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Discussion Starter · #1 ·
I recently purchased an 04 crf50 for a few hundy. Bike is absolutely wore out and engine is blow. I'm new to this and need some direction. The bike has been a little modified but still stock ride height but, in very rough shape. Basically everything cosmetic needs be replaced. Question is, do I try to keep it stock as possible or turn it into a pit bike with piranha suspension and engine in mind. I cant seem to capture what these machines are worth so any help would be greatly appreciated.
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I'm more of a vintage bike guy...but from what I've seen...unless is was in pristine stock condition...it's not really a collectors kinda bike. I'd say you could do anything you want with it. Make it fun...for YOU.
 

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From what I can tell at first glance it has some decent parts on it. Tall bar kit with Sano triple clamp, and presumably Sano fork springs and bushings and +1 legs, billet throttle, two bros. footpegs, aftermarket skidplate and exhaust. If it's a Honda motor that's not a bad buy for a few hundred. A good degreaser and/or simple green bath would do that bike wonders. As others said choice is up to you. But in stock form like you have here, they are a blast. If it's Honda motor I would rebuild that over going chinese crate motor. If you want to build a chinese bike you might as well just buy one complete. By the time you build this one up you will have taken off every part on the bike except a few items.
 

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Discussion Starter · #6 ·
I'm more of a vintage bike guy...but from what I've seen...unless is was in pristine stock condition...it's not really a collectors kinda bike. I'd say you could do anything you want with it. Make it fun...for YOU.
 

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Discussion Starter · #7 ·
Thank you guys for your advice. Definitely gave me some direction. I don't know how to tell if the engine is original honda equipment. If it is I would rather rebuild it. The bike is getting it bath today. Stunt-ur thank you very much for letting what is what because I honestly dont know what I'm looking at. My goal is to give this bike to my daughter, she is 12 with no riding experience. Please guys keep the comments coming. Really want to where to buy a quality rebuild kit for the engine. Mind you I'll have to replace everything in the case. Thank you!
 

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Discussion Starter · #11 ·
What is a recommended complete rebuild kit that includes upper and lower? I might have to replace the crank maybe even gears. I guess I'm preparing for the worst lol!
 

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What is it that makes you think the engine is in such bad shape??
Most likely you'll only need a top end rebuild...
You might have to split the cases to replace the shift forks and wear parts. But the trans and crank are usually fine. I usually advise to get it running, then decide what it needs, lol. (I'm betting it would run...as is) Does it turn over?? If you spin the flywheel?
 

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What is it that makes you think the engine is in such bad shape??
Most likely you'll only need a top end rebuild...
You might have to split the cases to replace the shift forks and wear parts. But the trans and crank are usually fine. I usually advise to get it running, then decide what it needs, lol. (I'm betting it would run...as is) Does it turn over?? If you spin the flywheel?
I was thinking the same thing. These little engines can run in all kinds of condition, and a top end is usually all it needs to perk it up, if it needs rebuilding at all. Do what Kirrbby said.
 

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Discussion Starter · #14 ·
The engine doesn't turn over at all. The kickstarter lever seems to be frozen unless you hold the geat shifter down in first gear. But, once the kickstarter does turn the piston doesn't move nor does it seem to engage the the crank.
I was thinking the same thing. These little engines can run in all kinds of condition, and a top end is usually all it needs to perk it up, if it needs rebuilding at all. Do what Kirrbby said.
If do need to build the top end...what's is the best kit would you guys recommend?
 

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The engine doesn't turn over at all. The kickstarter lever seems to be frozen unless you hold the geat shifter down in first gear. But, once the kickstarter does turn the piston doesn't move nor does it seem to engage the the crank.


If do need to build the top end...what's is the best kit would you guys recommend?
What you are describing as far as the kickstart engaging and not engaging and not turning the engine could be a frozen clutch. Take off the right hand engine cover after draining the oil and take a look, but I bet your clutch plates Are frozen together. Unfortunately, what usually makes them freeze together is rust, so getting that cover off will give you an idea if you have an internally rusty engine. Hondatrailbikes.com has a lot of the parts that you would need to freshen up or modify this engine. There are also some other vendors like Tboltusa.com , hondanuts.com ,and dratv.com that carry oversize pistons and big bore kits. If you were going to keep it stock, I would just look for a 50cc new cylinder, piston, and rings. You can get an oversize piston, but then you need to have the original cylinder bored. It is often about the same price just to pick up a replacement cylinder. Most of the cylinders you’re going to find in an online search, even the cheap ones, will work just fine.
Edit: Thinking about it, there is also a good chance the piston is seized in the cylinder, also most likely to rust. Before taking it apart, you might try to get the piston loose by spraying penetrating oil (PB Blaster is a fave) into the spark plug hole, let it sit a couple days, heat the cylinder, find a hill and a heavy rider, shift into third gear holding the lever down, get up to speed and release the lever. Sounds a little goofy, but it can work with lightly rusted rings. The other alternatives are a gear puller to press the piston out once the cylinder is loose from the block, or a hammer and wooden drift to drive it out.
 

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If do need to build the top end...what's is the best kit would you guys recommend?
That all depends on what you want to do and want to spend. You can go from MILD to WILD with quite a few options in between. The TB Parts kits are the best bang for your buck, by far.
 

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Discussion Starter · #18 ·
This just a follow up. I pulled the clutch case and the clutch assembly the attaches to the case fell out and I found broken case fragments. I inspected the internals of the engine and it all seemed really clean. The case fragments is where the previous owner has blew through the bottom of the case mounting the foot peg cross member with a to long of bolt. With all the said, with the clutch case off I now can kick the engine over. It has compression and spark and I haven't as of now tested the fuel system. I dry put the clutch case and linkage back on and can still turn the engine. So in conclusion I believe the previous owner didn't put the clutch back together properly and thus failed to kick over. Thank you all for your advice. I will be back to ask more questions as the restoration continues.
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