|Posted on Wednesday, December 24, 2008 - 09:44 pm: ||
I've been looking into rebuild kits for my stock CV40 and ran across this at American Sports Bikes.
5025 - Carb Power Tube Kit, CV40, Master
All carb Models with CV40 Carb. Atomizer Power tube that converts fuel from a squirting liquid to a fine mist. Better atomization means better performance. Comes complete with the emulsion tube, yost power tube (press fitted into the emulsion tube), Blue and Red needles, 1/8" drill bit, 7/64" drill bit, compression spring, 165, 175, 185, 195 main jets, and washers.
FOR RACE USE ONLY, please see here
I was wondering if this was as good as it sounds or a waste of 106 bucks.
I also found a guy on e-bay will rebuild mine for around 189 dollars. But best I can tell he doesn't use this Atomizer.
I was wondering if this " Atomizer Power Tube" has been used by anyone. And if so , is it cool as it sounds ?
The e-bay CV 40 rebuilder is in Glendora Ca.
Killer is on the top of the rebuilt carb. Its a good looking Carb.
|Posted on Thursday, December 25, 2008 - 01:25 am: ||
This reply might start an argument.... & I'm willing to hear from smarter people.
IMHO.. the Yost power tube is a waste of money. why? Because it's designed to add fuel to a modified engine, or one that is too lean to start with.
The Cv40 ( this is way simplified ) has 3 different adjustments to change the fuel air ratio, at 3 overlapping throttle openings.
The main jet determines wide open throttle. If it's too lean, you lose power & can even melt pistons from too much heat. Too rich and the bike blubbers & you lose power. I can't seem to read the new plugs as well as I used to, so the best bet is a Dyno tune with a fuel/air sensor. Second choice ( what I've done ) is to take the bike to full throttle and see if it picks up power if you back off, you are lean.
( ignore their jet #'s your Cyclone has way more power & flow than the example )
The needle position ( and the shape of the needle itself, there are several ) determines the mixture from small to fairly large throttle openings, and is over ruled by the main jet at WFO.
The idle jet & idle needle adjustment affects idle to about 1/3 throttle, but also can change the mixture across the board, as the idle jet ( I think ) keeps flowing at all throttle openings.
Most older, carb'ed IL4 Japanese bikes, and some year H-D's, were set up on the lean side to meet emission standards. That's why the K&N/jet kits were so popular back in the day, you really could get noticeable performance gains by "fixing" the carbs to run closer to performance perfect, as opposed to clean running perfect. Modern Fuel injection systems usually run much better stock than a carb would ever let you tune it.... but need gizmo's such as "power commanders" and remapping to deal with any performance mods, like cams, free flowing muffler, etc.
On my '01 Cyclone, I richened up the idle jet & it starts & warms up much better. I raised the needle because that seemed to be the midrange trick to improve throttle response. I went to a smaller main because that's what the bike seemed to want, and a larger main jet made it burble & choke. Yours may be different....so builder beware.
Since you can get all the parts you need to rebuild it, why not do it your self? I can't see what mods you have ( they are hidden in your profile ) but if you are running a slip on muffler, and changed your filter/airbox arrangement ( either mod'ed stock box, race filter or Forcewinder ) proper jetting will be relatively easy and the Yost power tube will just cost money, both on purchase and from the poor gas economy. Or, it could work great...I don't know. If you have a ported or big inch motor, maybe. Check the knowledge vault, it seems that a relatively stock engine does not gain too much from big carb changes, even a Mikuni really only gives you better tuning ability, a little, and costs you the CV's big strength, automatic altitude compensation. If you are running from the Gulf to the Ozarks a lot, that might make a difference. If you lived in Colorado it would. etc.
Let the corrections to my ignorant views begin.
|Posted on Thursday, December 25, 2008 - 07:09 am: ||
Thanks Aesquire for the insight and the link.
|Posted on Thursday, December 25, 2008 - 07:14 am: ||
Hey... I got another question. Does the CV come in different sizes. I think the guy I got my bike from said it has a CV 44, The kits I'm finding are for a CV 40.
Does this matter?
|Posted on Thursday, December 25, 2008 - 07:41 am: ||
As good as the CV 40 can be with the proper set-up, I took the easy way out and installed a Mikuni HSR 40 "Easy Kit" with excellent results. I would do it again.
Just another option to consider.
|Posted on Thursday, December 25, 2008 - 07:56 am: ||
Yes I think in time I will probably switch to a HSR 40, and the Buell Oval
Right now I'd be happy to see what my CV 40 can do with the bread box.
Merry Christmas you all...
|Posted on Thursday, December 25, 2008 - 08:40 am: ||
The CV44 is a Screaming Eagle hi performance unit and puts out several more HP then the stock CV40. It also takes a special intake manifold so the CV44 is not just a bolt on. KK
|Posted on Thursday, December 25, 2008 - 07:17 pm: ||
The CV44 is a little trickier to set up on a high performance engine according to Aaron. ( High compared to the already almost double factory HP comparing a M2 and a Sportster..ie. ported heads/cams/nitrous )
If I remember the Mikuni is easier to change jets on, since you don't have to remove the float bowl each time. ( and dump a bit of gas on the bike/ground/hands )
I'm not sure you'd get more power with a stock engine with a CV44...but you sure can with heavy breathing mods.