Compression on hpi 5b 23cc fuelie

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J

Jallen

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My 5b has set for a 8-9 years after my son brought it back not running. He was going full blast and said it just quit. I took the gas tank out and carb off. I will get them clean tomorrow. It has spark. I am not sure i have good compression. Anyone know what compression i should have in the stock 23cc CY engine?

Also, can i rebuild the top end without removing the engine?
 
Over 100psi
How does the cylinder and piston look through the ports?

You can rebuild it in the truck, but I'd recommended removing it.
 
I for sure do not have 100psi by “seat of pants” feel.

I went ahead and took the top end off. The piston was smeared on the exhaust side and ring was stuck. We put an aftermarket pipe on it when new but i do not remember the name of the pipe.. Caused the smear? Looks like i need a new top end.

I looked at my parts that we bought with the baja new. I don’t remember why (10+years ago),,but i bought a +2mm stroker crank (p/n dd308) and a 35mm top end (no p/n) kit labeled as Daves Discount Motors. I assume that top end will not work unless i also change the crank? Would need different carb?

I am leaning toward a stock top end unless there is a better option. I want reliability,,not speed. It is fast enough for my 7yr old grandson already. I would rather not rebuild often.
 

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We did not change any carb settings when i installed the pipe. Education is expensive sometimes! I will richen it up after rebuild.

Any idea what that pipe is in the pic?
 
If you installed a pipe and didn't richen it up when doing so that is probably the culprit. Adding the pipe increases air flow and with the added air you need to also add fuel. Be sure to add fuel when you get it up and running. Don't be shy, start out pig rich and take fuel out from there.
Also, if it sat for a while be sure to check and clean carb. Sometimes they can get clogged up from old fuel sitting in them, the passageways are so small it doesn't take much to plug them up either.

No clue here on the pipe .
 
Smokinwheel,,I will definitely do that. I will go read up on what it should sound like when adjusted correctly.
 
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