About a week and a half ago I went to the Imperial Dunes with some family members. A few hours after we got there, my YFZ stared having trouble starting. It would turn over but not start, it sounded like the batery had a bad connection or something. I tried to start it a few more times it sounded like the battery was getting lower and lower until it finally gave out. So we were sure that the battery was just going bad, afterall it was the one that came with it when I bought it so it was about eight months old. So we packed all of our quads up and drove back to Yuma. There we bought a new battery for it and installed it. After that it started fine. So we started it a few more times to make sure that it worked then went back to the dunes. We got there and I rode around on it for about twenty minutes and it began to do the same thing. It would run fine while it was on, but once you turned it off it would not turn back on. We push started it and it ran fine again. But I didn't really want to ride it because I knew something was wrong. So when I got home I took it off of the trailer and noticed a small hole about the diameter of a regular pencil on the right side of the motor, a few inches above the header pipe. I took it down to a local quad shop and told them all about what had been hapening. They said it sounded like a compression problem and said that they would have a look at it. So it has been down at that shop for over a week and today they just called and asked if I could bring them my owners manual. When I was there I asked how it was going and they said that there was really something wrong with it and they hadn't figured it out yet. So I'm just wondering if anyone has had this problem with any of there ATV's. And if you have, maybe you could shed some light on this subject for me. Thanks.

 

I am not sure of what you mean by a hole??

Any ways, if the machine runs good after started, and has plenty of power, it doesn't sound like a compression problem anyways?

Did you do the cam mod, or....?

Do you ride with the lights on? If you ride at lower RPMS (trail riding), I read that you are supposed to turn the lights on to make sure the charging system is kicked in to make sure the battery doesn't become run down.

 

There is a hole that a small screw will screw into. I had never noticed it before I noticed it missing. The guys at the shop said that that spot holds all of the compression in. I haven't put a cam on my YFZ yet. My lights were off but I was going from abuot 30 mph to 50 while it worked. So I don't know if that's the problem or not.

 

Speed is not as important as RPMs.
Supposedly, if you are not keeping the RPMs high, then the charging system does not kick in, and the juice to run the ATV will come strictly off of the battery. After a while, the battery runs low (according to what I've read anyway).

To avoid this, they say to either keep the RPMs up a lot, or turn the lights on to make sure the charging system is kicked on.


It just sounds wierd that it would run, or even start to begin with if you had a hole, allowing the compression to leak out??

 

I know, this was a very weird thing that happened. The people at the shop were a little worried about this and I sure as heck hadn't ever seen that hole before. I think that the compression is just leaking out when I'm trying to start it becasue it will turn over, just wont start. Well I guess the only thing that I can do now is hope they don't have to rebuild my engine or something. The last thing I need to do is have to pay hundreds of dollars for some problem with my bike right now. [img]i/expressions/face-icon-small-sad.gif[/img]

 

it could be a compression problem. What would worry me the most is the fact that the shop needed an owners manual...

At any rate it could be a number of things. I would check the cylinder compression first.

 

I'm going in to see whats wrong in detail. I was really worried when they needed to see the owner's mannual that's when I knew something was really wrong. I'm gonna go in to check up on it tomorrow or the day after tommorow. I will ask them if it's the cylider compression when I'm there.

 

My thoughts exactly. These guys have no idea what they are doing, and apparantly have no shop manual.

 

Here is a write up on the compression release plug which may be what you are referring to.



Here is a good write up on battery issues and Here is another one from Gust's web site.

 

Thanks briansgi, I'll take a look at that right now.