| Author | Message | ||
     Saszta |
So what about using a timing light to check the timing on an XB9? I've read the method in the manual that involves using the digital assistant or digi-mechanic or whatever they call it and I've also read about someone stabbing the leads of a voltmeter into the connector wires of the ecm, but what about the simple use of a timing light? Why not just check the advance/retard by looking at the timing mark through the inspection hole while the engine is idling? | ||
| Buelltroll |
Got a pic of this mysterious "inspection hole" ? I know my XB is minus any holes in the case. | ||
| Saszta |
here's a pic of what's in the manual. It's right above the ignition cover but there is a plug in it that needs to be removed. Mystery solved?   | ||
| Buelltroll |
try it then since u do have a pic and everything | ||
| Sparky |
Mystery not quite solved. The picture above refers to Static Timing. In other words the timing mark you see is what you strive for when the engine is static (not running). What happens when the engine idles however, is that the timing advances, and that static timing mark will move out of view of the window. So at what precise rpm do we set the idle speed in order to see the advance timing mark? Is there an advance timing mark for the front cylinder on the flywheel? There may be. If anybody knows, please chime in. Another problem would be the accuracy of the bike's tachometer. Is it 1% accurate, 3%, 10%? If I want exactly 1050 rpms, what if the tach reads 1050 but it is actually 1150 rpms. That might be 1 degree more advanced than at 1050 due to the timing map. What would 1 degree advanced timing do? Maybe not much but it could lead to unwanted detonation. It's better to be dead-nuts on target than guessing. The other thing is that the static timing not only adjusts the ignition timing but it is the basis for the fuel control maps as well. I don't pretend to know the idiosyncracies of Buell's DDFI, but if the factory doesn't recommend strobe timing, I wouldn't do it. But you can try. Be sure to plug that timing hole with Harley's clear plastic plug, p/n HD 96295-65D before starting the engine. You don't want to get sprayed with oil while aiming the timing light into the timing hole. Don't ask... | ||
| Rocketman |
With a Snap-on digital timing light (strobe), you can advance or retard the light itself, which offers a more accurate way to read any timing mark. For example, if the timing is set at 16 deg BTDC you would dial the 16 deg into the timing light and read the mark on the flywheel aligned with corresponding mark when it's at TDC ie; 0 deg. There's less visible fluctuation reading the mark at TDC. You can also advance and retard the light whilst you're looking at the mark, be it at TDC if you've dialled your timing figure into the light, or at the timing mark figure itself if you leave the light at 0 deg, and by doing so you can watch your preferred mark move either way as you dial in or out a degree at a time so you can more accurately make your timing. You can also calculate how much your timing is out by this function too. The timing light takes its signal from the High Tension pulse so the timing lights built in RPM counter is absolutely accurate regardless of what your vehicles RPM gauge might be saying. Never used my strobe on the Buell though! Rocket | ||
| Reepicheep |
Whats wrong with the static timing approach? You don't need any fancy tools, you can hear the fuel pump come on at the right moment. I didn't even have to pull the plugs. There is a nice post in the knowledge vault for doing it... I printed it out and it sits in my service manual. It can be done by one person alone, but would be easier with two. | ||
| Saszta |
Thanks for the warning and the chuckle Sparky. Rocketman, my timing light doesn't seem to be as sophisticated as the one you mentioned. Since you don't use it either I think this is probably not the best(or easiest) method for this bike. Reepicheep, seems like you have a pretty good point - try easy first. Thanks guys, Steve. | ||
| Rocketman |
Whats wrong with the static timing approach? Nothing - and no one said there was. I was explaining the virtues of using a digital timing light where possible. If Buell had made such possible by providing a good place to read timing marks, then nothing would be more accurate and simpler to time a Buell than using a digital timing light, with or without built in advance \ retard option. Rocket |
