| Author | Message | ||
     Captjoe |
Ok, here's a question that has been on mind for a while. Why are there 2 exhaust exits per cylinder on my 1125R? They are both small and then combine into a larger one. On my harley, I have only one exit per cylinder. I'm sure it's some performance thing but I'm rather curious to exactly what it achieves or attempts to achieve. | ||
| Jcjohnson33 |
To me looking at it. It comes down to fit. The large pipes won't fit coming off the engine within the frame and plastics and overall fit to the bike. So 2 smaller exits move the same volume of exhaust as 1 large one. Giant fat pipes on a fat ass Harley they like that, on our bikes lean and sexy is what I like | ||
| D_adams |
There are 2 physical holes there, one for each valve. It's just a design choice, probably just to make it a little more compact. Smaller hole, higher initial exit velocity. Borrowed another one of Mike's pics.  | ||
| Jdugger |
> On my harley, I have only one exit per cylinder Yea, slow POS '60s era technology vs. modern sportbike motor. | ||
| Christaylor |
Maybe if we open one intake valve slightly before the other and then open one exhaust valve slightly before the other we could help introduce a swirl to promote a more complete combustion and exhaust cycle? (Message edited by Christaylor on November 12, 2011) (Message edited by Christaylor on November 12, 2011) | ||
| Mickeyq |
I'd go so far as saying hd tech is 1920s. AJS had a 350cc Supercharged watercooled SOHC V4 in 1935. The 1939 500cc version was way ahead of suspension available at the time: "1939 AJS 500 V4 Racer Total production: 2 Claimed power: 55hp @ 7,200rpm Top speed: 135mph Engine type: 495cc overhead cam, two valves per cylinder, supercharged, water-cooled 50-degree V4 with 180-degree crankshaft and chain-driven Zoller volumetric compressor Weight (dry): 405lb (243kg)" http://www.motorcycleclassics.com/classic-british- motorcycles/1939-AJS-500-V4-Racer.aspx#ixzz1db9oMN Ni | ||
| Cycledoc59 |
Your antique Harley (even the new ones are antiques)have but one exhaust valve. With two, a separate exit for each would produce better flow, and the total area of the two smaller pipes is greater than the one larger pipe. It's all about efficiency. A lot of good engineering to produce such power; while Harley snoozes along on vintage boulevard...and nothing wrong with Harley; if you like to snooze. -Disclaimer: I own a '41 Harley | ||
| Duphuckincati |
Indian, around 1912- (but single header pipes) http://motorcyclemuseum.org/asp/classics/bike.asp? id=8 (Message edited by duphuckincati on November 20, 2011) | ||
| Crustyxpunk |
I had 2006 sportster I put a lot of money into Rhine wise and out. It was anything but slow and used "antique technology". Yea it was only pushing 90hp at the rear wheel but itwas also pumping 86ft/lbs of torque. I ran the 1200R heads, the same ones on the XB. lots of people make really good power with this "antique tech". This is the problem I have with sport bike riders and Harley "riders" they don't like each other and call the other groups bikes pieces of shit. I ride both, I love to go fast and I love to modify stuff. At the end of the day as long as you ride who cares what it is that you ride. Not everyone wants to ride balls out, some people like to cruise. Now I can't stand people who have garage queens and then get suited up 6 times a year and play biker, but I also don't care what kind of bike you ride. End rant. | ||
| 46champ |
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| Hybridmomentspass |
oh how easy it is to forget how buell has the same technology except for the 1125.... | ||
| Sprintst |
Same technology? The Harley engine Buell used put out more power than any of the Harley ones | ||
| Geforce |
I think the term...technology, could be applied to the entire motorcycle also. Buell was making the best out of a forced situation. (the sportster motor) And they managed to squeeze more power out of it in the long run. The rest of the motorcycle was entirely different from anything HD had to offer up. I think the youtube HD commercial put it best. "Harley Davidson... 1920s Technology at 2011 Prices." | ||
| Clk92vette |
Just because a given architecture is old, does not mean it isn't competitive. A good case in point is the OHV vs. OHC IC engines. The modern OHV V8 is arguably superior to the OHC from the standpoint of power/packaging/efficiency even though it is considered to be antiquated next to the OHC motor. I am not trying to argue that the 1203 motors are superior to the 1125 motor, but I will say that the most entertaining bike I have ever ridden on the street was a XB12S. But when it comes to a track day, I would definitely choose my 1125R. | ||
