what will i gain by eliminating box muffler on hs142?

worksuxxx

worksuxxx

New Member
I am still running the stock box mufflers on my two cruisers with the hs142 motors. I tend to like the look of the box muffler for the simple fact it fills the space better as well as it looks good. But, i may give that up for a different exhaust setup if the benefits will justify my doing so.
Please chime in if you have some info to share, i would prefer those who had ran with the stock box muffler and made the change to post their experience.

Thanks in advance..
 
You get more noise, a good noise too.
I used a kit 2 stroke kit exaust with the tip cut at a angle, looked cool (profile pic)

I noticed that the throttle response was better, more power, felt it pick up speed better when I was riding it around.

Check spark plug to so that u don't run to lean
 
ocho ninja said:
You get more noise, a good noise too.
I used a kit 2 stroke kit exaust with the tip cut at a angle, looked cool (profile pic)

I noticed that the throttle response was better, more power, felt it pick up speed better when I was riding it around.

Check spark plug to so that u don't run to lean
Click to expand...

As ocho ninja said......if nothing else, your engine will be louder and that is not necessarily a better thing. Don't confuse louder exhaust tone with better performance ;)
 
I wasn't quite sure of much gain by putting a pipe on. I wouldn't think a 2.5 hp motor would benefit much.
I drilled some holes in the air filter box cover to allow better air flow yesterday, i did notice a liitle difference with that.
I also have been playing around with the valve clearances. It seems to me .004 .006 mentioned elsewhere in this forum gave me the worse performance out of this motor. Setting the valves to .007-.009 and .11-.13 gives the the most pull from a stop all the way up through the rpm band. After riding for a while at these settings going back to .004 and .006 it feels the motor has no acceleration.
Just wanted to throw out there the valve settings for anyone who hasn"t tried a different setting. You might like it..
 
Sure you can throw a pipe on these.

2_BigRed2L1280.jpg


In many cases even a stock 2-stroke pipe will work out the right side just by elongating the pipes bolt holes so you can adjust it.

BigRedDoneR.jpg


The box exhaust is nice and all, but it exits pointing down right above where your foot is.

4-strokes have valves so you want the exhaust to exit with ease with just a little back pressure and mufflers usually provide.

The examples above were just as quiet if not quilter as the box from a riders ears but I didn't really notice any power difference, then again I wasn't looking for that.

I haven't messed with the valves yet but I will explore your tip, actually I haven't done anything aimed at performance on them yet!
On my next 142F I'll play with performance, I haven't done that yet and it sounds fun.

gasbike HS 142F / 4G kit buyers alert.

There will be a change in the output shaft and sprocket options on the 2014 production run of 4G's.

I can't publish the actual engineering drawings Don and I have been working on but output shaft won't be that fixed sprocket with retaining nut and busing design.

The new output shaft will be a bit longer 15mm shaft slotted all the way to the 4G with both 9T and 10T slotted output sprockets with 180 degree offset set screws.
 
I cut the 2 stroke exhaust to a nub and ben conduit to make a better looking exhaust.... Runs a little better and doesn't look so much like a generator engine on a bike.....

 
I can't speak to any performance change as I just finished building yesterday, I went with the Phantom exhaust mainly for the aesthetic, and getting the hot exhaust away from the front. What I wasn't ready for was the noise, I'll be looking into their "silencer" add on tip. It's pretty loud while riding, very soft purr at idle.
RSdPYW2.jpg
 
The box muffler is rather restrictive - but it does work.

It's excellent for midrange torque, but if you plan on extended 6K-7K+RPM operation, an aftermarket exhaust will deliver noticeable gains.

An old chinagirl exhaust can make a great header. Just cut the pipe about 2-3" from the flange. Bolt a flexpipe or equivalent to it, cap off with a Briggs 4-8HP muffler.

The muffler can be had at Ace Hardware or Home Depot or just about any lawnmower shop. I got mine for $5 at Ace.

You'll get better sound and a little more average power with a proper exhaust. You'll notice it mostly at high RPM pulling power.

Here's what it all looks and sounds like:
http://www.youtube.com/watch?v=n7-TsrRGswg
 
I can understand the box exhaust can be restricted to an extent. I am also gguessing you are right about more power in the upper rpm range. But with my experimenting with different valve settings, i have to say most of my torque is at low to mid rpm range with valves set to .007-.011. I really like the torque for take off and for regular cruising speeds. I do notice though my top end does suffer the lower torque while trying to get to full speed. But a majority of my riding is not full speed. With the valves set to .004-.006 my take off and mid range torque is very noticeably lower, yet much better pulling power from 20-30mph. So i guess it all boils down to where you want the torque curve to be at to match your riding style. I have a few days off early next week, so i plan to put on a 4 stroke exhaust pipe, then experiment with different valve adjustments to see the difference in the torque curve with a less restricted exhaust.
 
Most of my own riding is in the 3600-6000 RPM range (19-32MPH in 5th gear)
I keep my valves set to the settings dictated in my valve adjustment thread (link in signature).

Right now I'm running without a muffler, just straightpipe. I had better overall performance with the muffler, but the damb thing fell off awhile back lol
 
worksuxxx said:
I have a few days off early next week, so i plan to put on a 4 stroke exhaust pipe, then experiment with different valve adjustments to see the difference in the torque curve with a less restricted exhaust.
Click to expand...
Cool, I look forward to your results ;-}
 
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