Friday, September 11, 2009

Monday, May 4, 2009


These are the flywheels for the turbo bike, they started out at 11pounds 12ounces per half, first thing I did was knife edge them to see how much weight I could pull off of them. It took a nice bit off, but they still weren't quite where I wanted them so I just knocked the knife edge off and reduced the diameter of them. I was shootin' for seven pounds per half once they're finished but I left them a little heavy so I have plenty to work with when I balance them right now I'm at seven pounds 12 ounces per half. That's eight pounds off of the combined set. Should be damn snappy.

shaving them down that far really fucked my scraper clearance, but it's nothing that a little welding and machine work can't correct.

I'm also running S&S rods, but they're for an evo sportster, which changes things quite a bit. First off, the biggest difference is that they're just under a half an inch shorter than ironhead rods are. If I remember right the ironhead rods are .480" longer. The shorter rods increase the rod angle during the middle of the stroke, which basically gives them better leverage on the crankpin for more torque. Another thing that the shorter rods do which will really benefit the turbo is that they increase the piston speed during mid stroke, more piston speed means gases moving through the motor faster, which means a faster spool. The shorter rods do bring some problems into the picture though. First off, if the flywheels weren't shaved the pistons would crash right into them, secondly your pistons are now way down in the bore compared to where they should be and if you don't correct that you're gonna end up with a mighty 4:1 compression ratio. To correct the compression problem and prevent the rings from being raked across the drain holes near the bottom of the cylinder I'm going to have to machine .050" off of the cylinder decks on the case and .150" off of the cylinder bases, then I'm gonna have to knock off around .300" off of the head gasket end of the cylinder I'm not sure exactly of that number, the determining factor on that will be setting up the squish area in between the piston and head. After I do all that it'll be time to break out the burette and figure out the compression ratio and determine how much of the dome I have to mill off of the pistons to get an 8:1 ratio out of it. Another little issue is the one of the pistons wanting to crash into each other at the bottom of the stroke, but that is easily fixed with a little bit of clearancing on the back skirt of the front piston.

I just got my Keith Blacks in about a week ago. I love these pistons, I run them in everything I can get 'em for. They're Hyperutectically (high heat, high pressure) cast in steel molds out of a high silicon content alloy that holds up to tremendous amounts of heat, they have some of the lowest thermal expansion rates of anything out there which lets you fit them very tight in the bores and not have to worry about scuffing the skirts, and the alloy that they're cast out of is hard as hell which coupled with the tight clearances means you've got a piston that you can run extremely hard and still get 50k+ miles out of easily. And to top it all off they're quite a bit lighter than a stock or forged piston.

I also got my new trap door for the tranny, ditch the frail aluminum one in favor of a cast iron piece and you're well on the way to a stronger transmission.

That's all I've got for now, I just dropped the cylinders off to be bored, once I've got those back I can do the final fitting on everything. Ride fast and smart. -Dave

Thursday, April 2, 2009

New carb for the shovelhead.

Took a super G and punched the venturi out to 50mm, shortened the emulsion tube, and did a couple other little tricks to get it ready for pressurization. Almost fucked the body up when I intersected the passageway for the air bleed, but I got some brass tubing that is the same I.D. as the original passageway, drilled the passageway for a nice light press fit and tapped it home with a little red loctite. Disaster averted. Top end power with the bigger carb is ridiculous, launch hard and slip the clutch up to about twenty then you better be holdin' on cause it's a rocket ride to the far edges of sanity.

Billy's new project

Ironhead clutches and transmissions suck. Best solution??? cut that shit off and put something back there that's got a fighting chance.

Saturday, February 28, 2009

I got the heads back togheter for the shovelhead today. I didn't think to take any pictures before I started, but I took care of some valve shrouding that was going on since the valves are sunk in deep to make TDC clearance with the cylinders shaved down as far as they are. While I had everthing apart I back-cut the valves, in the pictures up above you can see the cut valve on the left and how it started out on the right, you end up with a valve that has a nicer shape that'll flow alot better with just enough seat material to let it run for a long time with no problems. I'm gonna put the bottom end togheter tomorrow and if everything goes to plan I should have it ridable within the next couple days.

Monday, February 23, 2009


Hands down the most difficult exhaust I've ever built, Two into ones are a real pain in the ass to keep the tubes equal length and short enough for a nice powerband up top, keeping everything in tight so you don't burn the shit outta yourself all the time proves to be really tough too, as does trying to package it all so it doesn't look like a big turd either. I'm pretty happy with the way it turned out though, and now my powerband should really be pulling hard between three and six grand, right where I want it. Before It started really kickin' at about two grand and you could feel the pull taper off at about five. Should run quicker now, when you shift the optimum powerband up higher in the rev range the motor is spinning quicker and therefore pumping more air, when you pump more air you can burn more fuel and make more power, and that all equates to more get-up-and-go. It's an endless cycle, almost an addiction if you choose to call it that, build it faster, get bored with the new power, build it faster again, get used to it again, the cycle will only stop when you run out of ideas on how to make it faster or run out of "cubic dollars". It is a hell of alot of fun and a learning experience all along the way though.

Monday, February 16, 2009

trouble-proof shovel exhaust ports.

Thanks alot Billy. All evo style shit, pipe ends, clamps, and gaskets. No more pipes falling outta the heads or blown out gaskets for me! Now If I can just make an exhaust system outta this pile of buell pipes I've got here I'll be sitting pretty!!

Norton that a guy brought in to rebuild the brakes on and just go through. It's in beautiful shape, the one guy's owned it since brand new. One of the nicest things about being a mechanic is all the chances I've gotten throughout the years to ride cool shit like this.

sweet pan

The guy who owns this bike has been bringing it in for me to work on for at least a year now, nothing major, just little leaks here and there and maintenance work. I love those skinny fatbobs. Just a nice bike all around, plain and simple, very original.

114" knucklehead

3 13/16" bore x 5" stroke. 8" carrillo h-beam rods. Ross racing pistons. Roller rockers. Flathead power heads setup for dual carbs. Heads aren't ported, but the ports are a beautiful starting point with thin stem valves on the intake side. Still has a 1:1 rocker arm ratio, which really limits cam selection. Look at that cam, itty bitty base circles, it looks huge, but the lift is only .450" at the valves. The lifters are gonna live a rough life though. In my opinion the guy shoulda done it with shovelheads. Woulda been much faster, and the valvetrain woulda been easier on itself, but some guys just gotta have what they've gotta have.