Just started in on pilot I purchased everything good but have coolant coming out of breather tube bad base gasket or head gasket? Only comes out when rpms are up on motor (( Internal Combustion Engine ? )) not at idle any hints ideas?

Well coolant hoses routed wrong someone had coolant pumping in balancer area people never seem to amaze me. Drained coolant out hopefully rinse out refill with oil everything will be OK. Does the water pump have a seal to seal coolant out of balancer area?

Sounds like the Mechanical seal.

Guy had hose that goes to carb with coolant hooked to vent and balancer filled up with coolant drained it out hopefully mech seal still good. How hard are they to replace? Will I need to split the bottom end if it is bad?

No I replaced the last one by just pulling off the water pump cover and drilling a small hole in the seal and using a screw & pair of pliers to pull it out. Not really the correct way to do it, but got it done just the same and didn't need to pull the case off.

Your 100% sure it was plumbed wrong?

Usually when the coolant side of the pump seal leaks it DOES NOT leak into the balancer oil and balancer case, reason why is their is a vent\drain at the bottom of the cases so if the pump leaks it can drain out on the ground, I never studied what could or would happen if the drain hole was blocked and pressure built up, perhaps it could leak into the balancer area?

Drain the balancer oil, refill change run it a 1/2 hr drain it again see what the oil looks like, foaming or milky change again go another 1/2 hr and drain repeat until oil looks normal then I would change it after every ride trip.

I change my trans and balancer case oil after every ride trip or two or more tanks of gas has been run. Even the good oils are cheaper than parts in your trans or Engine balancer case.

Based on your previous posts it doesnt sound like mechanical seal but if it is, heres a write up. viewtopic.php?f=111&t=13821

It probably more info than you need but will explain some of the process.. Hope it helps!

Yes it was plumbed wrong probably filled all these way up with coolant. When I corrected didn't think to drain that may explain pushing some out vent hose when revved. After draining haven't rode so maybe tommorrow will see if oil looks milky. Hopefully not :)

Flushed radiator and cooling system. Had to get balancer oil rinsed out. Rode around farm today no problems. Happy mechanical seal still good. Here's pic of first fl400. Doesn't rev as many rpms as my built 350s though is this normal?