------------------------------ Subject: 21. Cam Specifications -- Sportster Technical Chris deHahn supplied his notes for this section. V prefix for 1985-1990 4 speed Evo XL N prefix for 1991-up 5 speed Evo XL Timing specs taken at .053" cam lift in crank degrees, top spec intake, bottom spec exhaust. Spring travel specs are the minimum for setting coil bind. TDC list specs are for stock Evo 1.633 rocker ratio. SPRING LIFT @ GRIND TIMING DURATION LIFT TRAVEL SPRINGS TDC ----- ------ -------- ---- ------ ------- ------ STOCK 2/41 223 .458 - STOCK - 41/14 235 .414 - - - V2/N2 22/38 240 .465 .495 STOCK .198 46/18 244 .440 .470 - .198 V4/N4 30/46 256 .490 .530 STOCK .198 52/24 256 .490 .530 - .198 V6/N6 34/50 264 .490 .530 STOCK .215 56/28 264 .490 .530 - .215 V8/N8 32/44 256 .490 .530 STOCK .223 56/28 264 .490 .530 - .215 V9/N9 33/53 266 .555 .600 ANDREWS .240 53/33 266 .555 .600 - .240 BV/NV 35/59 274 .590 .640 ANDREWS .260 59/35 274 .590 .640 - .260 Pre-Evolution ------------- Timing specs at .050" SPRING LIFT @ GRIND TIMING DURATION LIFT SPRINGS ----- ------ -------- ---- ------- P/PB+ 34/40 254 .400 STOCK 43/31 254 .410 Y 35/47 262 .425 STOCK 53/29 262 .425 R5 33/41 254 .445 STOCK 43/31 254 .445 X 35/55 270 .450 STOCK 57/33 270 .450 GX 35/63 278 .445 STOCK 57/33 270 .450 V9 32/52 264 .490 ANDREWS 52/32 264 .490 AX 29/57 266 .550 ANDREWS 57/29 266 .550 BV 34/58 272 .520 ANDREWS 58/34 272 .520 DX 38/66 284 .550 ANDREWS 66/38 284 .550 XR1000#1 48/60 288 .560 STOCK 60/40 288 .560 XR1000#2 32/44 256 .486 STOCK 52/24 256 .486 Red Shift --------- Timing at .053" Evolution --------- GRIND TIMING DURATION LIFT ----- ------ -------- ---- 530V2 24/104/49 253 .530 54/106/18 252 .530 531V2 28/104/51 259 .531 60/107/19 259 .531 625V2 32/103/58 270 .625 62/107/29 271 .625 694V2 28/104/56 264 .694 59/107/26 265 .694 710V2 41/102/63 284 .710 38/106/34 282 .710 710/694V2 41/102/63 284 .710 59/107/26 265 .694 Pre-Evolution ------------- GRIND TIMING DURATION LIFT ----- ------ -------- ---- 520 25/107/54 259 .520 61/107/18 259 .520 550 32/103/58 270 .550 62/107/29 271 .550 625 41/102/63 284 .625 68/106/34 282 .625 665 42/99/62 284 .665 66/108/38 284 .665 610 28/104/56 264 .610 59/107/2 265 .610 625/610 41/102/63 284 .625 59/107/26 265 .610 535XR 25/107/54 259 .535 61/107/18 259 .535 605XR 37/96/51 268 .605 55/103/32 267 .605 ------------------------------ Subject: 22. Ignition Basics Technical First a few terms: Dual Fire - In the stock HD ignition system, both spark plugs fire at the same time, so one plug is firing when it's piston is not at TDC of it's power stroke, "wasting" a spark and igniting unspent gases. This causes a noticeable and unnecessary vibration. Dual Plug - In this popular Shovelhead modification, an second spark plug is installed in each head, on the side opposite the stock plug. This brings much less benefit to an Evolution motor, as its head is of much more efficient design. Rev Limiter - The ignition retards the timing at a preset RPM to prevent the motor from revving higher than desired. This is a Good Thing as high revs will prematurely wear a motor. Single Fire - Spark plugs fire independently and only the correct time. "Unfortunately, CCI (Custom Chrome Inc.) has taken it upon themselves to reverse the definitions of dual and single fire when referring to their proprietary Rev-Tech ignition products. Rev-Tech dual fire systems are really single fire systems, and vice versa. Caveat Emptor." -- Christopher deHahn "Some cams will flow up to around 6K RPM with the stock heads, so moving up the rev limit helps there too. Single-fire will not provide more HP but will give better idle and better throttle response off idle to 3K RPM. A hotter coil is also a must for these mods." -- Mark Cronenweth "I've installed alot of different single fire ignitions from Dyna 2000's to the Dyna S's to the Accell Mega Fire to the RevTech's piece of shit to the Crane's piece of shit to the MC Power Arcs to the Stinger's with points and Stinger's with a stock electronic ignition. I do notice a difference with'em all. They do help the motor run smoother with less vibs, response is better and they start easier...except the ones that were pieces of shit. I'd never run mine without single fire...that's when the real difference is noticed. I run mine with points and a Stinger so that blows the Dyna advance curve