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Steve
Steve, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 6828
Experience:  30+ yrs. experience, MMI, HD technician, HD early, engine rebuild/performance, bike builder, kit bike program manager, CCI 2001-2004
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It spotters and backfires. It doesn't have any baffles in

Customer Question

It spotters and backfires. It doesn't have any baffles in the exhaust pipes. Would that cause this problem?
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: I bought the bike a year ago and is done it from the first day.
JA: What is the model/year of your motorcycle?
Customer: 02 softtail
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I've worked on a lot of cars but never a bike. I bought a book and thought I would start learning. I haven't done anything yet. Been going through a divorce and it was final today so I can now get back to living.
JA: Anything else you think the mechanic should know?
Customer: Like I said, it really needs baffles
Submitted: 3 months ago.
Category: Motorcycle
Expert:  Steve replied 3 months ago.

Harley's will run with or without baffles.

if you want baffles, you can install them. they are available aftermarket from any shop that sells parts for Harley's. including the dealership. just tell the parts guy what size (diameter) pipes you have and he can order baffles.

back to your complaint.....there are several things that can cause the engine to "sputter", but the only thing that can cause a "backfire" is an ignition problem, and a voltage issue can cause an ignition problem.

therefore, the first thing to check is the battery and charging system.

measure the battery voltage under the following conditions:

- ignition OFF.

- ignition ON.

- with the start button depressed.

- with the engine at 2,000 rpm (fast idle).

let me know what you find. we can continue then.

Steve

Customer: replied 3 months ago.
I might have explained this wrong. It's not really a backfire but a miss. When I'm accelerating it will miss and it doesn't matter what gear I'm in.
Expert:  Steve replied 3 months ago.

your "miss" is a lean mis-fire.

it could be caused by several things.

- it can be caused by installing straight pipes and failing to tune the carburetor.

- it can be caused by a vacuum leak in the intake manifold.

- it can be caused by fouled jets or a restriction in the fuel flow to the carburetor, especially if the bike was parked for a long time.

- it can also be caused by ignition problems and/or a problem with the voltage to the ignition.

I'd like for you to make those voltage measurements, just to ensue you have no hidden problems.

other than that, installing the baffles may correct the issue, if the carb was not tuned after those pipes were installed.

Steve

Customer: replied 3 months ago.
This may be a really stupid question but I'll ask it anyway. I have a regular electrical voltage meter that I use on household electrical repairs. Can I check the voltage with that?
Expert:  Steve replied 3 months ago.

if you can give me the make and model of the meter, I can tell you.

Steve

Expert:  Steve replied 2 months ago.

let me know if you need more help.

if not, please leave a POSITIVE RATING.

thank you,

Steve