| Cycledoc59 |
Crustyxpunk, I wouldn't disparage the well-to-do Harley riders who play dress up on occasion. They have kept Harley alive and well for the last 25 years.. My fave backroad ride is my XB12Ss; well, it was before the 1125R. Before that is was another XB, a Cyclone, and many other brands. I've owned a few Harleys; knuckle/flatty/ shovel/3 sportys/evo. If you like to wobble thru the twisties, there's your ride...and if dumping money into old school to get power up to '70's levels is fun, enjoy. | ||
| Hybridmomentspass |
"Same technology? The Harley engine Buell used put out more power than any of the Harley ones" the discussion wasnt about how much power, but the technology and how old it was. The 1203 motor is almost identical to those used in the sportsters thats the same basic motor they've been working with for decades. I know its a pain to read, to read that your beloved buell has connections to the evil Harley davidson, but its true. " Buell was making the best out of a forced situation. (the sportster motor)" I dont think anyone forced Erik Buell to start putting sportster motors in his first bike, that was his decision. Please correct me if I am wrong, but I was under the impression that he bought those motors from HD and then built his bikes, not forced from harley. And think of it this way, you start a brand new company, how can someone FORCE you to use a certain motor? Now once he was owned by Harley, sure, thats a different story, he had his hands tied, or as Court has said many times a "Leash" was placed on him. Much different situation than him choosing to start with the Vtwins from Harley after the square 4. | ||
| Dktechguy112 |
"I had 2006 sportster I put a lot of money into Rhine wise and out. It was anything but slow and used "antique technology". Yea it was only pushing 90hp at the rear wheel but itwas also pumping 86ft/lbs of torque. I ran the 1200R heads, the same ones on the XB. lots of people make really good power with this "antique tech". This is the problem I have with sport bike riders and Harley "riders" they don't like each other and call the other groups bikes pieces of shit. I ride both, I love to go fast and I love to modify stuff. At the end of the day as long as you ride who cares what it is that you ride. Not everyone wants to ride balls out, some people like to cruise. Now I can't stand people who have garage queens and then get suited up 6 times a year and play biker, but I also don't care what kind of bike you ride. End rant." You used the XB heads? Eric was forced to use the antique sporster engine on the XBs, and because he is such a genius, was able to get some decent power out of 50 year old design. Even if you sporty was making over 100 hp, how much did you have to spend to get 100 hp? My first bike was a sporster and my brother has an iron. In the looks department they can't be beat. But the performance is not good, you take your sportster and dump $5k in it, and a stock 1125 will still smoke it in everything performance related. And lets not forget that 90 hp is diluted by the fact that the bike weighs over 500 LBs. I don't call other groups bikes POS, I just laugh when people try to argue that the sportster is a performance bike. | ||
| Cycledoc59 |
Back in the day, a single engine would make it's way into many motorcycles. J.A.P. engines, for instance, were used in many different brands. Today isn't then, and at the time, what would have been the other available choices for Eric to use...? Plus the simplicity of the Sporty engine was a positive; air cooled, hyd valves, one throttle body, and available.... What's amazing is how well the package that he put together works. I've had a few gripes with my XB, mostly engine centered, and mostly now resolved. It's a hard bike to beat on humpy, twisty back roads, like the "triple nickle" (Rt555 in Ohio) Ah, well, till the 1125 came along anyway.... But, with the 1125, we got complexity; the clutch/valves/stator and such can frustrate while the XB's just keep on rolling. I'm torn between the simplistic antiquated XB spread, and the near leading edge complexity of the 1125. Glad I have both. | ||
| Bob_thompson |
I believe Dean(Adams) got it completely right. Its about air velocity through a performance engine. In most cases its about high air velocity through the combustion chamber, which smaller head pipes do, and attaining the corresponding high volumetric efficiency and then scavenging properly to get good H.P. Cam profiles, intake area/velocity, valve sizes, squish area and other things contribute also to produce the best H.P.to torque and the very reason our 1125/1190 series of engines produce such great performance in all rpm areas. Just my take over the years and I'm lovin'it. | ||
