Looking for some help; I recently replaced stock carb on my '95 FLSTN with an S&S Super E, set at factory settings and rode great without special jetting. Rode it for a couple months, no issues, then I took it to a mechanic for new tires and a tune up, fluid changes, filters, new plugs, etc, a couple week ago. Ever since it's been running like the plugs are misfiring. The exhaust sputters and pops at low speed in neighborhood, runs great at full throttle but at cruising speed, maybe 40 or 50 mph, 4th gear, every few minutes or so it's like it just loses power for 3 or 4 seconds and jerks a little just like it's running out of gas with no acceleration, then goes back to cruising, no problems till the next time. I rode it maybe 400-500 miles like that (long Saturday ride) and now worried it may cause engine damage since it started blueing my pipes, too.

I assumed it was bad plugs but when I called the mechanic he suggested maybe a manifold leak or ignition problem. Now I'm starting to think when I installed the new carb, that maybe I didn't get the intake manifold on perfect or may have came loose (didn't use loctite) and is sucking in air? But it just seems odd it was right after the tune up / plug change.

Any thoughts or suggestions here, I am def no mechanic so need to know if I am on the right track or if I should be doing something else.

Thanks in advance!

 

Not one reply???

 

Any of those things could cause the problem. Start with the easy stuff. Replace the spark plugs and check the spark plug wires. If you still have problems check for intake and exhaust leaks.

Any chance you got a bad tank of gas? Water in the fuel will cause the same problems.

 

Thanks nhrider1. No chance of bad gas. Rode it bone dry a couple times and have filled it with 91 octane each time. I'll start with the plugs and wires cuz their easy and cheap, but I suspect an exhaust leak since I didn't use loctite when replacing the intakes. Didn't realize that was such a big deal. haha