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Shovelhead
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Discussion Starter #1
I was talking to a mechanic at the dealer about installing the 103 cu. in stage III kit on my 09 FLHX verses boring my original cylinders and buying after market cams, push rods valve springs etc. He told me...... get this. He said that the block on the touring models is different than the FX models and that the touring model blocks won't hold up to the stage III as well as the FX blocks will. He said that Harley uses an A and B block on these two models? Has anyone else heard of this?
 

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Just passing thru
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Yes and no. The B block stands for counterbalanced. The touring models are not counterbalanced but they are rubber mounted.
 

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I {Heart} Hookers.
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31,321 Posts
In 2007, Harely introduced 96B engine, that has a counterbalancer.

The 96A engine does not.
 

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Shovelhead
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391 Posts
Discussion Starter #4
What's you opinion on them holding up?

I know of many, many friends that have done the Stage III with out any problem.

I remember something else that the mechanic said...... that they use a heavier bearing in the FX models?
 

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I {Heart} Hookers.
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31,321 Posts
HD stopped using the tapered bearing for a while and went back to it in some models. It's stronger and more desirable. Lasts longer and takes a load better.

As for a counterbalanced engine: Generally, they don't take the abuse because the block is weaker due to now housing another shaft, and the counterbalancer is the weak point, as it's small bearings and shaft diameter become an issue at high RPMs and hard loads on the Harley engine.

It's not to say it can't be done, but it's one more thing to consider as it's a known failure point.
 

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Road Glide
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348 Posts
HD stopped using the tapered bearing for a while and went back to it in some models. It's stronger and more desirable. Lasts longer and takes a load better.

As for a counterbalanced engine: Generally, they don't take the abuse because the block is weaker due to now housing another shaft, and the counterbalancer is the weak point, as it's small bearings and shaft diameter become an issue at high RPMs and hard loads on the Harley engine.

It's not to say it can't be done, but it's one more thing to consider as it's a known failure point.
A friend of mine has a 124ci S&S in stock HD cases on his 00 Heritage. Only problems he has had are S&S's ability to assemble it properly and remember to use loctite. Once they supplied the parts and he built it all is OK.

1984 FLHS if you have an 09 bike it's a 96ci. By installing the big bore kit you get 103ci ( I'm pretty sure ). If you buy a factory motor it meets all the EPA BS, cheaper and faster if you or a tech builds your motor. I think you will be surprised what a set of cams and a BB can do, provided it's set up right.
 

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A friend of mine has a 124ci S&S in stock HD cases on his 00 Heritage. Only problems he has had are S&S's ability to assemble it properly and remember to use loctite. Once they supplied the parts and he built it all is OK.
I've heard that about S&S as well. The parts are good, but you can't trust their assembly procedures.
 

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Shovelhead
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391 Posts
Discussion Starter #8
Ya the stage III is a 103 cu. in. So is what you are saying is that I should just try cams first rather that the bi bore.

I can't understand why HD would both with 2 diierent blocks with one known to be weaker.
 

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Shovelhead
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391 Posts
Discussion Starter #9
A friend of mine has a 124ci S&S in stock HD cases on his 00 Heritage. Only problems he has had are S&S's ability to assemble it properly and remember to use loctite. Once they supplied the parts and he built it all is OK.

1984 FLHS if you have an 09 bike it's a 96ci. By installing the big bore kit you get 103ci ( I'm pretty sure ). If you buy a factory motor it meets all the EPA BS, cheaper and faster if you or a tech builds your motor. I think you will be surprised what a set of cams and a BB can do, provided it's set up right.
Ya the stage III is a 103 cu. in. So is what you are saying is that I should just try cams first rather that the bi bore.

I can't understand why HD would both with 2 diierent blocks with one known to be weaker.

FKKED that last post up!!
 

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I {Heart} Hookers.
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I can't understand why HD would both with 2 diierent blocks with one known to be weaker.
It's not that it's "known to be weaker" rather, just isn't a good candidate, statistically, for big bore applications, and the A-motor is better for that.

The B-motor was designed for a smoother ride and less vibration. That's what a counterbalancing shaft delivers.

The Mitsubishi 2.6 motors of the mid 80s to early 90's had a counter balancer in them. It was the common failing point for them, especially in the Turbo cars, like the Conquest. The other failures were head gaskets, but that was unrelated.

Not saying you CAN'T do it, but if there's been issues with other cases, then why take the chance of dumping hard earned money into something that may not yield the results you're looking for long-term?
 

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HD stopped using the tapered bearing for a while and went back to it in some models. It's stronger and more desirable. Lasts longer and takes a load better.

As for a counterbalanced engine: Generally, they don't take the abuse because the block is weaker due to now housing another shaft, and the counterbalancer is the weak point, as it's small bearings and shaft diameter become an issue at high RPMs and hard loads on the Harley engine.

