| Author | Message | ||
     Mad_doctor |
Here is something I've never seen before. I'v got an 08XT, with 5000 miles, I'm taking it to the homecoming next week, So I decide to give the bike a once over. It's running O.K., but there is a slight vibration. I Check the Primary, and adjust as needed, and change the oil. Change the oil filter, and add Mobil 1 V twin 20-50. Check the spark plugs, and the rear plug has "arc" marks on the wire end. So I decide to change the plugs AND wires. The plugs were originally 10R12A, the Book, (and dealer), tell me they SHOULD be 10R12X. I gap and change them, Take the bike for a test ride, and I have NEVER been on a pushrod V twin this smooth!!! heres the problem, It's SMOOTH, it's fast, BUT, not as fast as it was. I could pull the front wheel, in 3 gears. now I have problems lifting the wheel in Second gear. Top speed is now around 95 MAX. not like it used to be. The rear pipe is the same temp as the front, (so I'm firing on both cylinders), The mileage has not changed, It starts GREAT, as it always did. The pipe has not changed color,(on the inside), looks likes a clean burn. Is it possible the plugs could make THAT big of difference? or am I only running on one cylinder? I have not pulled the plugs to see if they are burning O.K. Any Ideas? Thanks, | ||
| Natexlh1000 |
Check the seating of the plug wires. That's the only thing I can think of. | ||
| Ourdee |
10R12X , what mine came with. | ||
| Ratbuell |
10r12x is correct for a DDFI3 bike. 10r12a will *work*, but the x has increased anti-fouling capabilities. My guess, although I have not done much research, is this is through a different heat range in the plug. Could it cause the difference you're seeing? It could. Could there be something else contributing? Absolutely. Make sure your plug wires have a nice seat on the plug (an audible "click" should be heard and they should snap into place) and on the coil. Use dielectric grease to fill the connection, to keep debris out of the boot. | ||
| Ronmold |
Hey Mad, how did you torque the front plug? | ||
| Mad_doctor |
I did not torque the plug, I always mark the ground tang on the plug,(with a marker), and pull the plug down until the crush washer is collapsed. This it not the True, (correct), way to do it, but unless you are able to get a torque wrench directly on the socket, any other way has variables too. The reason I mark the ground tang, on some older motors, you can stack crush washers to "aim" the spark where you need it. On my particular engine, both tangs were facing, (looking down from the top) about 7:00. The front plug is facing the intake valve, the rear is facing the exhaust valve. (Just my weird way to do things). | ||
| Sanchez |
It would be obvious if you were running on one cylinder. The bike would idle low and rough, sound funny, smell like gas, and have no power. Also, as you point out, there would be a big difference in header temps. I guess the thing to do would be to change the plugs and wires back and see if the bike returns to normal. If so, change just the plugs or just the wires to narrow down the cause. | ||
| Thetable |
Did you disconnect the battery? It may just be taking the ECM a little while to adjust the AFV. I know when I did my plugs (@12000mi), I started returning an additional 2.5 MPG. |
