Ninja Engine by GRP
#771
If you guy's want a little trick for the Ninja here you go:
Get two reamers (5.0010mm and 4.1810mm) and a few NovaRossi R5/R7 rods:
NovaRossi Crank pin= 4.9950mm
NovaRossi rod bottom= 4.9975mm
clearance= 0.0025mm
NovaRossi wrist pin= 4.0000mm
NovaRossi rod top= 4.0025mm
clearance= 0.0025mm
Ninja crank pin= 5.0000mm
Bottom of rod= 5.0150mm
clearance = 0.015mm
Ninja pin= 4.1800mm
Ninja rod top= 4.2000mm
clearance= 0.02mm
Ream the R5/R7 rods by hand since the top and botom ends are smaller bores and you are all set.
The R5/R7 rods are 0.01mm wider on the bottom and 0.01mm narrower on the top which will not affect anything since the bottom of the Nova rod does not go past the end of the Ninja crank pin and will not hit the backplate.
The clearance numbers don't look that different till you notice they are a decimal place more on the Ninja (10x more). Use the two above reamers by hand and you will have a more perfectly clearanced rod for the Ninja that is bushed on both ends.
I used four sets of precision Deltronics sizing bars (they come in 0.0005mm increments) and checked two Ninjas and two 321P's.... clearance numbers were the same for each brand. Hand reaming will result in a slightly larger hole than the reamer size you select.... that is why smaller reamers than you would expect were selected for the reaming process.
Get two reamers (5.0010mm and 4.1810mm) and a few NovaRossi R5/R7 rods:
NovaRossi Crank pin= 4.9950mm
NovaRossi rod bottom= 4.9975mm
clearance= 0.0025mm
NovaRossi wrist pin= 4.0000mm
NovaRossi rod top= 4.0025mm
clearance= 0.0025mm
Ninja crank pin= 5.0000mm
Bottom of rod= 5.0150mm
clearance = 0.015mm
Ninja pin= 4.1800mm
Ninja rod top= 4.2000mm
clearance= 0.02mm
Ream the R5/R7 rods by hand since the top and botom ends are smaller bores and you are all set.
The R5/R7 rods are 0.01mm wider on the bottom and 0.01mm narrower on the top which will not affect anything since the bottom of the Nova rod does not go past the end of the Ninja crank pin and will not hit the backplate.
The clearance numbers don't look that different till you notice they are a decimal place more on the Ninja (10x more). Use the two above reamers by hand and you will have a more perfectly clearanced rod for the Ninja that is bushed on both ends.
I used four sets of precision Deltronics sizing bars (they come in 0.0005mm increments) and checked two Ninjas and two 321P's.... clearance numbers were the same for each brand. Hand reaming will result in a slightly larger hole than the reamer size you select.... that is why smaller reamers than you would expect were selected for the reaming process.
#773
Originally Posted by Wanabrc
Where were you able to purchase individual reamers in those sizes?
, but just google reamers in your area, or look in the yellow pages and you will find someone that will grind any size you want. That's what I did for my Jaco rims.... they fit my Mugen axles too tight so I had a reamer made to 0.4735" to slightly enlarge the rim's axle bore. The 4.1800mm reamer will probably just be a re-sharpened 4.2000mm. The 5.0010mm will probably be a 5.0025mm re-sharpened reamer..... that's how they re-size them sometimes- just re-sharpening them takes off a touch of material. They normally come in 0.0025mm increments.
#774
#775
cdelong- That sounds like an interesting idea for reaming a different rod for the Ninja motor, but I don't quite follow your numbers for each rod, I cannot believe the clearances are what you state they are , especially for the Novarossi rod, .0025mm is .000098 inch, that is a VERY tight fit, I was always under the impression that most rods had about .001 to .002 inch clearance, epsecially the big end, that tight of tolerance would be almost impossible to achieve, way more hand fitting, precision reaming and checking, etc. that these motors go thru at the factory. I am not doubting the accuracy of your Deltronic pins, but maybe the accuracy of the measuring of the crank pin and the upper pin, something doesn't sound right to me to come up with these numbers.... even the sloppiest of tolerances you mentioned there is still only .00078 inches, please help me to understand more....Like I said above, I LOVE the idea of hand fitting a "better" rod to one of these motors, I just don't follow the math.....
#776
Originally Posted by Ffejdat
cdelong- That sounds like an interesting idea for reaming a different rod for the Ninja motor, but I don't quite follow your numbers for each rod, I cannot believe the clearances are what you state they are , especially for the Novarossi rod, .0025mm is .000098 inch, that is a VERY tight fit, I was always under the impression that most rods had about .001 to .002 inch clearance, epsecially the big end, that tight of tolerance would be almost impossible to achieve, way more hand fitting, precision reaming and checking, etc. that these motors go thru at the factory. I am not doubting the accuracy of your Deltronic pins, but maybe the accuracy of the measuring of the crank pin and the upper pin, something doesn't sound right to me to come up with these numbers.... even the sloppiest of tolerances you mentioned there is still only .00078 inches, please help me to understand more....Like I said above, I LOVE the idea of hand fitting a "better" rod to one of these motors, I just don't follow the math.....
#777
Originally Posted by Nitro$junkie
the new Tuned versons are out check Nitrohouse for prices
Expensive! MR12-T01T is $220 more than the stock version!! 



My R is good.
