| Author | Message | ||
     Jefc73 |
This winter Iam going to do an engine build on my S2. Nothing crazy like an Axtel engine etc. Just want some opinions from the masses on this and a good set up for the S2. I know the stock engine has the heavier crank so probably will only get so much out her. I want to be able to ride it without having to worry about breaking or blowing up. Iam schooled on engine type builds as my RoadGlide has a 107 ported motor etc. Here is what is in the bike right now. Thunderstorm heads, piston, and Andrews N8 cams. Dyno sheet says 84HP. This is what the previous owner did. Has stock headers with a borla muffler. Also has a screamin eagle ignition. I was thinking of doing the 1250 kit with some porting, matched higher compression pistons and a nice cam to match the porting specs. I know NRHS does this...Any other reputable engine building porting shops?? Also there are other parts that may need to be gotten as well. Upgraded tappets, roller rocker arms, adjustable or non adjustable push rods, valves etc. Just want to open up a dialog on engine builds for the S2. Chime away fellow Buellsters. | ||
| Phelan |
I'm planning a 1250 build this winter as a pre-stage for an 88" build later. We have nearly identical engine builds currently. My plan is stage III dual plugged Thunderstorm heads with 80 thou sunk 1.940" intake and 1.615" exhaust valves, 15* squish, and decked heads, shooting for 11:1 CR. We'll also be welding up the floors of the ports to mimic XB heads. Using NRHS CAT4 cams and stock (but replacing mine with lower mileage) rockers and lifters. I'll be using a Dyna ignition and Dyna coils. My goal is 110 HP @7000. BTW the heavy flywheel is really not much of an intrusion as it only slows the rev up, though it also makes the bike a lot more mannerable when you let off the throttle as it winds down slower as well. (Message edited by Phelan on October 03, 2014) | ||
| Phelan |
All my work will be done here at NRHS, because I'm a bit biased  . | ||
| Jefc73 |
How didn't I know that you would probably be the first to chime in. LOL. I hear ya on the NRHS. I have talked to Dan a few times already.  | ||
| Phelan |
Some other info- fixed length pushrods are stronger and lighter than adjustables. Much better to go with them even if you do spring for collapsible pushrod covers. Roller rockers are nice but add noise to the top end. I'm avoiding them only for cost reasons only and will likely add them when I do the 88". Stage II heads and CAT3 cams will net you 80% of the gains I'm looking for and the cams will play a lot nicer on the drivetrain. | ||
| Screamer |
There a lot of good combinations out there. We've had good success with Wiseco flat top pistons, ported Thunderstorm heads (stock valve sizes) and SE bolt-in (Buell Lightning/Thunderstorm) cams. Set-up properly and with good carb, air cleaner and exhaust, will be around 100 rwhp and very reliable. | ||
| Jefc73 |
Screamer that is basically what Iam looking for. Would like to get 100 rwhp and still be very reliable. I have used the wiseco pistons in the past as well. Will be putting a Mikuni 42hsr on as well. Just want a good combination with good porting. | ||
| Phelan |
02883R on XLForum put over 180,000 miles on his Sportster after his NRHS 1250 conversion, and his bike already had 100,000 on it when he did the conversion! He did have some other failures along the way but nothing related to the top end, and the bottom end was completely stock for the 280,000 miles! He's pushing 98 RWHP IIRC. | ||
| 4speeder |
I warmed up my S2 last year. Engine has 30,000 miles on it. I put stock Thunderstorm heads on it and matching Thunderstorm pistons. Andrews N4 cams, SE ignition, Mikuni 42mm flat slide pumper, K&N air filter in the stock housing, and Vance and Hines Muffler packed with steel wool. Dyno'd it after the build and it did 92.5hp at the rear wheel at 6,500rpm, which gives an estimated 100-102hp at the crankshaft. It's as easy to ride as stock, still has tons of off idle torque, and has a really smooth broad powerband very similar to stock, but is much more powerful. I really like this combo a lot. | ||
| Phelan |
That is a case where the result is better than te sum of its parts! Very nice results! Jeff and I have almost identical mods as you but we got 84 RWHP. | ||
| Jefc73 |
that's what I was thinking too. Not accurate. The flatslide will give some HP and the vance and hines might give more than my borla but I don't think 8 HP. Generous dyno. | ||
| Phelan |
Or it could be higher compression.. Also the combustion chambers were slightly different in Thunderstorm heads from 98-02. Later years had better casting along te squish. | ||
| 4speeder |
