Hello all,
I have started planning for this winters engine work, I want to increase the displacement of my 2002 TC88 beyond the magic 1700 cc. Well, to me that would be magic at least

I have already considered the S&S 4.5" stroke 106" kit, and the all bore 4" stroke 4.125" bore option.

But now another option has dawned on me, 4.375" stroke and 3.937" bore resulting in 107"

This seems like a nice compromise, no case boring and 4.375" wheels seem more easily available.

So now to my question. Both 88" and 96" twin cams seem to have the same rod length, 7.667". In my head this means that if I go with a 4.375" stroke flywheel I can use pistons designed for the 96" engine. Either 3.875" bore for 103" or 3.937" for 107". I could use both OEM Harley/SE pistons or aftermarket performance ones.

Is this correct or am I missing something?

Thanks in advance

 

Better check compression height of pistons to be used and cylinder length
Early TC (99-06 except 06 dyna) flywheels have the 7.667 rod length. 07 up 96" and 103" have a shorter rod length i believe. Not sure exact length. I ran into this issue when building my first 117 on a 99-06 s&s flywheel using 07-up s&s cylinders and pistons. Ended up pistons about 0.008 proud. So I just used 0.040 head gaskets.
Last one I built using custom base gaskets

 

The 96 engine is a stroked 88". Though I am not sure you can swap parts. I know many of the stuff is different on 88s and 96.

You could bore to 95" and get crank, which would get you to 103" People have been boring over 95" or getting bigger after market cylinders.

 

First off a 96 ci crank will not fit in a early motor unless you want to custom space a solid primary gear.

Second, depending on the crank chosen you may be limited in certain pistons depending on whether or not they are set up for ******** rods.. I suspect that most aftermarket pistons are clearanced..

While typically the 96 crank rods are about 0.010 shorter than 88 rods, the aftermarket rods may not be.. And the will be full width..

Add:

The big difference on stroking a 88tc to 4.375 is the piston CH drops from 1.270 to 1.090.

 

You can count on Max to keep you out of trouble in situations like this. JMHO but the 4"x 4.125" over square motor will be more fun anyway; very torquey and quick reving.

 

I'm liken mine..

107 ci Custom cylinders 11 to 1 cr, Delkron heads touched by WFO larry, CV51, SnS Tuned flow AC, Bassani RR3, DTT, Woods 9B cam.

 

Max, please explain "a 96 ci crank will not fit in a early motor unless you want to custom space a solid primary gear."

The SE catalog offers two "stroker" cranks for early TC88 motor, one with ******** rods and the other with full width rod ends.

 

The big reason is the crank end.. The splines are different on the drive side. Spacing for the primary sprocket is different so you are tied to using solid sprocket and respacing..

Without reference / pics, I'd expect that one is for 2006 Dynas (******** rods) and the other is for all the rest.. What year SE cat are you looking at?

Add: found it.. needed to look for flywheel and not cranshaft.


Here is my guess. The more pricey non ********* are made for early motors with 1200 gram piston set and the ********* let you use the std 96/103 parts that balance at something like 1030 grams.. The pricey ones could still be made by Jims, The cheaper ones by HD..

 

Thanks everyone for good replays. If I go this route I will use either a S&S or the expensive one (made by Jim's) of the SE cranks made for 99-06 engines so no issues with the sprocket splines.

But it turns out these are really really expensive over here in Europe, I will be paying at least $2500 for a crank, and then pistons on top of that.

So I'm pretty sure I will go the 4" by 4.125" all bore route. I can get the case boring done locally at a very fair price. Only expensive part seems to be cylinders, that machine shop want to use S&S 124" cylinders shortened to stock height, but these are also very pricey over here.

 

Sounds like the way to go.
The way they should have been built from the factory