| Author | Message | ||
     Roadwrench1 |
Hello, anyone swap fuel injection for carb? Buddy is building a Redneck Mutant chopper using an 05 XB12S engine. Installed S&S carb with Crane Hi-4 dual fire ignition. Will idle poorly but will not pull off idle. Backfires through carb and exhaust, dies. I have built several HD Big Twin engines, but this Buell has me stymied. Almost seems cam timing on XB12S engine is outside the parameters of the Crane ignition? Any help would be greatly appreciated. | ||
| Justin_case |
You need a timing cup from a carbed sporty. It will have 2 slots in it. The Buell one has more slots for injector timing and single fire ign. | ||
| Roadwrench1 |
Thanks, but already have -84 cup installed. Actually idles better with OEM cup, but I know -84 cup must be used. (Message edited by roadwrench1 on March 16, 2007) (Message edited by roadwrench1 on March 16, 2007) | ||
| Justin_case |
Jetting OK? Acc.pump stroke OK? Intake leak? Which coil are you using? | ||
| Justin_case |
Are you using a VOES? The HI-4 should come wired for one. | ||
| Roadwrench1 |
I did not install carb(leaks),but intake leak would mainly cause backfiring through carb. This beast shoots flames out pipes and carb. I did remove float bowl to make sure jets were installed, came from S&S jetted for 1200cc Buell. Accelerator pump is operating properly. VOES can be used with Hi-4, but is not for this application(cosmetic). VOES only retards ignition for easy starting. Would only cause run ability issue if stuck in retard position. Engine acts like its firing on valve overlap instead of compression. I even flipped Hi-4 upside down, changing timing 180 degrees. Ran the same? Wondering if my buddy didn't take gearcase cover off to "see whats in der", and slipped a cam in/out without noticing timing marks? Engine ran perfect in stock chassis, with only 400 miles. | ||
| Justin_case |
You can check valve timing without pulling the cam cover. Pull the primary and put a degree wheel on the crank. Pull rocker box top covers to access rockers. Compare valve opening and closing angles to specs. The VOES changes to a less aggressive timing curve under heavy loading to prevent pinging, well worth the cheap money. | ||
| Roadwrench1 |
Thanks, but this is obviously going nowhere. I was mainly looking for, will Hi-4 work on 05 XB12S? A VOE "switch" is just that no/off, ounce bike is running ignition is advanced as far as possible. VOES will not retard ignition more under a load. VOES will not change how the engine runs, only makes it easier to start. I have installed adjustable pot vacuum operated rheostat on supercharged big twins to reduce pinging, but pinging is not the issue here. |
