General 96" TC info

[alakso]

Greetings Mike. I have a few questions for you about the 96" TC motor.

Bottom End:
How do you feel about the 4.5" stroke for the 96" TC motor considering engine durability (Rod Bearing life), reliability, and piston speed at 6K RPM?

Sprocket Shaft Bearing:
Do I have the SE heavy duty "lefty" sprocket shaft bearing already installed from the factory on my mid-year '08 96" TC FXDF Dyna?

How much RW TQ can the SE heavy duty "lefty" sprocket bearing handle?

Cases:
How much increased bore can my cases cylinder spigot bores handle before they become to weak around the cylinder studs?

Cylinders:
I saw in a post on this forum that the 4.250" bore cylinders for the TC motor caused some problems with piston rocking resulting in poor ring sealing and poor cylinder life.

What is the reliability of the 4.000", 4.060", and 4.125" cylinder bores considering piston rocking, ring sealing, cylinder cutouts and loss of piston skirt for piston to piston clearance?

Cam chest:
Should I replace my stock TC inner cam bearings with the Torrington inner cam bearings? And if so what is the Torrington part # for these Bearings?

Heads:
What is the combustion chamber cc's for the SE Pro Kompressor heads?

What are the valve sizes for the SE Pro Kompressor heads?

What is the CFM flow for the stock SE Pro Kompressor Heads?

What would be the corrected compression for a set of SE Pro Kompressor heads on a '08 96" Dyna w/stock flat top pistons with a cams intake closing of 40 or 42 degrees with an .030 head gasket?

Will I need ACR's installed in these heads if my corrected compression is 9:1 or a little less and my mechanical compression ratio is around 10:1 give or take a little?

Intake:
What is the stock TB size for my mid-year '08 96" Dyna?

How much CFM does the stock 96" TC TB and intake flow?

EFI remapper:
Mike, with you having experience with both the SEPRT and the TTS Master Tune remapping software which EFI remapper would you suggest for my applications?

Will both of the above EFI remapper allow readjustmet of speedo for different gear ratios i.e., 30 tooth Trans. sprocket?

Thank you for your time and consideration Mike, I appreciate it very much!! Alakso

[Mike]

For comparison, max 6k piston speed for 4.00 stroke (stock TC 88) = 6494, 4.375 (stock TC 96) = 7148, 4.625 = 7590, while 4.5 = 7368. Rod ratio = 1.917/4.00, 1.704/4.5, 1.752/4.375 and 1.658/4.625 (Axtell 124). Piston speed will equal stroke X 1000 at 6k. As piston speed goes up and rod ratio goes down, piston stability (life) suffers. Average piston speeds below 4600 are generally considered acceptable. Piston side loading may be more important to longevity. Lower rod ratios increase side load. Longer stroke and/or bigger bores decrease piston skirt area. Generally, the 4.5 stroke is considered Ok from a life standpoint.

You should have the "black" heavy bearing but I cannot 100% confirm this. The real world max tq capacity is still unknown but we recommend the Timken conversion with expected numbers above 130 ft lb.

Case boring to 4.312 is considered max (Axtell 4.125 bore cylinders). You also risk cutting into the oil returns and case dowel o-ring grooves with larger bores, depending on stroke/cylinder spigot lenght.

Some cylinder manufacturers consider the 4.250 bore to be too unstable with respect to rear piston skirt lenght. When combined with short rod ratios, piston life is VERY short with a real risk of piston roll over in the bore. Add Nicom cylinders and short spigots (to keep case bore to minimum), all make for a questionable combo.

Any of the listed bores can be very realiable based on the stroke used. 4.125 bore on a 4.00 stroke is extremely reliable but not so when used with a 5.00 stroke.

With cams over .550 lift and heavy valve springs, the torrington bearings would be recommended. 99-06 TC are B-148 and 07L (06 dyna) are B-168.

The Kompressors are advertized at 76cc. They use stock valve sizes. Do not have CFM values. Based on a 10.5 compression (.030 gasket), corrected would be 9.7 at 40 deg.

Compression releases are recommeded for corrected pressures above 9.5.

Stock t-body is 46mm and flows approx 274 @22in.

We recommend TTS master tune over SEST/SERT when a larger throttle body is to be used. Especially on ETC bikes.

Only TTS has the speedo correction feature.

