Are mechanical tachs from different Secas interchangeable?

Are mechanical tachs from different Secas interchangeable? They're listed as different parts numbers in the OEM parts fiches, so I'd have to assume no. Another way to look at this would be do the guts move identically across Seca mechanical tachs, or do the same RPMs move the needle different distances (not on the gauge, but actual mm or inches)?

Just curious, any information would be greatly appreciated.

Thanks!

 

I'm only familiar with the electronic tachs, I've not seen the mechanical tach on a Seca. I'm also noting that your running a 400, would you be able to post a picture of your tach front and rear? It's worth a thousand words and might help members I.D. if your swap is possible.

 

Re: Are mechanical tachs from different Secas interchangeabl

Based on my experience, I'd think that they are interchangable.

I'm currently using the gauge cluster off an '80 650 Maxim on my '81 550 Seca. The speedometer and mechanical tachometer (the '80 650 used a mechanical tach) work fine.

It didn't require anything special. I just screwed the speedo and tach cables on the Seca into the Maxim gauges.

 

Re: Are mechanical tachs from different Secas interchangeabl

I will second this seeing as how I'm using an '82 550 cluster on an '82 650. The mechanical stuff "just works".

 

Ruptured...you're looking at swapping the gauges and I want the other end. I am considering capping off the mechanical port and getting an electronic tach from a seca to swap in there. This mechanical one just keeps on leaking, and unscrewing itself.

Anyone know about going from mechanical to electrical on a 550?