APT SmartCarb

[gasgasman]

While perusing facebook one day, I came across the APT SmartCarb.
http://www.powerapt.com/smartcarb-difference.php
I have a weakness for new gadgets. e-mailed them for more info and the sales rep called me. We spoke in detail about the benefits. There are NO external vents on this carb. The carb has no jets. All adjustments are made with a spring loaded knob on the top of the carb.
So I said what the hell and ordered one.

Got the carb in. Went to mount it up and the throttle cable fitting was way different than the OEM GasGas cable mount. The ferrule where the cable slid into was about 6mm round. Way too big. Also, nothing there to hold the cable in.
Told them what was wrong. They sent me a new carb top. It would not work either.It was designed for the OEM cable that slid into the ferrule. I have a Motion Pro cable with the captured threaded end. After a few back and forth dicussions with the engineeer at APT, the right carb top was sent out.
Future carbs will have the new throttle cable mounts.

Mounted the carb on the bike and it would not start. Found the spark plug was fouled. Contacted APT and found out the floats may bind up in shipping.
To solve that problem,attatch the fuel line to the carb without installing it on the bike and give it a few good shakes. Look for fuel in the carb throat. If none-you're good to go.

Reinstalled the carb. The carb is 3/4" longer then the Keihin carb. It was tricky to install. I had to remove the carb boot off the reed block, slide the carb into position. Reinstall the carb boot, then install the carb into the boot. Then connect the filter side boot. There is no binding of the carb boots with the longer carb.

Kicked the bike over, fired up in 3 kicks. Sounded very raspy and the exhaust smelt different. Idle was fine, so I did not have to adjust the idle.

Took the bike on its maiden voyage the next day.
Bike fired up after 3 kicks and choke on.
Bike ran flawless all day. Thought it lacked some low end grunt, so I clicked the carb adjuster 1 click leaner. Holy crap- bike pulls like a scalded ape. The drive out the corners and out of deep whoops were mind boggling. My bike has NEVER ran this good-even with the OEM carb bored out mod. The bike started so easy-1 kick all day.

The power with this carb is seamless. It just pulls and hooks up. Low end power picked up quite a bit. Mid to top end power is much stronger. Bike revs faster to power out of turns if needed-quick fan of the clutch and you're off.
Mileage is improved. We have a 22 mile loop that we ride on and I have to refill with roughly 1 1/2 gallons. The refill took 1 gallon-eye ball estimate. Probably took 1 1/4 gallons to do the 22 mile loop.
Everyone commented on how good my premix smelt.
You know for a fact the the fuel has a finer atomization and more precise mixture control.

The initial issues I had are all corrected on the production versions. Mine was the first one released to the public.


This cab is pricey, but well worth it. Especially if you don't like messing with jetting.
There is a die cast version coming out that will have a better price point.

Carb on the bike.

Carb needle does have a "taper" to it. Contrary to what I said in another post.

 

[siaknijustin]

Thanks for the review, GasGasman. I am excited to hear that you've had good results with this Carb.

+1 on the long term testing. I would like to know how this thing holds up.

I emailed APT with a number of questions about the SmartCarb and received not one, but two replies from company reps. They also sent me a brochure (I tried to attach it but the file was too large).

One of the questions that I asked was about the die cast version of the carb and what we might expect pricewise. Here is their answer:

"We are receiving our first sample of die cast 38mm bodies in the next two weeks and will run tests to verify the process and begin moving forward into production. Projected costs are in the $350-$400 range for the 36-40mm sizes. $425 to $450 for the side pull TPS 40-44mm sizes and $275-$325 for the 20-27mm sizes. Other sizes coming and yes taperbores."

I asked them about a projected time frame; their response:

"We will be releasing a investment cast carb later next year. We are currently working with some OEM's to get are technology in the market on some of there units. We are still sourcing out parts for the investment cast, so we do not have a price for you yet. The billet racing carbs we have in stock are priced at $775, but we feel with all the benefits our fuel system offers, its worth the price. We do not have a large margin in the billet application."

I also asked this:
"...are there any independent test/reviews being conducted by a respected name in the powersports industry? If so, when might the public see the published results?
Their answer:
"Yes we have a tremendous amount of third party data: Northwest UAV?s (a military drone contractor), GASGAS factory, COBRA factory, Harrison Wolfe (Ryan Tovatt) emission certification lab, California Environmental Engineering, many labs in China, Pikes Peak racers, (Tim Seebold, Zach Warnock, Matt Meinart, etc). Some was published on our website, since been removed, but I?ve told our marketing team to put it back on. We are scheduled for several back to back reviews for Dirt Rider and Hi Torque Publications this spring on 300cc two stroke Enduro dirt bikes."

