind up as well in the upper rpm's.  Granted these were 200's, but if it were me I'd go for the 38.  There are several for sale on KTM Talk.

Fuel consumption was low on both bikes.  If I got 40 miles per gallon out of the 38, I got 41 out of the 36. I did ride an 80 mile enduro with the 38 on less than 2 gallons of fuel, only guy on the line with a 2 gallon tank.

Edited by poldies4
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when inquiring about a lectron for my 02-300 I got this from jeff slavens:

 

 

"2008-16 (300) use the 36 stock. Lectron always recommends sticking with the stock size for most applications."

 

 

I cant imagine using a 38 on a 250 would help you...

Edited by THUMPERRRR

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I have ran both.... If you are a top end rpm type rider then go 38.... But for trails I think the 36 is best and seems to not only give you more top end but you get a good bit more low end... Better fuel consumption also... That being said on my 13 300 with porting and sx ecu and head I could get 90 or so miles on tight single track. Currently I am running a 36...

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Ok thanks guys, I'll go for the 36mm. As a side question, would getting a used lectron make it way more difficult to "tune"? I'm worried about buying a used one that someone has fiddled extensively with, then it'll take me ages of fiddling with to "get right". I'll read up a bit more on tuning them, but it does have me worried. I think the metering rods are all the same now (2-3), but I know that when ordering new, they try to get it as close to possible for you depending on temperature and fuel you use (I use shitty fuel and low elevation, always hot around 80-110). Or should I go ahead and save some cash with a used one since they're fairly easy to adjust? 

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All 3 of mine still needed adjustment from their settings.  Granted they were minor, but it still had to happen.  YMMV. 

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I have run 36,38,40 mm lectron on my KTM 200, because I had them laying around.   All three carbs were an improvement over the stock 40 keihin that came on the bike.

When I ordered a new crisp Lectron I bought the recomended  36mm, works great,  I can't say top end is different, I think the 36 works the best in the mid range with the recomended needle.

The big plus running the lectron is the smooooth linear throttle response from low to the top end.  So mx track...........naw,  rock piles and sliippery creeks and 3 ft logs,  the Lectron is hands down winner.  I have loaned out my old junky  38 mm lectron numerous times the last 10 years,  makes a believer out of guys that think they have a crisp running two stroke. One guy turned his so so yz250 into a real woods bike,   after he bought his own 38 lectron , he found he could ride tigher nastier woods and his high first gear bitch went away.   Dan tried it on the last year KDX 200,  huge upgrade to a bike he though was jetted spot on.  When he bought the new 36 Lectron, carb we did the right thing and cut the frame so the carb could sit upright as it should,he  now has the no kill tractor motor.

You still have to jet and adjust the Lectron.............lots of posts on this, I have posted several times and helped guys dial the Lectron.  The factory has pretty good suggestions.  Buying it thinking it can be dialed to your bike from 2000 miles away is absurd.  It can be close enough to ride.......ok. but perfect would be a million to one hit.

 

 

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Thanks sledman. So do you think saving $150 or so by getting a slightly used one would be a smart move? Or am I better off buying directly from them to hopefully be "closer" to where I need to be from the start?

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Ok thanks guys, I'll go for the 36mm. As a side question, would getting a used lectron make it way more difficult to "tune"? I'm worried about buying a used one that someone has fiddled extensively with, then it'll take me ages of fiddling with to "get right". I'll read up a bit more on tuning them, but it does have me worried. I think the metering rods are all the same now (2-3), but I know that when ordering new, they try to get it as close to possible for you depending on temperature and fuel you use (I use shitty fuel and low elevation, always hot around 80-110). Or should I go ahead and save some cash with a used one since they're fairly easy to adjust? 

Rods are different for some bikes and different conditions... For instance if I run mine as a snowbike I put in a different rod for winter than the summer... It's worth talking to lectron... In my opinion new is the way to go... They do have to be rebuilt ever so often because of the seals starting to weap like any other carb.

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I wouldn't hesitate to buy a used one. Just make sure they have a good, newer metering rod installed (newer ones deliver a better a/f ratio). If its cheap enough, you can get it and then call Lectron for a better rod.

 

If you buy new, I personally would go directly to Lectron. They send the adjustment tool with their carb. Slavens charges another $18-20 (according to what he says in his YouTube video). Imo that's bs to charge for it.

 

Also, if dealing directly with Lectron, MAKE SURE you tell them to check their choke and not to send you a crap one. Don't ask me how I know lol.

 

Edit: oh yeah, and like others have said, you likely will have to adjust for your bike. But its very straightforward. Sledman actually posted a great tuning guide in another thread (I believe it was him?) here on 2 stroke ktm. Mine came extremely lean from Lectron and I had to go 3/4 turn on the rod. It took a couple rides, but if you're lean, you'll know it with the lectron.

 

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On ‎5‎/‎12‎/‎2017 at 10:52 PM, Bitteeinbit said:

Thanks sledman. So do you think saving $150 or so by getting a slightly used one would be a smart move? Or am I better off buying directly from them to hopefully be "closer" to where I need to be from the start?

Call  Lectron and David will ask Bike, rod and what length.  Things are simple to work with but folks seam to over think it.

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If you don't mind making some adjustments and ride enough to evlauate the changes, then a complete lectron used is nothing to be scared of.  The issue used,    is often on ebay I see 25 year old carbs for sale with no power jet, no idle adjuster,   no choke..........used on fuel drag  bikes,   idle adjusters on the right which you can't hardly reach on most dirt bikes.  The junk Lectrons I have were pickup up at swap meets and are old drag bike carbs,  $10  each............not much of a gamble.  Surpisingly, after adding a power jet and ordering the correct needle from Lectron for the application,  performance was as good as a new carb. So I proved a point to myself,  Lectron was   the way to go again, it worried me riding 50 miles from the truck with the old junnk Lectron  with patches of  DEVCON and home made power jet, so I cowboyed up and bought a new one from the guys in Texas.  The newest Lectron Dan bought a couple of weeks ago  is a good step up with oring type gasket on the float bowl.  Buy a new one and ask for a choke extension cable, good improvement on my 200exc where carb is almost hidden by the tank and you have to stand on your head to find any carb choke. 

My   "new" Lectron on my  KTM 200 is now 3 year old.  So 5 years with the bike with a Lectron 38/36 on it.    More times than I care to admitt  I though I had the settings absolutley perfect, couldn't be better.    Then I would go ride some  different weird trail, or have to ride 3 miles of interestate and I could see how just one more tweak would be an improvement.  In every case that tweak was richer on the needle,  takes gas to make hp,  the temptation is running the needle  "  clean and lean "  no sponge, sounds like hoover vac................smooth no two stroke left off rumble,    but sometimes that     clean and lean  is just a little flat on tight woods uphill switchbacks at 8000 ft.

Keep in mind if you ride in the mts at altitude, LOW END  jetting will often be back asswards to what most expect,  needs more gas to work right off the bottom in the high county,   why, because the loss of hp as altitude gets extreme has a bigger effect on your motor than  lower air pressure effecting the tiny amount of gas delivery right off the bottom.

Anyway, have fun with the Lectron.

 

Right now I tore down my antique KTM 200 exc and just   GOLD VALVED the shock/bladder kit/new oil and seals/new progressive rate spring,  GOLD VALVES  this morning in the forks and new springs/oil,   and over all put in spacers to lower the overall bike  1.5 ",     making a crossover poormans    x trainer ?    we shall see.

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