As the title says I gutted my stock 66cc China kit muffler and I found it was both worth it, and not easy with a few unforeseen issues.
Sorry for the lack of pics, had I known what I was in for I would've documented it.
First off my muffler is the non catalytic type with a baffle that looks like two freeze plugs connected by two small pipes, and this whole abomination slides into the muffler and is held in with a couple tack welds in the interior. So I spent a good half an hour with a Dremel attacking the two tack welds and it was free, YAY! After that I simply tack welded the cap back on after cutting the part of the stinger that protrudes into the muffler and now I was ready to hit the road with my hotrodded motor bicycle, well so I thought.
I fired it up and it sounded nice, I was pumped to see if it would make a difference and it did, it ran like trash! Specifically it was 4 stroking everywhere, hot or cold, part throttle or wot, idle or max RPM it was a 4 stroke riot. I actually had trouble, trouble shooting this, because despite the fact it was very obviously rich every mechanical instinct I had told me that if any thing it should be lean after opening up the exhaust. I tried running with the choke part way and and the engine just wouldn't run, ok I finally got the hint.
Through what could only be witchcraft (or my muffler is now acting as a crude expansion chamber) I realized I was somehow running rich so I verified this by fattening up my oil mix from 26:1 to 16:1, set the C-clip to max lean, and removed to the air filter and things certainly improved. I now knew for sure I was running too rich so I ordered the fancy micro drill bit set off amazon, then I soldered and re drilled the carb jet a bit smaller and all of a sudden it was running like a raped ape! To give you guys an Idea I clocked 36 mph on a level street and I weigh 300lbs, btw did I mention it's a 26" steel frame mountain bike? Hill climbing (again 300lbs here) noticeably better I just don't have to pedal up the hills that I used to, and I unlocked a top end which I just never had before.
So if you didn't want to read my looooong winded post here is the TL;DR version.
1. Gutting the muffler, which was a bit of a project in itself
2. Despite common logic, gutting the muffler made my engine run rich and I had to rejet
3. Fat guy now gets up hills
And then there is the sound, many folks here will warn you of how obnoxious your bike will be with a gutted muffler and to be very honest it just isn't that much noisier. Sure it is louder but it is far from "pissing off neighbors" territory, my weed wacker is louder, and my chainsaw is easily twice as loud as my bike at WOT, and it just sounds like a legitimate 2 stroke now.
Possibly relevant note: I am using a 5" chunk of rubber hose on my intake due to my carb not clearing, was this a contributing factor? I don't know but it ran well before I gutted the muffler.
Sorry for the lack of pics, had I known what I was in for I would've documented it.
First off my muffler is the non catalytic type with a baffle that looks like two freeze plugs connected by two small pipes, and this whole abomination slides into the muffler and is held in with a couple tack welds in the interior. So I spent a good half an hour with a Dremel attacking the two tack welds and it was free, YAY! After that I simply tack welded the cap back on after cutting the part of the stinger that protrudes into the muffler and now I was ready to hit the road with my hotrodded motor bicycle, well so I thought.
I fired it up and it sounded nice, I was pumped to see if it would make a difference and it did, it ran like trash! Specifically it was 4 stroking everywhere, hot or cold, part throttle or wot, idle or max RPM it was a 4 stroke riot. I actually had trouble, trouble shooting this, because despite the fact it was very obviously rich every mechanical instinct I had told me that if any thing it should be lean after opening up the exhaust. I tried running with the choke part way and and the engine just wouldn't run, ok I finally got the hint.
Through what could only be witchcraft (or my muffler is now acting as a crude expansion chamber) I realized I was somehow running rich so I verified this by fattening up my oil mix from 26:1 to 16:1, set the C-clip to max lean, and removed to the air filter and things certainly improved. I now knew for sure I was running too rich so I ordered the fancy micro drill bit set off amazon, then I soldered and re drilled the carb jet a bit smaller and all of a sudden it was running like a raped ape! To give you guys an Idea I clocked 36 mph on a level street and I weigh 300lbs, btw did I mention it's a 26" steel frame mountain bike? Hill climbing (again 300lbs here) noticeably better I just don't have to pedal up the hills that I used to, and I unlocked a top end which I just never had before.
So if you didn't want to read my looooong winded post here is the TL;DR version.
1. Gutting the muffler, which was a bit of a project in itself
2. Despite common logic, gutting the muffler made my engine run rich and I had to rejet
3. Fat guy now gets up hills
And then there is the sound, many folks here will warn you of how obnoxious your bike will be with a gutted muffler and to be very honest it just isn't that much noisier. Sure it is louder but it is far from "pissing off neighbors" territory, my weed wacker is louder, and my chainsaw is easily twice as loud as my bike at WOT, and it just sounds like a legitimate 2 stroke now.
Possibly relevant note: I am using a 5" chunk of rubber hose on my intake due to my carb not clearing, was this a contributing factor? I don't know but it ran well before I gutted the muffler.
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