2010 Eton Sport 50

[tattoodirt]

Ok I am puzzled as to what size valves the Eton Sport 50 has. The engine is 1P39QMB if that matters. I want to do some performance mod to it. Like a bbk. Or better yet I would love to do a gy6 swap and put a 150 on it. But Im dont have the resources to do metal work. So the bbk would be the best. I have already changed the ignition coil and cdi. The stock cdi was rev limited. Changed out the intake and exhaust to free flow. Plan on getting a better carb also. Stock carb came with 85 and 35 jets. Removed the variator washer too. It was restricting it as well.

I wrecked the scooter last sept and broke both legs so Im just really getting to where I can try to fix it back up. It was running fairly decent until it ex valve broke off. 

Heres my questions
1) Is it possible that the valve breaking off in the cylinder has done any damage to the bottom end?
2) What bbk should I get for this, 72cc 80cc or 100cc?
3) What are my valves, 64mm or 69mm? 
4) Or does valve size matter as Im switching to bigger head with bbk install?
5) What size jets would I need after bbk install?
6) Does ANYONE else own one of these Sport 50s? 

Any info that anyone can give me would be most appreciated. 
Have a good day and ride safely.

[Rebel]

The 139qmb is a 50cc gy6 motor. 150 cc parts will not work except the cdi, spark plug that sort of thing.

Don't worry about the valve size if your big bore kit has a head with it.

Yes youcould have some bits of metal floating around in the crank case after a valve breaking off and it would be good to nake sure you don't.

I would suggest it would be best to go with a 72cc bbk. These motors are not known for strong crank bearings and going bigger is putting more stress than would be prudent for a daily rider.

Best performance gain for the monet might be a performance variator.

Glad you recovered from the accident.

[tattoodirt]

What is looked like when I got it. Wasnt the best but she run.




Heres a few pics from last year before I wrecked it






And my tail light

Now for some crashed pics

[tattoodirt]

Ok now Im not really a mechanic but I am learning how to work on mine. What would I need to do to make sure the bottom end is clear of metal or what not from the valve breaking? Will it be hard to do?

[Rebel]

Did it go through the piston? If the piston was intact you shoild be OK. If it has a hole in it, the only sure fire way to be confident is to take the case apart amd clean it all out. It is less work than it sounds like. But it is taking it all apart.

[tattoodirt]

I haven't gotten around to taking this thing apart to see what the damage is to the inside.It will be a few weeks before I can get a replacement head. I do know that when it blew the valve if took the head off my spark plug so it cut off instantly.

Do you know of anywhere I can find a tutorial of the bottom end and how to clean it and take it apart? I got to study up on it before I order the parts. I like to study up on things I know nothing about. I may just end up cleaning it out just to be 100% sure it wont be a problem later.

Once again thanks for all your help.

[Rebel]

Well I have shop manuals in the help area. Look at my sig line for a link to them. They would have all the needed info.

[tattoodirt]

Thanks Reb, you been a great help. Im glad I found this board.

[Rebel]

You are welcome.