Hi guys,

I had a strange thing happening to me when on a long ride with some buddys.

First, I have swaped cylinders and pistons to make it a 95cui, and put in a map so it wont run lean.
I have a 2-1 thunderheader system on it nd SEH35 cams. Was running stock airfilter at first and the bike run rich.
Before we left I serviced the bike changing out the sparkplugs and so on.
The old plugs where completely black from sot, so the bike runs rich for sure.
I also put an Arlen Ness big sucker air cleaner kit on the bike.

When on the trip the bike behavied just fine, but on day two it suddenly started running bad under 2200 rpm... Was in 5th gear and gave it throttle, the eninge then started to missfire and studder. The red engine light came on. Dropped a gear and the red engine light went away....

When i got home, i pulled the plugs, they where white on the tip, butt black arround the edge...

What could be the problem?

 

Run a diagnostic scan for ERRORS.

 

Fouled plug?

Get the bike tuned..

 

Hi,

I will for sure get the bike both scanned for faultcodes and also tuned.
But it was such a strange problem, that suddenly apeared, that I had to ask if someone else have had the same problem.
Specially since the bike run just fine for 150 kilometers before suddenly acting up....

 

Possibly bad gas?

 

Hi,

Checked for fault codes, and the only thing that came up was " Front Cylnder No Combustion".

So, its either a bad map that causes this or there is something else wrong with the bike.

After clearing the fault code the bike still didnt run like it should on low rpm or on cruise. Twisted the throttle in high gear and low rpm on my way home, and the red enigne light came back and the bike started to studder and missfire until I downshifted.
Then it went away...
So would be fun to se if the faultcode is back again.

Anyone got any idea?

 

I would love to see pics of your plugs. From what you described it sounds to me like you carb is not jetted correctly at all. Running lean down low and running way to rich at 3/4 to Wot. What position was you mixture screw in when this all occurred.?

 

Hi, my bike has EFI.
but here’s pictures of my plugs.

 

Dude you are running super lean down low. And slightly rich up top. The plugs are running cold by the lack of color on the 2nd to 5th threads on the plug which should have a golden hue to them. The ground strap has no markings at all. Meaning lean as f*ck. The insulator has no color either. Which should be coffee /tan / light brown. Another sign of a lean condition. You need to check your needle, the float height and the float needle that it’s not damaged and fully seated in the carb when it supposed to be. Your carb is completely untuned. Where was your mixture screw during this. What jetting, pilot and main are you using and what stage of upgrades have you done. Air intake. Full pipes. Baffle or no baffles in the pipes. Have you checked for leaks around the intake manifold, cylinder heads and exhaust gaskets. Spray some carb cleaner around the areas with the bike running. If you have a leak anywhere it will suck in the carb cleaner and your rpm’s will jump for a few seconds.

 

This should clear up any misconceptions on reading plugs….