TRX250R.ORG
Workshop => Carburetor, Intake, and Exhaust => Topic started by: 363 stroker on July 03, 2013, 11:35:39 PM
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I think I am going to pull the trigger on one of thier billet versions for a 363 sphynx. Tell me why I shoudn't.
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DO IT! only if you can post the results =)
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Man I have no problem posting results but I have a brand new engine so I have nothing to compare it to. But from what I read it sounds like the next best thing to sliced bread.
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I can tell you why you should.. I have one on a 363 also , pro x not a cpi though. I have rode mine about 6 times now the latest a couple of weeks ago with rblack from the other forum. I know people are probably tired of hearing about it but I love mine. I got the 40mm and it has worked every bit as good as apt claims it would. So far every ride it has ran perfect, not a single bog or miss and this last ride we rode mx. It was probably high 80's or low 90's. Before when it got that hot I was changing needles and jets.
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Thanks oldschoolr, I was following what you had going on, and everything else I have read I think I am going to order one.
I will def give a ride report.
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I hope you have as good luck yours as I have with mine. Definitely give us a ride report im curious what someone else thinks about it on a R..
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Was it hard to get tuned at first or just bolt on an go ?cast or billet ? Price ? Do you need different needles for major temp changes or for different size motors ?
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keep an eye on ktmtalk they have a lot of info on there on the smart carb. keep us posted
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keep an eye on ktmtalk they have a lot of info on there on the smart carb. keep us posted
From what I read on there and what Oldschoolr said I think I am sold.
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Was it hard to get tuned at first or just bolt on an go ?cast or billet ? Price ? Do you need different needles for major temp changes or for different size motors ?
All I did was bolt on and go, mine is the billet 40. It started right up, I played with the low speed adjustment a little and set idle but that was it. They do have a metering rod that can be changed if needed. But tuning is a thing of the past for me now because it always runs perfect. Rblack doesn't know this yet but the next time we go ride I'm gonna put it on his esr 310 just to try it.
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Do you use the same throttle cable as p w k ? Intake and air box boot stock size?
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[ATTACH=CONFIG]146[/ATTACH] It uses the same cable as a 38/ air striker and is pretty much the same size.
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Nice thread. I'm really interested in these carbs.
I am with you on this one Dan, interesting to see the results on some of these hard to jet BB's.
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Dan I've already paid for a room from the April trip that I couldn't make. Lil Sahara is letting me just move the dates rather than losing my money. As soon as everyone settles on a date im gonna try to go. I have someone to work at the shop now and it's after my busy season.
Tony that is another reason I got this carb because the last time I went to Lil Sahara I never did get it jetted right, I spent half the time changing needles and jets.
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im real close to buying one. kevin at lectron said the issues im having with my carb is my problem. he fails to admit his carb isnt infallable. thing leaks and he wont rectify the problem. he keeps saying its my engine or electronics.
john
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I definitely want to hear more about this carb as well. Seems like i am always playing with the jets to get it right. But the tech still blows my mind. How does it know how the engine is burning?
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va***e draws the fuel in burns, piston going from TDC to BDC with no air leaks creates va***e
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Its just a carburator but with a differant way of sensing the motor vacuum or signal strength of the motor.
It seems to do a better job sensing the signal from the motor from what I here, but I do not believe it can make more peak power than most any properly tuned carburator of a differant make.
Haveing better fuel mixture abilities at differant rpm points of the the power range would be huge advantage over a carburator that only accels at one certain area, much like a Lectron tends to be much better suited as a wide open racing carb.
this is from the cr500 site
Hey guys. Here are my findings thus far. Copied from another forum. Running the 76 metering rod 75 clicks out
Well I got my smart carb yesterday evening. My wife had to work this morning. As soon as she left for work, I headed out to the shop to do the install. I had one minor snag specific to the cr500 where the throttle cable is a touch too short to allow the slide to close all the way. I had to counter sink the top of the carb 3mm to allow the slide to seat properly. This was per Corey with apt recommendations. I was a little concerned with the fit as this is a custom bike. It fit no problem and the thing sure is a pretty. Corey sent me 2 metering rods with the carb. I went with the richer one as I have heard from other folks that the cr500 liked a pinch more fuel up top with the smart carb. I set it to 75 clicks out from full rich which was the recommended setting with that rod. The adjustment system for the low to mid range is the clicker on top of the carb. You hold the throttle wide open to engage the adjuster, push down on the knob and start clicking. Ingenious really. Anyhow, I finished putting the bike together. Other than changing the metering rod and having the minor cable issue, it installed just like any other carb. Here are a few pic of the install
So I rolled the bike out in the driveway. I pulled the choke, turned the fuel on, and kicked her over. I didn't use the decompression button just to get an idea of hit started with the new carb. This is what happened. Fired up first kick and idled great.
http://i262.photobucket.com/albums/ii120/rodgini/1DF5C38F-81C0-438A-950A-52F58BD...
My inital obervation was the motor seemed quieter and smoother at idle. I let it idle for thirty seconds while i put my helmet On. It would not idle like this until warm with the pwk. i then took it for a ride on a grass track near my house. It rained 1/2" last night so the things were swampy. I noticed the bike did not seem as cold natured like it was before. It seemed to take forever to warm up before. It also didn't seem to make much smoke, no spooge and the exhuast just smelled different. The power off idle is completely different. It pulls right off idle and the Low end torque feels stronger and smoother. The bike had a pretty violent hit in the mid range before and a slight hesitation right before which made it worse. It now pulls smooth from the low end to mid range. Suiting up now to go test the top end and over rev! More to come. Very impressed
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va***e draws the fuel in burns, piston going from TDC to BDC with no air leaks creates va***e
Ya i get that. Not my first time around the block. But it would seem to me that jetting varys from enging to engine. and for this thing to be perfect for all engines just makes kind of defies what i understand.
