101 Sportbike Performance Projects
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Sportbike performance projects? Like they would need any. But how about H-D performance projects? Sure there are million in the net but I have not seen one that is balanced and considers different alternatives in terms of bang for the buck and reliability. Any hints there anyone?
- cruiz-euro
- cruiz-euro
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3,415 Posts
The key to HD performance is twisting the throttle. I'm amazed at the money some people throw at their bikes for various performance parts then still never go above 3k rpm. I guess it's part of the game but if all you're going to do is poke around why spend the money?
A K&N filter, jets and good performance pipes as opposed to just plain loud pipes is all the enhancement most people are going to need. After that it's rider skill and a willingness to crank in some revs.
A K&N filter, jets and good performance pipes as opposed to just plain loud pipes is all the enhancement most people are going to need. After that it's rider skill and a willingness to crank in some revs.
Looks like my kind of book, especially the "cramped, poorly lit garage" part. It doesn't help that I end up trying to do everything with a 10mm socket, small channel locks and the last torx screwdriver left in my once well-stocked tool box.
The switch pods/throttle assy. on my wifes Hawk is all askew after my clip-on installation. It works but doesn't look good.
I would probably just buy the book but still not do the projects unfortunately . . .
The switch pods/throttle assy. on my wifes Hawk is all askew after my clip-on installation. It works but doesn't look good.
I would probably just buy the book but still not do the projects unfortunately . . .
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10,904 Posts
Joe says punch it out to 95 inches and then.....
For those of you who are not familiar with Bill's reference to my earlier Twin Cam 88 recommendations, let me give you a brief recipe:
* Change the cam design to one that closes the intake at near 30-degrees after bottom dead center (ABDC). This starts real power at or near 2500 rpm which is 55 mph in top gear. Either the Screamin' Eagle 204 with a Crane 4-degree advance engine sprocket or an Andrews TW21 performs well. My JM20 cam set is no longer available as Bartels' Performance Products has not ordered any from Andrews for some time now.
* Fit a Screamin' Eagle or similar free flowing air filter. Avoid those filters that have the air turn corners or that directly expose the filter element to the air stream. The Screamin' Eagle, Rivera "Smoothie" or Arlen Ness "Big Sucker" are good examples.
* Use the stock header pipes or pipes that have the same length and diameter.
* Fit mufflers with free-flowing baffles. If you like the traditional shorty dual mufflers then use old style (loud) Screamin' Eagle slip-ons or the same thing from Cycle Shack. For touring riders, there is no better than the SuperTrapp touring mufflers with the performance baffle set; this is the same as Screamin' Eagle touring mufflers & SuperTrapp baffle set mentioned earlier.
* If your engine is one of the carbureted versions, fit a Mikuni HSR45 with the Mileage Kit (Fox Distributing, near Chicago (630) 513-9700. This carburetor greatly improves throttle response and ups peak power between five and seven HP.
* If you have EFI, then you might use the Screamin' Eagle Race Tuner kit or a Power Commander from Dynojet to get the mixtures just right. Stock 'jetting', carbureted or EFI, is very lean in the 20 - 40% throttle range and become more so after the air cleaner and muffler changes. You must re-tune the EFI after the modifications.
These modifications are simple, relatively inexpensive and extremely effective. Hundreds of owners have modified their engines to these specifications and none that I know of has regretted the changes. These moderately altered engines have a very wide power band, much wider than stock. It starts at about 2200 rpm and extends past 6000 rpm. They are also more tractable and pleasant to use than stock. Passing or climbing power in top gear is remarkably improved and a Harley with such an engine will generally blow the doors off most big-cam, high-hor$epower bikes in a top gear roll-on.
For those of you who are not familiar with Bill's reference to my earlier Twin Cam 88 recommendations, let me give you a brief recipe:
* Change the cam design to one that closes the intake at near 30-degrees after bottom dead center (ABDC). This starts real power at or near 2500 rpm which is 55 mph in top gear. Either the Screamin' Eagle 204 with a Crane 4-degree advance engine sprocket or an Andrews TW21 performs well. My JM20 cam set is no longer available as Bartels' Performance Products has not ordered any from Andrews for some time now.
* Fit a Screamin' Eagle or similar free flowing air filter. Avoid those filters that have the air turn corners or that directly expose the filter element to the air stream. The Screamin' Eagle, Rivera "Smoothie" or Arlen Ness "Big Sucker" are good examples.