I'm excited because where I live we have such varying temps and elevations. I fully intend to purchase a 36-38mm taper bore when the die cast version is available.

 

[Corey]

Phil, there’s no school like old school. You're right the similarities are many, however the distinction between the Lectron and the SmartCarb spans over 40 years of development and is the final design in the long line of Edmonston designed single circuit flat slide carburetors, including the Lake Injector, Pos a Fuel, Lectron, EI Blue Magnum, Quicksilver and AFT”.

The Lectron is widely recognized as a “drag race” carburetor because it works very well in applications where maximum power is desirable. Which it does well, what it does not do well is provide high signal to the metering rod throughout the whole range of throttle opening and therefore smooth throttling suffers, requiring many different venturi sizes (every 2mm) and has thus gained a reputation as not being very streetable. The reason: Throttle opening and closing is symmetrical in relation to the throttle bore area, which is more or less round. While there have been small improvements over the years with Lectrons, the SmartCarb has a patented variable venturi shape that concentrates and accelerates airflow past the base of the metering rod under all throttle opening positions. This shape provides an extremely high pickup signal to the metering rod in all conditions and is also specific to enhancing air/fuel flow balance in both two cycle and four cycle engines.

The SmartCarb automatically and immediately corrects air/fuel ratios for changes in air density and elevation. The operating principle between the SmartCarb altitude adjustment circuit and a dial a jet (what Lectron calls its Power Jet) is the same; static pressure in the venturi is directly communicated to the float bowl to adjust fuel driving pressures, and ideally fuel flow remains proportional to airflow. The difference is a dial a jet has only a limited number of manual settings and must be reset for large changes in barometric pressures and/or elevation. The dial a jet also has opportunity for flow reversion at very high speeds because it is directly exposed to the venturi via the signal tube. The SmartCarb vents the float bowl directly to a scoop isolated in the venturi away from any opportunity for flow reversion.

$299 will get you dated technology from 30 year old dies. $775.00 will get you state of the art 6061 billet construction, unbelievable atomization, instant throttle response, 30%+ gains in fuel economy, 10%+ gains in HP, 8%+ gains in torque and an emissions reduction.

 

[nambo-trev]

alright gasgasman see what they say group buy seems to be not a great idea if they say there is little margin on the billet version but worth a shot! i dont want to wait for the die cast version but need new trelleborgs, thats 700 bucks alone

 

[GMP]

I would be interested as well if price was reasonable. I'd rather wait for the more compact lighter production unit though.

Remember, this thing can go from bike to bike in the future like your damper and Flexbars, so not a loss at sale time.

 

[nambo-trev]

agreed that is why i dont think its a waste of money because im only planning on keeping my current ride another year. its like someone said earlier on, its like a steering damper i can keep that and the carb on my new bike!

 

[Todd5774]

I'd be interested in a group buy..

 

[Jakobi]

I might like a diecast one.

For me the only real issue would be that you lose the opporunity to change the power delivery with needles. I mean, how can their specific taper be right for all conditions? It sure does sound mighty easy to work with though and fuel economy ssounds ace too!

 

[gasgasman]

There are different needles available.
The bike runs exceptionally well that you don't need different needles.

 

[GMP]

A two stroke will always want to have some hit, its the nature of the beast. It runs best in a resonant RPM range. When you change deleviery with needles what you primarily do is REDUCE fuel in certain areas, then add it back in others, to surpress or accentuate this.

This thing would be like tuning the bike on a dyno for max power through all throttle positions. Like developing an EFI map.

 

[Corey]

Ok Folks, I realize money is tight, but lets put a few things in perspective.

1) You will not find a cheaper or easier 10%+ gain in HP (actually 14% on a 2012 GasGas 300 on GasGas's own dyno). People pay a lot more than $700 for porting work that leaves their cylinder irreparable and still won't make those types of performance gains. And the list goes on...pipes, reeds, carb kits etc. even combined a lot of times those mods won't afford you those type of gains and cost more.
2) Depending on riding habits a 30% gain in fuel economy will more than offset your initial costs of the SmartCarb and will soon pay for itself at the pump.
3) The SmartCarb can be removed and reinstalled on your new steed.
4) Performance gains, fuel economy gains and an emissions reduction, I challenge you to name one other product that can do the same thing. And I think you will quickly find that $775.00 is a bargain.
Nevertheless it is our goal to make them available to the masses on a wide scale so we are working to make them cheaper while retaining quality to more satisfy all parties and follow the scope of our vision. However to make a call on the value of the SmartCarb is a little premature don't you think? I look at it like the difference between a Rolex and a Timex; they both will tell the time but only one is a value added product that is worth more than the sum of it's parts.

 

[Corey]

No we get it. Any hope to supply to manufacturers will require production die cast bodies, my only point is that there is intrinsic value to this fuel system and it's all too easy to misinterpret its worth because of an unclear understanding of what it is.

