| Author | Message | ||
     Natexlh1000 |
Has anyone tried to run an automotive-style carb on an XB engine? How do you think they would run with a small plenum and two barrel carb with vacuum secondary? I bring this up since people seem to slap a carb on tubers when they go racing. What do the racing XBs use in "formula extreme"? | ||
| Tramp |
a two-barrel carb (such as the poseuresque holley that HD was touting a few years back) does little to improve the performance of a twocyl. engine. It'd be like running 4 2bbl.s on a v-8, as opposed to one big 4 bbl. no advantage. | ||
| Spiderman |
Nate, When Dave S used to work in Iowa the boys out there threw a downdraft on his 9R that was equiped with a 1050 kit. Now Dave may be able to tell you more or Craig for Iowa. The one thing I do recall is they were having trouble dialing it in??? | ||
| Tramp |
that's the problem- it's actually a bigger pain-in-the-••• to ddial-in a big twin with dedicated plenums than it is for the shorter stroke 4-cyclinder machines. I can slap a manometer on a cb750 and get her dead-nuts on, but the longer-stroke of the v-twins makes synchronicity somehow more elusive. I used to have XR customers who were bringing me their sleds regularly to dial those DelOrtos. I sued to dun my own T120 bonnevills with tr6r heads just so i could have the synchronicity afforded by a single Amal...or Mikuni...or Keihin.....or DelOrto.....the stock HD Keihin CV worked wonders on some of my Tr6r heads....actually ran a PVC reducer.... (Message edited by tramp on December 31, 2005) | ||
| Spiderman |
There was only one carb on Daves old 9R. | ||
| Fullpower |
synchronicity. nice word tramp. I beleive the Waterloo IA experiment involved a downdraft snowmobile carburetor on a big bore XB9. some of the issues addressed were fuel pressure regulation, and ignition timing. I dont reaclll hearing that the lash up ever made it out on either street or track. | ||
| Tramp |
was the downdraft a single throat/bbl.? On HD powerplants, I associate downdrafts with XRs, which were, of course, priamrily twincarb | ||
| Slaughter |
I've been watching Jeff Ecklund getting more and more pissed off TRYING to keep the Bartels FX spec bike going with 2 downdraft flatslides. Knowing how the FI systems work, it pisses him off that Bill Bartels has a fetish for carbs. He will race it because that's what he's hired to do. Sooner or later, folks will come around and realize Fuel Injection is a good tool and its versatility is HUGE compared to carbs. | ||
| Tramp |
maybe so, but for folks like me, the simplicity of a carb, which I can completely dismantle, examine and reassemble in well under five minutes, and the absence of solid-state or digital mgt for my fuel and aspiration, make it far and away the superior choice for ease of maintenance and tuneability. try tuning your FI alongside rt. 80 in Wyoming... we're not all racers, here. | ||
| Daves |
Not sure if they ever got the 9R to run right with the carb. Maybe Craig can tell us? | ||
| Slaughter |
Yabbut - you got good points bout the carb. Can't argue the busted by the roadside thing. Swapping out to a carb from a FI just doesn't make sense - unless somebody's just LOOKING for a complicated project just for something to do. | ||
| Tramp |
it would make sense for me, slaughter. I demand simplicity and ease of repair from my vehicles. that's one of my primary reasons for riding a buell. For me to remove the FI from an XB and replace it with one of the dozen or so CVs on my shelf would be a very simple project that would yield me a far simpler future with my machine. I'd also make $ by selling my FI components. It is NOT a complicated project at all. I could actually pull the harness from the XB, along with the carb and manifold (and there are some whio've used their FI manifold with the carb, and who've also used the stock XB harness and just taped off the FI leads), replace with one of my spare harneses, along with one of my spare M2/S2/S3 ignition modules I have leftover from upgrade work, and head out on the road. What's so complicated about that? I don't take shots at racer types running FI, as I understand their reasoning. why the shots at my preference? | ||
| Tramp |
all that being said, did I miss something in regard to that job? I'm sure you have more experience than i do with FI and with performance buell wrenching in general, and if I'm overlooking something, believe me, I trust your word on it. | ||
| 99buellx1 |
Carb came off shortly after Dave left. That was a project that was going nowhere. I dont know the exact details, most of that went between Dave and our tech. | ||
| Tramp |
why was it such a "project"? | ||
| Rick_a |
Why not a single downdraft carb? Seems it'd be simple and shouldn't be that hard to tune. I like carbs. A properly set up FI can be a bit crisper under some conditions, but I love the feel of a properly tuned flatslide. I also like simplicity. Call me crazy but I converted my pickup from an early TBI to a carb. | ||
