break in oil for new motor?

[mhewitt]

ok so i have my freshly rebuilt motor sitting in the frame waiting for me to ride it but first i need to know is it ok to break the motor in with synthetic oil or should i use a conventional for a break in period? i usually run royal purple 20/50 in both sides so i f i should use conv. then what weight and for how long before i switch back to synth.?

[Lquad71]

for break in i use 10-40 semi-synthetic from honda. (silver bottle)

[eastside 400]

use something cheap since you should only put a couple break in runs on the oil before you change it. i like the shell rotella 15w40

[Pacheco_450r]

I've heard running synthetic while breaking it in doesn't allow the the parts to break in properly. I agree just use cheap conventional for the first few oil changes since you will be swapping it out a lot at first.

[PSNL05]

You may get a little blowby with a full synthetic since it has smaller polymers and may squeeze by the rings, but once they seat properly, you won't have any issues. May be a better idea to run a semi-synthetic blend for break in and then switch to a full synthetic once you are ready to start riding.

[hondarider421]

something cheap not synthetic id say a few runs maby even a few hrs on first run then change it one time back to non synthetic run it fairly hard to set rings use the full rpm range then go synthetic

[Ichoptop]

I dont know so much about TRX motors but in the car world it is very well known that you never break in a motor with syn. It takes to long for the rings to seat in the cylinder or may cause them not to seat properly. All the parts mfgs. (Arias pistons, Ross, Dart, Crane, Isky etc) post it very boldly on thier tech sheets. I use regular dino oil for the break in and the first 2-3 oil changes then switch to syn in the drag motors I build.