1997 Harley Davidson Fowling Plugs?

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Clint G

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I have a friend with a 1997 Harley Davidson 883. He can ride the bike about 80 miles before the spark plugs fowl out with carbon deposits leaving him stranded. He runs the stock Harley plugs for the bike. He has also tried different makes of spark plugs to see if it wold help the problem. He has also had the timing adjusted and has changed the gap in the plugs several times but the plugs still fowl out. My friend carries a spare set of plugs to get home.

He has taken the bike to 3 different motorcycle mechanics including a Harley mechanic from a local Harley dealership. The mechanics could not figure out why the bike fowls the plugs. It has been suggested that he has had “bad gas” or that there is something floating around in the gas tank and that the he needs to get the tank cleaned. The bike as far as we know is in good mechanical shape with about 20,000 miles. Do you have any suggestions to help us find the problem causing the fowled plugs?
 
Make sure the air filter is clean and the timing is set correctly. If it is:

If the spark plugs are fouled with a sooty black, use a colder spark plug and/or go down one jet size on the main jet.

If the spark plugs are fouled with an oily black, do a compression or leakdown test and if it's within specs go to a hotter spark plug.

Also check the VOES and make sure the timing advance is working. And if the carb has an enrichener make sure it's closing when it's turned off.
 
Easy, It's either oil or gas. If it's oil you will see the bike smoking blue in the exhaust, If its gas, which I would bet, You may or may not see
any exhaust smoke, and if you do its brown. I really suggest you have the carbs checked. If he changed or had changed the intake or exhaust (air filter, air breather, exhaust pipes) and didnt adjust for it, Then this is it ! Also a dirty air filter, choke butterfly stuck part way on, or EFC/I computer adjustment is in correct.
If harley cant find this asap, you need another dealer !
 
if the deposits are black on the spark plug you are running too rich or your air filter is dirty good luck
 
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