Shortening pipes on cruiser - what an effect?

[putin]

What is the point of long pipes on cruisers? I am planning to buy Suzuki M50, and want to cut the pipes in half, just like the view. How it will effect running of the bike? Shall i keep whatever inside stock pipes? And i want sound quiet and deep.

 

[Fire-medic]

What is the point of long pipes on cruisers? I am planning to buy Suzuki M50, and want to cut the pipes in half, just like the view. How it will effect running of the bike? Shall i keep whatever inside stock pipes? And i want sound quiet and deep.

Well, what you're doing will probably accompany just the opposite of what you want. Sure, 'keep whatever inside stock pipes,' I'm unfamiliar with the Suzuki exhaust guts, I suspect things are a welded component, so trying to do that will likely result in its destruction. There are baffles of various sizes available aftermarket. You could search for something whose O.D. is a close-fit to your remaining pipe I.D. but if it's not a tight-fit, the rattle will probably drive you crazy. An 800 cc V-twin will never have a 'deep' tone, it's too-small. Short straight pipes will be loud, probably annoyingly-so. What have you found on the 'net for short straight engineered replacement exhaust systems?

 

[MaxMidnight]

In addition to what Mr M has said above another consideration will be how it affects the running.

In many respect an exhaust is like an organ pipe it has a gas going through it and when it comes out of the end it makes a sound.
These sound waves have amplitude (i.e. the maximum extent of a vibration or oscillation, measured from the position of equilibrium.)
These waves travel up and down the pipe; at their maximum the pressure will be highest and at there minimum it will be at its lowest.

Manufacturers will time the arrival of the maximum pressure back at the exhaust valve to push back any un-burnt mixture to maximise the bang.
They will also time it so that the lower pressure will arrive as the exhaust valve opens to help scavenge the exhaust gas.

Can you imagine what will happen if you get these events arse about face?
You won't know, unless you do the calculations how chopping the exhaust will affect how the engine runs; you may be lucky or not or you may be somewhere in-between.

Place your bets now.

 

[putin]

I saw on youtube guy just cut pipes on m90. Looks like nothing wrong going on. Sound louder, of course. I don,t see nothing short aftermarket, what i likes. Probably i will try cut the pipes.

 

[Parminio]

There's a reason most bikes have long pipes. It's called "Carbon Monoxide Poisoning".

Cars and trucks and bikes all have the same basic rule: the exhaust must exit beyond the passenger compartment / area.

It prevents people inhaling Carbon Monoxide straight from the exhaust during rush hour traffic and traffic jams.

You should check the laws in your particular state so you don't wind up getting cited, having your bike impounded and after all that expense is over having to shell out for a new exhaust pipe.

 

[Fire-medic]

Your bike, your choice.

I wouldn't do it. I suspect at some point you'll sell the bike, A stock unmolested bike is an easy-sell, a modified bike with a stubby exhaust is likely going to be a harder-sell. If you do decide to cut them, try to choose a point where you could re-weld them back together easily, if you ended-up with asking yourself, "why did I cut those?" A package of hipster cloth exhaust wrap, and no-one will be the wiser.

 

[Itgoes]

You could try something like these: Muffler 13 Big Mouth Satin 2.0 not too expensive and appear to be well made. Here is the main website.......other less expensive stuff available as well. Mufflers | Niche Cycle Supply | Motorcycle Parts Online Store

Or I've used these guys in the past if you feel like being adventurous. Motorcycle Components-Cone Exhaust Stuff
https://www.coneeng.com/pdf/motorcycle/MC-finished-Mufflers.pdf

 

[putin]

Thank you all for great input. Probably keep the stock and buy a shorty. But first need to buy a bike. I want to make a bobber.

 

[02GF74]

Re MM, yeah but the length of the exhaust will help the engine at certain rpms. Changing the length will change the rpm.

Read up about yamaha exup, a cunning valve system that changes the length of the exhaust.

If you are chopping the exhaust for looks and not bothered about the effects on the performance then it doesn't matter.

 

[Fire-medic]

Re MM, yeah but the length of the exhaust will help the engine at certain rpms. Changing the length will change the rpm.

Read up about yamaha exup, a cunning valve system that changes the length of the exhaust.

If you are chopping the exhaust for looks and not bothered about the effects on the performance then it doesn't matter.

Re MM, yeah but the length of the exhaust will help the engine at certain rpms. Changing the length will change the rpm.

Read up about yamaha exup, a cunning valve system that changes the length of the exhaust.

If you are chopping the exhaust for looks and not bothered about the effects on the performance then it doesn't matter.

An 800 cc V-twin needs all the performance assistance it can-get. I suspect RWHP for something like that is in the low-40's. That should be able to maybe break 100 mph, but as Jeopardy's James Holzhauer might-say, "all-in!" With the typical cruiser/bobber feet-forward riding position, buckhorn bars, and not-much power that last 10 mph is likely going to-be a white-knuckle exercise in wobbly aerodynamics. Those bikes aren't made nor suited for that-type of use.

 

[MaxMidnight]

Re MM, yeah but the length of the exhaust will help the engine at certain rpms. Changing the length will change the rpm.

Read up about yamaha exup, a cunning valve system that changes the length of the exhaust.

If you are chopping the exhaust for looks and not bothered about the effects on the performance then it doesn't matter.

True, but unless some calculations are done you wouldn't know at what revs that sweet spot would be.

To be pedantic the EXUP valve doesn't change the length of the exhaust but mimics the effect of a longer or shorter exhaust by altering the harmonics which is what I was alluding to in my previous post.
The power valve and its clones had a similar effect on two stroke which are far more sensitive to alteration in exhaust geometry.

I agree that it is Mr Putin's bike so he can do whatever he likes.
That said surely it is better to be aware of potential consequences before applying the hacksaw?