Convert 1976 XS650 to TCI using 1981 donor engine

[Wilsonsk]

I’ve been scouring the various TCI threads and I am seeing fragments of what I need, just looking to confirm my thoughts/assumptions…

I can replace the 1976 stator and rotor with the 1981 stator and rotor?

I can use a GN250 igniter in place of a stock Yamaha igniter (I didn’t get that with the donor motor, which was replaced 30 years ago because of some top end failure)?

I will need either a stock coil for a TCI 650 or a Honda MP08 coil?

Are the pins the same on the 6 pin connector coming from the engine for both? Can I just plug that in?

I found a picture of the 3 pin pickup plug and corresponding colors, I’m not clear on which pins on the GN box those go to and which are used for power for ON/OFF and KILL. I am assuming I’ll need to make those connections myself in the 1976 harness.


Am I on the right path?

Thanks!

Steve

 

[Jim]

looks like you're on the right track. The charging systems are different pre and post TCI. As long as you know which system (Type A or B) you're gonna use, it's not really a problem.

 

[Wilsonsk]

Thanks!

My plan is to convert everything to post-TCI, stator and rotor, that’s where I wanted to confirm if I can plug the 6 pin plug from the 1981 stator/rotor/neutral safety into the mating plug on the 1976 bike.

 

[jpdevol]

If your '76 stator is good, I'm not sure you're gaining any reliability or performance by going to TCI with a GN250 Igniter. What parts do you already have and what do you need to acquire?

On the wiring, the brush wires will be different between the two and I'll have to find a diagram of the '76 connector block to see how it configures vs '81

 

[Wilsonsk]

I have the 1981 engine with stator, rotor and pickup. I think the only thing I need is the GN250 igniter, which costs the same or less than a set of Chinese points. I’ve had bad luck with points availability the last few years, everything comes out of China. I was thinking the TCI would be more reliable than dodgy points. I got the 1981 motor for free, something wrong with the top end.

Are the regulators compatible?

 

[Jim]

On the wiring, the brush wires will be different between the two and I'll have to find a diagram of the '76 connector block to see how it configures vs '81

Just off memory.... the pinouts should be the same, just the wire color changes on the brushes.

 

[Jim]

I have the 1981 engine with stator, rotor and pickup. I think the only thing I need is the GN250 igniter, which costs the same or less than a set of Chinese points. I’ve had bad luck with points availability the last few years, everything comes out of China. I was thinking the TCI would be more reliable than dodgy points. I got the 1981 motor for free, something wrong with the top end.

Are the regulators compatible?

The GN boxes themselves have become a little iffy as far as quality goes, but yeah... carry a spare or two, no more than they cost.

No, the regulators are different. Type A regulators (the newer version) are relatively inexpensive if you build your own.
Have a look here... https://www.xs650.com/threads/55842

 

[jpdevol]

OK. Here's the wiring on the '81

So I reckon first thing is you'll have to wire-up a Type A regulator or convert the '81 brushes to work with the Type B on the '76.

White (3) will go to harness white and the Sky Blue Neutrals to each other. You currently have no harness brown at the stator (can use the '76 green depending on which regulator. The harness black at the stator wouldn't be used if ya go with a type A regulator ( I better stop there as it's 11pm )

 

[nj1639]

Here's what I referenced while doing my conversion, thanks to INXS- first post in the thread "Some electrical diagrams", archived in the Tech section. I believe I had all the parts and pieces needed coming from an '81 parts bike and there were no major hiccups along the way....mebbe a bit of head scratching and some fab work for placement of the coil, reg/rec. and igniter. I'd do it again.
Keep your points parts and pieces, you might have to go back, but that's another story, another thread.

 

[Wilsonsk]

Thanks for the info! I am keeping everything, I fully understand that this doesn’t eliminate all possibility for an ignition problem, just maybe a little less fussy than the low quality points available, combined with my fingers not working as well as they used to with little screws.

 

[Wilsonsk]

Update, I have gathered everything I need to convert, I have been riding the bike as-is, with the points ignition, I have learned to get a good feel for what’s going on with everything when something has sat this long (parked in a shed in 1997). Replaced throttle and clutch cables, cleaned carbs. Put in new crap Chinese points, pulled them and put in the ones it came with, filed them a little, runs great, fires up immediately cold, wants little to no choke. My charging system is working well, I may do the conversion to my rotor and mount the pickup and just convert the ignition portion. I may decide to do something crazy and buy a 750 top end kit for that spare motor.