Can't get bike over 23MPH

TheWizzerd

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I have never had the fastener loosen up...The tabs the bolts go through on the fender is what always breaks due to vibration and harmonics, The metal tabs are not strong enough...I even reinforced mine and it was still not enough for most of these cheaply made fenders they are putting out these days, hence the reason why I just eliminate them altogether now...lol.
This is why I said to use fender washers to reinforce the area. There are some that have a little tab that needs removed entirely, then use the hole left from it to fasten through using fender washers, and appropriate fasteners.

I agree the fasteners are less likely to back out than the tabs breaking for sure. Some of these fenders tabs break just trying to remove and install them. But if I'm doing it, I'm going to use better fasteners...
 

DAMIEN1307

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This is why I said to use fender washers to reinforce the area. There are some that have a little tab that needs removed entirely, then use the hole left from it to fasten through using fender washers, and appropriate fasteners.
Did that too...And it still failed...What I am saying here is for the benefit of folks here that are buying these cheap Walmart bikes, like most of us do and the "Chinesium" metal these fenders and even the chain guards are made of these last few years now will just not hold up to the metal fatigue and speeds these motors cause.
 

Emcee

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I'm not sure if having the exhaust travel upwards like that would affect performance, but if you try the other exhaust you'll find out.

I was wondering the same thing. When I go to my parents house over the weekend I got my drill there, I am going to oval out the holes in the stock exhaust so I can move it more and see what happens.

See, I have three exhaust stories. The stock exhaust wouldn't fit because of the pedals, I unscrewed it a few turns so I could move it sideways more. Gunk would go all over the front of my engine because there was just enough opening in between the exhaust, gasket and engine for junk to spew out.

I then bought the banana exhaust, had clearance problems but I don't know what my max speed is on that because I was doing my break in with that exhaust.

I then ordered the flex exhaust. The only feasible way was to bend it upwards like I did. I did think to myself the other day of having it like that would affect it.

I do understand the importance of not only having a muffler but making sure it's tight. I once took the muffler off to see how it would feel and sound and it was absolutely horrible. Not only was it super super loud but I also had s**tty performance.
To be fair when it's raining / muddy I get the most amount of crap off of rear tire anyway... I'd take water / mud in face vs faceplanting from 10ft in the air @ 30mph

If I ride at 15mph, will I only faceplant from 5ft in the airm
 

Greg58

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I've had to drill the flange holes larger to offset the muffler, add removable thread locker and a mount near the rear of the muffler. You need the rear mount because the muffler will crack from vibration, I had one to break off where the pipe enters the muffler body.
 

Greg58

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As for fenders I remove them, I haven't seen a modern fender that would hold up to the vibration. A friend of mine was determined to keep his, he tried several things but the rear fender cracked just past the reinforcement.
 

Nickt919

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I had similar results. No matter how or where I added reinforcements or heavier brackets hairline cracks showed up right outside the reinforcements. After a few tries I pulled them off.
 

FrizzleFried

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As for fenders I remove them, I haven't seen a modern fender that would hold up to the vibration. A friend of mine was determined to keep his, he tried several things but the rear fender cracked just past the reinforcement.

Seatpost mounted rear fenders should be able to hold up... but frankly, i'm not a fan of how they look. I've decided the "look" of a fender simply isn't worth the potential risk. No fenders for me... at all... ever.
 

Emcee

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So I have another strange problem.

My first 66cc was black so when you see the word "black" that's what I'm referring to. Current engine is silver.

I thought to myself maybe it's the head that's the problem. I took the black head off of my first China girl and put her on my engine. When I would roll the bike I would get this bright sharp metal sound pulsating as I roll it. When I put the original head on it goes away. My RPMs were great with the black head on it. I was getting around 5100-5200rpm at 20mph with the black head on it.

When I had the stock NT carb I was getting around 5100-5200rpm at 20mph. I noticed when I put the Bofeng that I'm getting around 4800-4950RPMs at 20mph.

1. I would record a video of the sound but you cant hear it too well on the video. I can't figure out why I would have a bright sharp metal sound with just swapping the cylinder considering the piston isn't moving when it's rolling.
 
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