| Crustyxpunk |
Dktech- I spent $1800 on the heads, matched jugs and pistons from NHRS (great company by the way, who does a ALOT of stuff with XB's) cOnverting my 883 into something fun to ride. I got a great deal on a set of 2-1's and spent about $260 on my ignition module. So all told prob about $2500 after rejetting etc. That's not even with head work or cams. Plenty of guys make well over a hundred hp for less than $5k. Of course it's nowhere near the performance as an 1125 but it's still fun and ridiculously reliable and cheap as hell to maintain. My original gripe was about people saying "oh it's old tech and slow". I've passed up plenty Of people riding sport bikes and my sportster handles pretty damn well in the twisties. You can have all the new tech and performance in the world but if you don't use it and just putt around whats the point? And well said cycledoc. | ||
| Georgehitch17 |
I've seen old POS harley motors make over 240hp. So what if there was 50k invested in the motor hahaha | ||
| Dktechguy112 |
If you passed a true sportbike on a sportster then either you are an amazing rider or they are terrible. I'm just looking at it from a cost/fun. 1125- cost me $6700 OTD brand new with a two year warranty and I have an FMF pipe and an EBR ECM on it. my total cost is $7400 Sporster- cost $8-10k new. plus your $2.5k puts it at $10.5-12.5K. The sportster is heavier, and for 2.5k you aren't over 100 HP at the wheel. The sportster looks better, but I don't see paying that much for a bike that will get owned by a sportbike. Like I said, my first bike was a sporty, I put 13K miles on it in less then a year and sold it for more then I paid for it. It was a cheap reliable bike that looked cool. But the performance was terrible. I don't see the point in dumping $5k in a sporty when you will never get it on the performance level of a stock 1125. Not to mention a sporty with over 100 hp is not going to be as reliable. I would love to have a sporty as bar hopper someday, I think the new Irons look amazing. You put some pipes, and an air filter and they look amazing. | ||
| Cycledoc59 |
Harleys excel like no other in ability to convert gasoline into noise, without the side effect of horsepower. My '95 Ultra Classic dynoed at 60 stock RW hp. It was a great low-speed handler; and could do figure 8's in a driveway. I used it to chase parts. I could haul 15 qts of oil, 2 gal antifreeze and a buncha filters w/no prob. But on an interstate trip, it sucked; the famous "batwing" fairing caused miserable buffeting, and it was almost toes up at 75 mph. In hot weather it was like riding a kerosene heater. Riding it in twisties was a constant struggle; being tailgated by an RV is unnerving. Getting blood out of such a turnip is expensive, and pretty much pointless. Want something with power that handles well?...look elsewhere. A turkey with 100hp+ is still an 800# turkey. If excellent paint work, a unlimited supply of farkles, fringe, a nice warm crotch and the fun of dressing in a Mardi Gras riding outfit turns you on, I'll wave as I pass.... Check out the Harley (and other cruisers) fave website: http://slayerhater.com/ | ||
| Crustyxpunk |
Guys, I'm not saying a sportster (I am talking about only sportsters, I should have clarified) is going to be as fast or as much ho bang for the money. I'm just saying you can make a fun quick bike for not that much money. Pick up a used sporty for 4-5k a 1200 mind you and throw some head work and decent (2-1 not short loud pos pipes that don't make power) exhaust on it. But yes big twins are heavy, slow, and handle like crap. Dktech- you don't see the point because you're more into sport bikes and that's fine. I'm not saying you should replace your 1125 with a sportster. I like variety plan and simple. Oh and if you get a bar hopper don't get an iron, do yourself a favor and get a nightster or buy a used sportster and put some work into it. The iron 883 is slow as balls, 1200 not so much. | ||
| Dktechguy112 |
If I could only have one bike, then it would have to be the 1125. The sporty is a fun bike, and if I got one it would have to be an iron, it looks so much better then a nightster IMO. I would just swap in the 1250 kit from NRHS. I know all about NRHS, and I agree you can make a sporty fun for about $7k, but its never going to be an 1125. But someday I would love to get a  The 350Z is mine, my daily driver when its raining or if I need to carry stuff.   The Iron is my brother's, and it is the best looking bike IMO. |
