I'm looking for information on trans break in

[rm250cy]

I just got my engine from ken oconnor for a complete rebuild. I am looking for information on breaking in the transmission gears. I normally run ATF in the gear box but I'm not sure if this is a good fluid for a break in. Also what process should I follow? Just run through the gears and low PRM's and change the fluid and repeat writhe process several more times?

[IamRooster151]

I usually will break it in (trans and bottom end) the same way I break in the top end. Typically, I will throw in a new piston and rings if I am doing the bottom end and trans, since it is already apart. To be honest, I don't think there is anything special way on how to break in a trans due to the fact that there is no rings to be seated like on a piston. I usually will run some Bel Ray gear saver 80W and change it every ride for the first few hours, then I go back to Shell Rotella Triple T. I like to keep an eye on things like the coolant level and oil level to see if there are any leaks. Have not had any problems the way I have been doing it. Good luck

Edited August 18, 2016 by IamRooster151

[Tankslap]

I also use ATF.  If it were me, I would put ATF in it and do your normal top-end break-in procedure that you prefer, and change oil early and often.

 

I also use a magnetic drain plug, I know it would drain out anyway but I like that any shavings will gather there and stick between rides.

[rm250cy]

That sounds good. Thanks.

[IamRooster151]

+1 on magnetic drain plug

[numroe]

When a trans is new or rebuilt I avoid smash or power shifting it. Use the clutch up and down and be gentle with shifting, but go hard with the power if you want. Change gears with a full throw of the shifter with normal force.  Change the oil more often. When I can feel it's starting to shift smoother and easier then I believe I've done the break in, and I'll do more harsh shifting and take the oil to maybe 8 hrs instead of 4.

 

I'm a fan of ATF type-F. But my last 4L bottle was Castrol ATF Dex III, and the shifting and clutch action has been excellent. Bike is a YZ250 2004 with new trans bearings installed about 20 hrs ago. Clutch is the Rekluse ZS-Pro.

 

I like magnetic drain plugs. Just be careful you don't get a junk one where the tip comes loose.  Might be one of those things where you get what you pay for. I've not had a tip break loose yet, and I think they're awesome because of what they pull out and what you learn about your usage and wear rates.

Edited August 20, 2016 by numroe

[rm250cy]

Just ordered my plug. Thanks for the great advice.