Dunno. Dyno is in my nephews shop (Open Road Customs) and he did the run himself to be sure it was right. He was actually surprised at the numbers because he runs a lot of modded HD's across his dyno. The bike was showing rich AF mixture in the midrange too. The 30,000 mile jugs showed minimal taper so I just broke the glaze and put stock bore rings in it. Back in the day the race guys would say the engine was put together "loose" and would make slightly more power than a fresh built engine with tighter tolerences. It is what it is, and makes no matter to me because the dyno doesn't measure my smile when I wick the throttle open on the bike, and trust me, its a BIG smile!!! | ||
| 4speeder |
Phelan you may be right. I put .010" thinner head gaskets on it to bump the compression up a little and I used the correct T-storm pistons. My nephew told me that he sees T-storm headed sporty's in the shop and sometimes when he pulls the engines down for work, a lot of them don't have the matching T-storm pistons in them. Those bikes would be way down on compression. | ||
| Screamer |
92 seems a little high without a race header (or some equivalent) but not impossible. Machining and assembly stack-up can cause variability (including compression) from engine to engine. As an addition to Phelan's note, 03 and later Buell engines had more than a better casting - they are an entirely different chamber design. | ||
| Phelan |
True Screamer, but I mean the tuber Thunderstorm heads were actually slightly in the later years, I believe 00-02 or so, though they had the same part number. The squish band has tighter tolerances than the earlier castings. The XB heads are indeed another animal, though thunderstorms can be worked to perform just as good as a worked XB head. By welding up the floors in the ports, a Thunderstorm head can effectively be an XB head with smaller fins and a squish band. | ||
| 2kx1 |
Well , everyone here needs help spending money!!! 08 crank and carillo rods. 8000 rpms all day. Somebody needs to be the guinea pig. | ||
| Court |
My S2 motor was blue printed by NHRS and chimes out 111 RWHP with a simple Supertrap. I start it once a month, have new tires sitting in the garage. Now sure if I'll get them on before I sell it . . .but just starting it periodically is fun . . . it sounds like the earth coming to an end. I push it down the street to protect my relationship with the neighbors. If anyone is looking for an S2 or a great motor . . .drop me a note! | ||
| Screamer |
I know I'll probably regret this. The engine that 4speeder described, "stock Thunderstorm heads with matching Thunderstorm pistons" and "N4 cams" (nearly identical depending on the vintage to SE Bolt-in/S1/X1 cams) has a top-end and valve train package that is essentially a Thunderstorm motor. It doesn't have the lighter flywheels that the early Thunderstorm engines had or the even lighter flywheels that were in the early 1999 engines. Despite the difference in quickness to spool up, 4speeder's engine should have similar HP output to an early Thunderstorm. Judging by the description of a "Vance and Hines muffler", I'm guessing it does not have a race header. The race kits were promoted as capable of producing 90+rwhp on a Thunderstorm motor. I found that the exhaust header with either the race can or early Supertrapp was worth 4-7 hp - and I've heard of larger variations. So I've believed that the header was the largest contributor. To my original point, 92hp on a motor with a stock Thunderstorm head and piston combination and a presumed stock header seems high - but not impossible. To Court's point, engines in the 100 to 115 range with stock headers are not unusual. They would seldom have stock heads combined with stock bore and stroke. | ||
| Phelan |
Court's bike is an 88" beast, whole other animal . I'd love to buy it if I had the $$$. | ||
| 4speeder |
"4speeder's engine should have similar HP output to an early Thunderstorm". That makes sense to me and seems right in line with what I have. Weren't the T-storm motors rated at 101hp at the crankshaft? That's no doubt with an open exhaust and a velocity stacked carb on a lab dyno. I put a 27 tooth drive sprocket on my bike and took the 29 off so I could run the little skinny twisty roads around where I live and actually get the bike into high gear sometimes. With the 29 tooth I rarely ever got out of 4th gear. The 27 tooth sprocket would make an increase in hp at the rear wheel, but has no bearing on engine crankshaft horsepower. The downfall of chassis dyno's is actual crankshaft hp is difficult to determine because of all the other factors, with drivetrain friction being the biggest. The chassis dyno measures the power the wheel has, not the engine. Dropping the air pressure to around 15psi in the rear tire also reduces the diameter of the tire, so that helps the dyno hp reading as well, and also increases the rubber contact area on the roller so slippage is reduced, giving you a more accurate reading. My build is certainly nothing special and the N4 Andrews cams mimic the factory installed Buell cams from 1998 I think. I'm not interested in a horsepower pissing match here or a buildup