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2012 AC ZR 120

le700

Expert
Joined
Oct 16, 2005
Messages
240
Location
Hammerfest, Norway
Cool that we have a 120 area now.
In 2012 I bought an AC ZR 120 for my kids. That was the year before yamaha painted them blue and started selling them as srx 120`s. If I don`t remember wrong they got yamaha engines in 2011.
So except for the color it is practically a srx 120.
Our sled started out green and black, but I did not like the look of it. So I ordered all the green parts available, all from the 2004 model.
If I had known about the srx coming the next year I probably would have waited for it.
As for modifications we have none yet, beacuse my girls are satisfied with it. But when they get bigger we may have to get a sharper engine and some risers for the handlebars.

For anyone in need of tuning parts, recmotor(dot)com is the place to be. They have everything for these mini sleds. (Admin can delete this line if it is not allowed to mention other web sites.. Maybe they are willing to sponsor the 120 part of this site..)

When we got it:
P1010720.jpg



Modified:
P1010842.jpg
 

Hello again. Changed the oil last night on this beast. Drained the old out, and put it up to 18,5 inches under the front bumper as the manual says. Then I filled it up about 6 dl of good 0w40. Today right after start up the kids got stuck sideways in a trench (which i probably made yesterday with the mach-z..) at quite an angle (45-60 degrees). So I yelled at them to shut it off. But they did not hear me, so they didn`t. Right before I reached them the sled stopped. When I checked the recoil start it appeared that the engine had seized. So I towed it back to the cabin. After a while it was possible to turn it a little bit (one round) with the recoil. Then I removed the chain guard and turned the engine with some pliers. After a few rotations it seemed fine. It started up, and it smoked a lot at first. Put everything back and rechecked the oil level. After that it has worked well.

What happened? Could there have been a lack of oil when it was idling at an angle? or could it somehow have been "hydrolocked" by the oil as it was laying at an angle?
 
Difficult to say exactly what happened, but if the engine stopped and the machine remained on it's side/at an angle in the trench for a while, then I would think it is possible that the oil filled the cylinder, especially if it appeared to be physically seized and would not turn over. Large radial aircraft engines are supposed to have the lower cylinder spark plugs removed to drain out any oil that may have leaked into them if the engine sits for very long (even as little as a half hour). If this is not done, there is the potential of bending the connecting rods as the oil cannot be compressed when the engine starts turning over.

I wonder if the engine running at that angle caused it to even pump some oil into the cylinder, causing it to shut off by basically flooding it (with oil, not fuel). That would almost make sense, since you mentioned that it smoked a lot when started up. Maybe we will never really know what happened, but I am glad to hear that it is working for you again!
 
Thanks.
Well there are a lot of these sleds out there, so it can`t be the first time one has been on the side.. Please chime in if someone has any experiences to share..
 


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