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What??
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Im about to build a "stunt/fighter". Basicly a more durable and stronger streetfighter to do wheelies whit..

Im going to put a cage on the bike and there is not enough clearance between the ground and the stock exhaust, its too wide and too long.

So i bought a V & H ss2r slipon, cut off about half of it and its much more closer to the bike and will not be any problem, but its louder (sounds great) and im not sure if the new slipon is good for the engine. Its more like a straight pipe than a silencer..

Is this bad for the engine and what damadges could occur? (Rest of the bike is stock)

 

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It wont hurt anything, choppin on a can wont throw off the exhaust flow enough to cause air/fuel problems.

Could damage your hearing and make your neighbors hate you lol
 

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UnicycleMode
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7,569 Posts
Haha yea. I just heard that the pistons could get burned or something.


You would have to run it so long running noticeably lean on a stock bike that it would boil off coolant before it ruined the engine. Not to mention if you could even get it to run lean enough to do that sort of damage it would amaze me.


(*lean = too much air, not enough fuel)
 

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Impulse Buyer
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25 Posts
Im about to build a "stunt/fighter". Basicly a more durable and stronger streetfighter to do wheelies whit..

Im going to put a cage on the bike and there is not enough clearance between the ground and the stock exhaust, its too wide and too long.

So i bought a V & H ss2r slipon, cut off about half of it and its much more closer to the bike and will not be any problem, but its louder (sounds great) and im not sure if the new slipon is good for the engine. Its more like a straight pipe than a silencer..

Is this bad for the engine and what damadges could occur? (Rest of the bike is stock)

It'll just free up the exhaust flow, you may want to upjet slightly to counterbalance, especially if you have aftermarket filters. I ran a 125 with no can on for a month or so, didn't kill it (bearing in mind I needed to rev that thing to shit just to keep up with traffic!). You might be breaking some decibel or emissions laws, so be mindful of that, but otherwise, it shouldn't harm the bike whatsoever :)
 

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watches you sleep.
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9,116 Posts
The length of your can is perfectly fine. Ive run mufflers that were only 6" long total length and no I didnt tear into my engine to check for burnt valves or anything but I ran them like that for a long time and never noticed any problems. It also depends on the bike and whats been done to it. As far as your setup goes, you shouldnt have anything to worry about...but dont quote me on that! lol
 

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Less back pressure results in more fuel/air mix blowing out the exhaust valve, so less in the cylinder, resulting in a leaner condition. The pilot (idle) circuit isn't really affected, but often raising the needles(midrange) a clip and going up a size on the main (top end) will result in a mild power gain compared to stock..we're talking a few percent at best. Large bore bikes (bigger v-twins and thumpers) seem to be a lot more sensitive to backpressure than inlines. My hot rod sportster ran like a turd after putting an open 2-1 exhaust in, lots of dead spots in the rev range and zero bottom end punch- putting a solid eye bolt in the exhaust made a night and day difference.


Prolonged WOT use with a lean motor can in theory burn a piston or a valve, though this is very rare except in extreme cases.
 
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Imho you are going to be down on power as it will run lean, shortening a can or altering the length of a link pipe either way affects the scavenge affect the exhaust has on the motor, a quick way to check if its lean is to do a plug chop

& 'back pressure' has bugger all to do with it as there is no such thing :) its scavenge effect IE the speed of gasses through the exhaust helping to pull the next charge in so a less baffled can or a bigger dia outlet can alter the speed of flow at the head & therefore air speed at the carb inlet resulting in less/more fuel/air mixture being pulled through = lean or on rare occasions rich

The above is true of most but not all bikes EG if it was setup (chucked together) rich at the factory then what you have done could clean it up & make it run spot on

Try it, see how it runs, do basic checks & go from there

hope it helps
 
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