GY6 150cc Camshaft Question By mikey (Read 3,052 times)

[mikey]

Where in relation to the rotation limiter does the cog/lug on the camshaft sit when re assembling or does it automatically locate itself?  I am not sure if I have it correct.  I have used photos from bashrans thread on this forum to hopefully show what I am talking about.  Many thanks all esp Bash for his really infromative thread on dis and re assembly.
This photo shows the rectangular cog/lug.

This one shows the rotation limiter

[Alleyoop]

You do not have to worry about where it is located it is a set place no worries. What that does by the way is stop the motor from running backwards that is all it does. Some motors do not come with a camshaft stopper as some cams do not have the protruding stopper on the cam lobe.
Alleyoop

[mikey]

Thank you very much, Alleyoop, you have put my mind to rest. I bought a 5 year old vento that had been in a river for some time and so far all I have had to do to it is general cleaning, change the camshaft and today I will be changing the gasoline for some fresh stuff and seeing if it will run. Fingers and everything else crossed.

[Alleyoop]

WOW!! Scoot in the river for some time THE VERY LEAST of your problems is the Cam Stopper. The major problems will be with the Electricals.
aLLEYOOP

[mikey]

Yessir indeed, Motor back together and in, I am sure I have the cam and chain right.

Removed the PAIR system, it was all clogged up, have the airbox and exhaust off the motor. Turns over well on the new battery, no mystery noises or clanging, seems to be in the right configuration, all the gas/vacuum hoses are in the correct places, dismantled and checked all the carb internals, all ok, got fresh gasoline and a strong spark but it wont start.

Just about ready to give up and take it to my local Italika bodge artist spanner boys here in the village. I live in Mexico by the way. I have tinkered with real motorcycles all my life (31 years riding) but this is my first scoot I cannot get running, I have repaired and sold three of them recently, just badly looked after and neglected.

Any suggestions would be appreciated.

Mike

[mikey]

Gimme a BMW boxer with push rods or any two stroke to work on and I'm a happy bunny

[Alleyoop]

First thing you want to do is PUT the exhaust back on and the AirBox on. These 4 strokes do need some back pressure and with no Air Filter on to much air and not enough fuel will get sucked in. So that is your FIRST PROBLEM right here.

You need fuel, spark and compression for the motor to run. Also timed right or at least close.

After you fix those two things then we can check on other possible problems.
You said you have Spark (DID YOU CHECK FOR SPARK ON THE MOTOR OR FRAME)? It has to spark on the motor sparking on the frame means nothing. If the motor does not have a good ground the plug will NOT FIRE while in the motor.
After cranking it and it does not fire ONCE take the plug out and see if the plug is wet or dry.
If DRY then gas is NOT being sucked into the intake if WET then the plug is NOT FIRING while in the motor SO check the ground wire from the motor to the frame.

Check the compression, if no gauge use the finger trick stick your finger in the plug hole nice and snug hold the throttle wide open and crank it. If it has descent compression it will lift your finger off the hole if you just feel some pressure then low on compression.

Also did you adjust the valves if a 50cc set them both to .003 inchs if a 150cc set them both to .004 inchs.
Alleyoop

[mikey]

Am trying all now, off to the shed...

[Alleyoop]

GOOD LUCK BRO!! Hope it is a simple thing.
Alleyoop

[mikey]

Ok, exhaust and air box on, spark from plug at valve cover not frame, took out the line with fuel filter and replaced with straight rubber just in case it's the buck fifty fuel filter. Yes have compression, enough to force my thumb form the hole.

Spark plug is DRY so how do I fix the sucking problem? Is it the petcock or a hose, what's a simple test?

BTW I don't have feeler gauges so I can't check the valve clearances, right now it's off season here and I won't have a job till November so gauges and clearances will have to wait.

Cheers

Mikey

[Alleyoop]

Not a problem if NO FEELER GAUGE, get a can of beer or soda and cut a piece off 1/2 inch wide and long enough for you to hold it. THAT IS YOUR FEELER GAUGE it is about .003 inchs thick

Ok lets first check fuel from petcock to carb.
1. Get a cup and take the fuel hose OFF the carb stick it in the cup and crank it.Fuel should stream into the cup. If so then the carb is getting fuel.

2. On the Carb you have a FUEL RATIO MIXTURE screw on the LEFT side Opposite the throttle cable.
Turn that screw clockwise until it stops then turn it COUNTER CLOCKWISE 2 1/2 turns. That is more than enough for a motor to start and run pretty good.
If after this IT DOES NOT FIRE ONCE then take the plug out and check if DRY or WET. If Dry then the PILOT JET and PASSAGES are CLOGGED and you will need to take the carb off and clean it out and make sure the passages are clear.
Like this:
TAKE THE PILOT JET OUT AND MAKE SURE YOU CAN SEE THROUGH IT. Then SPRAY INTO PASSAGE and SPRAY SHOULD COME OUT BY THE TINY PILOT JET OUTLETS BY THE BUTTERFLY.

[mikey]

Checked fuel to carb, took hose off and cranked, NO fuel came out. When I reconnected hose to carb and cranked I could see gas flowing into the transparent filter, but obviously not enough! When I checked the carb, the bowl had gas and all the orifices were clean. So I assume I just need a new petcock to let the gas run more freely. BTW the fuel air was just one turn out so it's now at two and a half as you mentioned.

Will try again tomorrow if anybody in this country has a new petcock on the shelf, if not it's two weeks waiting.

Cheers

Mikey

[Alleyoop]

Ok, good means lack of fuel, now make sure the hose from the tank to the PETCOCK goes down as well as the fuel hose from the petcock to the carb goes down NO UPS AND DOWNS the straighter the FUEL HOSE to the CARB the better. Fluid does not flow UP very well You have a Gravity fed system so the fuel must blow down to the carb also not lower than the carb then up to the carb.


TAKE THE VACCUM HOSE off at the INTAKE MANIFOLD and SUCK ON IT and see if FUEL FLOWS BETTER. If the Valves are tight and not sealing it will not create strong suction.

[mikey]

Many many THANKS for helping me out with the Vento all's good now and your help was invaluable.  I have another project LOL a 150 Vento frame that has Aprissa plastics and a 175cc Italika motor, all's running good just missing 12v at the rear light cluster.  Brake light and indicators work ok but no tail (running light) or license plate light, does this feed go through the magneto and or rectifier before it gets back to the bulbs?  Maybe I will have to replace those parts too.

[Alleyoop]

Usually on MOST scooters the running lights work off the battery and come on when you turn the KEY ON.
The other thing is on the right handle bar it may have a LIGHT SWITCH if so push it to the left they are usually set to come on if the switch is in the center or all the way to the left.

But go back by the light socket and TEST the BROWN WIRE that is the power wire for the running lights. The Green and Yellow is for the stop lights then you have a ALL GREEN WIRE for ground on each socket.
So make sure the bulbs are good and are grounded and the wires have not come off the socket.
Alleyoop