So I bought my son and eton rover and it would not run I got it home and today decided to check it out. I cleaned the carb and it was dirty it is good and clean now. There is great Spark. I couldn't figure out why it would not start so I check the compression. It's barely showing on the gauge at 30 pounds of compression. I could not believe it so I checked another one of my ATVs (90cc Eton 2 stroke) and it is showing a hundred and twenty pounds of compression so the gauge is working. The Gauge may not be the best in the world but it is showing that is getting to compression. Any thoughts before I tear into this thing? Any advice on the rebuild? Like where to get parts?

 

Also the guy said it would not go into gear. Any thoughts on that?

 

Think the po might have been stretching the truth a little. 30 psi is way too low for it to run. Similar engine as the Polaris 90 and minimum compression from the manual was 115. Plus always check for any up and down play on the rod. Plenty of top end kits on ebay.ETON VIPER 90 90R 2 STROKE AXL-90 90CC ATV CYLINDER REBUILD ENGINE TOP END KIT | eBay

 

Thanks opt... I agree Po may have been definitely been stretching the truth. Luckily I forgot my compression checker at home that day and bought it figuring on low compression on my price offer.

 

Opt I have a four stroke... Any suggestions on which one to buy?

 

Piston kit 47MM for Eton 4 stroke Viper 90R Silver RXL-90R09 9KD | eBay

This one?

 

Since it's a 4 stroke I'd make sure on the valve clearance also. Plus you really won't know the damage until you tear it down. I'd hold off on parts until you do.

 

Opt do you think it would be good to do a leak down test?

 

Wouldn't hurt as you can pretty well narrow down the problem area. Under pressure you can either hear air from the intake or exhaust if valves were really leaking or from the crank case vent if piston/rings were worn,or possibly both areas.That's up to you as far as a leak down test as you can check the valves for leaking by pouring solvent in the intake and exhaust ports in the head when you have it torn down. Hopefully it's just a worn piston and rings,plus you can always pull the valves,clean up carbon build up and use fine lapping compound to seat them back in.

 

first things i would check is make sure the previous owner did not mess around with the timing or valves. Could be as simple as the timing is out of valves are way to loose