Hey guys, Im trying to order some rod bearing for this R6 motor but the rods have no etching on the sides. Can not see anything not even residue. Are these garbage?
Express to him that reusing r6 rods results in blowed up engines, or at least a high probability of a severely damaged one, if not completely ruined. Hard to believe some doesn’t see the value in professional advice...
....and, if the customer is still adamant on re-using well more power too him, and then you can collect more from him when he comes back with a blown motor that needs overhauling subsequently.
lets pretend he ordered new OEM rods.. it's the number stamped on the crank that dictates what rod bearings you use isn't it ? i think the combo of case # stamp and crank number dictate the main bearing color (ps, i don't build motors, i have just enough know how to be dangerous in this area)
Right, that's in theory, in practice you'll get blamed every day until Sunday even with a signed waiver and a stamped seal of notary.
You use crank stamp and a number on the rod. It’s the same as the crank and case number to get mains, this you use rod and crank to get rod bearings.
I envision the customer being notified, not doing rods, then the thing spinning a bearing or worse in the dyno during break-in/tuning. Not super likely, but definitely not outside the realm of possibility. The customer isn’t gonna excited to pay for anything at that point. Anyways, carry on...
No, there's some math involved that uses the rod marking, subtracts the crank markings. The main bearings use the numbers on the case. There's also a weight range stamp (letter) on the rod. Proper method would be to install bearings, measure the ID of the torqued rod big end with bearing, then measure the crank journal and compute oil clearance. Use a different bearing to get what you want. No stamped numbers theoretically necessary. What you will find with used stock rods is that they are not round so the oil clearance varies. Almost every R6 rod I have ever seen is 5E. Occasionally 5H. I'd recommend to Darwin that he set the rods up as 5 and plastigage if he does not have bore gauges and micrometers to measure with. And yes, the engine builder gets blamed if it blows up almost every time. Therefore, my recommendation to use new rods.
So here is the story behind this question. Im not doing the work. Guy calls me from overseas and wants me to order him bearings only. I asked him for the crank numbers and rod numbers and that was the situation. When I told him to replace the rods and I told him the price he told me he can just buy another engine. LOL I told him with out the rod numbers I can not order him anything. I even offered him some used rods I have that are 5H and he did not want to spend the extra 100 bucks. Rick since I checked thru a box where I have a bunch of old rods and all where 5 he decided to go ahead and go with 5 as the number and ordered him that.
Is it not possible to re-machine the rods round? I know its common in automotive, so there must a reason its not done?
A new rod assembly is about $98 from yamaha. I would imagine the re-con of a rod would be around $50 ish plus the new fastners from Marine or similar machine shop
If you can afford it, use new rods. Use the rod bolts in the new rods to size up the proper bearings. In my opinion, do the math on the proper bearing Yamaha calls out for and start with one size smaller (tighter clearance). When finished sizing, discard the rod bolts and press in brand new rod bolts to assemble. Order and use the latest (BN6) part number. Definitely Mo Bettah
been using 1 smaller bearing for a long time now, with success.. did you mean use the old rod bolts to measure clearances, then press in the new bolts that came with the new rods.. or use new bolts for both measuring and assembly. ?
