why is my 2006 yamaha raptor 350 blowing out the carb instead of sucking

[Yamess350]

so I bought this raptor from my bubby because it sat in his garage for a year or suck long story short the guy who lost worked on it didn't know what he was doing can just did some of the worst work I've ever laid my eyes on but I recently had the thing running and delt with a lot of problems getting the damn thing to spark need new stator/ cdi and wiring harness and I had finally got the thing to run and drive had a blast omg I love this thing but sometimes I pray it would just stop giving me problems I've road the quad 2-3 time and found there was a huge leak and I took the head off its new btw its black and shiny but the last guy who worked on it did a horrible job and lost parts any ways I fix his mistake and bought oem parts and gaskets but when I when to put the piston back in I could not find a good thread on the orientation on all the rings on the piston and it is a bit confusing how people describe each ring I need a layman's terms like talk to me like I'm slow lol but don't be rude and I need help 1 in the orientation on all the rings and also my engine stopped sucking threw the carb can it be the valve is not seated on intake/exhaust should I reopen the head and redo the rings on the piston or can it be the valve spring gap idk I need help all I know right know is I need a break from the bike and collect information for now can I get some help without people pointing me in all kinds of direction 

[Yamess350]

the cam gear and cam is no longer attached the shear pen broke it was a pos make sure kids to buy oem 

[Matman]

I had a little trouble following your information, so I simplified your questions to break some possible answers:

1. Put the piston back in.....and ring orientation is a bit confusing....I need layman's terms on the orientation of all the rings

2. My engine stopped sucking through the carb. Can it be the valve is not seated on intake/exhaust? Should I reopen the head and redo the rings on the piston or can it be the valve spring gap?

 

Answer 1. In general, the most important step is to install the rings facing up or down, ring gap position around the piston is secondary. Rings can have chamfer or a bevel or other features on the inside diameter of the ring to improve performance.....which requires you to install them facing up or down. These are always have a stamped markings in the ring. Follow your installation instructions that come with the new rings. There is usually a mark on the top of the rings if there is an up-facing side. Keep in mind however, I've also seen some rings that don't have a mark, but they are clearly not symmetrical, and that visible difference is how you identify the up-facing side to install them.  Some simple motors don't matter if they're facing up or down, but make sure you follow the directions.

For ring end gap locations in 4-strokes specifically, the simple answer is count the number of rings to install and split them evenly around the piston. This is the simple answer. There are longevity and performance additions to this thought....

The more complicated answer is avoid installing gaps on the exhaust side of the piston. As the piston fires on a compression stroke, the piston's "exhaust side" sees the hardest work and most heat on that side when running, so for longevity, do not leave any end gaps on the exhaust side wall.

Lot's of videos exist on locating gaps....search videos on the web for "4 Stroke Piston Rings From A to Z || Identify, Install and Orient Gaps CORRECTLY!"

Answer 2. Ring end position will not be related to no more vacuum being pulled through the carb. My hunch is your timing chain and Cam are very off, maybe even 180degrees off. Most engines these days are designed with interfering valves meaning if your cam is off 180degrees the Piston will likely clip your valves and break things. If you are seeing the cam gear break or sheared off... or other broken parts, this may have been what happened.

Others may have better suggestions for troubleshooting?

Edited April 10, 2022 by Matman

[Curtis Underwood]

Matman is correct about the rings one way to tell is if the ring on the outside edge has a beveled egdge if it is does this beleveled edge goes up otherwise you will have excessive wear on the cylinder wall(if it does not it does not matter which direction goes up this is usually on cheaper engines though). You need to dress the cylinder wall with a cylinder facing hone. This breaks the glase and allows the rings to seat. You will hear of people saying to use gasket maker on the head gasket don't just make sure head and cylinder is clean I use a very fine grit sand papper 1000 grit to clean it. As to #2 yes the intake valve can cause blowback(stop sucking thruogh the carb. If it is adjusted to tight then there will be blowback. Some other thing that can cause blowback is carb running to lean or to rich, timing is off a little and the ignition system having an issue with stator or sensor.

[Fish0rDie]

When mine did this it was a valve issue. Something had actually lodged it's way in the valve and stopped it from seating. Just to give anyone else checking this an idea of what else could be causing this.