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Is this tachometer broken or something else?

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Is this tachometer broken or something else?

PostAuthor: John1c » Thu Apr 20, 2017 7:03 pm

https://www.youtube.com/watch?v=7MVo7FPp3fM

The carbs have been thoroughly cleaned. There are no vacuum leaks. The wiring is a bit of a mess, e.g., 3 ground wires connected to the same spot on the frame, cut then reconnect wires, etc.

Notice in the video that I didn't turn off the bike, I let it go below 2k and it just cut out. So I'm thinking the tach is not reading correctly and it cut out because the rpm was actually too low. Also notice, that when I blip the throttle, the rpm reading stayed the same.

Could this be something other than a bad tachometer? TCI, r/r, pickup, other electrical problems, etc.?

PS. The bike has aftermarket exhaust (don't know the brand, PO install it) but does it sound right to you guys?
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Re: Is this tachometer broken or something else?

PostAuthor: Aussiexv1100 » Fri Apr 21, 2017 12:53 am

The tacho seems to be erratic and also showing faster than the actual engine RPMs. If someone has been messing around with the wiring, it's a fair bet that the wiring is wrong,...somewhere, or bad TCI. I think that the tacho is most likely OK.
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Re: Is this tachometer broken or something else?

PostAuthor: drainplug » Fri Apr 21, 2017 9:28 am

From the sound it would seem he (the PO) hooked the Tach to both coils.
When you have it at 2000 RPM it sounds like 1000 RPM
Suggest you go thru everything on that bike and check any work the PO did, or even touched.
Some people have a knack for making things worse by fixing them.
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Re: Is this tachometer broken or something else?

PostAuthor: John1c » Fri Apr 21, 2017 12:09 pm

I didn't think it was possible to hook up both coils to the tach. Seems to make sense as the motor sounds like it's 2x what the tach reads. I'll try to go through all the wiring this weekend. I really hope it's not a TCI problem.

Any other suggestions since I'm in there?
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Re: Is this tachometer broken or something else?

PostAuthor: John1c » Fri Apr 28, 2017 7:24 pm

drainplug wrote:From the sound it would seem he (the PO) hooked the Tach to both coils.
When you have it at 2000 RPM it sounds like 1000 RPM
Suggest you go thru everything on that bike and check any work the PO did, or even touched.
Some people have a knack for making things worse by fixing them.
But that's where we find deals


Finally had time to check the wiring. The wiring is fine, only the rear was hooked up to tach.

Any other suggestions?
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Re: Is this tachometer broken or something else?

PostAuthor: mark75 » Sat Apr 29, 2017 3:14 pm

sounds like one cylinder is intermittent.
keep battery fully charged.
one cyl. will be colder than the other. check that plug, cable, coil ...
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