Type B motors

[doctordoug]

Is it just me or do others out there think the balanced motor is an improvement for our Harley's? I like the fact that my Deluxe doesn't shake itself to death and I can use my rear view mirrors. I also like the smoothness at low rpm's, the sound is the same, the feel is different. The ride around town is better, to me, than my old Wide Glide. Could these models last longer with this new engineering? Why does everyone think the factory went to a balanced engine? Lots of questions, appreciate the thought and answers.:newsmile020:

 

[Hoople]

Could these models last longer with this new engineering?

No, the engine would not last any longer because the engine is not truly balanced. It is actually the same imbalanced engine made to feel balanced by using counterweights that are not pieced to the fundamental imbalance. Therefore the stresses of the imbalance would not be felt by the rider but they are felt by the engines main bearings because the counterweights are chain driven off the crank and are not directly attached to the crank.. All the stresses within the engine are still in fact present, but just not felt.

I have a friend who has a model B engine and yes it is truly amazing how "balanced" it feels. I never rode his bike, but I bet it is very enjoyable.

 

[pigrider]

While Hoople has a very good point about the engine itself the rest of the bike should last longer, you won't be back tracking down the road picking up pieces you forgot to loctite on.

 

[ultra...good]

Rode my cousins Goldwing a few years back and I couldn't feel that thing running. Didn't really care too much for that. On my Ultra you can feel the motor shake a bit when it is idling, but after that, you don't really notice it. Have never had the mirrors shake where i could not see out of them because of the motor, but my shoulders, well those have impaired my view a few times.
On my 74 XLCH, again, a different story. Anything above 1500 RPM and you cannot use the mirrors. A street with a grade, if you leave it idling on the kick stand it will walk itself right down the street.
I guess what I am trying to say is if i wanted smooth, i will either take my Caddy, or get a metric bike (yeah right).

 

[Breeze3at]

Why does everyone think the factory went to a balanced engine? Lots of questions, appreciate the thought and answers.:newsmile020:

The reason they went to balanced was to improve the comfort of, and insure the continued popularity of the Softail line. The rubber mount system can't be used on the Softails because of the frame swingarm design. So HD adapted the counterbalanced system that Japaneese mfg's. had been using since the 70's.

 

[eleft36]

The reason they went to balanced was to improve the comfort of, and insure the continued popularity of the Softail line. The rubber mount system can't be used on the Softails because of the frame swingarm design. So HD adapted the counterbalanced system that Japaneese mfg's. had been using since the 70's.

Detroit 2 stroke diesels have had this balance technology on all of their 53 & 71 series engines. The balance-rs are on the cam shafts it also offsets the torque effect.

Al

:USA
:CONNECTICUT

 

[Bud White]

also dont forget on average the B motor will make 3% less power than the Same A motor because for parasitic loss of the balancer setup

 

[eleft36]

also dont forget on average the B motor will make 3% less power than the Same A motor because for parasitic loss of the balancer setup

If you can actually feel the 3% power loss!:bigsmiley18:

May I suggest a 2 psi air increase in the rear tire to compensate for the parasitic power loss.:s


Al

:USA
:CONNECTICUT

 

[Bud White]

just stating the facts

 

[doctordoug]

No, the engine would not last any longer because the engine is not truly balanced. It is actually the same imbalanced engine made to feel balanced by using counterweights that are not pieced to the fundamental imbalance. Therefore the stresses of the imbalance would not be felt by the rider but they are felt by the engines main bearings because the counterweights are chain driven off the crank and are not directly attached to the crank.. All the stresses within the engine are still in fact present, but just not felt.

I have a friend who has a model B engine and yes it is truly amazing how "balanced" it feels. I never rode his bike, but I bet it is very enjoyable.

There are very few engines that are in true primary balance. Straight 6, flat 6 and v12 are the most common. Most automotive or motorcycle engines use balance shafts that hide the imbalance. If the balance shafts are tied to the crankshaft or not the imbalance is still only being masked, it is not eliminated in one case and not the other. I like the sound, ride quality and vibration I still get from my Deluxe. I seem to remember an engineering exercise that Lexus put forth that seemed to contend that a 4 cylinder in line engine with and without balance shafts had different life spans and running characteristics. I will find the article and post it because I am always interested in the why of engine design. My understanding is that a coupling of balancers to a crankshaft via chains actually does affect the stresses on the main bearings. I could be incorrect on this and I will do more research. Thanks for the thoughtful reply.

The reason they went to balanced was to improve the comfort of, and insure the continued popularity of the Softail line. The rubber mount system can't be used on the Softails because of the frame swingarm design. So HD adapted the counterbalanced system that Japaneese mfg's. had been using since the 70's.

My understanding is the MoCo went to the balanced engine in the softails because they are rigid mounted for looks and these frames don't have clearences for the engine to flop around. You can use an unbalanced engine in a softail style frame, this option is available from many aftermarket suppliers. There are tons of S&S engines in softail frames.

If you can actually feel the 3% power loss!:bigsmiley18:

May I suggest a 2 psi air increase in the rear tire to compensate for the parasitic power loss.:s


Al

:USA
:CONNECTICUT

I agree with you. I don't expect power or performance from my Harley. I never thought that this is what the average owner wanted. I expect terrific quality, killer looks and a wonderful riding experience that only a Harley can provide. I have had various models for over 50 years. If I want speed and handling I'll take my Ducati Streetfighter out for a spin. With 150 plus rear wheel horsepower I don't need to worry about parasitic horsepower loss, I need to worry about hanging on!:59: