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I started my search for a little more power by investigating the possibilities of swapping my stock pistons for a couple high compression pistons. It's a simple process and generally a higher compression piston will give more power. But, I quickly found out compression ratio is far more complicated that I thought. The numbers we're most familiar with are static compression ratios and that is far from the end of the game. I did find some 13.5:1 pistons but later on in my quest for a better understanding of the whole power building scheme, I found one caveat after another and without understanding what else is going on during the combustion and exhaust process, you can be peeing win the wind so to speak. Iactually had a good taste of this phenomenon back in 1984 when Harley Davidson was offering a winter special (big bore and cam kit for the 80 C.I. bikes. It sounded like a real deal, more displacement along with higher lift cams and they did all the work for about $1000. Pistons and cams would normally cost more than that and labor would be another half a bill at least. Luckily they did a dyno run before and after the work for comparison's sake. To my dismay, the new setup made less power than the original. It have have made a little more torque but I was looking for H.P. as I felt I already had enough torque. Lesson learned. In an endeavor to get a little more power, most "shade tree" enthusiasts go for a set of pipes and/or a high flow air filter, mainly because it's pretty easy to replace them and relatively inexpensive. If you are/were a subscriber to Cycle World or one of the other Cycle rags over the years, there have been many articles on the complexities of modifying the intake and exhaust on your motorcycle and why, bigger isn't always better. More flow, and in the right place (RPM wise) is how performance is enhanced or diminished. Cycle World had a really good article a year or so ago about why your stock intake system shouldn't just be butchered or eliminated if power was a concern. Basically it said, "a lot of work is put into making the air cleaner container flow as much air as possible and at the right time. The same goes for the exhaust system, even if it's "too" quiet and maybe a little porky too. Any way, I found this article that may just enlighten people before they begin to start surgery on their bike. Maximizing Cylinder Head Compression Ratios for More Power - Part 12
 

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I started my search for a little more power by investigating the possibilities
Some things come the hard way, late teens I tried to swap in 29mm carbs for stock 26mm, so I could really go places. I went places all right, straight to being the slowest ride in any group. Could never get a main jet/needle jet combo that worked cause there wasn't enough vacuum to pull fuel in.

Been thinking about power mods too for this winter off season. I would like to see how somebody else put the bike on a diet to change power to weight ratio. I lightened with Yoshi exhaust, I know about battery swaps to lithium.

But what else is easily in reach if you go for less weight? I know where the fat is on most bikes, but this rider is already down to 155 lbs no offense to anyone please no flames...
 

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I also have a Yosh pipe and that does get rid of quite a few lbs. I put a Yosh fender eliminator on and that may have shed a lb. or two at the most. I put on a short fender on front, may have lightened by a couple ounces. I never ride with a pillion but I really don't want to change the seat or the rider pegs as I never know when someone may need a ride and we share our car because we decided that because we're retired, the costs associated with a second car just aren't warranted. Half of the time my wife sends me on her errands. There's not much a person can do to lighten the XSR700 without hampering the overall attributes that make it such a nice bike. I've seen some that do a "hack-job" and cut off the subframe but for my 2 cents, that ruins the bike. I'm still considering a set of high compression pistons but I'm not sure, going up a whole 2 points might be a bit much and I don't want to have to run premium fuel. The more I looked into the Aprilia RS660, although it's a faired bike, that 100 h.p. is measured at the crank, not the rear wheel and the 370 lbs. is a dry weight. Add oil, fuel, and coolant and it could easily be 400 lbs. According to the latest I've read, Aprilia is looking at a price tag for the 660 at a tad over 11 grand. If I was going to spend over $11,000 there are several bikes in the 900-1000 class you can get. I guess I'll be hanging in limbo for a while.
 

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There's not much a person can do to lighten the XSR700
I'm so completely satisfied with the bike I built out with Ohlins all the way round, 2wdw flash & Yoshi pipe, stuff++.

It's like riding a dirt bike on the street, planted and composed until I decide to loft the wheel. Only minor dislike is ABS, no stoppies, and that annoying "rattle rattle-cack back" when it kicks in. If you didn't practice triggering that ABS it would probably scare the crapola out of you first time you're too deep and it kicks in. That's a good tip someone should pass on to the new riders - practice triggering that ABS front and rear regularly so there are no surprises when it matters.

Maybe we can lose weight by filling out tires with helium? How many party balloons does it take to fill a rear tire? ;)
 
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