740 carb review also known as DFT DFTA weber

[mjanderson]

Sounds good!

 

[joedrum]

think i am going to up the primary main gas jet .....going to trade the 140 gas jet for the 120 thats in the primary along with the 220 air in primary we will see what happens ...it seems to have some lean pops to it ...going up the rpm slowly ....another cloudy moist day here its been raining over the night ...

 

[joedrum]

ok vid with 140 gas jet in primary...220 air beed
[video]https://www.youtube.com/watch?v=e4STpmUJQqQ&list=UU4n-jRpq9fmvvCw15KDERGg[/video]
almost seems i can still go higher ..but will stay here for now ... :thanks:

 

[slabghost]

Sounds pretty good.

 

[joedrum]

ok went to 150 gas jet...220 air
[video]https://www.youtube.com/watch?v=izIxgOUdE8w&feature=youtu.be[/video]
seems the primary jetting is going rather big ...

 

[dan filipi]

Explain why you went bigger primary and why it died.

 

[joedrum]

dan filipi » Tue Dec 23, 2014 4:37 pm[/url]"2qhddy9]
Explain why you went bigger primary and why it died.

ok ...as i worked with the idle and off idle ..the jetting started as 45 idle 120 gas 220 air ...when counting the switching of the air bleeds from 160 stock to 220 now ..the 120 gas jetting is about the same as stock was ...maybe 1 step up ...just more air added to the charge ....when i would rev it ...i could hear slight lean pops ... so today i started bringing up the gas jet to get right with the 220 air ....first try was to go to 140 ..rather big move but i was confident it was lean a lot ....

as it turn out i could still here some lean pops ....much better ....i was going to leave ..but couldnt cause it just hadnt showed me something different enough ...so i went 150 ...this change the entire sound the bike was making ...i was also really turning in the mix screw also and had it just 1/4 turn from bottoming out ...i am sure this is the reason it died ...i was in no way land there and really was expecting it to die ...its very easy to get idle even throttle plates were closed so it was as close to off as it gets .....

i like the way it got smoother through the revs ...so i am going to stay here and move to secondary now...i expect quite a boost in the jetting here also about 2/3 of the air flow goes through here maybe a bit less ...i am going to try an get this optimum in the gas charge ...when i do i will take hooch for a ride.....

video above shows how the carb is going to work for 95% of ride time you will be in the primary ..at least me anyway :thanks:

 

[joedrum]

going to be hard to leave the 150 gas jet alone in primary ...next step i have in bits is 160...seems all signs point towards going bigger so i will i am rather sure ....i dont dont want there to be any thing lacking in gas charge want the most hooch can deal with and run crisply .....on 2 staged carbs where you have a second carb come in at 1/2 throttle or less ...is the perfect set up for these oldwing motors ...kind of like the clark kent and superman thing going on in same package ....it will be interesting where things end up today in jetting ....its possible i may over do it ...but i think i am at a place now with these carbs i know them better than most by far now ...and thats really all that matters here ....

one of the big things coming up today is the secondary air bleed is 160 right now ..was stock with 220 air 95 gas jett and idle jet was 60... it is now 80 idle jet....140 gas jet...160 air ...this is already about 12 steps up in gas setting over stock and may not change much .....tricky territory here to get good transition to second carb ...and power blast here with no hiccups at all ...great thing to do on christmas eve to me :builder: :thank_you:

 

[ekvh]

It sure must be a heck of a lot easier with jets accessible without pulling the whole thing out. Reading your posts reminds me of my experience with the stock rack, not a good memory going on.

 

[joedrum]

yes ..this thread is about a better way ...in all ways of looking at it ...some things are just incapable to achieve and will never reach there purpose ... the wisdom to know the difference is a great thing ...i will never regret the day i pic up the this carb and read the numbers on the side and said in was going to try it ...it was all me ..i didnt go by anyone elses work or post about this carb .....

in the end this is no different than a dual weber set up ...witch most feel is better than stock carb rack ...well i am rather confident this is better than a dual weber setup ... and looking forward to the day to get around one ... this is a huge performance boost over stock ...and i am really pleased i carved my own path and still doing so ...these dft carbs are so much more adjustable than stock carbs...that they look stone aged not the other way around ...

i dont ever expect to get out carb by any stock rack oldwing equipped bike .... :thanks: but anything is possible :hihihi:

 

[joedrum]

ok went to 160 gas jet on primary ..i think everything is up for a test ride now got into secondary a couple times and heard nothing to discount at all ...seemed to go in sweet and hard ....
[video]https://www.youtube.com/watch?v=4N3DpLoeDyg&feature=youtu.be[/video]
when the primary barrel is doing its thing at a good clip ...the scondary dosnt have to makeup for anything and its all pulses ... only on the road and the seat of your pants can help in the secondary jetting ...to feel it got its best in the sweet spot of the oldwing motor output cant wait for the test ride :thanks:

