| Author | Message | ||
     Jon |
The S2 let out an awe inspiring backfire about 8 weeks ago. Idle was really rough after that with lots of backfiring. Heard lots of advice about what to check, like electrical components. Since the bike seemed to idle well when on choke, but only backfired when off, we took the carb off the S2 thinking that might be the culprit for the rough idling and backfiring. A friend of mine cleaned the thing out thoroughly at his machine shop. It was really filthy inside the bowl and the main jet was clogged. So I re-installed the thing, put fresh spark plugs in and still it idles on one cylinder, or so it sounds. I pulled out the rear spark plug and it's freshly fouled as it has been since this whole problem appeared. So the carb work needed to be done, but it wasn't the problem. We'll start looking at electronic stuff now. Hope to find the problem soon. I'm really short on time and am not a mechanic, so it's slow go. Thank goodness for friends like Alan and Peter, both veterans of ASBN's Death Valley Rides. On top of all that, the turn signals are literally rotting off. Neato! | ||
| Phelan |
Did you check the intake seals? | ||
| Jon |
Thanks for that suggestion. I will be doing that tomorrow after worky. Also will replace the spark plug wires as they feel old and the one that goes to the rear spark plug doesn't seem to purchase well on the spark plug. Probably will buy a main circuit breaker just to have it handy as well. Hopefully these will yield some results. | ||
| 4speeder |
Idling on one cylinder is a classic Harley intake leak signature. I would check for intake vacuum leaks as Phelan mentioned, then go from there. | ||
| Reepicheep |
Cam position sensor failures can lead to backfiring also, and they can cause lousy idle, though they would not typically cause just one cylinder to drop out. If you have access to any kind of ocilloscope, you can check that pretty easily. (With decent pocket scopes down to under $100, they should be in more garages these days). | ||
| Firemanjim |
And do a compression check | ||
| Jon |
Will do. | ||
| Fxdrydr |
May be a reach but - you might have solved the original problem but made a new one. The way its running sounds like how they'll run if the carb is incorrectly assembled and the needle is not at the bottom of the vacuum piston but is instead, in the white plastic basket. Don't ask me how I know or if I've ever done something like that... | ||
| Jon |
I'll look at that if everything else yields no improvement. And I won't ask if you've ever done something like that! Sometimes the best lessons are the ones that drove you nuts for a while. | ||
| Jon |
Both spark plugs are firing just fine. We used a spark plug tester. We noticed that the rear cylinder intake manifold bolt was loose. So we tightened that up and will put everything back together and see if that does it. I did buy new seals. However, and unfortunately, the intake manifold bolts are pretty boogered up. Ultimately I need to replace all the bolts and the seals and I will. But I want to see if tightening the loose bolt gets me two firing cylinders. I'll report tomorrow. | ||
| Jon |
Everything is fine, the beast thundered loud and both cylinders fired in anger. I will order the long ball socket tool I need for the future manifold work.The turn signals need help. But the S2 is back. Thanks for the suggestions all. In the process, I discovered some things that I will need to attend to later. |