[alakso]

Thanks Mike, GREAT INFO!!! And sorry for asking some questions here that should have been asked under a different topic. I'll repost those questions under the correct topics so we can continue the discussion on those questions there. Also let me say how much I appreciate your help.

Mike, I'm curious as to why max piston speed goes up with stroke?

I would like to keep piston speed at 4500 so it looks to me like the 4.5" stroke would be the max that I would want to run.

With the 4.5" stroke what would be the piston speed for short bursts to 7K?

Would you be so kind to briefly explain rod ratios and piston side loading and how they relate to longevity?

Mike, when it comes to making serious power it's true that "bigger is always better", but it's also true that "The biggest isn't always the best". So for me it's always been very important to have a very efficient well tuned engine no matter what size it is. With that in mind and from your experience with countless dyno runs, and real world results and with all things being equal are there any bore and stroke combinations that are more efficient and produce more HP/TQ per cubic inch than other bore and stroke combos?

Mike, which of the following bore and stroke combos would you prefer that are very reliable, durable, and capable of making serious power with the right set-up?

4"x 4.375" (110 ci)
4"x 4.5" (113 ci)
4.125"x 4.375" (117 ci)
4.125"x 4.5 (120 ci)

My first inclination when I got my bike was to try and square up my motor as much as I safely could by just adding a bore increase. Mike, is there a performance advantage to squaring up a TC motor?

Mike, how much rear wheel TQ can the stock 96" TC rods handle?
How much RW TQ can the SE rods handle?

How much RW TQ can the '08 "press together" 3-piece flywheels take before they'll shift?
How much TQ can the SE wheels and rods handle?

I've run my bike pretty hard this past summer and haven't had any problems with the oil pressure light coming on or even flickering so hopefully my bottom end was done right and the MoCo has resolved it's crankshaft issues.
Mike, are the '08 cranks assembled in China?


When you say upgrade to the Timken Bearing for expected TQ above 130 ft. lbs. do you mean 130 TQ at the Rear wheel or at the Crank?

Mike, please feel free to correct me if anything I've written or believe to be true isn't. The only way I'll learn is if knowledgeable people like you educate me.

Thank you for your time and help Mike.

[Mike]

For a given rpm, piston goes up with stroke because it has to travel a greater distance (stroke) in the same amount of time (rpm). Max piston speed at 7k for a 4.5 stroke is 8596 with 5250 average. Bursts to 5000 or even 5500 are considered acceptable, in street applications.

Piston side loading, in a H-D motor, is a function of rod ratio, wrist pin offset, wrist pin location, operating rpms and piston skirt area. Rod ratio's around 2:1 (rod length devided by stroke) are (by some) considered ideal. With frame, motor height physical constrants and available rods this can rarely be achieved. As the ratio gets smaller (increasing stroke without increasing rod length), the angle of the rod to cylinder bore (crank pin/pistonpin) gets greater. This results in the rod trying to push the piston into the cylinder wall (side loading). Severe ratios (1.5) can cause the piston to push through the oil film (scuffing). Offsetting the wristpin can help to reduce side loading (our 110 pistons have this feature). Coatings also help reduce scuffing potential. The closer the wrist pin is to the dome also helps but this is dictated by ring grooves, dome heights and rod end size. Piston skirt area is also a problem in H-D motors. As bore size and/or stroke increases, piston to piston clearance near BDC decreases, neccessitating greater cutaway on the rear piston for the front to pass (rear is cut because the cut will be on the non-thrusting {under load} side). Stroking further reduces skirt area on both piston sides to clear the flywheels at BDC. Thrusting a piston with little skirt load bearing area into the cylinder wall, with reduced oil film strength while running at high speeds results in extremely reduced piston, cylinder and rod bearing life.

So the ideal would be a rod ratio around 2:1, offset wrist pin, pin as high in the piston as possible, coated, little or no skirt cutting and operating rpms that result in 4500- average piston speeds. We actually built an AMA Pro-Thunder motor with similar design criteria. It ran at 9000 rpm very happily. Unfortunately, for most applications, much of the above has to be compromized in some way.