We are working on several ways to increase awareness of the SmartCarb's benefits. Last weekend we equipped Jim Ryan's (Utah Dual Sport) 2011 EC 300 GasGas with a 38mm SmartCarb and rode it throughout the weekend during the pro endurocross invite only trails benefit ride. You'll see about it in Dec or Jan Dirt Rider Magazine. Anyway you could go ride Jim's rental and get a feel for how smooth and tangible the benefits really are once you ride with one. EVERYBODY that rides one swears it makes them a better rider. Just sayin...

Anyway here's a tease of the die cast bodies coming, I don't think you will be disappointed.

 

[Corey]

Phil, its all about the signal to the metering rod: The thing to remember is a caburetor is a passive device and can only respond as well as the engine it’s attached to; in terms of airflow and overall efficiencies. The shape of theSmatCarb’s venturi does an outstanding job of communicating mass airflow to the metering rod, insomuch that the caburetor becomes fairly indifferent to the metering rod (more specifically the size of the aperature at the needle/nozzle interface), and only shows problems if it is way too lean. I think Glenn stated earlier in this forum that what he thought it sounded like “is that you can go a lot richer and still have efficient atomization” and he is correct, you can run the carburetor very rich and still have decent performance. An interesting side note is conversely if the metering rod is too lean it simply won’t run hard enough past idle settings to hurt the engine, eliminating burned pistons. You don’t have any intermediate circuits to cheat it long enough to run through to the point of overheating the piston.

We do have different sizes and series of metering rods. Most changes are usually related to displacement of the engine only and have little to do with engine modifications. We typically use only one metering rod, from full mods to totally stock and have excellent results.

The ideal way to change the “preferred characteristics” with a SmartCarb is venturi size. For riders who like a milder hit with a lot of top end we recommend a 40mm for 250-300cc’s, for those who like a lot of torque and a little less top end a 36mm is recommended and for those who like both we offer a taper bore 40/38mm and 38/36mm.

Corey

2011 GasGas EC300

 

[Corey]

Nambo, best case for die cast sales will be early spring 2013 and will be announced, with pricing, on APT's website: http://powerapt.com

Thanks for the interest,

Corey

 

[Corey]

What about 4stroke

We have several prototype models in the field right now, one won Pikes Peak on a Honda TRX Modified Quad this year, the other is on Marco Belli's TM powered Zaeta 530 racing in Italy throughout the fall. 40-44mm push pull cable TPS models coming late summer 2013, with other size models following. These are designed to replace the Keihin FCR.

 

[Corey]

When (not if ) I turn my bike upside down on some hillside - where does the fuel go considering this carb has no vents/overflows?

Right now it drains the float bowl straight into your engine if you leave it upside down long enough New models each vent tube has a one way check valve (ball).

Good question,

Corey

 

[GMP]

Sometimes the small mfgs like GG have trouble getting Keihin carbs on time for production runs as they just don't order the numbers that the big five do. Now with Beta and Sherco coming out with new 2strokes, perhaps this is an OEM opportunity.

 

[Corey]

Glenn you're on it. Clay Stuckey will tell you they actually hired someone to source off the shelf Keihin PWK's just to satisfy last years North American production. Dani Quintana told me that they can't get their orders in ahead of KTM and the reason Gassers come with a 38mm instead of the preferred 36mm that comes on most of KTM's two strokes.

I'm sure the tsunami/flood didn't help but the general consensus is that no one wants to work with the Japanese. And yes the time is ripe for an OEM application, actually all OEM's. This is the reason we have been testing with GasGas and if it hadn't been for their airbox issues last year and Spain's overall economic woes you would be seeing production Gassers equipped with the SmartCarb. It's not as easy as it sounds though and many things are in play. I will say one last thing though it will be all about who can meet emissions in the most cost effective way that will be the primary player.

Corey

 

[Corey]

Yes, they would work very well for you. I have Wobbly trying a set on a 400 twin GP bike in New Zealand right now. Should have a report by the end of the week. I will post his results here.

Corey

2011 GasGas EC300
2009 KTM XC300
2006 Yam WR450R
1997 Kaw KLR600 -
1991 KTM D-XC250
1989 Yam YZ250 -
1979 Can-Am TNT250 -
1978 Kaw KE125 -

 

[GMP]

Corey,

I suspected as much, my new bike came with an older 38mm and notched slide and gave me fits jetting it. I'm not so against the 38mm on a 250, I have an '07 bike that just runs perfect with one. My '12 runs a hair softer off the bottom but revs to the moon, I suspect that is some porting variation as all else is the same. What has been the Smartcarb size of choice from GG testing? Is the taper bore a vertical taper, like some other "keyhole" bores?