3TJ conrod bearing ID numbers - what am I looking for?
Posted: Tue Jan 27, 2009 8:58 am
This is a question to help me order the right parts for the FZR400RR 3TJ. I need to replace big end conrod bearings.
According to the service manual, I need to compare the numbers on each conrod with numbers stamped on the "crank-wed", and subtract one from the other to determine the size of bearing required. The manual doesn't show clearly what I'm looking for exactly.
I can find the numbers on the crank no worries - there's numbers for the main bearings as well. But it's the conrods which have me puzzled. One one flat surface on the outside of the big end, there's a printed stamp "5E", across the conrod and cap (to help with getting the right pair back together, as they're not all printed accurately acrosss the split the same way). On the other flat surface there's printed what looks like "9AN", on the conrod part only. On the bottom of the cap, two of them have a Q and two have an S raised in the casting, and three have two small obviously intentional pimples below the letter, and one has three pimples in a triangle formation below the letter.
The manual isn't clear which of the markings is the one I should use for the bearing requirements calculation. It seems the number on the crank is subtracted from the number on the conrod, and given my crank numbers are 1 2 2 1, if the conrod numbers were the pimple dots, I'd have 2 2 3 2, and the resulting bearings would be 1 0 1 1, but the lowest bearing number they have is 1.
So my question is this: in your rebuilding and bearing replacement experience, what is it about the conrods which determines which bearing to use with it? Or do I just order a heap of them and rely on the Plastigauge? I'd like to kind of be in the ballpark with my bearing order though, and base it on some kind of science.
Tristan
According to the service manual, I need to compare the numbers on each conrod with numbers stamped on the "crank-wed", and subtract one from the other to determine the size of bearing required. The manual doesn't show clearly what I'm looking for exactly.
I can find the numbers on the crank no worries - there's numbers for the main bearings as well. But it's the conrods which have me puzzled. One one flat surface on the outside of the big end, there's a printed stamp "5E", across the conrod and cap (to help with getting the right pair back together, as they're not all printed accurately acrosss the split the same way). On the other flat surface there's printed what looks like "9AN", on the conrod part only. On the bottom of the cap, two of them have a Q and two have an S raised in the casting, and three have two small obviously intentional pimples below the letter, and one has three pimples in a triangle formation below the letter.
The manual isn't clear which of the markings is the one I should use for the bearing requirements calculation. It seems the number on the crank is subtracted from the number on the conrod, and given my crank numbers are 1 2 2 1, if the conrod numbers were the pimple dots, I'd have 2 2 3 2, and the resulting bearings would be 1 0 1 1, but the lowest bearing number they have is 1.
So my question is this: in your rebuilding and bearing replacement experience, what is it about the conrods which determines which bearing to use with it? Or do I just order a heap of them and rely on the Plastigauge? I'd like to kind of be in the ballpark with my bearing order though, and base it on some kind of science.
Tristan
