[Steaming Demon]

Have 81 interstate, 1100, was damaged on rt timing cover, repaired by previous owner. engine knocks below 2000 rpm. Would 86 1200 engine fit this frame? Would rather swap engines than rebuild, any thoughts?

 

[mowerdoc]

are you sure the engine it bad it could be the carbs are out of sink the Guru's will be by shortly

 

[Bike...and Dennis]

First, no, the 86 won't 'drop in'.
But like Mowerdoc said, this sounds more like a carb problem. Engine knock would be more pronounced on the road @ 3~4K rpm or higher.

 

[ScottInIowa]

My 1100 made the same sounds below 2000 rpm. Was very much out of sync.

 

[Steaming Demon]

Rebalancing carbs, found linkage prob, knock tuning out! Thanks

 

[DaveO430]

First, no, the 86 won't 'drop in'.

Why not? Takes a little more than just the engine to make it work but it will fit.