markjs
XS400 owner, bike lover
OK, so we're reviving an old XJ650 Maxim, and we have one coil that quit altogether. The only replacement we had available today was from an 85 Shadow 700. It seemed to work at first but the spark is at best weak and intermittent. I was only able to get two plug caps, and both new caps were on the problem outer cylinders. No matter what we do the outer two cylinders dig out under throttle.
Another strange thing is under mid throttle the rpms jump up and down a bit, very rhythmical, and I've never seen that?
I worry the issue could be the ignition unit, which, best as I recall can only be tested with a replacement unit. In that case, we have two Maxim 550s but afaik it's not interchangeable?
The guy working on it with me is sure it's just the coil.
Hoping some others have insights?
We've not taken a multi tester to anything yet but I have two more new plug caps on the way.
Another strange thing is under mid throttle the rpms jump up and down a bit, very rhythmical, and I've never seen that?
I worry the issue could be the ignition unit, which, best as I recall can only be tested with a replacement unit. In that case, we have two Maxim 550s but afaik it's not interchangeable?
The guy working on it with me is sure it's just the coil.
Hoping some others have insights?
We've not taken a multi tester to anything yet but I have two more new plug caps on the way.
