Planet Minis

grw66

What's up PM people. My son's 1984 z50 starts and runs great but it sounds like a tractor. Something in the motor is making a clicking or thumping noise. It sounds like it could be a noisy valve train, or maybe the bike needs rings and a piston. Honestly, I have no idea. I'm not much of a mechanic. The bike also burns oil or smokes a lot when it's running. Besides the noise, the bike runs and start without a problem. I just would like to fix this noise before it does cause a problem. Any ideas would be great. Thanks.

RonKMiller

Do you have a missing pet hamster?

I'm sure to catch hell for this, but I would just buy a new Chinese clone for a couple of hundred bucks, bolt it in and be done with it.

The symptoms you have described are NOT good, and odds are severe damage has already been done.

By the time you pay a "professional" to diagnose the problem, order OEM parts, and pay hourly for repairs you could probably buy a new Porsche instead, or put him through medical school at Harvard.

Your results may vary.

JohnnyB

Bring it over to FastMc's house . He knows his stuff .

cmktech

Disassemble the top end and check for damage there first. No use in tearing into the bottom end right away.

JohnnyB

Recently I heard a bike with just such noise and it was the big end rod bearing . Once the top end is off , check that too .

allmakesmx

Check the timing chain...could be way out of adjustment. Made one real quiet just doing this adjustment...see hondaheaven.com for pdf file service manuals.

Lair

I went there and didn't see a manual. Do you have a link?

allmakesmx

Try this for Z50R models:

http://www.hondaheaven.org/files/manuals/z50r-shop.pdf

and this for Z50a models:

http://www.hondaheaven.org/files/manuals/honda50.pdf

Portland

I ride with Grw and i am pretty sure its not a lower end noise. I believe the valves need adjusting, and the cam chain as well. It does make noise, but its not that bad. not like a knock or anything like that. I think it could also use rings.

Its not the tranny. the transmission makes no noise at all. The noise increases with RPM no matter if you are moving or not.

Lair

Thanks!

arlindsay1992

Based upon that, I'd agree that you should first adjust the valves, then adjust the cam chain. Much better than wasting money on Chinese motors. Some people just don't know how to fix things so they replace them.

grw66

Great Idea's fellows. I'll get Portland right on this. I'll let you know what he finds out. The bike still runs great and the last thing I'd do is put a china motor in it. I'd just part the sucker out and buy another bike. Thanks for all your help.

RonKMiller

Yep, that's why I spent 4 years in engineering college and 2 years in aviation tech school afterwards to get my Masters and FAA Airframe and Powerplant rating. A waste of time since I don't know how to fix (or build) anything.

Do you know that Lifan is the world's largest producer of motorcycle engines and that they are ISO certified? You DO know what ISO certifications are, right?

You are totally arrogant and ignorant to think that a 40 year old simple piece of **** 50cc engine like those that Honda produces cannot be mass quality produced in China. They are built to much higher standards than Honda made them even in 1986. Cessna is entirely building it's newest airplane in China. Boeing has Chinese made rudder assemblies in it's newest plane, the 777 Dreamliner. A piece of ****, no doubt. BMW has many major components for their engines built in Taiwan and very shortly, China. IT'S ALL JUNK 'cause the Chinese are a bunch of idiots that don't know **** from shinola.

This is for his little kid's mini bike for christ's sake - not a freakin' Grand Prix racer.

The engine is TOAST, VAPOR and HISTORY.

firepower354

You could toss an 88 kit and late model take off head for cheap...

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FastMC

Sorry but I have to agree with with arlindsay on this. Fix the stock motor. I will now think twice before ever flying again. Toast ?

cmktech

I hope Cyclerider will chime in about the schooling.

Cue "College is a place where....."

arlindsay1992

Honda sold over 55 million of the Honda cub. They all after a certain point had the same base motor as the Z's and CRF's of today. The Honda cub is the most sold motorized vehicle EVER in the WORLD. So I doubt Lifan is near that. I don't care what you know about airplanes because I don't work on airplanes. I work on minibikes. And just because his engine makes some sounds it is not "TOAST, VAPOR and HISTORY." It is likely a very easy fix and you make me question whether your are "totally arrogant and ignorant."

If it ain't broke, don't fix it. But if it is broke, for Christ's sake try to fix it!

grw66

Very nicely said, or written arlindsay1992. I am going to give you an honorarily degree which, like some of these college degrees, are useless, but nice to have. Thanks for the input. Trying to fix it first is the smartest and cheapest route and heck, that's what this hobby is all about.

Portland

Grw, try putting sand in the oil fill.

arlindsay1992

That's a good idea. It acts like sandpaper and cleans up all the deposits and residues in the cases. Everything looks fresh afterwards.