How do I know when to clean my 2stroke exhaust pipe

Khalil Brooks

Member
May 10, 2020
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I’m noticing that I get a bit less speed at the top end than I had a week or two ago. I richened my fuel mixture one notch around the same time and I can’t tell if I need to clean my exhaust or change my carburetor back.

How can you tell/ how long should you go before cleaning the stock exhaust pipe
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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up north now
Look at your plug- how is it? Black/oily/wet? Too rich. Your pipe will accumulate a lot of carbon and oil quick, but generally it takes a lot of miles to plug up a pipe. If your plug is very light gray to white, it's too lean (doubt it).

Your loss of top end could also be because it's way too rich. You didn't say why you richened the carb....

Mix your fuel at 40:1 regular oil, or 50:1 synthetic. Be accurate EVERY TIME YOU MIX IT. If you mix it "pooty close" then you are never going to get it in tune with any consistancy.

THEN- run it for a half hour or so as long as it runs ok. THEN check your plug and see where you are at.

If you are curious as to how crapped up the pipe is, take the end cap off and have a look.

Finally- I find Tony01's "advice" lacking. Not much help at all was it?
 

Khalil Brooks

Member
May 10, 2020
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Yeah even though Tony01 may have a point, I like to know for the future what to look for. I appreciate it
 

Khalil Brooks

Member
May 10, 2020
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I’d changed my carb setting because it was at its leanest. While dialing the bike in to start for the first time I’d fiddled with it, so once the bike started running I figured I might try to richen it (my plug was a sort of ashy gray and I wanted to see if I could make it golden). It went from ashy gray to a darker gray/black and that’s why I wondered if it was too rich. Although I didn’t clean my spark plug (ran out of spray). But Bikeguy Joe reminded me that I’ve been ruining my fuel mixture. I’ve been running 32:1 for about 60 miles and had some 16:1 laying around and mixed it with the 32 for the sake of not wasting it and not buying more gas to leak out of my tank. So I’m guessing the slight loss of power comes from the fuel being too oily in comparison. I’ve returned the needle to the leanest setting and on the way to and from work today I’ll see if my hypothesis about the fuel mixture still stands
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
Now, if you want to experiment, raise the needle one notch, and ride it for awhile, then compare the plug to how it is now.
 
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Khalil Brooks

Member
May 10, 2020
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This is actually what I was doing, until my gas tank sprung a leak and I messed up my fuel ratio. But with the same weird/ unknown fuel ratio today’s ride with the leanest setting seemed more responsive and had more torque than the last week with the richer setting (raised one notch)...my way to work is all downhill so the real test is to see what it’s like on the way back.....and to regulate my fuel mix
 
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Khalil Brooks

Member
May 10, 2020
39
10
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Before my bike self destructed it was doing really well. I’m going to leave the carb the way it is and see what 32:1 and 40:1 look like later on.....I forgot to tighten bolts after every few rides and my front brake caliper fell off, caught my spokes, tore off my forks (carbon fiber) and threw me off the thing