new guy needs some advice

[Baron]

Hi, I just bought 2 used atv's for my kids. A 90cc and a 150cc both are made by Baja and both are 2005. I've never owned atv's and never worked on cars, bikes, etc... but I'm very handy around the house (carpentry, plumbing...) so I thought this would be a good learning experiance. Anyway they were well ridden and both need some work. I only paid $250 for both so I was willing to take a chance. I was told they ran but have been sitting for over a year.
I changed the oil, put in new batteries, changed spark plugs, drained old gas, cleaned carbs, cleaned air filters, lubed chains, and added brake fluid today.
With the help of a little starter fluid I got the 150cc to start but it would die almost immediatley.
The 90cc will try to start but doesn't.
Does anyone have any ideas of what i should try next? What could be the problems?
Please keep in mind I know little to nothing about engines/atv's. So please explain any advice to me simply.
I watched youtube to learn how to clean the carburetors Thanks SO much for any help.

[TurboT]

Well firstly, welcome!

..and I warn you, us ATV guys have been waiting for the next problem to pop up so you are probably going to get slammed with advice!

My first thought would be to make sure you have any fuel shutoff valves in the open position. Some ATV's have them, and some don't. It's a good idea to install if you don't have them.

Trace the line from the bottom of the gas tank to the carb, and see if there is a switch in between. There should be a plastic fuel filter, and it's not a bad idea to change them either. You should be able to easily tell the difference between the fuel petcock/valve, and the filter even without being an engine wizard.

My next bit of advice would to be make sure you have the choke in the position for starting. I'm not familliar with your specific brand machines, some of the choke levers are on the handlebars and some are on the side of the carb. If your 150cc is like the GIO's, it will have an electric choke and won't be the issue. Since they haven't run, you made need to keep fuel in it with some throttle until it warms.

Let me know if you're aware of these items and if you've tried them before I start blasting more info at you.

One last note, where are you located and how cold is it outside? A lot of discussion here of late about cold weather and good running quads, so it's possible your machines will run fantastic in the summer, and not so well now.

-TT

[FastDoc]

Did you take the carbs apart to clean them? Remove or otherwise blast out the jets?

Welcome to the forum. We'll help you through this.

[Weldangrind]

Welcome!

I'll add that the stock spark plugs are junk. Replace them with NGK plugs.

Cheers!

[Baron]

Thanks guys.
To answer your questions:
I did make sure the fuel line was open.
I opened the choke on the 90cc, couldn't find it on the 150cc
I live in FL. 70 today so cold isn't a problem
I did take the carbs apart and blast them and the jets with carb cleaner
I replaced the old plugs with NGK plugs
Any idea what could be the problem?
Also if I don't have luck with these I may buy new. Do you recommend any certain low $ ATV for kids.
Thanks agian.

[TurboT]

Did you try the 90 with the choke closed or half open? On my 50cc, the lever has three distinct points. Up, middle and pushed down. It won't start with it up, but won't continue running for long with it down (where it needs to be to start) It's annoyingly very sensitive.

Your 150cc is probably an electric choke model. How's the idle speed when it did run?

[TheRealWorld]

In my experience it might pay to look for any place air can leak into the the air fuel mixture. If air can get in between the carb and the intake, it will draw air into the combustion chamber rather than pull fuel in. No fuel no run! Can you smell fuel in the exhaust?

[MICRider]

I have a cool little PDF that I got off the forums here that covers basic troubleshooting of chinese ATV's, but I cant find the thread in a search, and I don't know if I can attach a PDF here... Hmmm, I will do a little more searching for the thread.

[MICRider]

That search did the trick! Have a look at this link, Waynec posted a good pdf with some basic troubleshooting stuff for quads and dirt bikes. Hope it helps

http://chinariders.net/modules.php?n...&highlight=pdf

[FastDoc]

Check valve clearance also. If they are too tight, and it happens, they may not close all the way and compression will be inadequate for combustion. Now that I think about it, that sounds pretty likely. You'll have to check the valves anyway. 8)

[TurboT]

Originally Posted by FastDoc

Check valve clearance also. If they are too tight, and it happens, they may not close all the way and compression will be inadequate for combustion. Now that I think about it, that sounds pretty likely. You'll have to check the valves anyway. 8)

Good advice but perhaps a bit technical for the newbie mechanic? If they have been run hard it's a possibility but I think he may need step by step instructions for that? A trained ear can hear compression in the starting rotation but I'm not sure if that is the case here or not.

It's just me but I'd be more inclined to have him ensure spark and fuel flow, and try tweaking the carb settings before ripping off valve covers and breaking out the feeler gauges.

You are holding the brake in and ensuring the dead man boot/kill switch is attached firmly and perfectly on the little one which won't catch?

[Weldangrind]

Does the 90 have spark (the 150 certainly does)?

[Baron]

The idle on the 150 seems ok but it only uns about 5 seconds so it's hard to say.

I don't even know where or what the following things are: (I've owned atv's for 3 days now)
Combustion chamber
air fuel mixture (is this where the air filter box connects to the carb?)
Valves (clearance)

I am holding down the brake.
Is the boot/kill the plug in the back for training young riders? If so I "think" it's firmly attached, but I'll double check.
The 90cc does have spark
I'll check out the link.

I'll be spending a good part of my weekend working on this so please keep the advice coming. Simple explainations are best, but I'll look up how to do stuff that I don't understand if need be.
Thanks again, you guys are great.

[MICRider]

Definitely sounds like fuel issues... Especially if they were running and were left to sit for a year, now if they had been partially torn apart when you bought them, then it would be a whole nother kettle of fish! They both have spark so you know its not an electrical thing. You said you checked for fuel flow at the carb by pulling the fuel line off right? If you have good flow to the carb I would be inclined to think there is still some gummy deposits or such blocking passages in the carb. Another cleaning might be in order. How did the inside of the float bowl look when you had the carbs apart? Were they clean or did they have crud/varnishy looking stuff in them?

[Baron]

The PDF from MICRider explains how to adjust the air/fuel mix. So I'll try that tonight.