Running without a silencer...

[Korn]

Anybody know what the practical implications are of ditching the can and going without? Don't worry this isn't for my storm - it's for the gokart.

Thinking of just chopping the link pipe down at the point marked in the picture - any ideas what effect that would have on power/running?
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[Demonic69]

I think the engine would need setting up to run without a can.
I also think having the can at a right'angle would be best Make the pipe either straighter or more towards the right then have a 90degree bend in it. Sorted
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[MarJay]

AFAIK it would allow more air through the engine faster therefore making it run very lean.
Lean=hot.
You clould blow the engine if you have no silencer at all. If you rejet the carbs with bigger jets you could make it run fine with no can afaik. It would just be extremely LOUD!

Drag bikes run with virtually no exhaust at all and they run okay.
Back pressure could also be a problem, but methinks you're not looking for midrange poke a la exup valve.

How does the engine run with no can?

Try rejetting for no can and see what effect it has. If it works, you can cut the pipe back and it will still run the same.

If I were you though I'd attach a couple of wheels onto the exhaust there to stop wheelies!
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Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Hex]

Running with out a can will mean it will run leaner but apart from that I don't really see any problems.

Its not like it need an expansion chamber or you have the exhaust tuned by length (now that is a real black art to me ).

So an adjustment of the mixture (possibly the jets) should see it running just fine can-less, in my opinion mate.
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[MarJay]

Incidentally,
are you running a diff on the rear axle, or is it mainly for straightlining?
It won't corner very well if not.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MarJay]

[andrew]

Which is exactly his point

[Hex]

[Kickstart@Work]

[paulit]

Exhaust tuning

All exhausts have to be tuned regardless if they are 2 or 4 stroke. and all need some kind of backpressure

hows it done, by increasing or decreasing to length of the pipe that leads into can. the wrong length can make the engine run lean or rich.

simple test.

I have a scorpion can on my r6 where the can will allow the pipe to slide in or out of the can. run the bike at 5000 rpm and slide the can further on the bike, the engine speed will increase as it gets leaner, pull the can the other way and the engine will slow down considerably as it gets richer. somewhere inbetween is the right setting. Its called a tuned pipe and thats how the manufaturers do slip ons where no re jetting is needed.
Shorten or lenghen the pipe will require rejet.

As for running with no pipe its very possible by using a reducer on the end of the pipe to create some back pressure. getting the right length is a bit more tricky and is a trial and error excercise.
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[Evilbob]

well i just got my race silencer pipe put back on with a dodgy made up pipe and its longer and does seem allot better mid range and at the bottom and lost a bit just before top????!?!?!
but only cost £20 recon i should try and make it the same length as the original??
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my karma is dieing not fair who cares about spelling? i get the point across, most of the time

[Kickstart@Work]

Hi

On a 2 stroke the expansion chamber design is the important bit.

All the best

Keith
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[P_J]

How about fixing it so that you can quickly/easily, fit/remove when you like?

Sure it wouldnt be too hard to bolt it on when needed.

Suppose it could be a pain in the arse if you do have to re-tune the engine to compensate for no end can/pipe in the first place though.


PJ
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[TiN]

Here's some inspiration for ya:

https://www.zorstec.com/gallery_trikes/38big.jpg


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TiN
dotgems.net

[Racer X]

Frikken cool!!!!!
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< Live To Ride & Ride To Live >

[Beezkneez]

afaik running without a can on a 4 stroke that isn't jetted will burn the valves out or something like that.




Bazza
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[stevo as b4]

Lots of stunt bikes/bandit's have those like really short 4-6" cans fitted, and i would expect that there would be a slight change in carburation with a shorter pipe, but like keith and others said, on a four stroke its the length of the headers, going into the collector for a 4-1 or 4-2-1 system that really counts, and a sports bike motor might not barely run it this length is altered, as its a designed length to suit the engines characteristics. After that point you can probably set it up fairly easily to run any length of silencer/tailpipe, so long as you re-jet the carbs as required.

[NSR125-Kid-UK]

I was going to say something about back pressure except it seems to have been said. All i can suggest is that you/zim get some earplugs!
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