Hello all, I need some help : )

[Tsunami Surf]

Ok so I'm pretty new to these bikes. I got 2, I'm not even sure what type or cc it is. Long story short, I noticed one of the head bolts was loose and had 2 washers spacers while the others had 1. I assume the person I bought it off was trying to make it seem like it was tighter than what it was maybe? When I take it out the nut on top will not come off, the bottom of it is slightly slanted at an angle. So I took off all the spacers, put it back in now it is tight, is this fine? Do I need those spacers? 2nd issue, the exhaust gasket looks horrible and broken up with small holes everywhere. I need a new one of course but what caused this? The head being loose? Lastly my choke pushes itself back up when I run it for few mins. I accelerate and I watch it go up by itself
Is this all one issue or separate? The bike I'm talking about is a 18 speed mountain bike. The 2nd one I got is a old Murray but it's super fast, my mountain bike is much slower and bogs on hills when the other has no issues. Is this the weight difference in bikes? Thanks for any help, new to this but dang I love these things

 

[Bikeguy Joe]

O.k.....the acorn nut tightened because it "hit bottom" (top?) which means it is probably not tight, just seated on the stud without tightening down on the head, and that's why they had the washers on it. I remove those and use regular metric nuts, not the acorn (capped type). For now put some washers under it and tighten them all to about 12-15 ft/lbs.

The exhaust gasket is like that because the exhaust was loose and ruined it . Auto parts stores will have gasket material, and you can make a new one.Tell them you are making an exhaust gasket, or take the old one and they may be able to match it with something. I recall someone using a gasket from a VW beetle (heat riser gasket?)

The difference between the two bikes could be anything.
Are you mixing the fuel/oil at 40:1 or the recommended 16:1? Don't go with 16:1, that's just bad and wrong. It will do more harm than good.

Look at the plugs in both engines- do they look the same, as far as color goes? If they aren't running the same air fuel mix/air filter cleanliness/spark plug/ ect. they will run different.

 

[Tsunami Surf]

I will reply more when I go look into what you said and I will have more questions I imagine. I really appreciate your reply! The exhaust is only loose atm cus I took it off to get a pic of the gasket. It was suuuuper tight hard to get off really. When it was tighter it still had some play in it up and down ( when sitting on bike looking down at it) I figured it had gotten eroded. They were both new so I took it through the break in period, 4 tanks of gas worth. I will go look and compare the both. I use the same mix as I was told they were both new and needed broke in. I was told to do 20:1 for break in. He told me he made it himself but as I researched more on the bikes, he straight copied it off of bike berry. So this is why I assume he tried to hide the difference of the head bolt being loose by adding more and making it look less loose. I spent about $650 for both bikes. I really just needed it built and I figured I could do better maintaining and fixing then starting from scratch myself. Again I really appreciate all the help, I love these bikes, I've read and learned so much from this exact site and a few others and I'm into them il never go back lol. So I took off those 2 and it is just the acorn nut and the bolt. Nothing in between. Is that fine for now until I make it or do i need to fix those now? Il get more pics, the 2nd bike is just the bolts and a square top kind of like how the exhaust ones were. Let me know any info you need, I will go look over them both more

 

[Greg58]

You need the washers under the acorn nuts, the stud it's screwed on could bottom out in the nut before the head is tight. That's why Joe recommend using standard nuts.

 

[Greg58]

The reason one bike runs better than the other could be a lot of things, I've built several over the years and only a couple ran as they should out of the box, most of them I had to jet to get them right.