TE/TC '17 TX300 Time to dump the Lectron?

Do you have the original carb to throw back on ?

Have you done anything with the squish ? I know they were on about the stock heads being average and needs tightening up.

I do have the stock carb, but I am terrible at jetting. My experience with the Mikuni is that there are way too many variables to play with in order to get it to run right. Many people with the '17+ TX or TEs are throwing in a JD kit, and when that doesn't work, they throw in different needles or slides. Ain't nobody got time for that. The Lectron is supposed to solve that particular shortcoming of mine. On my WR300 the lectron was a set it and forget it deal. I literally set the rod once and rode the bike almost every weekend for over two years. Rain, shine, hot, cold, didn't matter. It just ran.
But on the TX it is not plug and play. I have a feeling the High Velocity mod is somewhat responsible for its new touchy behavior. It's now on par with the Mikuni in terms of needing constant fiddling to keep it running well.

And as for the squish: nope. I still have the stock head and base gaskets in it. I really didn't want to spend yet another $350 (for an aftermarket head) on a $10,000 bike to get it to run right. I already had to buy a skid plate and spark arrestor since those are curiously absent on this off-road bike.

Head - I think this is worth a small cost . Improves fuel economy and is best bang for your buck mod you can do on a two stoke .

Getting it set up by a tuner should be less . I am a tight arse and I just got my '14 head shaved .35 by a local car cylinder head shop for $50 to bring squish down to 1.35.
This would bring more low to mid power - for the cost of a carton of beer.

Carbs - I am suggesting that if the stock carb has better response then the Lectron is the main issue . Did you have issues with the Mikuni ? What do Jarvis and co run - Mikuni . Those bikes sound sweet and crisp - responsive. He zaps it up those rocks with no issue . I personally like the feel of Mikunis .

This is from TSP website :-

The new 250/300 engine is very well designed and makes decent power, however there are some small issues with this engine that have a huge impact on how it runs. The biggest complaint we get is that low end power is very spluttery and weak and fuel economy is very bad. Its fairly common for stock bikes to get less than 60kms out of a tank. The 2 key areas that need addressing are the head (stock squish clearance is ridiculous, around 2mm), and the carb. Stock jetting is way off and none of the needles that are supplied in the spares kit are close to being correct.

We suggest setting up the head properly and rejetting the Mikuni as a minimum for this bike. This makes a huge difference to how the bike runs and dramatically improves low/mid power as well as fuel economy. Opening up the airbox will add extra hp up top but do this at your own risk as these bikes are still very prone to taking in dust. Our ignition mod is simple and cheap and adds a noticable amount of power from bottom to top with no risk to reliability.

Busting some 2017 myths…
There is a HUGE amount of rubbish going around the net regarding the 2017s. Unfortunately a lot of it is aimed at selling unnecessary products to uneducated riders so do yourself a favour and get some advice from someone who knows their stuff before buying some of these expensive “instant fix” products.
The stock reeds are absolutely fine, having a small air gap between the petal and the seat in still air has almost no bearing on what the petal will be doing when its opening and closing 100 times a second whilst covered in a film of oil. Dont replace the stock carbon fibre petals with the 1970’s tech fibreglass ones that are being sold on the net and advertised on youtube… they have a completely incorrect resonant frequency for this engine and are a big backwards step.
If you want to swap carbs on this bike then our suggestions is to consider fitting a short body Keihin PWK from an earlier model KTM125SX or a YZ250 (38mm). This makes a massive difference to part throttle running. There’s loads of accurate info about jetting these carbs to suit these bikes on the net and it will be a quick and easy install for most people. Fitting other aftermarket carbs that are marketed as “bolt on and forget” and “no need to adjust for temp/elevation” are usually not so straight forward in our experience…Â We have extensively dyno tested these carbs and have run them on our own bikes in the past. Take it from us… ALL carbs need proper setting up and constant adjustment for changing conditions, there is no way around this.
If you want the best value for money results then keep the stock reeds, setup the head and either jet the stock carb as best you can or fit a PWK. Anything else will simply cost you more.

If my local machine shop can do the head for $50-ish, I'd go that route. I've seen some videos of people who've bought the RK Tek head for $350 or whatever it costs. They show close to a 60 psi increase in compression. But some are reporting they don't do much to the bottom end. Which, I just don't understand.

I think the combo of AvGas with a little higher compression might get me a big bump on the bottom.


I might just throw the Mikuni on this weekend or next to see if I get any better results. I can tell you that when I had the Mikuni on for those first several break in rides, the damn thing had a serious hit to it. It was a handful in the woods.

$35 I vaguely remember paying more like $20 ea last time I bought rods. I don't know Brooks, but I'd keep him engaged and follow his suggestions, then squeeze him for a break on parts prices
I broke the PJ nipple on the 300s carb which I bought from Kelly, not Lectron. I called them for help fixing it and they talked me into sending it to them. They charged me $40 or $50 to fix the PJ nipple, but they also replaced the bowl with the newer reinforced version, replaced all the screws and hoses and cleaned it inside out to like new condition
And they sent me a cool hat to cover up my...I mean to help keep all this hair out of my face.

