Just thought I'd share some pictures of my hand ported manifold. I'm preparing parts for a 120ci build. I'll have some measurements of the stock 114" cylinders for reference as well as other engine parts. The stock 64mm manifold before.... After pictures, porting is based on the CNC ported SE Manifold.
Stand by for more good info....
custom precision is a beautiful thing! I'd like to do that for a complete engine build..back in the 70s and 80s we would port and polish our cylinder intake and exhaust two stroke mx race bikes, add 2 stage reed valves, tight top end, aftermarket heads, get a good pipe, jet em' spot on and man oh man hang on for dear life! it always felt great knowing things were done to perfection..those were indeed the good old days
Some more info...factory 114 cylinders. They will be bored to 4.125" which will leave me with a .110" spigot thickness, well into the safe zone. No where is it posted the length of the cylinder or spigot, so here you go..
Spigot length 1.225" Total length 6.090" Cylinder #2 spigot Cylinder #2 total length.
I have a set of CP forged 2618-T61 alloy pistons. With these pistions comes the standard wrist pins, most all piston manufacturers use the same 5100-series Chromoly wrist pins. They hold up well, they are made from case-hardened carbon steel bar stock, and come from Taiwan. These weighed in at 106 G and have a thickness of .150". I have had a set of custom Trend wrist pins made in the good old USA, these are H-13 tool steel which is about 3 times stronger than the 5100 series, I wanted to cut weight so my pins are 100G and have a thickness of .145", still much stronger than the CP pistons standard issue. My pins will also be cryogenic/rem treated to get the most reliable maybe 'overkill' wrist pins for this build.
If you are going to start messing with the reciprocating weight in the top end, you might want to consider how that will affect rotating mass down below ( crank assembly)
I don't know exactly what the total weight of the stock 114 pistons are, ' including rings, wrist pins' , Jecr responded with a 107 piston weighing in at 521 grams, I suspect the 114 will be a few grams more. I'm trying to target this weight within 5%, that way there should be a negligible effect to the factory balance. At worst I will be changing the balance factor and moving the RPM sweet spot lower in the rev range with a heavier piston assembly. It will move in the opposite direction if the piston assembly is lighter.
so curious what the goal here was / is other than 'Superbike' in the title..lot of time, effort and money..is it just because you want to, or something else, like track time or just build up the best possible powertrain to last for many years and tons of miles?
The title ‘Superbike’ is a little bit of a joke, but I wanted to document the build from start to finish, and hopefully the info will help others out. In the end, yes I will have a reliable motor, I expect around 120-125hp, and for a Harley, that’s a lot of power. I know there’s bigger builds I never thought I’d see 150+ but here we are. I figured if I can make as much HP as a 1998 Kawasaki ZX11 I’d be doing well. The numbers I see today are amazing, late 80’s early 90’s 125hp street bike would be a ‘Superbike’. I wanted a great street bike that was reliable, this is my 3rd HD motor build, it will probably be my last, it’s getting quite expensive these days.
The title ‘Superbike’ is a little bit of a joke, but I wanted to document the build from start to finish, and hopefully the info will help others out. In the end, yes I will have a reliable motor, I expect around 120-125hp, and for a Harley, that’s a lot of power. I know there’s bigger builds I never thought I’d see 150+ but here we are. I figured if I can make as much HP as a 1998 Kawasaki ZX11 I’d be doing well. The numbers I see today are amazing, late 80’s early 90’s 125hp street bike would be a ‘Superbike’. I wanted a great street bike that was reliable, this is my 3rd HD motor build, it will probably be my last, it’s getting quite expensive these days.
Or, you could drop in a cam, tune and maybe a pipe, and be bouncing off the same numbers.
That’s impressive for what’s done to it. My forged pistons will be a little more robust, and I’ll have full quality control, the bores will be perfectly straight, piston to cylinder clearance will be perfect, and I’ll have a few more cubic inches. I can also manage the compression for the cam I have picked. But I took serious thought to just bolt in a TTS100 cam and calling it a day. That’s and easy 95-100hp motor. Building the top end is more fun and the cost isn’t astronomical comparatively speaking.
01-05-2022, 08:01 PM
120ci build...(The M8 superbike)
I wanted a great street bike that was reliable, this is my 3rd HD motor build, it will probably be my last, it’s getting quite expensive these days.
