Ms460 carb help.

[francisjohn]

Update: tried to take the bike on a solid ride and my mounting screws ejected themselves. And the vibrations from the engine caused my exhaust to come lose. Thankfully I noticed and the engine was fine. Are motorized bike supposed to vibrate in the higher rpms? I felt it all the way to the handlebars. Need a shorter exhaust and a way to suppress vibrations.

Overall though I think I’ve successfully created an ms460 build with a completely unchanged bottom end.

What do you mean unchanged bottom end? The following needed to be done

1) Bolt holes re-located by filling them with aluminum
2) Transfers filled up with JB weld
3) Deck the case to the neccasary amount needed. On a 38.0mm stroke, I decked it 2.5mm to obtain a 1mm squish.

Here are the photos of the MS440 I did. It's a freaking ripper.

Regarding vibrations, you will need to balance your crank. My crank was balanced to 56% and is smooth from 4500RPMs to 7,000RPMS. Some cranks stock are better balanced than others. By using a heavier top end (everything but the cylinder) you are increasing the reciprocating mass which decreases balance factor and makes it vibrate like crazy

 

[Sloppyslopster]

What do you mean unchanged bottom end? The following needed to be done

1) Bolt holes re-located by filling them with aluminum
2) Transfers filled up with JB weld
3) Deck the case to the neccasary amount needed. On a 38.0mm stroke, I decked it 2.5mm to obtain a 1mm squish.

Here are the photos of the MS440 I did. It's a freaking ripper.

Regarding vibrations, you will need to balance your crank. My crank was balanced to 56% and is smooth from 4500RPMs to 7,000RPMS. Some cranks stock are better balanced than others. By using a heavier top end (everything but the cylinder) you are increasing the reciprocating mass which decreases balance factor and makes it vibrate like crazy

I know that’s the standard way of doing it but I wanted to test out something else. This is mostly a WIP and something I wanted to do for fun. Again yeah mine is still a completely unchanged bottom end and I mean completely unchanged.

Also I'm running a 40mm crank right now so obviously that doesn't help lol.

 

[Sloppyslopster]

Welp I tried to take the engine apart and was met with some pretty nasty scaring. This is probably from the crapping casting on the cylinder, lots of sharp areas. Think I'll take a break from this for now. Definitely need to find a way to either 1. make a 40mm crank work or 2. find a 38mm crank with a 12mm wristpin hole. Need to modify another cylinder unfortunately. Most likely will go with a hyway setup.