engine cranks, spark, but still no start :(

[jojo24]

So I've spent 3 weeks, had 3 different people look at it, and still can't fix my 2007 Roketa Aruba 150cc.

Here's a little background info..

I first didn't get spark, so I replaced the spark plug, spark coil, and CDI box and now it GETS spark. So the engine both cranks and gets spark but just wont start.

The day it stopped working, the scooter was lagging and going about 15-20 mph slower. For about a month before it stopped working, the engine would NOT idle. Anytime I would come to a stop I would have to give it gas otherwise it would die.

So many would now believe that the carb needs to readjusted which I did with no luck. So now it won't start and I'm left a sad lonely man missing his scooter companion and would love for anyone to please help

[jojo24]

Also, the fuel line that goes into the carburetor does pour gas out when i disconnect it from the carb so it's not a faulty fuel line.

[gary2gs]

It may sound stupid, but I've seen it before. If it just turns over without even try to fire up, double check the kill switch. If it's in the run position, you may need to ohm thru it or bypass it.
Good Luck,
Gary

[harrywr2]

Jul 31, 2009 13:29:24 GMT -5 jojo24 said:

The day it stopped working, the scooter was lagging and going about 15-20 mph slower. For about a month before it stopped working, the engine would NOT idle. Anytime I would come to a stop I would have to give it gas otherwise it would die.

Adjust your valve gaps...stalling at stop signs and hard starting are the warning signs that it needs to be done.

[rapidjim]

Have you tryed a wiff of starting fluid to determine if it is a fuel (carb) problem? What about compression? Have you adjusted your valves lately?

Just Ideas.

Good Luck

[jojo24]

I don't think its the kill switch bc it sounds like it wants to start. I just replaced it with a new carb and it still won't start. I don't what else it possibly can be and no I haven't adjusted the valve gaps ever, but that's the only thing I have left to do. Can anyone please explain how to adjust the valve gaps and if it's easy?

Thanks for all your help!

[harrywr2]

valve gap adustment procedure...50cc and 150cc is the same

scootdawg.proboards.com/index.cgi?board=discussion&action=display&thread=19177

Intake valve gap on a 150cc between .003" and .004" mechanics preference
Exhaust valve gap on a 150cc between .004" and .005" mechanics preference

Most folks do .004" and .004".

[jojo24]

Does anyone else know what it could be other than valve gaps? Would valve gaps be that big of a deal to not start up my scooter?

Thank you everyone!

[kz1000st]

Of course valve gap would be a big deal. Imagine a valve being held open slightly and the engine having no compression. Without it you also have no intake either so there's no fuel being pulled into the engine to burn. My scooter was running and idling fine but when I checked the exhaust valve I had to turn the adjuster back off about three turns just to get .000 valve gap and some more turns to get my .005 clearance. I was lucky I didn't burn the valve. If your valves are held open by the rocker arms, it's like having a compression release in the cylinder.

[jimh]

Adjusting valve lash may seem like a daunting task but once you do it you'll wonder why you didn't jump into it sooner. It's really a cake walk so just do it.

[Doug in San Diego]

I agree - valves (I had the exact symptoms)

Just buy a feeler gauge and do it. You will feel like the man after you fix this yourself

Heck I just took my entire head off and Im waiting on a new head and a new CAM.

1 year ago I was afraid to change the oil by myself

Just dig in and do it.

[gary2gs]

If I follow you correctly, at first you were running poorly, BUT RUNNING. Then you must have stopped running because you say there was no spark. Replaced some items and got spark but would not start. Adjusted carb. - no difference. Why not double check for spark again and check your carb adj. again.
If all that looks good go to the valves. Don't know your mileage, but on a 2007 you should have done a valve adj. at least once.
Look at it this way, it's already broken. If you take your time and be careful, you shouldn't make it worst.
After that, insure heavily and use a match. Seriously, good luck and keep us updated.

Gary

[jojo24]

Alright, I will try to adjust the valves because it seems like there is nothing else I can do. However, I am having a very difficult time locating the valves. There is a huge plastic cover over everything, do I have to take this off because it looks almost impossible to take off. Or are the valves located towards the front of the scooter where there is metal showing and a little metal U bar. If anyone has a roketa aruba or know where the valves are located on it and how to get them, I would greatly appreciate it.

Once again, thank you so much for all the help and posts!

[jojo24]

To help you get a picture of what my engine looks like, here is a link I found with a picture of it. It's in the middle of the page and it has a red, white, green, and blue arrow on the picture.

www.scooterforumonline.com/index.php/topic,1757.0.html

[Doug in San Diego]

On that picture (in fact all gy6) the valves are on the far left, under the valve cover (the thing with the U-bar)

Take off the u-bar, then take off the four screws holding the valve cover on.

The valves are underneath

here is a good link on how to

scootdawg.proboards.com/index.cgi?board=talk&action=display&thread=23946

Also search Youtube for gy6 valve adjustment

It is totally do-able.

[gary2gs]

In that picture the valve cover is the silver colored, square object on the left side: middle. That picture shows a hose with some electrical tape on it. I don't know if yours will have that hose or not. I think it's for blow-by emissions. There's a good post in this forum on valve adj. I'll try to find it in case you don't have it already.
Gary S.

[scooteral]

I'm not exactly sure how this works but doesn't the CDI receive a pulse from the stator to tell it where TDC is? If thats the case you could have spark at the wrong time and scoot still wouldn't start.
Someone correct me if I'm wrong on this.
You might check the connections on the CDI unit.


Good luck
Allen

[gary2gs]

I see Doug in SD. beat me to the valve pics. Must be the time difference thing between east and west coast. That's a good post. Have one from me Doug. I would still double check the work you've already done. You may have two problems which makes it four times harder to diagnose. "When you come to a fork in the road, take it."
Allen, I think it goes this way. Stator sends pulse (or trigger) to CDI at just a couple degrees before TDC. CDI sends a voltage to the to the coil. Coil steps up that voltage which then goes the spark plug when both valves are closed creating the power stroke. If this ignition timing is off to far, the engine may not start, may backfire, runs poorly.
Good Luck,
Gary S.

[scooteral]

Thanks for the info Gary

Allen

[Doug in San Diego]

JoJo

After you adjust the valves, can you let us know if that worked? Some people solve the problem and never post the result.

Thanks

Doug

[gary2gs]

Yea, what Doug just said.

[jojo24]

So thank you so much guys for all the help. After spending 3 hours trying to adjust the gaps (which will only take me 45 minutes to do now) I thought for sure that I just wasted all day on these tiny stupid gaps. But boy was I wrong when I heard my engine roar to life. So thanks to you guys I didn't have to sell my scooter or better yet throw it into the river and I finally have my own ride to work again! It's inspiring to think as a young college student to see how there are random strangers out there who are willing to take time out of their day to help another individual with NO monetary or physical benefit. I truly thank you guys so much, take care!!

-JoJo

[Doug in San Diego]

Right On Dude!!!

I could not agree more. ScootDawg is full of great guys who just help for no reason other than to help.

Feels good to know you can do anything if you put your mind to it