theory being the only difference...tho' there is a distinct difference with the Dyna in a wasted spark set-up over the stock box and coil BUT better response is noted in the single fire set-up. One thing I'd like to add/ask to end some of the confusion on terminology is the stock system is a wasted spark system and is sometimes called a dual fire. ... For the sake of clarity call a dual plug set-up a dual plug set-up...single fire a single fire...a Multi Spark Discharge an MSD and a stock set-up a wasted spark or a dual fire if you prefer. It makes a seemingly complicated subject simpler." -- Cheezie The Crane HI4 ignition is new, fits entirely into the nose cone, is RISC based (for techno-weenies), is very tunable and should be compared with the Dyna 2000. I have not heard any actual user experience with this part, but many VB&G barflies like and recommend the Dyna 2000. ------------------------------ Subject: 23. Suggested Carburetors Technical My wrench says he can make a stock Keihan CV carb perform as well as anything else. In this I do not doubt him, as he races a CV, but I do wonder what he would charge. Unless you are a carburetor wizard or are limited by a sanctioning body, dump the stock carb if you want to do anything more than wake up your motor. There are several good carburetors on the market. Two that are made in the US are S&S and Quicksilver. Mikuni is recommended by many wrenches, but is made overseas (hssssss). They do sell a hellova calendar tho... Because of its popularity, the S&S is well known by every Harley mechanic and has excellent parts availability. The Quicksilver carburetor is much newer. Its advertised benefit lies in its simplicity. Jeffery Stubbins reports that the milage is greatly improved over stock, stock w/Dynajet and the S&S. This carburetor is California Air Resource Board (CARB) approved. Its reputation is growing rapidly. "I ran the 38mm QuickSilver on a FTLCU with a Crane 316-2b and the Thunder header. It work flawlessly. Was able get 73 HP to the rear wheel[. T]he throttle response was great. Was a breeze to tune just put it on the dyno to choose the proper needle (could be done by reading the plugs but the dyno was more fun) then run it down the road a 2000 rpm and check the plugs to adjust the low end. There is only three adjustments total on the thing. The needle sets the mixture above 2500, the click adjustment sets the low speed mixture and you just set idle speed like any other carb. I liked the carb so much that when my engine gets back with the 96" kit in it I'm putting a 40mm QS on it. Of course the fact it supports the cruise on my Ultra doesn't hurt either." -- Leonard Pennock CV Carburetor Hop-up The following was provided by Leonard Pennock as "a very inexpensive hop up of the Stock Keihan CV Carb used on the late model big twins. The information for this was extracted from an article that appeared in the December 1994 issue of American Iron and an article that appeared in the premiere issue of Thunder Alley. These changes are only legal for offroad use (then again so are pipe, carb, and cam changes). Refer to the harley shop manual for your bike for disassembly instructions of the carb. There are three things that need to be done for the low dollar hop up of the CV carb. The first is to provide access to the idle mixture screw. This is done by using about a 1/16" drill bit to drill the plug that is covering the idle mixture screw on the bottom of the carb. After drilling the plug insert a sheet metal screw and pull out the plug. To adjust the idle mixture warm the bike up adjust the idle speed to 1000 rpm screw the idle mixture in until the motor starts to stumble and then back it out 1/2 turn. Then reset the idle speed back to 1000 rpm. The next area that needs attention is the hole in the base of the slide. This is the vacuum port. Drill this hole out with a #30 drill bit (.128"). This will improve the responsiveness of the slide and will also richen the mid range slightly. While the slide is out of the carb it is time to consider replacing the needle. Most of the CV carbs have a needle that is fat for about half the length which causes the CV to run lean in the mid range. The idle needle has an even taper and was used in the [19]88 49 state Sportster and is part number 27094-88. The next and final area of the low cost hopup is