Ironhead Truett and Osborn

[Mike650]

so sometime in the near future i plan on tearing into my ironhead and freshening it up. i already know it needs rings after doing a compression test. so far im having the top end completely re-done. i bought a Manley spring kit, kibblewhite valves, depending on the cylinder walls i will either stay with the stock piston/replacement or will be going +.010 with new pistons. but i think either way ill be putting in new pistons. but i have a question about Truett and Osborn. i came across a Truett and Osborn flywheel on jpcycles and i haven't heard of these guys. but i did some light reading on a shovelhead forum where some guys prefer these over S&S. so im wondering if anyone here runs T&O on their ironhead or knows the performance of the flywheel. i wasnt really planning on touching the bottom end (only cleaning) but depending on what it looks like i might just re-build that too just to avoid having to tear into it after already having it open once. but any info on the T&O lower rotating assembly would be much appriciated. im trying to get what parts i need in line and ready to go before i start the work.

[fdny37]

T & O are basically hot rod parts (stroker flywheels). You say you want to freshen up the engine so I'm guessing you don't want to stroke it. If you are going to keep the stock stroke and there is nothing wrong with your stock flywheels then you don't need T & O wheels.

[78ironhead]

T & O are stock or stroked. http://www.truettandosborn.com/FLYWHEEL.htm

[Mike650]

im not sure if i want to stroke it yet or not. still debating on that one. but from what ive read these are good flywheels. so even if i dont stroke it i may be putting in stock T&O flywheels either way.

[hcrashster]

If your going to build the motor and have the money, it might be worth going the whole way. T&O or not. This is what I found on my last rebuild. A junk sprocket shaft with one foot in the grave. A couple of high RPM runs and the cases would have been boat anchors. Looking will cost you time and very little money.

[forqueue]

T+O have been around forever, built many stroked Sportsters AND rebuilt many stock motors. They are one of the most honest and trustworthy engine builders out there. Call or email them for direct quotes and good, solid advice for a stock motor right on up to a big inch stroker.

[Hopper]

If you are not going stroker, there is usually no need to replace the flywheels.
Crankpin and sprocket shaft is where the wear usually happens.
Others on here have found you can send your flywheel assembly to T and O and they will rebuild it with the necessary parts at a pretty good price and ship it back to you ready to drop in.

[drhach]

I'll second that.

Originally Posted by forqueue

T+O have been around forever, built many stroked Sportsters AND rebuilt many stock motors. They are one of the most honest and trustworthy engine builders out there. Call or email them for direct quotes and good, solid advice for a stock motor right on up to a big inch stroker.

[rivethog]

Originally Posted by hcrashster

A junk sprocket shaft with one foot in the grave. A couple of high RPM runs and the cases would have been boat anchors. Looking will cost you time and very little money.

I'd be more inclined to believe that crack is due to improper assembly by a previous owner since the only "forces" on that lip are from the compensator, or from the sprocket shaft bottoming out in the flywheel due to faulty factory machining (somewhat prevalent in late 70's models).

[hcrashster]

Lord knows, A lot of used Sportsters are like a box of CrackerJack with a Black Widow inside. Flywheel was tight with good bearings all the way around. A friend of mine who is a machinist put the shaft up on an optical comparator after it was washed with a penetrating dye. Along with the fracture at the shoulder, micro fractures were found the entire length and the general consensus was improper heat treating. If you remember in how bad a shape HD was in at that time, a junk part on the assembly line was probably common. I'm not 100% sure what the cause was here, neither were the machinists that inspected it. So you may be correct. I'm just glad I found it in time.