 

[joedrum]

sheesh having electric problems with the lights in the doghouse today ...may try for christmas test ride

 

[tom foreman]

sounds great,joe. :music:

 

[joedrum]

ok i will post in the right thread now.....test ride was great ...seems all the jetting moves were spot on in the the thread ...jetting rather aggressive now ..could maybe use a bit more gas jet in secondary though its so close it just back to guessing .. shows no signs of fault here ...just takes a few seconds to get into the insane zone ...bike sounds totally different going through the rpm either hard throttle or anywhere less than that

the topic of this thread is the dft carb and the mods made to fit this bike ...in the end ..this custom induction system base on the dft carb out dose stock carbs by huge margin ...not even close ...it also proves old school is much better than new school will admit...with out a doutb in my mind now ..ive made a completely different class oldwing ...one that will compete with crotch rockets for its closest bikes to run with not oldwings :ahem:what a great project this has been ..with an outcome to run with anything out there today

 

[charles franz]

Done a great job, I have learned a lot on this carb!! Charlie

 

[joedrum]

charles franz » Thu Dec 25, 2014 11:31 pm[/url]":12u5raxt]
Done a great job, I have learned a lot on this carb!! Charlie

me too charlie.... hooch is the perfect example of why old school rules ... all new school tech is based on old schools perfect charge ..that never needed a computer mapping ... a good strait carb and a man capable of dialing it in will beat a room full computer driven techies ...simplicity and natural event rules ...that why hooch being a rocket hunter is no joke ..its for real ...hooch is at the limit of parts integrity ..any more power would be unreliable and break things ... i like the spot hooch is in ...it makes a lot of power per pound and totally reliable for long trips ...the outcome was much bigger than me ... i consider CGW the reason why hooch got to where it is ...just the right amount of environment here to push projects to there max potential..... :thanks:

 

[joedrum]

ok did a mod to carb i am am in the middle of testing on ....with all the mods ive done so far i gotten more and more better at idle ...but still i am in the more rich zone than lean...this is at idle circuit only witch includes..just off idle also ...there 6 holes in the carbs primary barrel that make up this circuit ...including the mix screw witch is still adjustable ive close off 2 more holes ...with mix screw in off position ...no flow ..i have now got this idle circuit cut down to 3 holes ...did this yesterday did run it ..temp was 30 degrees ....icing seemed instant ... took about 8 minutes to get where bike would stay running ...gas small seems less than before mod ...eventually the bike seemed to run well and did not seem to lean ...but it very hard to make much out of a run in so cold temps...waiting for better day to do ride test ... but i am pleased so with what ive seen from it .... :thanks:

 

[joedrum]

[video]https://www.youtube.com/watch?v=Cz2cRvqvxiQ&feature=youtu.be[/video]
ok ..its 40 degrees at video ... bike is warned up took a bit basically this is toeally modded idle circuit .... :thanks:

 

[joedrum]

ok ..took awhile but i finally got to road test hooch with the new carb top and idle orifice outlet block mod ... on the 24-25 dft carb with primary throttle plate hole modded in it...well everything was a total success it seems ...first indication was the instant start up ..although temp was 50 degrees and like paradise on a winter day...it took nothing to get it to run on its own ...less than a minute ..2 at the most ... so got dressed up and went for ride ....idle like it like to do it ... once down drive and on gravel road bike showed lots of power with the 1200 gearing idle can get crazy in a hurry ..seems to pull like tractor at pretty good clip.... any way down to corner and up the hill i knew it was better for sure ,, primary barrel kicks butt up the hill for immediate slow down ....ok motor to the hiway ... wait for some good space and took off ...im always measured in first gear but with secondary kicking in hard it hit 8000 quick shifted gears somewhere above that and second gear broke the back tire loose ..good power transfer and grab back and bike was gone again ...hit the next gear to but not long things were getting fast with no signs of let up....once i backed off hooch eent right back to running great down low and at idle .. cruised down the big hill and learned there was no back firing going on smooth perfect sound ....once down in the bottom i got close to the next hill and decided go up in almost idle position and 4th gear ..sheesh it hardly pulled down at all .. i was amazed at this .. its a rather long kill hill and didnt balk at all ...once i got home to deaded driveway ..it was a complete show of idle power....oh and one last thing it did not smell gassy at all ...smelled clean actually

to say im pleased is a understatment ... it is funny how things go ... if anything now it would seem the low rpm is the best spot ... :shock: it will take more riding than i did today to fully grasp all this ....

but i am liking it .. :BigGrin:

 

[sgq700]

:clapping: rock on Joe! Bitchen info