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kingkabong

APT Smartcarb

1,031 posts in this topic

Yeah, I'm pretty excited about it. I went from carbs to FI and now back to carbs. This seems like a huge step forward and still keeping the simplicity. I don't like dealing with fuel pumps and injectors and all the electronics.

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Hmm that billet carb would look very nice with the 300 kit, but how to spin 800 to the wife is the problem?

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by the time the mixture reaches combustion in a (warmed up) twosmoke fuel atomization is not a problem. Can't see much claimed advantage?

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by the time the mixture reaches combustion in a (warmed up) twosmoke fuel atomization is not a problem. Can't see much claimed advantage?

Check out the gasgas forum link I posted. The guy there, he's also on TT, has a 250 2T, so explains what it did for him. All I know is that I spend a lot of time messing with the carb, because I'm always thinking it could be better. Somethlng like this would help, I think, less options anyway, heh.

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I'd really love to see some data to back up these claims, especially the emissions stuff. I'll keep an open mind, but as someone who's spent the last 8 years working on carbs and efi from an emissions standpoint, I'll say that their claims are optimistic. Color me skeptical.

I'll definitely be researching it some more as I get some time.

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I think he has a clever design for the needle. Instead of a needle rattling around inside the needle jet, he has a consistent diameter with a single flat cut.

That could make fuel metering more consistent through the mid throttle range.

It wouldn't be very hard to punch out a standard Kehin PWM needle jet and make a copy of this type of needle to play around with. That would be a fun little project.

I have some other ideas for carbs (other meaning some of my own unique ones). One of these days I'll pick up a spare carb and get to messing with some things.

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I think he has a clever design for the needle. Instead of a needle rattling around inside the needle jet, he has a consistent diameter with a single flat cut.

That could make fuel metering more consistent through the mid throttle range.

It wouldn't be very hard to punch out a standard Kehin PWM needle jet and make a copy of this type of needle to play around with. That would be a fun little project.

I have some other ideas for carbs (other meaning some of my own unique ones). One of these days I'll pick up a spare carb and get to messing with some things.

Um, I would be a little careful, we have very strong patents and will aggressively protect them.

Regards,

Corey

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Um, I would be a little careful, we have very strong patents and will aggressively protect them.

Regards,

Corey

Which would be applicable if he were planning to copy them and offer the products for sale. If he's just doing it for his own personal use, then he is legally A-ok.

So, how about some more info on the SmartCarb? Any data comparing emissions to a standard carburetor? Could you post up the YZ250 dyno pic? I've seen it on several other forums now, but all require membership to view, and I haven't felt like registering just to see 1 picture.

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Which would be applicable if he were planning to copy them and offer the products for sale. If he's just doing it for his own personal use, then he is legally A-ok.

So, how about some more info on the SmartCarb? Any data comparing emissions to a standard carburetor? Could you post up the YZ250 dyno pic? I've seen it on several other forums now, but all require membership to view, and I haven't felt like registering just to see 1 picture.

No worries. Just making our position clear.

Corey

62534_367680266650422_1629115296_n.jpg

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Cory, you don't have to worry about me. I am strictly discussing my own experimentation.

I have had a few carb ideas (completely unrelated) for some years that I want to try out.

By the way, your needle design is very intriguing / clever.

You should consider making a needle-jet retro-fit kit for the Kehin and Mikuni carbs with your style of needle.

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Aw shucks. I was hoping for some yummy bottom end enhancement. It certainly like it loves open power valves and creates a nice steady power increase.

The test bike was a tuned motocross bike though correct? Any idea of the mods done to that engine?

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No worries. Just making our position clear.

Corey

62534_367680266650422_1629115296_n.jpg

A 29 hp YZ250? Was this test performed at part throttle, or at 8000 ft elevation? I understand things differ from dyno to dyno, day to day, etc, but that would be more like a stock KDX200 dyno, not a modded YZ250! But the shape of the power curve appears correct, so it very well could be an applicable comparison, regardless of the numbers scale.

Aw shucks. I was hoping for some yummy bottom end enhancement. It certainly like it loves open power valves and creates a nice steady power increase.

The test bike was a tuned motocross bike though correct? Any idea of the mods done to that engine?

Lots of factors involved, there very well could be bottom end boost that doesn't show on the dyno. Part throttle power could be way up, throttle response, etc, but you wouldn't know that from a WOT dyno pull chart. That's why they are a tuning tool, not the carved-in-stone answer of how an engine runs.

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Aw shucks. I was hoping for some yummy bottom end enhancement. It certainly like it loves open power valves and creates a nice steady power increase.

The test bike was a tuned motocross bike though correct? Any idea of the mods done to that engine?

Yes, I believe Ace said it is fully ported and feels that way. Not sure of the pipe, however Alex loves the extra rev through in 2nd and 3rd gear. Enduro engines make nice torque gains, low to mid, with the SmartCarb though.

Corrected Rear Wheel Horsepower @7200' 29.92 in.hg.

Edited by SmartCarb

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A 29 hp YZ250? Was this test performed at part throttle, or at 8000 ft elevation? I understand things differ from dyno to dyno, day to day, etc, but that would be more like a stock KDX200 dyno, not a modded YZ250! But the shape of the power curve appears correct, so it very well could be an applicable comparison, regardless of the numbers scale.

Lots of factors involved, there very well could be bottom end boost that doesn't show on the dyno. Part throttle power could be way up, throttle response, etc, but you wouldn't know that from a WOT dyno pull chart. That's why they are a tuning tool, not the carved-in-stone answer of how an engine runs.

Well said and the reason I normally don't post dyno charts. :ride: However, everybody is extremely curious right now.

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So wich one do I need for a 2001 yz250-EG295 and what els do I have to modify? I got 800 bucks burning a hole in my pocket to not have to jet for altitude!

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