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[smdub]

I can tell you from first hand watching a Vertigo be kicked over and over to start that a FI smoker has a long way to go to be anything reliable. So a FI KTM and a carb KTM running the same mix ratio will make that much diff?

EFI on a kicker only bike is its own problem. Within the duration of one kick (about one revolution of the crank) you need to generate enough power and time for the ECU to boot up, measure some sensors, and get the injectors fired and spark lit off. Not easy at all to get the perfect kick. OSSA has the same problem back in the day. There was a capacitor kit you could plug into the light connector so that the first kick charged it and the second kick the ECU would be all ready to go. Today, they should just put a tiny lithium batt in FI bikes.

W/ the same engine EFI makes more power. 1) you can run less oil and only inject it when and where needed. 2) You can use a larger throttle body as you don't need the vacuum signal to draw fuel and 3) Fuel injectors atomize fuel better. Carbs are a semi-controlled fuel leak. Now when engine redesign is considered, the ability of a FI engine to not spray until the later in the cycle helps the port timing for emissions. You should be able to run more port overlap w/o getting into emissions or tuning problems. Of course, this is all what EFI *CAN* do not what implementations that exist do. I'm sure no one has gotten it perfect yet. But they will dial it in over time. Carbs have been around far longer and efi has already equaled/surpassed that. There will be more to come.

I have a AA racer class friend who has had both a 2019 Husky and now 2020 KTM 300XCW (both TPI). I haven't ridden it yet (next weekend!) but am told its *AMAZING* by folks I trust. The new 2020 TPI 150 makes more power down low than the carb'ed version. I have to say the carb on that '17 150XCW I picked up is driving me nuts. Fun as heck but it looses power like a light switch down low @ WOT. I have a plan to try and dial that out but in the back of my mind the 2020 is calling my name... FI doesn't leak and flood the bike when it falls over. FI doesn't gum up when it sits over the winter. FI (non pre-mix) doesn't require me to carry a little bottle of oil w/ me to fill up at the gas station when my buddies do (and guessing the right ratio at that.) FI gets much better fuel mileage and uses less oil. FI, other than cost and a small weight penalty, is better in every other way. I suspect the fuel economy alone would pay for the upfront higher cost in short order.

Speaking of lithium batteries. I'm waiting for bike manufacturers to implement starter/alternators like some cars and small RC drone engines. E-start w/ zero weight penalty and no added mechanical parts.

[Boom Boom]

All good points. Reality is I sold my e-start only FI 4-stroke that performed great after a close call out west where me and bike about went scuba diving. Realty sunk in fast what I would need to do to flush and bring back to life when 30 miles from any 2 track road. It was replaced with a carb 2 stroke and a kicker...The thought of a rescue effort on a dead bike that far back in was a huge wake up call. All that fancy sensors and stuff needed is fine if when it fails you are a 20 minute walk to your vehicle to take back to a shop with fancy tool in hops of finding the problem and fix. Sherco enduro 2 stroke was always e-start only. When complained it needs a kicker the reply was kickers do not for for FI and soon all will be FI so that backs up what you said sooner. With every rule you have exceptions and I expect the small companies will have a loop hole to avoid all this BS. Companies like Jotagas and TM are small enough they might slide by and then get a boost in sales from old farts like me that does not like having this save the world crap tossed down my throat. In the construction industry I get to see first hand how this stuff is BS. Diesel engines last half as long, consume more fuel oh and just enjoy the show when you dozer goes into regen mode and takes 30 minutes and blacks out the job site puking out all that nasty matter it collected up to that point. Then you have the locals rolling coal with pickup because where they live they are exempt and the truck is exempt. Neighbor has a Prius and has to get emissions done.....2 doors further down we have the farm boy with the coal stack sticking out of his truck bed. They need to look at impact and deal with that first....humm, how about planes for a start. One good volcano and we are all screwed so I will enjoy my smoker till the big one comes.

[smdub]

All good points. Reality is I sold my e-start only FI 4-stroke that performed great after a close call out west where me and bike about went scuba diving. Realty sunk in fast what I would need to do to flush and bring back to life when 30 miles from any 2 track road. It was replaced with a carb 2 stroke and a kicker...The thought of a rescue effort on a dead bike that far back in was a huge wake up call.

True, but all modern 2T run w/ a CDI ignition so they already have electronic sensors, alternators, and accompanying electronic failure modes. An efi SHOULD go into limp mode / open loop if some of the sensors fail. Cars do this all the time. True that injectors and fuel pump are new items to fail. But carb bowls leak and drain gas tanks on the trail (I've had the DRZ carb bowl seat stick, flood the engine, and hydrolock it TWICE. Yet another one of the reasons I hate carbs.) I'm not sure efi systems and any more prone to failure than carbs just that they are DIFFERENT types of failures. Its definitely true that a carb failure is more likely to be able to be fixed w/ zip ties and duct tape than something electronic. There are a lot of dead-reliable efi 4 strokes now though. The 2 stroke will get there.

