Thats strange 11 inch rear and 12 inch front, i would probably go with the 518 although the 420 should have plenty of power. Sounds like you are getting a fair deal around here the 4 trax are going for arounf 8200 and the Rubican are close to 10000

Well done. Perseverance always wins, giving up never does. To check the rod bearings you put at the top and move it side to side. That shows up play in the bearing. It will probably move about three mills side to side, but five mills is too much. The manual will probably give specific measurements. Then, to check for wear on the crank pin you rotate the crank a few degrees after top dead center, about fifteen degrees after, and then holding the crank from moving you push down hard on the rod and rock it forwards and aft feeling for any roughness. Then turn the crank again a little to about twenty degrees and check, then turn it to about twenty-five degrees and check it. If there is roughness on the crank pin it will be in that fifteen to about twenty five degree range.. perhaps even up to thirty degrees after top dead. I think I see some black aluminium oxide in the bore which is caused by an over heated/ near seized piston. Turn the piston so we can see both sides of the skirt and show us what they look like.That carbon build up isn't too bad and could be left there. As Gw says, check the ring fit in the grooves. Check all the way around looking for any part where the rings have more clearance that the other way around. The bore looks a bit scratched but that may buff out with a hone or wet and dry paper. If you can get it so you can't feel the scratches with your finger-nail it will be ok if the piston is reusable still. Put a top ring in the bottom of the bore and square it up with the piston then measure the gap. Then put the ring at the top, not right at the very top but just below where the top ring was rubbing to in use, and measure the gap again. The difference between top and bottom measurement, divided by three, will be close to how much wear/taper the bore has. If everything checks out ok I'd probably put it back together with new gaskets, rings and a valve lapping and valve seals..

Good Morning and Buenos Dios San Juan My hotel was in the "Tourist Compound area " ...OMG but close by the Cock Fight Bar. Definitely a Testosterone guy thing; but What a blast ! I was working but had time to have fun. Check out the Rainforest ATV guided tours...

Ok. It's your money your money. For anyone watching and interested, and for their future reference.. Engines, single cylinder engines, that only have 35Lb compression, don't start. They start getting real hard to start when they get down to about 80Lb. Also, if an inlet valve is leaking, then they don't like idling.. This engine we are discussing both starts and idles. The most likely reason for such a low compression reading is either that the throttle was closed while doing the test, or the gauge is faulty. The one thing that has the most dramatic effect on exhaust temperature is ignition timing being retarded or not getting advance. That will cause it even at low revs or little throttle settings. Lean mixture can cause exhausts to get hotter, but they have to be ridden with the throttle open to do that, and even then you seldom notice the exhaust red hot unless it's night time. A red hot exhaust in daylight is ignition timing..