We would want any of our motors to be well optimzed and so the bigger motor would have the advantage, all things being equal. Longevity wise, a small motor in an indurance race may not live much longer than a large motor because it has to work harder (rpms) to do the same job. Another way to look at it is that you can build a big motor and slightly detune it to live longer, if it will satisfy the hp target in that detuned state. Most racing involves class rules dictating motor size so this is not always an option. Another thing to consider is that a larger motor is generally going to less effecient just from a friction and parisitic loss standpoint. I.E., hp/cube goes down as motor size goes up (at least for 45 degree V-twins and most other platforms)or becomes increasing difficult to maintain. But big motors make power by virtue of size alone. Obviously, a 113ci motor making 1hp/cube (113) will outperform a 80ci motor making 1.4/cube (113hp) because of its tq adantage. Both may similar longevity because the 80 will be more highly stressed in order make that higher hp/cube number. Tune the 113 to 1.4hp/cube (giving 158hp) and you'll have a motor that will be less lived, vs the 80, due to the higher stress loads and in-effeciencies.

My personal preference is to try and build motors with the largest bore possible. This opens the cylinder up for greater valve diameters, more ring groove clearances (for valve pockets), better cylinder fill (more open, but also takes more time to fill), less valve shrouding and typically results in less stroke for a given motor size. Looking at it from a physical viewpoint (rod ratio, piston skirt, available parts, ease/cost of build, etc), the 4.125/4.375 looks the best. Real world experiance also bears this out, the 117, historically, has proved to be a very "happy" motor combo.

I cannot give diffinetive numbers on what the cran and rods will handle but what I can say is when we get in the 130-140+ tq (rear wheel) we like to see the pin "pro-lugged" and welded (Darkhorse crankworks). Shifting can also be a function of how the bike is riden (or abused). Sudden stopages due to burnouts, bogs or accidents can shift the wheels. I've never heard the "china" rumor and strongly suspect its false. All numbers I've referenced are rear wheel and based on dyno testing using 5th gear with STD corrections.

A really good series of books regading much of this info are those by William Dennish, "The V-Twin Tuners Handbook". Worth the investment.

[alakso]

Thanks again Mike.

I understand that piston speed goes up with stroke. I guess what I'm wondering is how to put the "max" piston speed into context. Does "max" mean at what speed the piston melts down? Wouldn't the "max" piston speed be the same for all strokes? Having a hard time wrapping my head around the "max" piston speed concept, HELP?

Wow, thanks for the info on piston side loading and rod ratios.

Mike I really appreciate your thoughts on a reliable, durable, performance TC engine size. I had kinda been leaning to the 117" engine size as a happy medium. I even emailed Axtell a couple of weeks ago for info on their 117" Mountain Motor. I also told Mr. Baisley a few weeks ago in an email I might be leaning towards the 117" engine size.

Mike your info has really changed my paradime!! I was told by some big name shops that I should upgrade to Timken at 110 TQ. But now I learn the SE black lefty Bearing is good to 130 TQ. But to be fair they might have been talking about the stock HD lefty sprocket shaft bearing and didn't know what the SE black lefty sprocket bearing was capable of. Plus as you stated the rods and wheels are good to 130 TQ also. Now let me ask you a question Sir:

How much TQ can the rear belt safely and reliably handle?

Mike, now lets look at engine size in terms of HP/TQ needed. I think 120-125 HP/TQ would be a good number to shoot for a reliable, durable, performance TC engine build. It seems to me once a person gets over 130 TQ that the price and work required goes up quite a bit when you throw in Timken, Darkhorse crank, rear chain drive, heavy duty clutch, etc., etc..

Now lets look at our 117" motor build. I would think 120-125 HP/TQ would be easy for this motor when set-up right with a good tune. So is the 117" to much motor for a 120-125 HP/TQ target? It just doesn't make sense to me to pay for HP/TQ and leave it on the table, or to "de-tune" as you suggested. So mike if the 117" is to much motor for my target 120-125 HP/TQ target how do you feel about the 110" motor size? Would the 110" motor size be working to hard to make 120-125 HP/TQ? I would think that the 110" size would be almost stock-like in reliability and durability? Or would the 4.060"x 4.375" (113") engine size be perfect for a 120-125 HP/TQ target?

I read the so-called "China rumor" online at the V-Twin forum. But as a consumer it made perfect sense to me, especially with all of our recent quality control problems that have been coming from China. So with it being common knowledge that the MoCo. has been having crankshaft issues it's not a big leap to think the MoCo has outsourced some things to China. After all the MoCo has been using foreign parts since the 70's. If outsourcing to China isn't the source of the MoCo crankshaft issues then I'm more worried that there is a QC problem with the MoCo factory here.

