Gwbarm

It does sound good ! Relly nice low throaty growl, i always liked that 300 engine.

You will need to replace the rocker arms, how are the cam lobes.

The rev limiter is a small screw up by the thumb throttle. Did what you did help any thing

Thats great you got them out without breaking them. I see some pretty hefty scratching on the cylinder hard to tell how deep they are as to wheather they will hone out or not. The piston look fairly good i dont see any scratches on the piston but sometimes photos are deceiving. The rings look free they are not welded to the piston as i would have suspected. Overall it doesnt look as bad as i expected. Hard to tell much about the valves without seeing the sealing surface. The dried wrinkly stuff will come right off. Hows the bottom end does the crank rotate freely, take the rod in your hand and push down you should feel very little resistance as the crank turns. Then take the rod at its highest point and wiggle it up and down you should have no play there, but you will have a little play side to side. If everything checks out after a cleanup check the ring gap by putting in cylinder one at a time and measuring with a feeler guage to give you an idea of the wear and check to manual to see if it is within specs. If the scratches do not clean up you may have to get a rebore with oversized piston, or top end kit that comes with everything.

Wow! You have been busy! Valves look good i dont see any pitting. I would maybe lap the top one a little more you want it shiny all the way around like the bottom one. Double check the timing also sometimes the shaft that the timing gear attaches to can move so it will appear to be in time but check the cam lobes to make sure they are both pointing in the right direction.

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

I understand i admit i have reused head gasket in a pinch i would use the copper stuff, but be advised it is not a permenant fix it may work for a month or two but it will fail, look over the gasket very well before reusing it to see if you can see where its failed . If air is coming out the intake i would say it has jumped time somewhere or you have a bent valve inspect the valves very carefully to see if they are OK .

I never reuse head gaskets i would replace it and replace the o rings.

I agree you should probably pull the head and check the valves out, compression seems low even with a compression release . Then you can check the timing before you pull the chain off to see if it has jumped time.

Those wires down by the carb could have been for a carb heater that is no longer there. You might try following them to see where they go to get a better idea. Havent looke at a diagram on your bike but generally black and white go to the kill switch and orange goes to coil but you are running so not the coil wire.

My biggest concern is getting the old ones off, they are original to the quad and have been on there 20+ years plus old rubber is not very stretchy, and all the slime that has been put in there just since i have had it just to roll it around. Maybe regrets later but im going to give it a try. I take pride in doing everything for myself.

Just got my Bear Claws in, if you look closely there are 4 tires there all squashed up and out of shape, these should be fun mounting. I elected to mount them myself so i can take my time and paint the rims while they are off, or i may check into getting them powdercoated still trying to decide on the color the originals are gray.

Very peaceful beautiful place.

Sounds like your moving right along with the rebuild, did you put it new piston cylinder and rings or just rings. From what i remember from one of your earlier posts you only had a bad oil ring.

I havent shot a black powder gun in years, i have a 50 caliber Hawken sweet gun, after shooting a few times there was so much smoke i couldnt see the target, i loved the smell and really cool seeing all the smoke.

I figured you must have put the piston in first after i did the post,, never tried it that way, it might be easier that way, then you dont have to tilt your neck at weird angles to see if the rings went into the cylinder. It is definately a good idea to do the valves inside, we are also having some of those 110 heat index days, it so hot out there is hard to breathe and concentrate.

The way i do it is put the pin in the piston about half inch line up the holes and push it through. The part im not following, you say you have the cylinder on, how do you have the cylinder on if the piston is not attached to the crank rod yet.

Not necessarily, that depends on where it breaks, they typically break fairly flush with the cylinder but no matter where it breaks you can then lift up the head and get some penetrating oil where it needs to go, and best case senario is there will still be enough bolt sticking up that you can get vice grips on and keep working it to try to get it out. but dont give up on it just yet, keep trying it may take a few days with penetrating oil.

You can try that dont have to hit very hard just gentle taps.

There is one other thing you may try keep doing what you are doing when you get it good and hot hit the top of the bolt with an air hammer if you have one if not i wouldnt buy one for that but i have had that work before.

Thanks for the info just checked they dont have my size.

Im sure the Harbour Freight one is on the lower end of the list for quality equipment but it does seem to work well for a manual changer at its price point plus i may not ever use it again. A pneumatic one would certainly be better. Whats the price on that one i couldnt find it online.

I just ordered the Kenda Bearclaw EX as per Kendas recommendation good price on Amazon https://www.amazon.com/dp/B07RQW1RFD?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 I also looked at the Maxxis Bighorn very nice tire really like the tread design looks very similar to the SunF https://www.amazon.com/Maxxis-BigHorn-Radial-25x8-12-25x10-12/dp/B00EDNO3V2/ref=sr_1_6?crid=2NN0G6J24MHPG&dib=eyJ2IjoiMSJ9._5lRjgfwfhPXgSh035Dq1fk182IV0SX-L01PkawIQhGcEjiCP8l9tNwGRdFidc2fEDbe0Mjv65YlbVN7TQfS4-iLp-dyWpQR8SYdQ_XSMbbSRDAWCxGqdQ66fqy5jDHUmrkavQO9mMQa9IHrSTE44NoiQisqtIGQON3NOCaoNa3zWCtA-d478F9t91KEQpSnlXapXGNrFmGPNrDww-JPMyRdFADuDs01IpphFNt0yS2u87G5RWHHLCR6QnJIqhfZc1A-6MXzDi61hcuk6JNGF8nn-GIzDjuN2Dgja06uRT8.-_JHpY2YLslDeF3Hi2RVx6LlI88T7d9nJh6leoypMMk&dib_tag=se&keywords=maxxis+big+horn&qid=1753376231&sprefix=%2Caps%2C151&sr=8-6 Its really hard to justify paying more for tires than i paid for the whole bike, if these Kendas will just hold air which my current ones do not i will be happy, very good price for a name brand tire. I usually get tires mounted at a tire dealer but this time im going to do it myself with a Harbour Freight tire changer for several reasons, changing tires has gotten very expensive 20-40 per tire and they really arent very happy that you didnt buy their tires, also i need to paint my rims while they are off, i have thought of every option and the best way is do it while the tire is off, so that will have to happen after i take the tire off the rim. I hate changing tires they always fight me but will see how it goes.

Maxxis are great tires but you are right very expensive thats what i have on my Big Bear. The rim guard is an extra thick sidewall to help with sidewall punctures and also helps keep debris from getting into the rim and deflating tires.

Im a little surprized the impact didnt break the bolt, at this point you need to be very careful as tight as it is if your break the bolt probably wont be able to get it out without drilling. I suspect the head got so hot looking at the wear on your rocker arms that the bolt has welded itself to the cylinder, lets hope that is not what happened. The problem with penetrating oil on the head bolt is that you cant get the oil down where it needs to be where it goes into the cylinder to hold the head on. If you spray it down where the head meets the cylinder abundantly some may get in there and also put some heat on it. Start turning the bolt back and forth tighten and loosen tighten and loosen until you get some movement keep doing that sparingly dont try to gorilla it out or the bolt will break. Been there done that! Hopefully it will eventually let go. The heat will expand the metal and let penetrating oil seep down into the threads.