You will need 3mm solder to test squish . That cost me $27
I started mine today after the recent head shave . It started first kick which I cant remember it doing before . Just a quick ride up the road and it feels slightly better down low in that it seems like its less doughy. It also started with the starter which it was not doing until the bike had been ridden for 1/2 hour before . To work out how much to remove I would find out what others have done with their '17s . I wouldn't want to run AV gas .
I also didn't want anyone to mess with the bowl as I like the newer design as I think it has good low end characteristics. ( this is the '14 design ) . If I don't like it I can add thicker base gaskets to be more or less standard again .

Also have you tried adjusting power valve settings ?

Only thing I've done to the PV is add the green spring. When I did that I left the adjusting screw in the stock position. The manual says not to adjust it, so I'm not sure what to do with the adjuster.

Not sure on yours but on older models most people prefer the red spring for the power valve to start opening sooner ( dolly adjusted approx. 2.5 turns in ) This could be part of the lack of a hit issue .
There a heap of graphs done by JD jetting if you google it.


ADB Magazine settings : Mikuni - 43-72 needle with clip 2nd from top, 42.5 PJ, 450 main, 1.5 AS and difference significantly better with a much smoother and stronger bottom end, felt like it would come on power earlier and still have a great top end!

Here's an update:
I had a really bad sputtering problem on the low end, so Brooks at lectron said to go leaner. I did that last week and went 1/2 turn leaner. The power started to come back but still had some sputtering or blubbering from idle to about 1/8 throttle but beyond the very low rpm range, it was clean and crisp.

So to fight the sputter/blubber, I went another 1/4 turn leaner. But it won't go away. And I'm just making the mid range more and more lean. Which makes me nervous. I've been opening up the power jet to compensate, but I think there's a spot between very low RPM and the mid range, where its not covered by the power jet, which could be way too lean. Doing this has introduced a hit in the mid range that wasn't there before. And I think that's when the power jet kicks in. The power is really good now so I don't think I should go any leaner. For example, I've got the 3rd gear power wheelies back. And from a near standstill the bike can get out of it's own way. In fact, I might go back to stock gearing because with the power the way it is, I can't really use 1st gear at all.

I'm at the point where I really want to stop messing with it. But the sputtering and the lean low-mid is a real problem.

Kelly, the current rod is a 4-2M. Can they make one that is leaner on the very bottom end but about the same as the 4-2M from say 1/8 throttle on?

Realistically, though, I think the High Velocity mod was snake oil and destroyed an otherwise great carb. I'd love to put a 36mm normal, straight lectron on this bike and see what effect it has.

That would be 4-1 rod and they probably already make it.

"The biggest complaint we get is that low end power is very spluttery"

The spluttering would probably be fixed with a head mod -

Agreed. And, as always, customer service at lectron is second to none. Brooks said the 4-1 is a good rod but has a lean spot which would cause me some trouble at low elevation. So I'm going get a 5-1 and give that a try. He said the extra fuel on top (the 5 in the 5-1) could be compensated for by closing up the power jet a little.

What kind? More compression or a different shape?

Kenny,
I have experienced a lot of the same symtoms with my Lectron on my WR250.
Runs good but seems to be lacking any real hit off the bottom. Swapped from 3-1xl to 3-2 xl finally settled on 3-2m but always feel im 1 adjustment from perfect. Still have a little sputter right off idle that clears up right away. If I go 1/4 leaner to clear it up my midrange drops off. Must have pulled my tank off 50 times making thst final adjustment. The original owner gave me the stock Mikuni that he took off immediately to install the Lectron im tempted to try it just to see the difference. I feel your pain with this. Im currently running the 3-2m rod and feel its adjusted to the best of my ability. I think the Lectrons just run this way. Not a bad thing but you seem to lose the 2 stroke hit we are all used to.

Still do not understand all the problems I jetted my 2016 TE 300 stock keihien carb per the owners manuel and it runs perfect no matter where I
go to race it or ride it. I will also run a National # 2 number on it next year My 2017 TC 125 I put on a stock Keihien carb like the 16 bike and once again it runs perfect. Today I was reading a article in Dirt Rider how they were compairing a 2017 KTM XCW to a XC and Dirt Rider said they wish the bikes had the 2016 Keihien style carb.

My 300 with 38mm Lectron had a flat spot I couldn't get rid of with the 3-2m, but with 3-1xl it's crisp and clean all the way to the top. No big hit in the mid just pulls like a freight train to the big hit when the PV opens. So I don't think "Lectrons just run this way" Some folks installed Lectrons with no tweaking and some of us had to tune. I think just have to find the right rod, fuel and squish combo.

Lectron said the new "balanced" (2017+) motors are different. I actually specifically asked about running a non-high velocity 36mm lectron on this bike and they said it's not a good thing.

Carb porn

Is that a PWK Air Striker? Is it the shorty from JD jetting?

I bought it from KTMPartspro for $304.28 and sent it to RBDesigns for his work. Bore's it to a 39 and installs the divider plate and modifies the #7 slide to a #8 (leaner). I am running the Suzuki needles (NECH at the moment).

I just haven't been able to ride it in the dirt as I am 7 months into my ACL rehab. Hopefully in the next month I will be able to take it out. That's the problem with having too much time on ones hand.....it gets expensive