89 Motor in an 86

[MasterGuns]

Ok all you experts; I have a couple questions concerning replacing the motor in my 86 with a motor from an 89. I am of the opinion that the original motor either has a piston slap or some other type of subtle knocking noise only on deceleration. I am quite certain the knocking is there when riding but due to other noise I cannot distinguish this particular knocking from all the other noise. The knocking noise is quite noticeable when the motor is at normal operating temp and when still. Doesn't matter if the tranny is in neutral or any other gear. Anyway, the bike is in otherwise outstanding condition and looks almost new. So, I found another really good motor from an 89 that will be going in (41K miles). Here is my question:

 

1) Since the replacement is coming without carbs, will the carbs from the 86 mount and operate without any issues? I think they will but would like to hear other opinions.

 

2) I believe all the electronics are the same but what other concerns or issues might I be overlooking?

 

Thanks for the advise.

[dingy]

There should be no differences in putting 89 motor in.

 

Carbs are identical.

 

CDI is identical.

 

Wiring harness is identical with the only exceptions being noise filters on the front & rear brake switches and fan motor. None of these are involved in swap.

 

Mounting points on motor's are identical.

 

I am in process of putting an 88 into my 83, so I have looked into differences in model years.

 

Gary

[Squidley]

Good to see you back on Gunny, and like Dingy mentioned, I know of no differences in the 2 motors.

[skydoc_17]

Hey herb,

Great to see ya' Back! If you are going to pull that 86' motor this would be an excellent time to "A" replace the stock motor mounts with new stock ones or "B" Install solid motor mounts and fuse this engine to the frame to reduce frame flex and give your bike a much more solid "feel" on the road. (the front two motor mounts on all of the Second Gens. are mounted this way) You will see much better handling in the corners and much better weight distribution under acceleration. Also this is a great time to Moly 60 the splines on the drive shaft and dielectric grease EVERY CONNECTION you remove. Oh yes, check your Carb. boots VERY CLOSELY for cracks, Move the TCI to the Air Box, New plug wires, heavy duty battery cables, check the Carb. Float Levels! (you get the Idea)

Good Luck with this very interesting project.

Just my thoughts,

Earl