Has the MoCo resolved it's crankshaft issues?

Thanks for the info on Mr. Dennish's books. I've read some excerpts from his HD performance series online and it is great stuff, but not much on the TC 88 or anything on the TC 96 but they do have a lot of great theory! They are on my list of must have books. I've contacted Andrews Products to see if these books are still available and the prices. I've also purchased Mr. Bill Rook's book "How to build an HD TQ Monster" which I'm really enjoying. Mike, I'm really enjoying learning the finer points of the V-Twin engine performance from you and appreciate all your help Sir!

[Mike]

Thank you for the kind words.

Max piston speed referred to is the maximum speed the piston sees during a full stroke. The speed varies with crank rotation as the piston slows to TDC/BDC. Max speed is achieved when the rod centerline is at 90 degrees to the crank pin/shaft CL and also changes with rod ratio. Short rod motors will have higher max piston speeds vs long rod for the same stroke and rpm, even though average speed will be the same. Piston dwell time at TDC also will be different short vs long rods with dwell times greater for long rods. This can be important for cam and intake considerations.

The rear belt is somewhat an unkown at this time. H-D has been reducing it's width over the years but also improving it's strength. Depending on how the bike is used, the belt may be just fine for 150 ft lb or more. If it is going to see a lot of shock loading (I.E. burnouts, dragracing), it will not hold up. For everyday street riding with the occasional fast acceleration, it maybe OK.

Some engine builders like to recommend the Timken conversion for almost any build just to err on the safe side. Other than added cost, there is no real downside. Over 130 ft lb the world does start to change. This is something of an arbitrary number in the sense that it is not based on specific scientific data or testing but based on real world experiance and observation.

I cannot say the 117 is "too much motor" for 120-125. It would be very happy at those demands. Having said that, the 113 would be adequate. Since both are based on the same stroke, reliability would be similar. It'll just be easier for the larger motor to hit those target numbers (better for the motor builder/tuner, more likely to achieve the customers expectations).

We have not seen the crankshaft shifts that seemed to occur earlier. It could be the problem has been addressed or that it comes in batches. This too could be a result of individual riding habits and is not indemic.

Baisley stocks copies of Dennish's book. The guy doing the wheelie on the cover of Rook's book is a good friend of mine. I helped configure that motor years ago (along with Baisley), the owner did all the mechanical and has since. He's locally famous for those wheelies and the number of freinds in his win photo's.

[alakso]

Thank you again Sir.

Mike, have you met or do you know Mr. Rook in Alaska? Very cool that the guy on the cover of Mr. Rook's book is a friend of yours. He must be a great guy because as you said he invites all his friends into the winners circle with him.

Called Baisley HP yesterday to see about ordering Mr. D. William Denish's "Performance Pro Series" which consist of three books:
1) Big Twin High Performance Guide
2) V-Twin Tuners Handbook Vol. I
3) V-Twin Tuners Handbook Vol. II

I talked to Baisley Hi-Peformance about purchasing Mr. Denish's books. But unfortunatley they only have the "V-Twin Tuners Handbook Vol. I" in stock. The person I talked to said Mr. Baisley was going to contact Mr. Denish about getting more books. Now that's great news because I did some web searches for Mr. Denish's books and all I could find was used ones for $90 and up, OUCH!!! So Mike if you know of anyone else who has these books for sale besides Mr. Baisley then please let me know.

You bring up some good points about an engine size that will make 125 TQ.

Mike, how much CFM would a 117" motor need to make power to 7K RPM?

What would be the ideal valve sizes for a 117" motor?

With the right cams, exhaust, and tune what kind of power could one expect with a 117" Baisley Hybrid or Pro-Street Head build?

Which SE AND S&S Heads would be perfect cores for Mr. Baisley's Hybrid or Pro-Street head work?

Will the SE 110" Heads work for a 117" motor?

[Mike]

Know Mr. Rook only through his book.

As far as head flow numbers, valve sizes and applications, I would defer you to Baisley. They would be the source for any info I would offer.

As far as hp numbers. We've made 144tq/hp with a 5 speed , 04 Road Glide 117 with Prostreet heads. This bike was VERY happy and we've seen few others do the same. Normally we would expect 135-140 and with Hybrid heads, maybe 10 more.