50cc peace sports (gy6) By esstallion (Read 3,060 times)

[esstallion]

I just rebuilt the top end on the scooter. Valves are adjusted and carb is new. The stupid thing will not go faster then 15mph. It runs smooth with no problems but it only goes 15mph. I have 2 carbs and they both do the same thing. The only thing left that looks bad is the intake is cracked looking so i ordered a new one. Anything else you can think of that would make it only go 15mph? thanks.

[jct842]

What does it do on the center stand? is it possible to be off on the valve timing? It must have gone faster than that before you did the rebuild so go back over what ever you have changed.

[Bashan]

An intake leak would certainly cause it to run like that. You should get that off of the radar before you start trying other things. Rich

[esstallion]

Im not sure how it ran before, i got it given to me like that. The timing is set to small hole aligned with head and big hole up with flywheel set on timing mark, TDC. with the wheel of the ground it revs fast. I am hoping the intake is to blame!

[sprocket]

I think you are out a link the cam chain...you need to set the piston at TDC...the T mark may give you the ballpark, but I don't trust it to be accurate, although Rich says his was right on the 'T' on the rebuild...and I would never doubt him.

I say you want true top dead center use the piston to set the cam chain...pretty easy to check, just get a strong light and observe the piston through the plug hole

[esstallion]

I will give it a shot if the new intake dont work.

[esstallion]

When i suck on the vacuum line to the petcock fuel comes out at a steady stream. When i crank the starter fuel just spits out, Does this prove a vacuum leak or is that normal?

[sprocket]

Maybe..does the fuel filter always have fuel in it? Spitting is probably, OK

You have other issues, forget the intake elbow...you can easily check that with
a spray bottle and water...

[Cruiser]

Jun 27, 2012 19:53:47 GMT -6 esstallion said:

When i suck on the vacuum line to the petcock fuel comes out at a steady stream. When i crank the starter fuel just spits out, Does this prove a vacuum leak or is that normal?

That is a normal pumping action since the vacuum when starting the engine will be in pulses so the petcock will allow fuel in pulses. Once the engine is running, the vacuum will be steadier and the petcock will allow a steadier stream of gas.

[esstallion]

Scooter Doc, If I was out in the timing would this thing run as smooth as it does? It runs smooth but just wont pick up power.

[sprocket]

Is the variator moving right? The clutch isn't slipping? Check actual piston position , set to TDC using the piston and see what the cam sprocket alignment looks like....wouldn't take 20 minutes...then you can rule out the cam chain....

Are you certain the cam chain is on the crank sprocket..I have seen them run with the chain off the sprocket...

[esstallion]

I think the clutch and variator are correct. I took them apart and cleaned them and with the wheel off the ground the tire spins like it should. and I would say the chain is on because the valves move in time with the piston.

[sprocket]

Yeah..well maybe you don't have enough fuel or the spark is weak or intemittent. Something is wrong...do compression check

[esstallion]

I fixed it, not sure what was wrong. I spent the $65 and got the 100cc bigbore kit and put it on. Runs like a champ! Does about 40-45 mph. Wants to go faster but i think i need to rejet the carbs. What size should i use?

[sprocket]

What size is in it now? I recommend you buy a set of main jets...or try +4 larger than stock...