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Post by na96ek on Apr 17, 2012 18:22:04 GMT -5
Hello all. I have a 06' Vento Zip which im in the process of tuning. I installed an athena BBK last year which I put a few hundred miles on just recently installed an Athena Hyper Race pipe, malossi multivar variator, malossi yellow torque spring, and malossi yellow clutch springs. I just got it running a few days ago and started some tuning with the stock carb and essentially came to realization that I cannot get it tuned properly on the stock carb. So im in the market for an aftermarket one and I need some help deciding what carb to buy, where to buy it, and what else ill need to go with it. I am leaning towards a dellorto as I have heard they have a little bit better reputation. I also want a manual choke kit. I have looked at the 21mm PHBG Black edition. Is this a viable option for a vento zip with the stock manifold? If people with similar scoots, setups could chime in and make some suggestions id be greatly appreciative!
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Post by stepthrutuner on Apr 17, 2012 18:52:16 GMT -5
It is a good choice but you will need to upgrade your intake manifold and reed assembly to take full advantage of the larger carburetor. The larger carb by itself will improve your performance but you might only be able to utilize say 50% of it's potential by not upgrading your intake track as well.
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Post by na96ek on Apr 17, 2012 19:45:44 GMT -5
well last time i had my engine apart to replace my crank bearings i measured the stock intake pipe/manifold and i believe the inside diameter was roughly 19mm... it only grows larger from the opening so it seemed to me that opening up just the first inch or so of the pipe would give me full use of the 21mm, and leaving it alone id be using all 19mm with a 19mm carb. after taking another look at my scoot, i dont believe the the 21mm dellorto black edition will fit with the cable coming directly out of the top with no elbow as it will shoot the cable straight up into some of the underside plastics. what is a decent 19mm carb you would reccomend? and it is my understanding that some use electric choke only, some manual, some can even use both. and how would i know which one to choose? Basically im trying to get an idea of what is a common 19mm carb to run on a short case minarelli horizontal setup that wont have any clearance/fittment issues, can be used with the OEM intake manifold, and also what are some jetting points to start with given my level of modifications?
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Post by na96ek on Apr 17, 2012 19:53:20 GMT -5
i see alot of people with similar setups and similar climates talking about using vastly different jetting settings.. it seems it varies with carb manufacturers as well (ex a 90 mj on a dellorto being the equivalent of a 100 or more on an arreche) I am currently running an 82.5 MJ on my stock carb, but have an extreme lean condition when it gets on the powerband under low throttle positions, which is where i need to spend 90% of my driving, making the scoot essentially unuseable. it runs so lean that I even hear what sounds like either detonation or soft siezing. I am planning on going with a new top end soon anyways, but I want to get my tuning in check first.
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Post by jmkjr72 on Apr 17, 2012 20:14:39 GMT -5
so what athena kit do you have the hyper race or the regular sport kit
that will determine what size carb
if its the hyper race you dont want any smaller then a 21mm
yes jet numbers will very from carb to carb a 90 in brand a is not the same as a 90 in brand b
diffrent companies use diffrent formulas to give the jets there numbers
some go by flow some go by hole size and some go with a formual that mixes hole size and flow
what plug are you running the athean kit likes a br9hs (or b9hs if your scoot didnt come with a resistor plug or you are running a hot wire)
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Post by skuttadawg on Apr 17, 2012 22:01:49 GMT -5
How about a 19mm Kehin or Mikuni ? A larger carb can be leaner since more air and not really help you go faster as too big is overkill
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Post by stepthrutuner on Apr 17, 2012 23:13:41 GMT -5
You can get a 90* thimble for your 21 or buy a kit that already has one.
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Post by stepthrutuner on Apr 17, 2012 23:19:30 GMT -5
How about a 19mm Kehin or Mikuni ? A larger carb can be leaner since more air and not really help you go faster as too big is overkill Larger carbs can be tuned in to deliver a proper mixture at all speeds. It is more involved, especially with free flow air filters, but it can be done. |
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dr1445
Scoot Enthusiast
Posts: 199
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Post by dr1445 on Apr 18, 2012 6:53:38 GMT -5
vert did a study on various size carbs on a 90cc. i think he found the 21mm just about right for the 90. i have one of those 19mm dell clones from ebay for around $50 with a filter on my 72cc cast iron ventro r4. it seems to be a happy setup with a leo vince touring pipe. top end is around 48mph with 65mpg. with a slight incline and a cool day it can hit just over 50mph. also the 19mm was a plug in on the intake side. if you get a real dell carb it should come with a adapter to fit the stock filter.
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