I get that it works, i just dont understand how. Would be nice to see a cut away.
Even compression ratio affects jetting. So you have two identical motors, one running 180 psi, the other running 240 psi. They should draw the same fuel/air in, but the high compression ratio motor should require more fuel ? Maybe not not that i think about it. Maybe fuel is solely based on the volume of the air entering the motor and A/F should stay constant through the rev range?
Man i guess i get it but coming from regular carbs, it still defys me. Man i want one bad.
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these still have adjustments and differant needles for different type motors, you can not take this from a 250 and bolt it on a 500 and it work properly without changes
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smart carb still has issues for some people. few guys on ktmtalk were close to returning them for a refund, not sure if they ever did or not. never had a issue with keihin so ill stay with that for gas engines. supposedly smart carb gets alittle better milage, never once in my life have i ever cared about milage. supposed to compensate well for huge elevation changes, i ride at constant elevations so its no advantage for me. slight power gain was another claim but im not sure i buy into it because i have yet to see any concrete proof of it
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I recently purchased one- the 38 mm performance billet carb for a 295cc. Bought it because of the extreme variations in elevation and their promise of being able to compensate. Will definitely write a review after a few rides!
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Still waiting on it to be delivered... When I purchased it, it was to be delivered within 2 weeks.... It's already been 3 and they, apparently, are back-ordered... At this rate there will be snow on the ground before I get it!
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keep us posted on a ride report
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Just throwing my hat in the ring; made a preorder for the cast 38mm last Friday. Should have it in September!
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What's the cost on a cast version? Did I miss that somewhere?
$375
john
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Well I ordered a 40mm billet smart carb today. Should be here by the weekend so I will give a report as soon as possible.
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I have a 36mm on my 310. have lots of information about it on .net
not going to repost
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I'm gettin one for my walsh build
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wishing i had sprung for the billet version. I am having trouble waiting on the cast to roll off the line and onto peoples door steps lol
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wishing i had sprung for the billet version. I am having trouble waiting on the cast to roll off the line and onto peoples door steps lol
Same here. If they want to do more field testing on the cast versions before they release it I'll do some field testing! Lol
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anybody know if there will be a 40mm cast version? the contact link on the apt website is not working for me :confused:
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info@powerapt.com (info@powerapt.com) email them here
thanks :)
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Has anyone received the cast carb yet? I want to buy one but they couldn't tell me when it would be delivered.
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Goodluck with the cast version. I pre-ordered when they first released the pre-order. waited 6 months and just went with billet
almost another 6 months later and they still haven't released the cast version.
I love my billet though and hope the cast performs just as well at a lower price
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Brewer. Does the billet work as we expect it to? Clean crisp throttle /power and no need for adjustment once set up?
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So why are the billet ones ready and the cast ones keep geting pushed back?
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I have been doing this stuff for a lot of years and very seldom do I find a new product like this live up to its marketing claims. I would like to test one of these on the dyno and on the track back to back with a well tuned........ same size Mikuni or Keihin carb. Any one want to send me their carbs to test?
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there was a video showing +3hp with the smart carb but im skeptical. from what i recall they mentioned not being real familiar with using a dyno which throws a wrench in the accuracy of the test i would think. plus the pwk they were using they didnt even jet it but was pre jetted from someone elses recomendations if i recall. lord only knows what kind of tuning experience the third party user has. unless im recalling wrong which has happened before lol. this type of test needs done by a professional with experience. not some monkeys in the editorial department of a magazine
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I have been doing this stuff for a lot of years and very seldom do I find a new product like this live up to its marketing claims. I would like to test one of these on the dyno and on the track back to back with a well tuned........ same size Mikuni or Keihin carb. Any one want to send me their carbs to test?
Arlan at led is gonna be starting a puma build with 40mm smart carb in a ktm atv chassis for me in the next month, he is gonna dyno it and tune it in, he was skeptical about the smart carb, maybe he will do a comparison with a pwk
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I have a cast one on order. I should be getting it in the next week or two. Yes, there is a youtube video where dirtrider magazine runs a back to back dyno test on a ktm 300 against a keihin jetted to factory recommend specs. The video explains that the dyno is brand new, not the guy running it. It also explains that the keihin carb ran clean on the graphs (meaning it wasn't cheated). While I can't speak for the cast version's performance since I haven't tried one, the billet versions do exactly as claimed. Ask somebody who has got a billet one. They work extremely well. They make the engine run very smooth/crisp. You can hold a lower gear a little longer and pull a taller gear a little easier. It's one of the best improvements I have seen to widening the power band on a two stroke IMHO.
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Update....
Getting closer to delivery time!
http://hosted.verticalresponse.com/1379465/457e6c124a/571023585/4428b10fed/ (http://hosted.verticalresponse.com/1379465/457e6c124a/571023585/4428b10fed/)
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forgot we had a thread over here about these! I got an email from Liz at APT saturday night confirming my shipping address and the machines I would be running this carb on. STOKED to get the carb in my hands, i will be trying it on both the atc310R and the atc500R around xmas. EXCITING TIMES RIGHT HERE!!!!