| Slaughter |
T*R*A*M*P - Not so much your preference as much it was a shot at folks wanting to switch FROM Fuel Injection to CARB - kinda solving a non-problem. Truthfully I've watched some real talent trying to race a carb-converted XB and it has taken 6 months - v. a weekend on the dyno for the FI motor. No more power and more trouble to dial-in the throttle response. If I were building an XB-motor from scratch and had the intake figgered out, I might consider carb-ing the thing. I'll prolly go to half-an-XB throttlebody for the Blast/XB hybrid and get her injected. I certainly understand carbs (Atkins be hanged) - but I'm getting lazy in my old age. | ||
| Tramp |
Rick_a ("Crazy") said : "Call me crazy but I converted my pickup from an early TBI to a carb." nothing at all crazy about that. TBI really is a carb, albeit one with an electronically regulated atomizer/jet | ||
| Mr_grumpy |
One word, Mikuni! | ||
| Tramp |
Now, i love the Mikuni, i seriously do, but as far as overall HP gain, I've read and felt it to be very little if any at all. The HSR will get you to peak a miote faster, they say, but the added barmetric compensation of the Keihin CV makes it far and away the superior carb for my own application. I don't have to mess around with it at altitude changes, as do my Mikuni aspirated brethren. | ||
| Buelldyno_guy |
The issue on XBs are the frame rails no matter what you can fit between then it becomes a "restrictor plate" A good set of heads can flow more than you can get to them, Yes Bartels has done it, and I am not too sure how and what the carb bore size is? We use a Buell XB12 TB opened up to 53-mm and a custom stack. On our old S1 race bike we used a 48 Mikuni made 135 HP out of 88 inches. Last year the Hal's bike used new heads with a straighter valve angle and intake track. Rumor was it had twin 60's but who really knows? Over the last few years I have tuned both race and street bikes with FI and Carbs, I guess my point is that I don't see why anybody would remove a state of the art electronic system that can be tuned so precisely only to replace it with one that only knows 1/4, 1/2, 3/4, and WOT? ... Terry | ||
| Slaughter |
I'll find out what size the flatslides are that Ecklund is running in the Bartels bike. He's arguing with Bill (Bartels) about going to a bored XB12 throttlebody - what we're running on my XB1169. We might swap my induction system onto his bike. We know where we can get some developed maps for that basic setup on the 1340 motor. I'm at least 2-3 months away from racing yet (still paying down the bills) - and it would make a lot of sense for him if he could do a side-by-side comparo of carb'd v. FI I'll let you know. Feel free to email me directly too qedqed at verizon dot net (Message edited by slaughter on January 02, 2006) | ||
| Tramp |
buelldyno_guy: you're missing thye point completely. in fact, you're going on about frame rails, etc., which do not actually restrict the conversion of a carb. I already more-than explained why I'd change out FI to a carb in a NY minute. also, a CV carb give syou far more adjustability in infinte increments, which FI doesn't. FI is actually incremented, even though it's fine incrementation. twisting the throttle on a carburated machine actually gives smoother, non-incremented acceleration. further, not all of us run these buells as race irons... | ||
| Buelldyno_guy |
Tramp I was just trying to answer a few of your questions about who and how. Sorry I should not have let my opinion get involved. Now having said that the frame rails do enter in unless the CVs you have are down drafts? You also ask about performance there is not a CV out there that will flow what the large TB will. That was my point and I am sorry if I offended you. The nice thing about these boards is that we all get to say it like we see it, taking and leaving ideas as we feel. ... Terry (Message edited by buelldyno_guy on January 02, 2006) | ||
| Tramp |
hoo-boy. i gotta watch my posti-etiquette. (no sh*t, trampsky) sorry if i sounded offended, i wasn't. i was merely opining, as well. the bing 48 flows enormous CFM, not sure if it measures up to the FI, but i believe it might. | ||
| Buelldyno_guy |
Again the issue will be the intake track and how you get it turned towards the valves. The heads Hals runs straighten the track by changing the valve angle. When you do that there is now more room between the cylinders for a pair of downdraft anythings 45mm or better. I am hoping to see something from them (Buell) following Daytona. ... Again sorry. ... Terry | ||
| 2hogs |
I vote for preventive maintenance and whatever intake configuration you like. I'm a firm believer that regular services will head off problems before they rear their ugly head out on the road. Course, I just hope BRAG membership has roadside assistance like my HOG membership does :-) Just in case! Cheers |
