Super Jet 6m6 crank in Pro-Tec Ported 771 61x/62t

[Yami-Rider]

Check out this crank. Never seen this mod before. Is it common? I guess they do this to reduce rotational mass? Came out of a Pro-Tec Ported 771 61x/62t.

 

[Danman108]

I see what you are talking about how the edge on the one side is grinded down. What a trip im sure it just makes it spin more evenly but i also am not 100% on that.

 

[bobob729]

U could send that 771 my way lol. But very interesting I learned somrthing new today

 

[yurkanip]

6m6 crank is used in all 61x, 62t and 64x. Same thing, It's the cases that are different.

 

[Yami-Rider]

6m6 crank is used in all 61x, 62t and 64x. Same thing, It's the cases that are different.

Ya the 6m6 crank and 6m6 bottom case is used on all those motors. I was just posting up about that crack be modified. They are normally round, not flat on the top side like my crank is.

 

[yurkanip]

Gotcha. I see what you meant.

 

[yamanube]

Did you ever run this?

 

[kevbo]

That casting is for the crank wheel only, 6R7 castings on the 650s were slightly thinner. One of our local riders cut his crank like this and it ran for several seasons as a 760.

 

[MTRHEAD]

Common race mod in superstock days- 650 crank and machine like this. Use ArticCat 26mm pin/bearings and 760rods shot peened.