An EFI motor that goes scuba should be easier to get running than a carb'ed one. The FI system is sealed. Shouldn't need to clean the injectors or sensors. There is no carb bowl to take off and clean out. Should just be get the water out of the engine (& case), replace plug, and try to restart. A kicker would help as I bet you'll prob run the battery down trying to get an e-start only to refire whether it has efi or carbs. We've flooded an efi Jeep before and it was dry the motor out and re-crank. Though in the modern era of LiPo jump packs and little jumper cables, I'm not sure a kicker is really needed unless you are by yourself.

You can put a kicker on the new KTM TPI models. But the battery has to have enough of a charge to at least fire up the computer & fuel pump but thats miniscule compared to what a starter draws. I think my carb'ed 2 stoke is the same. Need enough battery to run the CDI when kicking.

FWIW, I've had an efi bike strand me at the office this yr. Ethanol eats the seals in the ducati tank where the fuel pump wires come through and it open-circuited. Luckily I could easily find another way home and not 30mi from nowhere. Crap happens.

[Firebolter]

No doubt from a power perspective, the EFI 2T's are about as good as it gets from a fuel/air/oil ratio perspective, but not so much that I can tell a difference on my bike to make me want to have the additional complexity. I like simplicity, I want to be able to McGyver my way home if needed and with EFI and all of the sensors and additional complexity, I prefer a carb. There are some new tech for carb's too that address alot of the environmental concerns as well. Look at the current versions of the smart carb. They are making real strides it seems. I might just try one on the TM instead of a Lectron.

I just bought a new TM250 and could have got the TPI version, but I'll keep carbed bikes for now. Again, I prefer the simplicity and don't mind carrying oil with me. Hell, I can get over 90 miles to a stock size tank on my 300 XC-W with the Lectron.

Here's some info off Smart Carb's site:

REDUCED EMISSIONS. The SmartCarb reduces emissions by as much as 50%. By highly atomizing fuel prior to combustion, more of the fuel is consumed during the combustion process, resulting in net emissions reductions. The SmartCarb has twice received North American EPA Tier II and CARB certifications, notably without requiring the use of precious metal catalysts.

[smdub]

I've looked into the Smart Carb a bit now that I'm playing with a Lectron. They both work on the flat tapered rod metering approach to do most of the heavy lifting. They differ in how the top end enrichment is done. The Lectron uses a 'Power Jet' that uses engine vacuum (derived from air flow across the venturi) to suck fuel into it and richen the top end. The Power Jet is nothing but an adjustable needle valve on top of the carb. The Smart Carb uses the airflow to pressurize the float bowl to richen the top end (and presumable across the whole throttle range somewhat.)

I'm not entirely convinced that either can fix the lower speed bog in the 150 as at those speeds it has very low airflow. Low airflow can't create vaccum for the Lectron power jet to work. Low airflow can't create bowl pressurization in the Smart Carb. Fuel atomization for both will be lousy in that situation too as the fully raised slide has opened the metering hole as far as it will go. Very slow airflow across a large hole equals really big drops/dribbles of fuel.

I'd be extremely interested in any experiences you have w/ a SmartCarb vs Lectron if you get one.

FWIW, none of this is 'new tech' as its based on 70's(?) era technology. Smart Carbs patent (8931458) is for pressurizing the bowl via the air inlet scoop. Other carbs already do this AFAIK so not sure how they got it patented (I have a couple patents so have cursory experience here.) Their 'novel' approach looks like it was just applying that scoop to the single jet type (Lectron) carb.

Also specifying the Smart Carb EPA Tier II means little w/o all the details. The HC+NOx limits (0.8gm/km) I think are roughly equivalent to Euro2 which is a 1996 standard. Carbs are open loop. They can't compensate for a cold engine during start/warmup for example. Modern cars have mere seconds to meet emissions standards. Its why they have to put pre-cats up in the headers now. Carbs can't compensate for ethanol blend. As simple as they are, their days are numbered.
https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100O9ZX.pdf

Also a couple of dirt bikes isn't what the EPA/Euro are after. Our numbers are but a tiny drop compared to all the 2-stoke scooters and power tools. We simply get caught up in it.

[Firebolter]

Yeah I am not saying the Smart Carb or the Lectron is the end all answer, and I am purely talking about dirt bikes as opposed to true EPA approved, street legal bikes which I agree, EFI is the only path forward to be compliant. What I mean is (and I should have been more clear) a Smart Carb or a Lectron gets you the fuel efficiently (MPG's) better than a regular carb and on level with EFI. good power curve and performance and NO JETTING. I like how consistent the bike runs all year, all temps and humidities. I am happy with my Lectron on my 300 XC-W. No issues as you talk about with the 150 or smaller displacement relative to vacuum on the bigger bikes. I just really like no electrics, no sensors, no fuel pumps and for me, that is what I like, simplicity. I got bit by the fuel pump on my 2010 Husky 310 one time, and that left me loving a plain jane carbed 2T. If they outlaw them, or make them no more imported, so be it! I got 2 good ones that will last me many years!

[Boom Boom]

Well the guys that take the choked down specs the new bikes come out as and build a new program will be smiling as first thing done will be send off your EPA compliant dirt bike to have tuned to actually work.