I was just wondering, what is the differance between an 88a and an 88b engine? I have noticed that dynas are an A and the rest of Harley's 1450s are B.

 

The B is for the balanced engine. The Dynas are rubber mounted and don't need "balancing".

 

Technically there is no "A" engine only TC88 and TC88B and as of '07, TC96 and TC96B. As mentioned the "B" engine is a balanced engine. The "B" engine is only available in softail frames. The Touring and Dyna chassis all use TC88 or TC96 rubber mount engines.

 

Thanks for the info guys!

 

The B doesn't vibrate as much at idle. I think I would miss the shake. I love the way the dynas shake until you accelerate.

 

Also, I understand that the B motor redlines 1,000 revs lower than the non-B motor. Not sure of this though.

 

Harley recommends not exceeding 6200 RPM's with the "B" engines. Technically, the non-balanced TC engines shouldn't exceed 6200 either since they have cast pistons. In stock form, they have the same red line. If you build the engine and use forged pistons, the "B" engine still should not exceed 6200 RPM's but the non-balanced can exceed 7000. If you build either engine using Cast pistons, the engine should not exceed 6200.

 

The "B" is for a BALANCE SHAFT. It doesn't mean the engine is balanced like a race engine to within .5 gram.

The balance shaft is a 1/2 order cancelling device. It runs off of the crankshaft and rotates opposite cancelling out the normal vibrations of a twin cylinder engine in the case of the HD.

A lot of engines have balance shafts...2.4L Mopar, 1000cc Arctic Cat, 3.8L FWD Taurus and Windstars, lots of Japanese cars, etc.

B engines have a rev limit because the shaft would leave the crankcase.

I almost went with a 07 Softail Custom because of the B engine, but I love the DWG to much. The rubber mount has it's negative too, but the future for my bike is brighter without a balance shaft.

 

So that explains why my left grip and mirror jumps up and down at stoplights on my WG I love the vibes though - that's why I love Harleys so much - they are "alive" and not just an electric buzz...

 

I always knew the balanced and rubber mounted part of the difference, but on the harley website the dynas, softails and baggers all have different torque numbers. Are all three just tweaked a little different or something?