750 Seca engine

Will a 81 750 Seca engine fit into a 82 xj650 Maxim or would it require modification? I am hoping that it would be a direct fit.

Thanks

 

Yes, it's a direct fit, no mods needed. The only difference between the two is the cylinder displacement, which you can't even see. Good luck and keep us posted on your progress.

 

Excellent. thanks for your quick reply.

The 750 Seca engine has a starter clutch problem. How tough is that to fix?

Thanks

 

Triump,
I've never had any issues with mine (yet) so I guess I can't give any helpful advice. I'm sure there are several who can answer your questions. >PD<

 

Sounds like you need to follow this thread. Same issues.thread

 

Two methods, Yamaha service manuals will show splitting the case, the other way is talked about here.....

http://www.xjbikes.com/Forums/viewtopic/t=1700.html

 

There are a few differences between the engines on a 750 Seca and 650 Maxim. The engine mounts are different sizes on the O.D. to the case but they will bolt right in. The issues are simple, the 750 has an electronic tachometer and as such, does not have the pickup for the mechanical tach on the 650 Maxim. You would need to source the head off of a 750 Maxim in order to preserve this option. Otherwise a good choice for swapping.

 

Thanks for all the great info.

I can get this engine for $100 or best offer. I was thinking about offering 75 bucks. Do you guys think it is worth it? I have done the top end and rings in bike and car engines before but never split cases. Do you think this job might be within my scope? Or am I wasting my time.

Thanks again.

 

Oh. One more thing. What would be involved in changing the XJ650 tack to a electrical one so that it would mate with the Seca 750?

Thanks

 

If your 650 motor runs ok, this project is going to be a lot of work for not much reward.

39 bolts to split the cases. Bolts of different lengths.

Everything but the crank and gears comes out. Parts everywhere. Couple of hundred bucks. Tach hassles, airbox hassles, jetting hassles etc.

I'd be tempted to leave well enough alone.

 

Simple conversion, just swap out the instrument cluster. Easier said than done however. With the electronic tach comes the required wiring and converting for it is a choice: modify existing harness or get correct harness from instrument donor bike. The tach picks up it's signal from the coils primary input line. +12VDC and a ground return and you should be ok. Of course then there is the wiring for the instrument lights but that is fairly straight forward.

 

OK. So even if I were able to replace the starter cluth, I would not be able to use my 650 carbs as is. I would need to rejet? And the air box is not the same. I did not realize that. I was hoping if I were able to get the starter cluth replaced that it would be a direct swap.



Also Robert, thanks for you help also. I looked at the tack on my bike today and I think it is electronic. There is no machanical cable going to it at all, just wires.

Thanks for all your help.

 

Your carbs might bolt right up, but they will be jetted for an engine 100CC smaller, so a rejet is a given. Another guy on the board has put a 750 into his 650. He said it wasn't worth the effort and will probably put the original motor back in. I have never done this swap. I have done a starter clutch in my 650 turbo, and that was more than enough work on its own. Please don't let me dissuade you from doing something interesting with your bike, but saying it "bolts right in" is simplifying matters quite a bit.

 

I certainly appreciate your input. Atleast if I get into it I will know what I am up for. I am thinking that if I can get the engine for a good price I might try the starter clutch . If that goes ok then i MIGHT try to put it into my 650. I am basically looking for something to do while the snow is on the ground.

Again, I really do apprreciate your input.

Thanks

 

I simply swapped out the jets from my 650 carbs to get them to work on my 750. Really easy swap. I would not worry too much about the airbox, the air filter is the same and I'm assuming you have the boots to go with the box.
If you have an electronic tach already, your golden.
Splitting the case is not an excersize in rocket science, just take your time, plan out the mission, clean as you go and you'll be fine. I've done this before and it really is not that hard. Don't forget to replace the starter chain guide while you are in there. They do drop dead and will lock up your tranny. $20 extra is cheap insurance if your splitting the case.