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Post by jeff84 on Nov 4, 2017 23:08:04 GMT -5
my crank has some blueing on it, making me think there may be a problem with it even though it and the con rod and bearings are all in spec. looked into buying a new crank and all the pics I see online of the new parts have blueing in all the same places. so my question is why are the cranks blued around where the big end attaches? and is this a bad practice on the manufacturers part?
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Post by Corrosion on Nov 6, 2017 8:01:34 GMT -5
I watched a Video, and it looked to me they are heated with induction heaters and then quickly jig assembled. They cool and are checked.
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Post by 190mech on Nov 6, 2017 12:52:11 GMT -5
I watched a Video, and it looked to me they are heated with induction heaters and then quickly jig assembled. They cool and are checked. Id love yo see that vid,got a link???
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Post by Corrosion on Nov 6, 2017 13:53:25 GMT -5
It was saved on my work laptop, and I turned that it in when I stopped working. It was either Jasil, or Alberto Motorie, I believe the later. It was a 20 min manufacturing Video. If I find it I will post it. Is the arrow where it was blue. That is where it was heated and and pressed together.
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Post by 190mech on Nov 6, 2017 14:54:03 GMT -5
Thanks!Ive seen it mentioned by some 2stroke crank builders about heating the crank wheels,but no more than that.When I worked at an automotive machine shop as a young man,we had an induction rod heater to install piston pins,worked slick,could push them in by hand..Guess they are using something similar,too high tech for a backyard builder though...
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Post by jeff84 on Nov 6, 2017 17:38:25 GMT -5
yes that is where the blueing is. on mine it extended all the way to the outside edge of the circle. it is from a different engine though.
in any case I have already buttoned this bad boy back up, so lets hope the crank holds up. its a 250 with a 290 bbk installed. seriously thinking about trying to turbo the thing. it will a couple of years yet before it ever sees the road as I cant get a mc license right now. the plan is to put this engine in my Honda ruckus, and hopefully see 100mph
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Post by RollingThunder on Nov 6, 2017 20:26:21 GMT -5
Not that it matters anymore, but all the pressed cranks I've ever worked on for both snowmobile and ATV applications look like that from the factory. I've watched guys rebuild cranks before and some heat them and some don't. It usually depends on how easy they come apart and go back together. I wouldn't worry about it.
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