crank issues

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yamaha17

New member
Joined
Mar 6, 2011
Messages
6
Location
new brunswick
hi.. tore my sxr700 down for an inspection and noticed some blueing near two rod bearings on the crank. Sled was working great... but the colouring has me concerned. Are my rod bearings or crank bearings maybe getting bad? and is the crank reusuable with the blue color. I notice alot of cranks on ebay have this same blue color.
 

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I had the "domestic engineers" sled tore down couple weeks ago (2000 sxr 700) It was my first time and I had my buddy help me as he has rebuild a dozen or so different redheads as well as being ASE certified mechanic. Mine had the same bluing on crank and he told me was from part of the assembly procees, that the polish it upp so it looks all snazzy but after you run engine for a lil bit bluing comes right back. Refer to thread from a couple days ago on "center cylinder blow" we have put 400 miles on wifeys sled with no issues.
:letitsnow :letitsnow :letitsnow :letitsnow :letitsnow :letitsnow
 
Just took mine apart as well an noticed the samething, was concerned about heat as well, hopefully it is notihng to worry about. Gonna have it checked out before putting back together. Nice to hear mine is not the only one this way.
 
thats from the heat used to put the crank halves together. the stub/pin is built into 1 half, the other half is female hole, the hole is heated and pin inserted, have to heat it to assemble as most press fits are about 10 tons of pressure!!!

nothing wrong with crank, thats normal.
 
thanks for the replys... I feel a little better now. going to order new gaskets and upper rod bearings and new rings and start putting her back together.. hope for the best.
 
rod bearing clearance

hi.. how tight is the rod bearing to crank fit normally. all 3 of mine have end play within tolerance. But it seems as though you can tilt the rod a little back and forth on the needle bearing. Is this normal? Visually I can't see any signs of wear on needle bearing. I can;t lift rod any up and down... just curious of the tilting action. thanks for any help.
 
yamaha17 said:
hi.. how tight is the rod bearing to crank fit normally. all 3 of mine have end play within tolerance. But it seems as though you can tilt the rod a little back and forth on the needle bearing. Is this normal? Visually I can't see any signs of wear on needle bearing. I can;t lift rod any up and down... just curious of the tilting action. thanks for any help.
Click to expand...

So strange yamaha17 i have the same issue with my center cylinder, not sure of how much play there should be, but I'm sure hope we can find an answer on this site.
 
Mine had same side to side, maybe 1/2 inch @ wrist pin from all the way laef to all the way right. My buddy said it was fine. Bought brand new caged wrist pin bearings and even they had a lil side to side tilt. :letitsnow
:letitsnow :2strokes: :letitsnow :2strokes: :letitsnow
 
Devilin AblueDress! said:
Mine had same side to side, maybe 1/2 inch @ wrist pin from all the way laef to all the way right. My buddy said it was fine. Bought brand new caged wrist pin bearings and even they had a lil side to side tilt. :letitsnow
:letitsnow :2strokes: :letitsnow :2strokes: :letitsnow
Click to expand...

1/2" inch side to side is too much!
 
It's about the specs. We can talk about stuff all day on here, but to do it right when rebuilding an engine you have to know the tolerances and have some way to check them; ie a dial indicator or something. I know a lot of guys with experience say they can tell by feel or whatever and maybe they can, but to be sure you have to do the work of checking all tolerances and that usually means having a manual unless you have a great resource like this site to help with the tech details. just my humble opinion of course.
 
Checked the tolerances in the yamaha manual. End play on the large end of rod on crank is 0.010 - 0.030. on small end of rod (wrist pin end) the tolerance for side to side is 0.031 - 0.040. Checked with dial indicator... and everything is within spec.
thanks for replys
 
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