Hey guys, I have been looking through old threads trying to see if this question was specifically answered but to no avail... anyone know if the 2KR and 3LN conrods the same? @downunderfzr asked me if I had some... I have some of his rough measurements and have measured up one of mine and they seem to be the same. Part numbers are different though: 1HX-11650-01 for 2KR 3LN-11650-00 for 3LN Anyone ever checked these in detail before? I wouldn't want to supply one and have it crunch up a crank as that is a huge issue. I saw @Linkin had investigated a conrod before but not sure if it was compared to a 2KR one at some stage? @GreyImport being the resident FZR expert have you ever checked? I know the pistons are different so I'm a bit hesitant to just go with it without precise measurement. Cheers
I have a 3LN one, he has a 2KR one. They seem to have the same dimensions give or take a couple of mm (will need more precise instruments to know for sure). I just wondered if anyone has compared. The bulk of the part number seems the same so it is feasible they could be.
Yamaha part numbers are like that. 3LN is the model code, the numbers in the middle are the number for that type of part (eg conrod), and the last 2 digits are the revision. 10 superceding 00, 20 supercieding 10, etc. If the bore and stroke of the 2KR is the same as the 3LN then it's likely the rods are the same item even if they have a different model code at the beginning.
It would be the revision for that particular model... so the conrod for the 1HX is revision -01 and the conrod for the 3LN is revision -00 Nothing to do with one pre-dating the other... just the way part numbering goes... The devil is in the detail for compatibility though... Bearing sizes, width, distance between centres, height of the bearing cap, width even materials of construction (forged or cast etc) and oil drillings...
Sometimes parts get superceded by another part entirely... eg the original fuel tap for the 3LN's has a part number starting with 2GH, the late model 40HP FZR's have more or less the same thing but the part number starts with 3LN
The genuine manual supplement that I have contributed to the forum and is also available on my web site, shows on page 1-6 that the 3LN rod C-C is 82mm and the earlier model is 80mm. I believe the stroke is 34.5 which yields a rod stroke ratio of 2.37 to 1. Wow, biggest number that I have seen. I guess these engines rev pretty high
Which would mean a different piston crown height above the gudgeon pin... given the stroke is the same... hence different pistons.
For what it's worth, the 2KR/1HX and 3LN pistons have different thickness groves for the oil control rings. The top 2 compression rings can be interchanged.
Malestrom is right onto it, the difference in rod length is accompanied with the different compression height (gudgeon pin location) between the two pistons BTW this info is spelt out in the FZR250 service manual - the beginning details the differences between 2KR - 3LN models, I cannot read Japanese however the graphs and numerals make sense
The original FZ250 may have had a 1HX-11650-00 conrod,which may have been revised when the 2KR came out with it's 1HX-11650-01 conrod
Time to revive a dead thread. I measured up a 2KR and 3LN conrod and they are almost identical aside from a 2mm difference in length and a 3 gram weight difference. The 2KR rod is 111.7mm and 230g. The 3LN rod is 113.7mm and 233g. My measurements might not be the most accurate.
