| March 3, 2014 | 2 Comments

My new optically triggered ignition from C5 Performance showed up last week and I can’t tell you how excited I was!  Since this is the very first kit they’ve created for the Yamaha XS750/XS850 I agreed to be the guinea pig and confirm the fit for the adapter plate, the encoder adapter, and also make up some options for mounting the new coils.

Here is a brief comparison of the hardware from C5 and what comes stock on the XS750 –

I removed the side cover on the XS750 this is what you’re looking at –


The base plate has 3 retaining bolts.  Typically when these are installed by Yamaha they are only removable with an easy-out.  The previous owner must have replaced them with these new brass bolts instead.  The big black hexagon is the ‘pickup’, and in the middle is the nut you turn to crank over the engine.  Before I started I made sure that I set the engine to TDC.

I tried removing the bolt in the middle holding the nut on but it kept slipping on the socket.  I think tried drilling a hole and using an easy-out but I busted my easy-out in the process.  One of my dad’s friends had stopped by and when I went to get lunch he noticed I was using a 12 flanged hex head socket, so he tried it with a 6 hex head and it came right off.  Dopey me…

Nut and bolt out –


Base plate off exposing the Governor Assembly –


And everything removed –


You can see there is one more screw to remove in the upper left hand corner.  This was put on by the factory and has obviously not been removed.  I’m going to keep this on there because it is really easy for me to just pop the governor back on and see if the engine is at TDC.  There are a couple other ways to check for TDC without having to leave it on, but I’d rather go with this because it is what we used when rebuilding the top end.

We then attached the C5 ignition module to the new base plate and put it on for a look-see –


All and all if fit well.  We’ll be making only a few small modifications, but this will be for customization mostly.  The ‘encoder adapter’ which is the shiny cylinder in the middle was a few millimeters off in length, so we’re going to make a new one out of aluminum and then send our results back to C5.

We also spent a little time trying to determine how we’re going to mount the coils –

Next time I’m down at the shop I’m hoping we’ll be able to wire her up and do a test startup.  I still need to bench sync the carbs, so maybe it might be a little further down the road.  But at any rate, it looks like I’m getting alot closer to having a ride ready for this season!

Thanks for stopping by

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2 Comments on "Prototyping"

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  1. 78 Triple says:

    So, how’s it running with this kit? Any issues or words of wisdom?

    • ucr says:

      This kit is so awesome!!!!

      Here is a video I shot of the bike finally running for the first time

      The only challenging part was keeping the 1st piston at top-dead-center while tightening down the bolt into the crankshaft that holds the encoder wheel in place. I used the old governor assembly to set it to TDC, then removed it and inserted the aluminum cylinder that the bolt runs through, then made some marks with a felt pen and on it and on the crank shaft housing so I’d know while torquing the bolt down that it was lined up correctly. Paul had suggested putting the bike in second gear and having someone hold it in place while I cranked, but I think if I do it next time I’ll try 1st gear instead.

      When fuel finally started running through the carbs the bike fired right up, and did every time thereafter. There are also 4 pre-programmed timing curves that can be activated on-the-fly that I want to play with also. All it takes is hooking up a switch to toggle to ground.

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