| Author | Message | ||
     Sarodude |
I'm wanting to pick some brains about carb mods that go BEYOND simple tuning adjustments. Beyond the main & pilot jets... Beyond the airscrew... Beyond the needle... Has anyone messed with their carbs beyond that? I've been tinkering with a Dial-A-Jet - a predecessor to the ThunderJet. Both of these devices add another fuel circuit to the carb - usually obtaining the fuel supply right from the float bowl. I can't comment on the ThunderJet, but the DAJ served me well when racing 2 strokes since it eliminated most of my main jet swapping due to its inherent adjustability. Although my current implementation of this thing hasn't worked well, I'm going to re-do the installation soon and see what kinds of results I get then. AnywAy, I'm hoping theRe's sOmething comiNg from the more hardcore tuner types...  -Saro | ||
| Bigblock |
My carbs got a Yost power tube and I raduised the slide, both with good results, but I had to install a better petcock before I was able to tune properly due to float bowl starvation from pathetic flow rate of stock piece. I used a pingel with good results, but probably most anything 'll flow better'n that stock Harley piece! Let me know how that DAJ works for you, since that fuel quality reduction we got hit with out here last year, I'm having a hard time getting enough fuel at the top, I had to back the timing off a degree.Cured the midrange, it's just a little soft for the last couple hundred. | ||
| Spiderman |
I'm planning on boring my carb out this winter to 44mm and getting one of thoes plasic throttel slides. The carb i have now is super beefed up just looking for a little mre air flow. | ||
| Jrh |
Saro My particular brain's not worth picking on much but i can say at least that concerning the Thunderjet,my local H-D,Buell dealer sells+installs Many of them on S+S carbs(which i think are basically a 2 circuit system stock).They have a mechanic,engine builder who builds just street+strip hi-perf v-twin engines.Apparently he prefers the S+S over Mikuni,which i thought was kinda odd until last night when i spent about a half hour in the back shop talking to him.Sitting in his work area was his ahdra Pro-Stock drag bike,sometimes with 2 bored out S+S D (2 T-jets each)carbs,this time with 3! Lectrons.The bike runs 7.5 ets@176mph,always being developed.His work area has his own dyno,flow bench,small machine shop,just totally fascinating to be in,and its all going on in the back of a Buell,H-D,Yam.,Hon.,Kaw. dealership.Oh Yah,he'd just dynoed the PS bike,265hp,240torque!He pulled a set of Redshift cams out of a drawer to show how the lobes are made separately and then he degrees them+welds them in place.I heard him start saying they had a 9 something lift but i didnt hear the rest of the numbers,i was laughing too loud at the absurd look of the giant lobes.A couple weeks ago i was back there and he was putting together a steet engine for an orange 98 S1W owned by one of the other mechanics,he mentioned stock dislacement,knife edged fly wheels with oil scraper,small Redshifts,Zippers cnc ported T-storm heads done "specially" for him with a few extras thrown in on them,S+S carb with T-jet.Anyway i asked him if it was broken in +dynoed yet+he answered,like it was really no big deal,116hp + he knows he can get more than that out of it!I guess the drag racers do things a little differently,but they sure still get it done. I know this doesnt really give you any info you're after but im so revved up after being in that atmosphere i had to babble about it for a couple minutes. Have fun | ||
| Jrh |
Bigblock I just read you put a Pingel petcock on your M2. Ive been wanting to do that,the fuel line inlet on Mik.42s is larger o.d. than buells petcock.The only reason i didnt go to the Pingel was i read somewhere the pingel adapter plate that bolts to the tank sometimes leaks + sometimes bubbles the tanks paint at the mating surface area.Any truth to that?Thanks much, in advance if you answer | ||
| Spiderman |
The pingle does leak if you do not throw an o-ring over the screws. I knew a guy who put a pingle in and had it leak he said he threw some o-rings over the screws an problem solved. As for the S&S great WOT carb nothin more nuthin less. | ||
| Jrh |
Spidy Thanks for the Pingel info.Thats what i always thought of the S+S carbs too,kinda crude engineering with only the 2 cicuits+the butterfly,but with the Thunderjet added this super tuner(+ he really is one) thinks they can carburate right through the rpm ranges with a mikuni,i was skeptical until last night,BTW,i read through the instructions for tuning a thunderjetted S+S,very complicated to me,looks almost impossible to get even close without a dyno,etc.The T-jet costs about $65,but the carb has to be set up in a fixture+machined,another $75-85. Im keeping my Mik. for its simlicity+nice throttle response,but this guy told me he can send my heads to Zippers,get my same reworked castings back in about 3 days,its really got me tempted,maybe this winter if things work out better. Oh,i just found out there was a Prostar dragrace a couple weeks ago at Norwalk,near where i live,if i'd known about it i would have tried to get you a picture of Larry Mcbride,1st + i think still only bike to run 5s,his nickname is spiderman+he has the spidy leathers+helmet set-up  | ||
| Snowdave |
I have added the yost power tube, O2 sensor, and digital gauge to monitor mixture. After much playing, my gauge reads a fairly constant .9V. However, I still have lean pulses. I purchased the Thunderjet kit months ago and now I am finally ready to install it. I can do the machining myself, all you need is a drill press. But what do you do about the bracket that holds the carb in? It appears that the thunderjet will run right into it. Anyway, I will let you know what the results are. | ||
