OK mechanical wizards, here is my situation:
1988 Moto 4 225 bought new and enjoyed for years
History:
1. 3 years ago bought new Wolverine, parked the Moto in the barn.
2. 2 weeks ago, resurrected the Moto from the barn for my little boy to ride.
3. Changed old fluids, attached jumper cables and started it.
4. A little smokey and rough but ran and idled.

OK it runs so I will restore it.

5. bought and installed new tires
6. repaired broken low range gear in transmission
7. cleaned carburetor
8. installed new plug
9. installed new battery
10. installed new air filter

Now it wont start...hmm....

11. check spark....OK
12. check fuel......OK
13. check compression at plug hole...OK
14. check suction at carburetor...OK
15. check pressure at exhaust...OK

Still nothing...not even a bark or back fire

16. buy and install new coil and wire....nothing (well spark is bigger and bluer)
17. get frustrated and spray starting fluid into carburetor....nothing....(figured that might at least backfire)

OK, Ive got spark, fuel, air and no clue as to why I cant get this thing to even attempt to start.

18. post for help on forum
19. wait

 

20. Just a question or two and then a few thoughts.

Is this a two or four stroke?
If it's a two stroke you may have flooded the case with fuel. (I don't think the moto is a two stroke. Am I correct?)

You say you have good compression but what is the numbers? Is the plug wet when you pull it?

You might pull the pipe off and see if it starts. I have seen mice and rats plug them up.

Any engine should at least pop if you give it ether and it has good compression and good spark.

Your missing something.

 

U mentioned that you cleaned the carb, with what did you clean it with and did you take the carb apart. If yes you did pull the carb apart then your missing something or whatever you cleaned it with is still in the carb. If you have spark, compression and fuel this thing should fire or at least burmp. What was the compression at? psi. This is a normaly trouble free ATV I had one a beat the crap out of it and would never break or even hesitate.

 

If the Moto 4 you have is anything like mine, with the sitting for ages, I'd recommend setting the valves and making sure the plug is not wet. You may have sucked a piece of crud into a valve and eliminated the compression also. Sounds like there's no fire when the plug is installed,.... Hard to say beyond that and what the others are leaning toward.... you're missing something.....

 

4 stroke- yes
compression- my tester is screw-in and wont fit (I'll get a press on today so we can get some numbers)
plug wet – no and yes (when I sprayed ether directly in the plug hole)
pull off the pipe - cool idea, I'll try that tonight
missing something - yes, that what you guys are for

cleaned carb - yes, dismantled, cleaned, reassembled, all parts as they were. clean tank with fresh fuel
burmp - yes I agree, but I get nothing
compression - OK I cheated on that by trying to hold finger over the hole (see above)
trouble free - totally agree, bought new in 88 ran daily on the farm for 17 years without a hitch (it would later pop out of low range but high and rev worked fine)

valves - I pulled the caps off to check if they were sticking (they were not) and I figured with as much suction at the carb as there was they had to be seated.
Fire in da hole – don’t know how to check that?????
missing something - yeah, and hopefully one of you guys will find what that something is.

Thank you guys for all your help, I really think this little atv deserves a second chance at life and my little boy would get years of pleasure from it.

 

It may be firing but is it firing at the right time?

Those old Moto 4s are the best 2wds I've ever seen in the mud.

 

It sounds like you have been very thorough and methodical but am wondering if you aren't sucking air now from the removal of the carb? It doesn't sound like you have done anything to change the timing, so I have to think it is fuel/air related. I wish that I could offer you more but don't know anything else it could be. I will be interested to learn what the culprit is. Good Luck.

 

I am having the same problem. When I got the machine yesterday.... it started hard... had to crank it... after 30 - 45 seconds it would start to pop... then it would start, idle and run fine.

By last night, and the third time starting it the battery is dead.

I am hoping to learn more about engines, that was the goal but I also hoped to ride it!