MikesXS Electronic Ignition Kit

OK, let's clarify needle terminology as it applies to these Mikuni carbs. First, the clip slots on Mikuni needles are counted from the top down .....

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To lean the needle, you need to lower it in the slide, to make it richer you need to raise it. This is what's confusing - to lower (and lean) it you have to raise the clip up, to raise it and make it richer you have to lower the clip .....

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Now I'm going to go back to the needle jet. You really haven't clearly answered about that. You said you bought new Mikuni jets from Niche Cycle but I checked their site and they don't sell the Z-8 needle jet your carbs require. They only sell Z-6 and Z-2 needle jets, both of which are leaner. If you did get some of those, that could be your problem. Your stock 4M1 needle is made to operate correctly when paired with a Z-8 needle jet. Even if you didn't change the needle jet, maybe someone before you did and installed the wrong ones. It's probably best you check them to insure they are the correct Z-8's. I'm kinda hoping they're not because it would help explain your issues.

Then I guess it's also possible that you don't even know what I'm talking about when I speak about needle jets. They're the long tube that the needle sticks into. They're not a small brass screw-in type jet like the mains and pilots .....

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Thanks for the really great extra information! I will check the needle jets tomorrow. Today I was able to get it running much better by going with 130 mains, putting the e-clip in the middle on 3, and changing the air screws back to the ones in the carb before I replaced them with the kit ones, and adjusting them to 1.75 turns out. I also rechecked the floats and they are both perfect at 24mm. The bike can now go 60-65 mph pretty well. I plan to continue fine tuning tomorrow. Thanks for all the good help! This forum is great!
 
Well, I've had a major setback. Yesterday and this morning, the XS650D was running fantastic. It accelerated evenly all the way up the RPM range and easily hit 60-70 MPH, and could keep on going. It had the following setup:
  • 4M1 needles
  • OEM Needle jets
  • Timing rechecked
  • E-clip in the 3rd middle slot
  • 130 mains
  • 27 Pilot jets
  • UNI pods
  • Balanced carbs
  • Float heights rechecked and both set at 24mm
  • Air needles 1.75 turns out
Then this afternoon, I took it for a ride and within minutes of riding and then trying to accelerate onto a ramp, it started cutting out again at about 3000 RPM, loss of power, and I could not get it over 45 MPH.

I have no idea why it would suddenly change like this. I'll have to tear into everything again and see if I can find what happened!
 
Maybe ask a question instead of going ahead and doing something your not sure about,.............I think this has been your problem throughout this thread

Blocked pilot circuit........???
 
Maybe ask a question instead of going ahead and doing something your not sure about,.............I think this has been your problem throughout this thread

Blocked pilot circuit........???

Or...are your coils breaking down?

It almost sounds like the ignition isn’t advancing. I don’t recall whether you’re using the mechanical advance system or some form of electronic system....
 
I'm using the MikesXS Ignition system found here: https://www.mikesxs.net/yamaha-xs65...ion-with-e-advancer-xscharge-pma-package.html

What started this thread was that the kit did not include clear installation instructions, and MikesXS was not willing or able to give me detailed answers to questions I had. So, I came here (first time). Everyone has been incredibly helpful and I've learned a lot.

The MikesXS kit includes new coils, new spark plug wires and caps, etc. I'll check the timing to see if it is advancing... it was yesterday. And, I'll open up the carbs again and see if something came loose or started blocking ports. The gas tank was very rusted and I had to do a lot of work to clean it out and recoat/reseal it. Maybe something small came loose as I put new gas in it this morning?
 
Hmmmmmm....yup, that could be. Have you installed fuel filters? It is challenging to fit them in between the tank and the carbs but it’s worth the effort in my view.
 
The gas tank was very rusted and I had to do a lot of work to clean it out and recoat/reseal it.
Ironically, the fuel tank replacement is right where I would have started.
But then, I woulda left the electrical just as original as possible. Aside from a Rectifier and Voltage regulator.
It’s still kinda fun to look how all this
“progress” is going :rolleyes:
 
Note: Regarding Needle Jets : Early 70's needle jets sometimes had more than one number
on the same jets produced by Mikuni/Solex - True - Don't ask me how to sort this out , Mikuni reused the same
number on very different jets used for the XS
 
The gas tank was very rusted and I had to do a lot of work to clean it out and recoat/reseal it. Maybe something small came loose as I put new gas in it this morning?

I’m just a hack, but my first thought was , it sounds a little like fuel starvation. You’re not running filters on the fuel lines?
If not, you could have a blockage. Also here’s a photo of the brand new petcocks that were on my XS2 when I bought it. The tank had been “ flushed with a steam cleaner” and had very little run time on it.
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The petcocks have an internal fine mesh screen that could also potentially be partially blocked. Don’t know if that’s your issue, but I’m just throwing it out there.

Baraboo is SO close............

Boy, that sounds like a life line being thrown out there! That’s where the wizard resides! :pimp:
 
Note: Regarding Needle Jets : Early 70's needle jets sometimes had more than one number
on the same jets produced by Mikuni/Solex - True - Don't ask me how to sort this out , Mikuni reused the same
number on very different jets used for the XS

The bikes a 77D.......Does that still apply??
 
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