2004 Road King
50,000 miles
stock TC88 except for slip on exhaust

I'm getting about 30 mpg after a routine service. I used to get 40.

I needed to get the cam chain tensioners replaced at 48,000 mile, so I decided to take it to a HD dealer and do a 50K service at the same time. The dealer recommended I put in a cam chest kit. (I think that's what they called it.) The kit consist of tensioners, chains, cam plate, oil pump, stock cams, lifters. Basically everything in the cam chest.
The 50k service was uneventful except for an in-tank fuel line that needed replacing. I also put on some chrome fork lowers.

Now it gets 25%+ lower mileage than before the service. I checked the crank sump. Minimal oil came out. The plugs look the proper tan color. No trouble codes. Dealer says they didn't change the MAP. Bike runs fine. The dealer says to watch it over a few tankfuls, I have. The last tank was in-town and ended up 29 mpg.

I'm not sure if the original cams were stock or not. (I bought the bike used.) One original cams say BB and some 2 digit number I can't read and the other says A and 85. There is an A stamped on the end at the bearing area.

Anything else I can check or do I just accept it and move on. I plan on talking to the dealer again, but I am not expecting much to come from it.

I've got a 4,000 mile trip coming up and if there truly is something wrong, obviously I want it fixed.

Kyle

 

I had the same exact thing happen on my '03 RK at the 45,000 mile service. According to the mech not a single thing was abnormal about the service. I went from 40-43 mpg to 33-36 mpg. The mechanic can't explain it and said he had never had one brought back because of worse mileage after a service......I replaced the plugs he put in ( HD with HD) and replaced the HD air filter he put in with a K&N. Everybody I confer with blames it on the ethanol in the gas......but if that's the problem, Why did it start the day I rode out of the shop??? I still buy fuel wherever I'm at when I need it.....

 

Try checking the spark plugs. Maybe one or both are poorly gapped.

 

These are the kind of things that drive us all crazy. It was fine before & now it's not. If you find the problem please get back to us. thanks & good luck

 

Your situation's now got me scared. I was going to have the same thing done (except for new cams) on my carbed 2000 EGC which normally gets 48-50 mpg! I would think that new stock lifters alone would slightly increase gas mileage, not decrease it.

 

So if i'm reading this correctly,the fuel dropped after the tensioner work?
Sounds like something is not right with the major work.
A regular 5,10,15 thousand mile service should not change anything.

 

Check your oil level to see if it is low. There may have been a problem when they installed the oil pump and the engine may be "sumping". In other words, it's not scavenging the oil out of the crankcase properly and oil is pooling in the bottom of the case. The flywheel then has to constantly turn through a pool of oil, causing additional drag. . If your oil level is down, then what your missing is probably sitting in the crankcase.

 

The oil level is OK. In fact, I pulled the crankcase plug and very little oil came out.

 

If the cam timing was off in some way, would that affect mileage?

Is there a way to verify the cams were installed correctly?

 

I don't think it would run very good if the cam timing was off. Seems it would be noticeable.