Does an OEM HONDA 250r crank have to be trued and welded?

[nemored]

I know a hotrods crank needs to be trued and welded but was wondering about a new Honda Longrod?
thanks

[C-LEIGH RACING]

Maybe & then maybe not.
Welding the crank pin is a process to insure no movement of the two crank halfs.
Welding, realy depends on how much abuse the crank will have to endure.
Abuse meaning what the engine will be used for such as xc racing, mx, tt, or drag.
An engine used for full on drag, I would say yes because of every race is a standing start where you want high rpm & all the traction you can get.
I guess what you need to ask yourself, how many standing starts you planning on doing. Dropping the cutch with all the traction you can get is in the end what will cause a crank to shift on the pin.

We tt race & every start is a standing start for us & on hard packed red clay, so most every time its as much traction as can be had. I dont have or have used a welded crank, but, it is something I am thinking about everytime that clutch lever is dropped.
If you do have it welded, be sure who evers doing it that they have done many cranks before & know for sure that they know what they are doing when welding one.
Get them to explain what happens while the crank is being welded & what to look for after the welding.
Neil

[machwon]

For a new OEM crank, just install it with new main bearings and run it. I wouldn't even weld a new hot rods crank either. The R motor would very very rarely separate the crank. If you have a crank that has had the rod pin pushed out and a new one put back in, or re-used the existing rod pin while trueing the crankshaft, I would consider having it welded. Then again, I personally would just start with a new crank anyways.

Welding the crank is very common in Banshee's. The helical cut crank/clutch basket gears create side stress that usually cause the crank to separate 95% of the time for those that fail. The opposing cylinder can cause havoc and make the crank go out of phase, but that rarely happens.