It's not to say it can't be done, but it's one more thing to consider as it's a known failure point.
I think where most people see issues with on built up B motors is when they spin them up quickly at high RPMs then use engine breaking to slow it down. There's a local drag bike builder/dyno guy that takes B motors up to 7k regularly, and as of the last time I've heard, he hasn't seen a counterbalancer shell out. I agree tho, that it is another link in the chain that you have to think about.

Right now, I have my rev limiter set at 6200 rpms, I think most builders would agree that 6200 is a safe limit for the B motors. If I ever have to tear into the motor, I am still debating on whether I want to keep the counterbalancers or not and raise my rev limiter to 7k rpm. Until that time, I'll keep my eyes and ears open for ways to strengthen the counterbalancers so that will be a non-issue. I'm getting kinda used to how smooth the B motors run. :D


In regards to the crank bearings, there's conversions available to retrofit the '03+ A/B motors to the stronger Timken bearings. I'm still running stock bearings in my bike. But like I said above, if I ever need to get into the motor again and mod it for more horsepower/higher RPMs, I'll do the Timken conversion.

'Course if I had a Sporty project bike, I'd be building that up and not be concerned about crank bearings and counterbalancers. :lol8
 

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Ya the stage III is a 103 cu. in. So is what you are saying is that I should just try cams first rather that the bi bore.

I can't understand why HD would both with 2 diierent blocks with one known to be weaker.

FKKED that last post up!!
What kind of HP/TQ numbers are you looking for? So far, I haven't read anything that would cause concern about you running a "B" motor.
 

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Shovelhead
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391 Posts
Discussion Starter #13
What kind of HP/TQ numbers are you looking for? So far, I haven't read anything that would cause concern about you running a "B" motor.

That's just it, the numbers aren't that high for the stage III kit's
100hp/110tq and the HD mechanic is not recommending this for my 09 FLHX. However they sell the kit. Any recommendations?

Thanks for all the knowledge guys.
 

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Well, as you can see from my sig, thats about the numbers I'm running.
 

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Shovelhead
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Discussion Starter #15
Well, as you can see from my sig, thats about the numbers I'm running.

From what I amt told though, your Night Train is an A motor right? The mechanic told me FX models A FL model B??
 

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From what I amt told though, your Night Train is an A motor right? The mechanic told me FX models A FL model B??
Nope, TC SoftTails have a "B" motor.

Your mechanic should have said "FXD models have the A motor". FXST models have the B.
 

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Road Glide
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348 Posts
Ya the stage III is a 103 cu. in. So is what you are saying is that I should just try cams first rather that the bi bore.

I can't understand why HD would both with 2 diierent blocks with one known to be weaker.

FKKED that last post up!!

No, there is no substitute for capacity. if it were me I'd go big bore up to 103ci. you can even have your 96ci jugs bored. Cams help as does flowed heads. Power costs money, how much do you want to spend ? There's about $1000 in the heads on my RG, cams with gear drive, then you need to decide how your going to adjust the fueling, I've got the SE race tuner, not cheap but it seems to do the job.

The balance weights on the B motor limit the rev's it can do, but how hard do you want to rev a big twin. MY Rg makes over 1000 HP and torque, but I rarely go over 5000rpm.

Deb's Ford mini van has a 2.3 Cosworth in it, that has balance shafts in the oil pan
 

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Shovelhead
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391 Posts
Discussion Starter #18
No, there is no substitute for capacity. if it were me I'd go big bore up to 103ci. you can even have your 96ci jugs bored. Cams help as does flowed heads. Power costs money, how much do you want to spend ? There's about $1000 in the heads on my RG, cams with gear drive, then you need to decide how your going to adjust the fueling, I've got the SE race tuner, not cheap but it seems to do the job.

The balance weights on the B motor limit the rev's it can do, but how hard do you want to rev a big twin. MY Rg makes over 1000 HP and torque, but I rarely go over 5000rpm.

Deb's Ford mini van has a 2.3 Cosworth in it, that has balance shafts in the oil pan

I won't be needing 1000hp.;) I already have the SERT, true duals and heavy breather. My next step as I said at the start of this thread is a HD stage III kit or after market cams 103 big bore etc. Just confused on the A/B block and why the HD mechanic would tell me this. It looks like from what I'm learning here is that for what I'm looking for my B block will work.
I will more than likely instal non HD parts.
Thanks
 

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Road Glide
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348 Posts
I won't be needing 1000hp.;) I already have the SERT, true duals and heavy breather. My next step as I said at the start of this thread is a HD stage III kit or after market cams 103 big bore etc. Just confused on the A/B block and why the HD mechanic would tell me this. It looks like from what I'm learning here is that for what I'm looking for my B block will work.
I will more than likely instal non HD parts.
Thanks
When I did my 01 Heritage, I just went up to 95ci ( it already had SE mufflers and air filter ). I stripped the valves out of the heads and just cleaned up the ports a little and lapped in the valves ( this doesn't get done in production ). I also mounted the inlet manifold the the heads while the valves were out, surprising how many of them don't match the inlet port and you can blend it in. Simple and inexpensive, but makes it more efficient.
 
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