| Author | Message | ||
     Ryker77 |
I'm swapping out my fuel injection X1 to a carb. I know I need a standard intake. And that a sportster carb would work. But I've seen on ebay lots of big twin carbs for a great price. I prefer to stick CV. OEM carb from '04 FXD Twin Cam w/filter element Harley 40mm HARLEY CV CARB Reworked 4 performance (Message edited by ryker77 on June 27, 2005) (Message edited by ryker77 on June 27, 2005) | ||
| Ryker77 |
My 02 x1 is running XB nallin stage 3 heads and andrews high lift N80 cam. Don't need any more power. In fact I wouldn't mind trading some power for better drivablity. | ||
| Tramp |
Yep- they'll work fine. I have a bunch here. the difference is in the jetting, which is a snap to change. Let me know if you'd like one. -Jay | ||
| Robr |
Make sure it has the excelerator pump, that would be 1989 and up... Rob | ||
| Ryker77 |
Jay, do you have any in near perfect shape with choke cable? also need intake manifold. | ||
| Tramp |
definitely not in near-perfect shape... let me check with my buddy's shop tomorrow. he also does a lot of carb refitting (S&S) & typicaly has a lot of newer ones (keihin). usually we both keep 'em in boxes and shelve 'em | ||
| Ryker77 |
which of the three options is the better value or better street able carb. 1-- a used like new CV40 carb from ebay for less than 100.00 2-- this rebuilt CV40 for 200.00 Harley 40mm HARLEY CV CARB Reworked 4 performance 3-- or a new MIKUNI HSR42 for $270.00 Don't mind paying for good stuff. But I know money doesn't allways buy a better product. Just want a tunable carb and one that is street driveable. 2002 x1 with XB Nallin stage 3 XB heads, Andrews N80 high lift cam, force intake and force exhaust. | ||
| Wyckedflesh |
The Mikuni is the better set up, more tuneable with the mods you have. However that being said you could get the CV's to work as well, but may not find the "driveablity" your after. | ||
| Henrik |
For the state of tune your motor is in, I'd be inclined to say Mikuni. Much easier to tune - and you ought to factor in some dyno time/$$ to get it right. Henrik | ||
| Tramp |
????? The PRICE on that MIK makes it the better value (more than $50- for any Keihin is an outrage) but as far as adjustabilty, let's don't forget the barmetric self-adjustability of the Keihin CV, what w/that excellent diaphragm. for OTR roadability, the Keihin is faaaaaaar and away superior. anyone else here ever ride over the rockies or the sierras with both brands of carb? the Mik will give you nothing but grief at altitude and temp. changes, while the Keihin CV will not miss a beat. seems it depends on what folks' idea of 'streetability' is/are. Jeez- I've fit so many bikes with Mikunis for guys, I prefer them for sport applications (they'll essentially get you to the same place a keihin CV will, they just getcha there faster), but i'm not sure i follow how they're more 'tuneable' | ||
| Henrik |
Tramp; right you are on the altitude thing. As for tuneability - being able to change the main jet without dropping the carb or at least float bowl certainly is a plus. Of course, the Mik may give you that cool flat slide rattle enjoyment as well  Henrik | ||
| Ryker77 |
I've got a fast bike... But I will hardly ever use its full power. Most of the time I just put around and make noise when leaving a stop light. Live on the east coast and a few trips put me on some mtn. roads --- nothing like the rockies. I've got an A/F gauge on the bike so I can tune it myself. So once the CV is tuned then it will be set. BTW thanks soo much for the detailed help and knowledge. cv40- Should I buy a nice used take off for around 100.00 or the rebuilt one for 190.00? | ||
| Ryker77 |
Mik may give you that cool flat slide rattle enjoyment as well not sure what that is? | ||
| Henrik |
If you go Keihin - which is a very nice carb - don't bother with the rebuilt one. A few $$ in parts and some "Shade Tree" mechanics will do you just fine. One nice item to add to a Keihin, in addition to new pilot and main jets, is the thumb-screw idle mixture screw available aftermarket. I'm thinking Al at American Sport Bike may sell those? Most of the aftermarket kits for the Keihin makes it easy to get the jetting in the ballpark, but I doubt you'll notice a big difference if compared with just changing the jets yourself, using regular HD available jets. The flat slide carbs are known for generating a rattling sound when the slide rattles back and forth in it's keeper groove due to the changing pressure/vacuum in the intake tract Henrik | ||
| Tramp |
yep- 'rebuilding' a keihin ( funny to use such a hard term for such a simple little task) is a joke. any child could do it easily and successfully. sure, removal of the keihin float bowl involves four li'l bolts (i ran one with a nice bing-style clip on an fxr years back), in order to change jets (yes, you leave the carb intact on the bike) but it only takes a minute, and if you're rejetting your streetbike so often that that extra minute really jams you up, wellllll... you might be a techno-dweeb. do NOT pay more than $50- for ANY used keihin. new ones are a ludicrous extra expense. whatever you do, do NOT spring even 50 cents for any edelbrock qwicksilver.... that li'l bong'll give ya herpes} | ||
| Ryker77 |
Edelbrock carb was out of the question. I knew that very few people use them. I tend to stick with the common items. I've been told that with my big Andrews N80 (bigger than the n8) cam the HSR42 with the adjustable accellerator pump stroke is the key to getting the carb dialed in. Uhhh. Seams like people like both carbs. The price on the new HSR42 is 280.00 or I can be cheap and get a used CV for less than 100.00 Just how bad is this "rattling sound"? I'd hate to spend 300.00 to make the bike sound like its a POS. | ||
