Build it, Break it, Repair it, Restart...

[Dasgood]

Hi all, Dasgood here, new to the site and just want to introduce myself.

So i've been starting the cycle about 4 months ago, stock kit, and a huge smile! everyone i pass in the streets cannot turn their heads quickly enough...

On the one day to work - yes i actually ride to work with the cycle - how can you not, it is so much fun and the expressions.. priceless - anyways, i was going downhill clocking about 50km/h and there was these yellow stripes on the road... not knowing they were small (about 30mm high) speedbumps... and there was a good 60 of them... shaking my but off, standing, ensuring control on the cycle, teeth grinding and done... got to the other side... all power on the motor gone..

Now this is where I had to start using those pedals.. oh man... slight uphill and another 10km mostly downhill to go to work..

The problem was not so much the "get to work" scenario, more the "get home from work" as work is most of my trip back home is uphill.

Got home, exausted, tired, hot.. but nothing is stopping me from checking out what got hurt...

So I pulled the motor apart, saw the barrel scratched, piston not looking to good, and decided i'll upgrade... hehe..

Just received my spares, started last night, replaced the piston, and will continue after this weekend...

Cannot wait to get back on the bike!

Hope to read and comment more on this site/forum as this new found hobby is awesome!

Dasgood

 

[Kioshk]

Hey Dasgood,

Welcome! Be sure to properly diagnose what caused your top-end damage. If you indeed took the engine COMPLETELY apart, I'm sure you cleaned it out and removed any residue which might cause more cylinder destruction. In my experience, I have lost a few in my learning-process. Upper needle-bearing disintegration was the #1 cause followed by lower needle-bearing failure and a wayward piston-clip (I'd tinkered so much with my upper-end that my clips lost their springiness). Of course, make sure you're using the right premix/air-mix too; I destroyed my very first cylinder via overheating.

 

[Dasgood]

Hi Kioshk,

thanks for the advise. I'm replacing even the barrel section of the motor, only thing that stays is the conrod and the head.

piston was really dark/black looking, so i'm thinking that i overfueled a lot as well.

Will keep posting my progress

 

[Dan]

Howdy Dasgood, welcome to the forum! (LOL w/ Marvin the Martian. http://www.marvinfiles.8m.com/sounds/new3.wav )

Your introduction made me think of the thread "I love getting that look" Great thread and a fun read.

 

[paul]

hello dosgood and welcome to the world of motorized bicycles, I use my bike to ride back and forth to work. I live on an island so I have to pedal assist but I figure I get a little exercise that way. great to have you with us

 

[CARider]

Dasgood- What kind of oil were you using? What mixture?
I would suggest getting just a new top end, piston and cylinder, and you'll be back on the road again. Are there any large scratches in the cylinder? If not, just watch out for the piston rings when assembling!
-Zane Smith

 

[KCvale]

Hi DasGood.

As you now know motorized bicycles do draw attention, even more in your part of world I would suspect.

... I was going downhill clocking about 50km/h and there was these yellow stripes on the road... not knowing they were small (about 30mm high) speedbumps... and there was a good 60 of them... shaking my but off, standing, ensuring control on the cycle, teeth grinding and done... got to the other side... all power on the motor gone..

That looks to be the 2013 gasbike.net 'parts in a box' 66cc skyhawk engine you have, is that correct? You installed the piston, cylinder, and head?

That is a darn fit kit from the Yang Dung engine factory you can see when you put the top end on.

So I pulled the motor apart, saw the barrel scratched, piston not looking to good, and decided i'll upgrade... hehe.

Did you check for spark on the plug before you pulled your engine apart?

I ask because the first thing that comes to mind to me after a series of bumps with an otherwise running engine is the crap CDI connection wires, the plug cap, or the carb float.

In short I just can't see hitting some bumps screwing with your internal engine parts if it was put together right to begin with is all.

 

[Theon]

Check under the piston crown.
Is it black, then she's been getting hot and possibly to lean, causing piston to expand and scratch.
It it's still shiny then it maybe rich.
These motors often come with a gut full of metal swarth from new, which would help to scratch up your barrel.