Don Terrill’s Speed-Talk

Manley do cutters for various stem seal diameters, the ones for .530" are, 41710 with .312" pilot, 41711 " .343" " 41712 " .375" " If you are doing different stem diameters you can buy one cutter head and get pilots separate, alternatively you can turn up pilots. Comp also does comparable tooling as...

If you go down Walter's bundy tube route, you could make the 3/8" end barb with a brake tube flaring tool by only doing the first step.

Turn down the barbed ones to what you want.

Most bearings are plated onto a steel backing using various compositions of metals for different attributes/benefits. Some race steel back bearings also utilize coatings on the running surfaces. They are still produced in the USA and Australia and a number of other kindred countries. Old white metal...

In the seventies flat plane cranks were starting to be run in F5000 here, the most common issue was the integrity of the tubs.
I don't recall what rectification was employed but as BCjohnny pointed out, if harmonics were addressed issues could be controlled.
Exhaust tuning was the aim then.

Cheers.

He gave a comprehensive rebuttal to the hypotheticals proposed. Be that as it may, all at once in the same millisecond??
Even if the rods were made from recycled coat-hangers, i still struggle with the time frame and duplication of the event, c'est la vie!

Buy lottery tickets now!

.060" to .080" is default minimum. Any contact can bounce the seal off.


Cheers.

Digger, the rod failure i posted is not the same engine. I would imagine the OP would have indicated if the failures were instigated at any point of modification? i see no mention of this, is it the case? ,, But for all to do the same thing in an instant?? My answer is to buy lottery tickets as the ...

What gets me is the failure is almost identical cylinder to cylinder, separation just under the gudgeon pins, total failure and destruction almost identical down to the appearance of the scraps. Here's a thing, no engine knows what it looks like, each cylinder thinks its on its own, it does not know...

I was thinking more is to be gained from around the seat area.

I'm thinking there is a whole world of improvement for that head in that photo, without the gain of .2cc or indexing. Although, it might have been the angle of the photo shot.

ELS, was the photo of the head you are working on a test head or the one you are actually developing?

Agreed Knight, Mouse and Rebel, a Sporty is a Sportster, not a shrunk big twin. If we wanted either we would buy either.
Twenty odd years ago i built a 100" Sporty for myself, trouble was it went real good! Real good! i didn't, my capability in riding was not up to the bike's.

Cheers.

I think Harley Davidson knew that the Sportster platform was nearing the end of its design life when they went to rubber mount, and did not want to heavily reinvest in the pushrod engine. Casting changes to accommodate mountings were pretty straight forward, internal simplification was also achieved...

Well spotted Tom, a quiet days testing some other bikes. I knew Johns name around the track but not personally. I was involves with fuel Harley's at the time,,, a well remembered team..