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Brian D
Brian D, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 536
Experience:  35 Years self taught shop owner, mechanic, Dyno tuner, electrical expert
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oil change using 20-50 Screaming Eagle synthetic.

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Hello. I have a 2008 FLHT with 6200 miles. I did an oil change using 20-50 Screaming Eagle synthetic. Replaced oil filter as well. I also put on some Screaming Eagle slip on mufflers. I also replaced my spark plugs do to some slight rusting around the plug nuts do to KY humidity. Didn't need to, just didn't like the look. Bike ran fine for about a week. Then RPM's went up from about 750-800 to 1000-1100. Also at that idle speed, my engine oil light comes on. I definetly have enough oil. Check at hot and cold levels. Now my engine runs rough at 2000-2500 RPMs. Of course my warrenty expired last month. Can you help me? Mike
Mike, Welcome to just answer. you need to check the intake for a vacuum leak around the clamp that holds it to the heads. best way is with bike warm and idling spray wd-40 around the intake clamps if idle changes you have a leak and need to replace those seals. this would cause the idle to raise and the rough running at low rpm's.
what kind of plugs did you put in when you replaced them? did you check the gap before you installed them?
the oil light could be a bad switch, but do you have an oil pressure gauge on the dash?
if you do does it read anything at idle?
what kind of out side air temps are you running in?
if you don't have the dash gauge you may want to have the oil pressure checked before jumping to any conclusions.
Mike check these things and get back to me. we will get to the bottom of this.
thanks Brian D
Customer: replied 7 years ago.
Hello Brian,
I will check the intake as soon as I get home from work. I used H-D plugs and checked the gap to the manuals specs. I will pull them again this evening and recheck. I do not have a gauge on my dash. Just the "idiot light". I plan on dropping the bike off at a local shop tomorrow and have the oil pressure checked. Hopefully it's the switch not a pump. Funny thing is when the engine is cool at idle, no light. Once it gets to operating temp, light ces on at idle. The outside air temperature here in KY is about 95 with 80 percent humidity.
Mike, check that intake and if that is leaking have them do the seals also. if that leaks it will cause it to run lean and in turn makes engine run hotter than normal. this could cause the oil to thin out enough to not hold pressure at idle. with 6200 miles there should be no problem with the engine or oil pump, so if they want to tear it down for any reason unless they are paying the bill i would not recommend letting them. let me know what you find. Brian D
Customer: replied 7 years ago.


Took your advice and gave the intake a good once over and I even rechecked the gap on the plugs. Plugs are gapped correctly. Nothing as far as a leak from the intake tubes/housing. However, I noticed some carbon on top of one of the jugs next to the air filter bracket. Upon further inspection, I found both of the nipple valves that hold the air filter bracket in place were loose. I tightened the valves, started the engine and low and behold no oil light and smooth idle. As smooth as a Harley could anyway. Thank you for your help. I am sure I will recommend your service to others. Sincerely, XXXXX XXXXX XXXXX, KY ARMY National Guard

Mike glad to help if you feel that i have help in the finding of you problem please accept this as my answer. that is what keeps us here for you when you need us. Thanks for using just answer. Brian D
Brian D and other Motorcycle Specialists are ready to help you
Customer: replied 7 years ago.


Thanks again for your help. Mike

Thanks for the accept. if you ever need any more help we are here for you. Brian D
Customer: replied 7 years ago.

Will do.