the carb jetting. For a slow jet use a #45 part number 27170-89; however, occasionally for engines with real hot cams it may be necessary to go with a #48. For the main jet start with a #165 part number 27116-88 which should be correct for most bikes. Some times it might be necessary to run a #170 but this is the exception not the rule. Read the plugs and use the dyno to find out for sure. This completes the low dollar hop up. The total cost of parts should be under $20 but since I didn't price them I'm not sure. This will give the CV a much better response and is really all the money that should be spent on one in my opinion. If you want more performance go with a good carb like the Quicksilver, S&S, Mikuni or Rev Tech and put the CV on top of a stack of papers (it works good for holding the manual open)." ------------------------------ Subject: 24. Pipes Technical Cross-over Tube By joining the two mufflers, the crossover tube reduces the resistance the exhaust gases must overcome, and allows the exhaust already moving down the pipe to suck the exhaust gases out of the cylinder whose valve has just opened. Both of these are Good Things. This is why the best performing aftermarket pipes for any type of motorcycle join the exhaust tubes. Removing it by only replacing the stock headers will cause a power _loss_. Porker Pipes and Drags On the question of installing open drag pipes: "unless you have had some engine modifications to allow for it, you _will_ be down on power (maybe more power than the stock, but less than if you used "tuned" pipes). Engines are built to compensate for a certain amount of back-pressure (i.e. the valves opening a little earlier), and if you remove the backpressure, the valves will be opening too early, letting some still-burning fuel into the headers. ... because of this, you can suffer (in extreme cases) from burnt exhaust valves if you hammer it too hard..." -- Mike Kelly To calculate the proper length of drag pipes the following formula was pulled from "The Design and Tuning of Competition Engines" by Philip H. Smith P = (A x S x D x D)/(1400 x d x d) P = pipe length in ft. A = exhaust valve opening in degrees of crankshaft rotation. S = stroke of engine in inches D = bore in inches d = exhaust valve port diameter in inches (the x is times and the / is divide) Also... "The pipe diameter internally is based on the dimensions of the valve throughway. This formula will do no more than ensure that the pipe is of adequate length to give a good pressure-wave action, particularly at higher speeds; it must be emphasized that there is no formula in existence which enables a system to be "designed" completely on paper, experiment being essential for the absolutely final result." [pgs 326-327 from the same above] "In almost every case I've heard the 2 and 2 1/4 inch porker pipes hurt performance of the bikes they were installed on. They may look cool, they definitely sound different but they hurt your engine. The tried and true 1 3/4 inch drags are the only way to go when running straights. They should be right around [32-34] inches long from the exhaust port to be most effective. These pipes work the same for BT as well as XLs. Porkers do have a variety of baffles you can stuff into them to keep the dreaded pipe checking device from entering them. Don't know about the sound level though. With any drag pipe set-up there will be a "soft" spot in the throttle. Where that occurs is up to where you have the carb set up and the cam you are using. Usually that spot is exactly the rpm where you cruise. ... why not try Thunderheaders? The difference in price is roughly 3 illegal pipes tickets." -- Jon Boulle The WB catalog suggests slip-on mufflers or a Supertrapp 2-into-1 pipe with 18 discs and a racing open end cap over their own Porker Pipes for performance applications. Recommendations The following is a list of replacement exhaust systems, listed in order of performance as rated by r.m.h conventional wisdom. It is important to note that there is not a great deal separating the four and that *by far* the slip-ons are considered the best value. o Python II -- Good mid and high range, though down on torque at low RPM o Cycle Shack o Supertrapp -- Only tunable pipe on the market o Thunderheader -- Quality control problems reported o SE Slip-on mufflers -- A Dyna was recently "King of the Hill" for two days at the Sturgis dyno with 116hp using SE slip-on mufflers. ------------------------------ Subject: 25. Heads -- Evolution BT Technical Mfgr. Flow Ratings All numbers below were pulled from the various manufacturer's specifications and are therefore NOT directly comparable, because of the variations in testing methods. All were normalized to 10 inches of water by Jon via his fancy engine simulation software. The Fast Company numbers were provided by Bob Schleiger, who notes "These numbers are at 10 inches and were done with my S&S intake attached to the intake port." H-D stock intake: 94 cfm @ .500" valve lift exhaust: 99 cfm Branch intake: 128 cfm @ .500" exhaust: 110 cfm B. C. Gerolamy intake: 139 cfm @ .500" exhaust: 120 cfm Edelbrock intake: 147 cfm @ .600" exhaust: 120 cfm Fast Company intake: 148.5 cfm @ .500 exhaust: 99.4 cfm @ .500 intake: 152.5 cfm @ .600 exhaust: 107.6 cfm @ .600 RevTech intake: 145 cfm @ .550" exhaust: 107 cfm S&S 158 cfm @ .600" S.T.D. 145 cfm @ .600" "Remember, this still is not apples to apples. To quote D. William Denish, "Valve size, valve lift and anything attached to the port during the test, such as an intake manifold, carburetor or radius entry flange, will affect results." -- Jon Boulle "S&S uses 2" intakes and oversize exhaust valves in their heads, unlike all the others. That, IMO is an advantage that is integral to their design, as is their piston shape." -- Christopher deHahn Optimal Flow Rates "I was going through my HeadQuarters catalog and found this chart for flow rates that are the optimal rates for different engines at different rpms. HQ says that the too much flow is as bad as too little and suggests that you stick pretty close to these numbers." -- Jon Boulle ENGINE SIZE (cubic inches) 82 89 97 106 RPM FLOW (cubic feet per minute) ------ -------------------------------- 5700 121 131 144 157 5800 123 134 146 160 5900 126 137 149 162 6000 128 139 151 165 6100 130 141 154 168 6200 132 143 156 171 6300 134 146 159 174 6400 136 148 161 176 6500 138 150 164 179 ------------------------------ Subject: 26. Heads -- Shovel Technical Chris deHahn contributed the following on Shovelhead heads. "TAKE THIS FWIW. It is not gospel, the absolute truth, or the American Way. It is based on my experience and those I trust. Corrections are encouraged. Head castings were changed significantly during the life-span of the Shovelhead motor. The castings have the date cast into them. Basically there were three major revisions of the head casting. The first appeared on the generator case Shovel and lasted into the early seventies. It is distinguished by a row of equal height fins in the center, between the rocker box areas. These are decent heads, but since they're old, many aren't in good shape. Valve seats were much improved over the Panhead, made of a hardened steel alloy. However, if you find a set of these heads, be prepared to replace the seats, as most of the used ones you'll see at the swaps have been cut several times and may exhibit significant valve seat recession. Seat replacement cost is around $50/ea X 4. The next revision came in the mid seventies, around 1974 or so and lasted until 1977 or 1978. These heads, known as 'crown' heads, had a row of fins in the center that formed an arc, or crown. The ports were opened up significantly, yet they had a lot of extra meat in the casting. This is why they make a good base casting. There's a lot of potential in them. The last revision was in 1978 or 1979. These had no fins in between the rocker boxes, and are known as 'late' heads. The late heads had very little extra meat in them to remove for porting work. In 1981, they changed the spring deck so that adding even a mild aftermarket cam meant you had to cut the spring seat to gain enough clearance, or fit high lift spring collars. The dates are approximate because AMF, in their infinite wisdom, used whatever castings were available at the time to assemble motors. It is not unusual to find a bone stock Shovelhead with one crown head and one early head on it. The next time you're at a swap meet and find two different types of Shovelhead castings, compare them. Look into the ports. It's pretty easy to see which ones are the better heads. Crown heads are in demand by HD drag racers and command a premium. You won't see too many at swaps."