Modern Vespa

Going to put a CHT and tach on my Allstate. Two questions:

- The temperature ring goes between the plug and the crush washer. The ring is about 1/16th thick which pull the plug out by that amount. Any impact?
- The cord is much longer than I need. If I wrap it will it have a secondary effect on the tach?

I removed the crush washer all together, per the instructions. Rule follower that I am. Hahha.

I don't know if that difference in plug depth will matter though, and the seal isn't as good with just the probe...

^ Agree with qa. No crush washer.

The excess CHT cable shouldn’t affect the tach unless maybe you wrapped the tach cable around it, which you weren’t planning to do anyway, right?

The cables are joined. So I can't cut them to make them shorter. So they are both, and/or the combined one are going to need to be coiled to shorten the length.

You can cut a section out of the CHT wiring to get the length right if you need to. I did it after I destroyed the end of one and it worked fine.

And there's no issues with the tach and CHT interfering with each other. They're just sensors and the CHT is only measuring resistance across a bit of ceramic at the plug. Barely even a circuit

Lots of this stuff can be hacked on, you just need to be willing to take the risk or have backed yourself into the, "It's try this or throw it in the bin and buy another" corner to find out what works and what doesn't.

So I put it all together this morning. Pics attached. Just two little coils. No crush washer!

I also included a pic of the plug that I haven't taken out since I installed the motor. Has the jet stack provided by Jonathan. Engine pulls well and does not bog. Granted, I have not ridden it more than maybe 20 miles since I installed it so no real data. Its making a funny noise. But the plug looks rich to me. Am I reading that properly? I also have a standard exhaust on the motor so Jonathan my have jetted for a performance pipe.

Will take it out for a spin sometime today.

I thought I read in the past, he sets them up a bit rich for the initial 500 mile break in period.

Looking forward to hearing about your experience with this gauge. I would love to have a tach and a CHT gauge and this is the only product I've seen that combines the two. Doesn't get great reviews for longevity though. If it works out for you, I'll probably get one too.

Took it for a 10 mile spin. Some open throttle - still running it in - but never got above 225 deg F. Don't think I hit 60 but definitely over 50.

The tach does not work, it bounces around and kind of goes up exponentially at what I think is 4 grand it is saying 12. Doesn't work on my super either. Works on my Stella. The inductive tach may have issues with resistive plugs or maybe the ignition. May need to adjust the number of wraps around the plug wire. I don't really know. Maybe the little loops cause the pulses to double but I doubt that.

Ideas.

Tach needs to be set for 2 stroke and get that tach wire a lot of turns around the plug wire

Yes, it is set for two stroke. Have about seven windings but will increase them and see.