* Use the stock header pipes or pipes that have the same length and diameter.
* Fit mufflers with free-flowing baffles. If you like the traditional shorty dual mufflers then use old style (loud) Screamin' Eagle slip-ons or the same thing from Cycle Shack. For touring riders, there is no better than the SuperTrapp touring mufflers with the performance baffle set; this is the same as Screamin' Eagle touring mufflers & SuperTrapp baffle set mentioned earlier.
* If your engine is one of the carbureted versions, fit a Mikuni HSR45 with the Mileage Kit (Fox Distributing, near Chicago (630) 513-9700. This carburetor greatly improves throttle response and ups peak power between five and seven HP.
* If you have EFI, then you might use the Screamin' Eagle Race Tuner kit or a Power Commander from Dynojet to get the mixtures just right. Stock 'jetting', carbureted or EFI, is very lean in the 20 - 40% throttle range and become more so after the air cleaner and muffler changes. You must re-tune the EFI after the modifications.
These modifications are simple, relatively inexpensive and extremely effective. Hundreds of owners have modified their engines to these specifications and none that I know of has regretted the changes. These moderately altered engines have a very wide power band, much wider than stock. It starts at about 2200 rpm and extends past 6000 rpm. They are also more tractable and pleasant to use than stock. Passing or climbing power in top gear is remarkably improved and a Harley with such an engine will generally blow the doors off most big-cam, high-hor$epower bikes in a top gear roll-on.
Evans has also written a cruiser project book as well - http://www.motorbooks.com/Store/Product_Details.aspx?ProductID=17016
-fonzie
-fonzie
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35 Posts
I bought this book about 6 months ago, just for fun, and its been an invaluable resource, both as a direct reference while undertaking a project, and asa general enhancer of knowledge.
Definitely worth the 30 bucks.
Definitely worth the 30 bucks.
When I was racing, I buily my own motors, set up my chassis and suspension, ad nauseum. Since I quit, bikes have become much better and need far less attention to achieve incredible levels of performance. I recommend a school, such as Reg Pridmore's CLASS schools for those with a reasonable budget to Freddie's or Kevin's schools for those with serious dollars to invest on the art of riding before spending any money on your new toy. The only exception to this is a good set of tires. The two things that improve a motorcycle's performance the most are good rubber (easy to buy) and a good rider (much training and practice needed, though most aren't willing to make that investment).
However, tinkering is the American way, and Evan's book is truly a great piece of work. Even if you never tackle any of the projects, you will learn a bundle. As far as I'm concerned, his article on engine break-in is worth the price of admission. Based on his recommendations, my bike was broken in in 82 miles. It is a completely stock 2004 SV650. It runs perfectly, doesn't burn a drop of oil and produced 73.1 HP on a DJ dyno. That's pretty impressive for a stock SV. This book is definitely a "must-read."
However, tinkering is the American way, and Evan's book is truly a great piece of work. Even if you never tackle any of the projects, you will learn a bundle. As far as I'm concerned, his article on engine break-in is worth the price of admission. Based on his recommendations, my bike was broken in in 82 miles. It is a completely stock 2004 SV650. It runs perfectly, doesn't burn a drop of oil and produced 73.1 HP on a DJ dyno. That's pretty impressive for a stock SV. This book is definitely a "must-read."
The performance of most modern sports bikes is way beyond the capability of the average rider, so fitting performance parts is usually just for show and bragging rites. I worked as a bike mechanic for a while and believe me; some of the mechanical work carried out by owners was terrifying to say the least. The ****ups like stripped threads, loose brake callipers, axle nuts, missing bolts on forks etc. The repairs kept us busy but it was terrifying to think that these guys play boy racers on public roads. Leave the modifications and vital mechanical repairs to the experts ,it cost less in the long run and could save your life.
I worked in a shop too and know exactly what you are talking about. Downright dangerous (usually about the same caliber as their riding skills). However, there are some that really are good at doing their own mods and, for those, this book is worth it's weight in gold.
One of the main reasons I do all of my own work is because of how terrifying some of the work I've seen from "mechanics" in bike shops and dealerships is. A mechanic that you know is good and really cares about his craftmanship and your bike is a rare happening and worth his weight in gold.
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