Cam chest rebuild = lousy gas mileage???
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Tourer
Joined: Dec 2006
Posts: 329
Likes: 1
From: Oldsmar, FL
Cam chest rebuild = lousy gas mileage???
A couple weeks ago I had the innards in my cam chest replaced with all stock parts on my 99 RK. The engine is now a lot quieter, and the bike runs great overall. However, I noticed that my low fuel light came on a lot sooner than normal the first time I rode it. So, I started keeping track of the mileage. On the second tank of gas, I got a whopping 30 mpg. I've been keeping track ever since, and after about 5 or 6 tanks of gas, I got 36 mpg last time I checked. The bike used to get 40-42 mpg before the rebuild. It seems like it's getting better the more I ride it, but I don't get it.
Any ideas??
Any ideas??
Seasoned HDF Member
Joined: Apr 2006
Posts: 10,675
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From: Billings,Mt.
I copied this from another post,,,,,,,,,
Sumping (if you are not familiar with it): if the O-ring in the crankcase suction is not seated causing a good seal ... oil will accumulate in the crankcase .... This will rob the bike of power because the crank will be like a paddlewheel ... sometimes described like trying to run in a pool, waist-deep in water ....
Sumping (if you are not familiar with it): if the O-ring in the crankcase suction is not seated causing a good seal ... oil will accumulate in the crankcase .... This will rob the bike of power because the crank will be like a paddlewheel ... sometimes described like trying to run in a pool, waist-deep in water ....
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Tourer
Joined: Dec 2006
Posts: 358
Likes: 24
So does that mean the oil will smell like fuel and more important, what is it doing to the oil? I would assume it's breaking it down rather quickly, no?
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Extreme HDF Member
Joined: Sep 2005
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From: Baton Rouge, LA
Poor mileage would be a symptom of sumping but the OP said his bike runs "great." Performance should also be down as well as an increase in heat if sumping was occurring. I wonder if the repair facility made some changes in the tuning. If so I assume something would show-up on the invoice, as they won't do anything like that for free.
Thread Starter
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Tourer
Joined: Dec 2006
Posts: 329
Likes: 1
From: Oldsmar, FL
Poor mileage would be a symptom of sumping but the OP said his bike runs "great." Performance should also be down as well as an increase in heat if sumping was occurring. I wonder if the repair facility made some changes in the tuning. If so I assume something would show-up on the invoice, as they won't do anything like that for free.
Only other thing I can think of, is that the new parts are actually causing the motor to run a little differently and that maybe the bike needs to be re-tuned. It has an old PCII in it, and it was dynoed a couple years ago. I have reason to suspect the parts that were replaced were worn out back then. So maybe that's the problem also.
And, as I said, I got 31 mpg on the first tank of gas that I checked. But 4 or 5 tanks later I got 36 mpg. So, the whole thing is a mystery to me so far.