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  1. #1
    HydroFool GPRSHO thomaswester's Avatar
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    yamaha sho engine (rod clearance) bearings color

    Hey
    For the first i try to search this but not find anything!
    I have the Molnar rod and wonder this, i have green berrings now and its way to tight.
    Example how much do the bearings build from color, to color if i say the green one is zero(example)?
    green =0
    blu= +/- ?
    black= +/- ?
    brown= +/- ?
    or which is the first in line?
    Hope you guys understand my question?
    If not jump into it and make more questions....
    Thanks
    Thomas Wester


  2. #2
    jetpilot785's Avatar
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    When I installed my K1 rods and did the plastigauge, the target was .00175". I was told the rods were a size 4 and the stock rods were a size 5. My engine came with blue bearings on the rod. I ordered black bearings and when I tested them with the 25+55*, I got .00125". I then checked the blue bearings and got the .00175" I was looking for so in my testing I found the bearing difference between the two I tested was .0005". Not sure if is the same across the board but I would imagine its close. Yamaha recommends on the stock engine to be between .0008 and .0022" to give an idea. The more mods you do to the engine will most likely require more clearance. I would say .0015-.0020" would be a good starting point. Hope that helps.

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  4. #3
    HydroFool GPRSHO thomaswester's Avatar
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    Hey
    Okay
    This is what i get with plastic gauge.
    Okey okey first Molnar dont rec platsic gauge,
    But i don't have the other fancy tool and i have done the plastic gauge on many other engines with good resultat my opinion...

    This is what i get (same rod same crank pin)..
    Brown .00120
    Blue .00140
    Black .00150
    Green .00160
    Molnar state you need clearance at 0.001 x per inch!
    Yamaha have a rod pin who is (42mm) 1.65 inch.
    That is 0.001 x 1.65 = min .00165 or more.
    My only chose here probly is to grind the crank so the green bearings is over .00165(my idea is to get as close to .00200 as possible)?
    Last year i stay on .00157 +,- .00002 that was engine failure after 15-20min driving on idle (rod 4 failure).
    Can somebody fill in a good answer to this so i don't get a bearing spinn agen and probably help others to.


    Thanks
    Thomas Wester

  5. #4
    Quote Originally Posted by jetpilot785 View Post
    When I installed my K1 rods and did the plastigauge, the target was .00175". I was told the rods were a size 4 and the stock rods were a size 5. My engine came with blue bearings on the rod. I ordered black bearings and when I tested them with the 25+55*, I got .00125". I then checked the blue bearings and got the .00175" I was looking for so in my testing I found the bearing difference between the two I tested was .0005". Not sure if is the same across the board but I would imagine its close. Yamaha recommends on the stock engine to be between .0008 and .0022" to give an idea. The more mods you do to the engine will most likely require more clearance. I would say .0015-.0020" would be a good starting point. Hope that helps.
    I also switched from blue to black, however my clearances worked out fine with the blacks (I did so after having my crank polished). All my rods where the same just my mains where mix and match but worked out by going down one color. Someone else mentioned the .0005 difference between bearings, i am impressed that yamaha has got the bearings so consistent.

    I also noticed molnar did not want plastigauge used . Next time i will buy the tools or pay someone to do it.
    curious though, do they feel it is not accurate enough??

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