Anybody here used the Cast Version of the APT Smartcarb yet?

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fst96se

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I read the 135 page thread, and could see where some here have bought and used the billet version to varying degrees of success. But in all 135 pages, I saw only one person who has bought the cast version. Once the cast version stated shipping, the thread just seemed to die.

I have an opportunity to buy a new in box cast version significantly below retail. It sounds awesome, but would love some real world feedback. Even anecdotal feedback.

Thanks!
 
Both of my brothers got tired of waiting for the cast APT SmartCarb and bought Lectron units, I held out because I really wanted to be able to compare them and because I can tune a Keihin to some degree.
Unfortunately, I just haven't gotten enough time with either carb to give a definitive answer as to which one is better. The reason that I (and my brothers) went the metering carb route is because we see such varied conditions. It's not uncommon to see 40f swings in temperature and 5000' elevation changes in a ride and to say the traditional carbs struggled is an understatement. These metering rod carbs aren't near as affected by the variables. However, you cannot tailor specific parts of your power delivery like you can with a traditional carb (although you can do more of that with the Lectron than you can with the SmartCarb via a greater selection of rods and the power jet). At this point I feel that the SmartCarb is less affected by the elevation and temperature changes than the Lectron (FWIW, the Lectron isn't affected much). I'd say that if you can get this carb for a deal and don't want to wait till APT ramps up production again later this fall, then go for it. If not, the Lectron is great as well. If you don't see much in the way of temp and elevation changes and like a very customized power delivery, then save your money. Clear as mud?;)
 
john r b said:
You'll have better fitment w/ the motion pro cable. slidelight 10-3000#
Click to expand...

John, can I use a +4" version? I have risers and tall bars, and my throttle cable is at its limit. Would be nice to go longer, and I've intended to do that for some time.
 
fst96se said:
John, can I use a +4" version? I have risers and tall bars, and my throttle cable is at its limit. Would be nice to go longer, and I've intended to do that for some time.
Click to expand...

No issues with running the longer cable, actually prefered in my case.
 
I just installed my SmartCarb tonight with a Motion Pro 10-3000 cable. The cable is very nice, love how it threads into the carb and throttle. I like that it is captured on both ends. I do wish it was about 2" longer though. It is almost exactly the same length as my factory cable.

I haven't started the bike with the SmartCarb yet. I need a longer fuel line from the petcock to the carb. The stock one wouldn't reach.

Also, can anybody give me an idea where to put the clicker knob to start? I heard reference to running it so many clicks from full rich to start.

This is an adventure, for sure! :D
 
Leave it where it is. Run it and then adjust after some time. Is it new or used? Billet or cast? Very sensitive to the slide height. Keep it low.
 
It is cast, and brand new.

However, I showed a friend the carb and the first thing he did was start turning the knob on top. Don't know how many turns in what direction, unfortunately.
 
fst96se said:
It is cast, and brand new.

However, I showed a friend the carb and the first thing he did was start turning the knob on top. Don't know how many turns in what direction, unfortunately.
Click to expand...

The knob only affects rod height when the slide is all of the way at the top (WOT). Turning the knob with the slide down should be fine.
 
pscook said:
The knob only affects rod height when the slide is all of the way at the top (WOT). Turning the knob with the slide down should be fine.
Click to expand...

Exactly. It actually takes quite a bit of finess to lift the slide, engage the clicker, and get it to turn, or at least it did on my billet model.

Try to avoid making any changes off the bat. Its claimed they need a break in period so be prepared for it to run like crap for the first couple rides. If you're lucky it'll start working well after that.
 
In looking at the APT website, they recommend ordering a 36mm carb for a 300cc for enduro riding. Most stock sizes are 38mm, what would be the reason for this recommendation?
 
desertgasser300 said:
In looking at the APT website, they recommend ordering a 36mm carb for a 300cc for enduro riding. Most stock sizes are 38mm, what would be the reason for this recommendation?
Click to expand...

The 36mm offers a better spread of usable power (prefered for enduro), where the 38mm will make power outright power but not as good in the low to mid rpm range.

TSPs dyno work with the Lectrons shows that the 36mm gained more power across a larger range of revs than it gave up in peak HP. I could try and chase up some graphs.
 
Started the bike with the carb tonight... Seems to run just fine! I probably won't be able to really ride it until Saturday.

I am stoked!
 
My cast 38mm come in the mail yesterday, it sure does look pretty. I hope to get it installed before this weekend.
 
Warmed the bike up and rode it a little on the street today.

I have an idle issue. The idle stays pretty high for a bit, starts to idle down and seems to idle rough, then slowly settles into a normal idle. If I adjust the idle screw to idle normally, it will stall pretty quick.

Any thoughts?
 
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