| Tramp |
it's not bad at all. the CV is the low-maintenance choice of the two (Message edited by tramp on June 28, 2005) | ||
| Henrik |
you might be a techno-dweeb. No "might" about it - techno-dweeb indeed.  Henrik | ||
| Tramp |
 | ||
| Road_thing |
Tramp's right, the rattle is insignificant. In fact, I've been running Mik's on two of my bikes for at least 5 years, and I never even knew they rattled until I read it here! My impression of the Mik's is that their throttle response is crisper and more immediate than the CV. If I lived in an area with significant elevation changes, the altitude compensation that goes along with the CV carb might be useful, but the Gulf Coast is as flat as p*ss on a plate... rt | ||
| Tramp |
while the Mik's alleged 'rattle' is insignificant at worst, the 'snap' of the throttle response is very, very noticeable  | ||
| Racerx1 |
I really like the Keihin carbs. Try to get a late model big twin if possible vs. a Buell. The accelerator pump has a check valve to keep from 'leaking' un-metered fuel during WOT. The late model big twin also has a 5 transfer port slow jet circuit vs. a 4 port Buell carb with better low throttle angle fuel metering. You just have to watch slow jet recomendations as the 5 transfer port carb body in general takes a 1 size smaller slow jet vs. a 4 transfer port body. EG a 42# slow on a 5 port body is roughly equivalent to a #45 on a 4 port body. the 2003 and up carbs also have a brass fuel inlet fitting vs. the break-able plastic fitting of earlier carbs. My drag bikes and road racers all use Keihin CV carbs. I have a base carb modification guideline that works very well I can share if your interested (UWGRIZ and BOMBER both run one of my set up CV carbs....) or send it to me Plus $25 and I'll set it up for you. | ||
| Bomber |
without wishing to make Racerx!'s life a living heck, I can attest to the fact that his setup flat out works! only trouble I've had with the carb he helped me with were self-induced ;-} nary a cough, meters well across the rev range, very responsive, and 50MPG if I keep my right hand under control -- what more could a boy ask for? (Message edited by bomber on June 29, 2005) | ||
| Ryker77 |
Now on the prowl for the later model CV carb. Thanks racerx1. | ||
| Henrik |
Wes; please do share your base set-up info for the newer style carb. Also, can you specify which years of Big Twin carbs to look for? Thanks Henrik | ||
| Krassh |
Yeah any markings or part numbers to look for, as I have a carb off my 92 electra glide that a jet kit installed that I could part with. | ||
| Essthreetee |
Just talked to my Dad...he has a stock carb (been rejetted) from a '91 FXR Low Rider...he said make offer... | ||
| Tramp |
offer him $30-. | ||
| Henrik |
Realistically, if the carbed Buells don't have the 5-port Keihins, then we'd be looking at '99 carbs or later - no?? Henrik | ||
| Racerx1 |
Henrik, no problem sharing! You want to find a 2003 and up Twin cam 88 carb (any model), or a 2004 and up sportster carb. These both have the check valve equipped bowl, 5 port body and brass fuel fitting (and a nitromethane resistant accelerator pump diaphragm if thats important to you...). For a typical race pipe/air cleaner modified Buell, your probably better off with the sportster carb, as it uses essentially the same accelerator pump calibration and the 2004 XL1200 needle is an excellant performance needle (N4NN) with a .45mm shim. Sometimes you have to shim it a full .90mm but I would start out at .45. stock slow jet is a #42, I would go to a #45. A lot of people used to the 4 port carb go to a #48 in the 5 port and thats way too rich. 1 3/4 turns out on the IMS screw. Install a Blast vacuum diaphragm spring. Main jet is very engine dependent and I have run everything from a 190 to a 250 in different engines, but a 210 or 220 should be in the ballpark. You have to be very careful on main selection as a buell will run very smoothly and pull decently with too lean of a jet (15-16:1 A/F!). If you don't have access to a dyno or A/F meter, I would suggest increasing main jet size until the thing stumbles/burbles at WOT, then backing down 1 size. Starting with a big twin carb, change the needle to either the triple taper 2004 sportster N4NN with either a .45 or .9mm shim. Another good choice is the stock Buell NOKK needle with a .45 shim, or the old straight taper N65C needle (might need a .45 shim depending on motor). A big twin carb already has a #45 slow so you don't need to change that. Blast diaphragm spring. Main jet of choice. Accelerator pump calibration is different on the big twin carb (essentially less fuel over a longer shot duration). Works better on modified motors. You can change out the check valve equipped accelerator pump onto your old Buel float bowl and maintain the original calibration if you just want to get the check valve. You will need to swap the sportster or Buell cable bracket onto the big twin carb as well. Other handy mods if you can find the parts is to put the 51mm CVH Keihin float bowl and main jet emulsion tube on a 40 or 44 Keihin. You get the benefit of handy jet access with the 51mm bowl and the bowl itself is deeper and holds a larger volume of fuel (great for road racing). The 51mm emulsion tube is identical to the 40/44 part, but longer and takes advantage of the deeper 51mm float bowl sump. You can also put large diameter fuel inlet seats (4mm) in a 40mm if you want to get crazy too. This should get you pointed in the right direction. Of course, every engine requires some tweaking, so I can't guarantee this will work out of the box, but the guys I have helped and my own bikes have responded well to these mods. |