| Rick_A |
I have a Thunderslide kit in a otherwise stock carb. Nothing too fancy...and I'm sure as hell no tuner...but after setting the jets, needle, and mixture screw to their recommendations the throttle response and midrange is greatly improved from stock and the mileage is great. No pinging or hesitation. I'm thinking of adding a Thunderjet once I get the heads ported one of these years. | ||
| Spiderman |
My cousin has his own head shop and ported mine also put in bigger valves. Talk about impressive a 18 hp gain with the stock pipe.  | ||
| Buellistic |
ATT: Buellers Get your buddy to buy a PRINGEL gas valve!!! Then you and your buddy do a gas flow TEST against your stock gas valve!!!!!!! Get both your buells on stands(level),remove both float bowls. Put a measureing cup under each carb and with a stop watch or watch with a second hand,SEE which one fills the quickest!! You wil be surprised and you will still have your $100.00!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! In buelling BUELLISTIC and/or Hardley-Harley | ||
| Spiderman |
Let me guess a hard lesson learned? | ||
| Aaron |
Pringel? Don't they also make potato chips? (just messin with ya) Dale A. and I stopped at a HD dealer in Wyoming, on the way to Bonneville, and asked if we could get a Pingel petcock. The guy insisted they were "Ping". But he didn't have any Pings in stock. Bummer. We found something in Salt Lake. | ||
| Bigblock |
Well Buellistic, I did a before and after fuel flow test on my bike, in fact twice with the stock petcock, the 2nd time after disassembling, thoroughly cleaning and inspecting, and reassembling, and the pingel on my bike flowed about 5 times the rate of the stock valve, I started with a full tank, and timed 1 gallon of fuel into a can, (straight out of the hose, not thruogh the carb, I don't care if you got the float bowl off, that's not an accurate test for a petcock! You are measuring the static flow rate of your needle and seat, your test doesn't compare the flow rates of the petcocks!)... and I was able to tune the carb properly on the first damn try, something I just couldnt do with the stock piece. My testing was done with the gascap removed to eliminate poor tank venting fron the equation, and I redid the test several times to verify my results. Maybe I had a crap stock petcock, or maybe they make em better now, but as far as 2000 model year goes, and I have tested a couple others for flow, well, they suck. The pingel has just started to seep a little, though, I will replace the gasket and try the o-rings this week...it's been on my bike 2 years and 14,000 mi. now. I would never recomend a product to anyone that I had not had good results w/ myself... | ||
| Hans |
What is needed: Lets say the bike burns about .5 pounds of fuel per horsepower per hour at WOT. Probably somewhat less: Somewhere between 0.42 and 0.48. Let`s assume it has 100 HP. Needed 50 pounds gas/hour. The petcock has to deliver with all the constrictions of vent, needle and seat: 50/60 pounds per minute. Specific gravity 0.75. That makes (after some conversions in metrics and back): 0.133 gallon/per minute. If the original fuel system delivers not (much) more than that I would be worried. In real life there is also the only partly opened valve needle and there are the engine vibrations which may counteract. Hans | ||
| Buellistic |
ATT: Aaron If you do not take the check valve out of the gas tank vent it does not make any difference how BIG a PRINGEL(pingel) you attach to the gas tank or how small a float valve is stock!!! RIGHT ON!!!! In buelling BUELLISTIC and/or Hardley-Harley | ||
| Aaron |
You are absolutely correct. Not only do I take them tip-over valves out (of the race bikes), I also drill the fitting bigger and then stick the inlet to the vent hose forward, under the headlight. It's my fuel pump. | ||
| Snowdave |
Well, I installed the thunderjet today and I am having a tough time telling whether or not there is any difference. The space does not fit flush against the outside of the air horn, so I wonder if it is even working properly or if I have to grind down the spacer first. | ||
| Sarodude |
Dave- Make sure that interface between the carb's and TJ's bodies is reasonably air tight. The DaJ comes with a hard rubber pad that helps a lot. I wound up using some metal epoxy to build up an area on the carb body that I milled flat before I drilled & tapped for the DaJ. Since mine is mounted on a Blast, it's on the right side. I see some interference when I try to install the stock airbox... -Saro | ||
| Rick_A |
I have a question... when does the stock fuel supply become insufficient on a carbed Buell? At what point in the power scale should one ask, "hmmm, I think I may need a Pringel, etc?" | ||
| Madduck |
For you budget minded buellers, The simplest way to increase flow is to remove the plastic bit from your stock petcock that gives you reserve. The petcock flows real good without that restriction. You do have to watch your mileage as your petcock now only has off and on. this simple test will tell you if a pingel will help with whatever problem you may be solving. | ||
| Buellistic |
ATT:Madduck I operate under the KISS program(keep it simple stupid). Just hate taking things apart. I just turn on RESERVE and go for it. The result is the same!!!!!!!!!!!!!!!!!!!!!!!!!! In buelling BUELLISTIC and/or Hardley-Hardley |