brag. It's a simple thing to make gobs more power from the 1203 by any competent engine builder. But with a normally aspirated engine without electronic engine management, it cannot be done without sacrificing low end grunt and smoothness, and low speed street drivability. I've built plenty of high strung car engines that kicked ass at high rpm, but driving them on the street was a pain in the ass. Back in the day compression was by far the easiest way to make cheap power, but with todays pump gas, and without electronic engine management, anything over about 10 to I leads to problems. If I took my T-storm pistons out and put a set of 12 to 1 slugs in the engine it would easily see another 5-6hp. This is not voodoo, magic, or rocket science, its just simple engine building practices. I had no intentions of trying to squeeze as much power out of my bike as I could get, I wanted a nice flat torque curve, with a ton of off idle torque for easy drivability. I got exactly what I wanted with this build. If it makes 92 at the wheel or 82 at the wheel it makes no matter to me. I'm interested in how it rides and drives as a package. I've been putting engines together for over 40 years and I'm past the point of getting hung up on street (not track) horsepower. It's a game that drains your wallet at a greater rate than it builds your ego….. | ||
| Hootowl |
"Weren't the T-storm motors rated at 101hp at the crankshaft?" For the X1 and S3, yes, in EPA trim, as they appeared on the showroom floor. You could expect 85 RWHP from them. I don't think 92 RWHP is unattainable with an aftermarket pipe and some tuning. | ||
| 4speeder |
That's good info Hootowl. Thanks for posting that. If the belt drive drivetrain sucks 15% of the engine power that's incredibly inefficient. No wonder guys trash the belt and go to a chain drive! | ||
| Hootowl |
The primary chain, transmission, and belt drive, not just the belt drive. The transmission is probably the largest consumer. Belt drives are supposed to be more efficient than chains, from what I've read. Chevy TH400 transmission can eat up to 50 HP. | ||
| Phelan |
Rear wheel weight comes into effect as well. A carbon fiber wheel will look a lot better on a dyno. | ||
| 4speeder |
Some good information you are posting Hootowl. Thanks for your insight. Years ago I read an article on toothed belts vs full roller chains and I recall it was something like 98% efficiency for the full roller chain and 93% for the toothed belt. I think that was back in the day when the toothed belts had squared off teeth instead of the rounded profile teeth we have now. No doubt belt technology has come a long way since then and they are more efficient. I'll bet the "wet" toothed belts that run in oil are really efficient. I really like the no oily mess, no noise, no vibration, and the infrequent adjustment intervals with the belt setup. When I first got my bike I went over the thing because it was a real mess. The swingarm/axle hash marks you are supposed to use were lined up close so I thought the belt alignment would be close. Boy was I wrong. I laid a 24" straight edge up against the back sprocket and aligned it along the side edge of the belt on the bottom side. The distance from the edge of the belt to the straight edge at the rear was about a half inch less than it was at the front! That's a lot of mis-alignment. I corrected it and set the belt tension and have never looked back. In the early 80's when I was a GM line mechanic we had to attend GM seminars to keep up on what was new. I remember being blown away by learning that the Delco/Frigidaire "log" AC compressor used on GM products took 10-12 horsepower to run, and with a low battery the Delco alternator needed about 6 horsepower to run it to charge the battery!!! | ||
| 4speeder |
That's an excellent point Phelan. Same would be true with a lighter weight rear tire. When I was shopping for tires I was amazed at the weight differences in the same tire size. I love Pirelli tires and have rode on them for years on my Guzzi. I was fortunate that the Diablo Rosso'a are lighter than some of the others. The less rotating weight the faster the wheel would spin up to speed. Same as a light flywheel on an engine. This is great discussion! | ||
| Hootowl |
"Chevy TH400 transmission can eat up to 50 HP." But it can also handle 1000 lb/ft of torque! It's a monster. I have one in my truck  | ||
| Jefc73 |
Ok reviving this thread...Have a set of Thunderstorm heads coming and wanting to do a 1250 and head porting with a good cam and 42 mikuni. More than likely a Dyna 2000 ignition as well. Now I know of both NRHS and Hammer what about any other reputable engine builders that do really good quality work?? This isn't going to be a pissing match but if anyone has some good info put it here. If its bad biased info then you can private message me. Thanks. | ||
| Jefc73 |
Anyone know anything about Lee's Speed shop in Minnesota? |
