tachometer calibration - part 2

[superwesman]

for some reason, I get server 500 errors when replying to my earlier post on this topic ...


http://www.motobrick.com/index.php/topic,6013.msg39475.html


I've got the console disassembled but I'm not sure how to correct this tach issue.  If I push on the needle, it just gently springs back into place (at 2500).  The service manual doesn't say anything about calibration, it mostly just talks about replacing bulbs.


any ideas on what to do next here?

[superwesman]

trying AGAIN to post photos, 1MB this time ...

[rbm]

You have to remove the indicator from the shaft of the tachometer servo, and re-position it so that the needle is pointing at zero.  Then push the indicator back onto the shaft, gently so as not to break any internals.  Have you tried this?

[superwesman]

yeah, I tried, gently, but it felt like I was going to break it.  If the indicator/pointer thingy is designed to come off, I'll try with a bit more gusto...


any idea how something like this can happen in the first place?

[Inge K.]

If the indicator/pointer thingy is designed to come off, I'll try with a bit more gusto...

Use two teaspoons.

[rbm]

As Inge says.  Look online for videos about how to remove watch hands.  They use either a special purpose tool ot two jeweler's screwdrivers and pry upwards. Fast forward to 7:00 in the video below to see the principle ::

[superwesman]

ok - it's very easy to get the needle off with 2 spoons.  great tip.  However, I'm not convinced this is the way to fix the problem.  I see now that the tach has a range... the post/pin on which the needle is attached only rotates through a range of about 300 degrees.  In other words, the needle can go from 0 to 10.  If I put the need on so that, at rest, it's pointed at 0, then it only goes up to a max of about 8.  I was able to adjust this a bit so that it goes from 0-10, but then it comes to rest at 2. 

I'm now convinced there's some mechanism to calibrate this.  I just need to find it ....

[Laitch]

ok - it's very easy to get the needle off with 2 spoons.  great tip.  However, I'm not convinced this is the way to fix the problem.

Not knowing what you've done besides what you've described, and knowing that you consider removing the needle an easy task, did you remove the needle when it stopped at 2 and reset it to 0?

[superwesman]

did you remove the needle when it stopped at 2 and reset it to 0?

I don't understand this question.  I put the needle in the place, pointed at 0 at rest and it would only go up to 8, which doesn't seem right to me.  Right now I've got it pointed to around 2 and here it has the full range of motion (mechanically) from 0-10.

I haven't done anything other than what I described.  I opened it up and stared dumbfounded at it.

[Laitch]

I opened it up and stared dumbfounded at it.

Did that help? :giggles  The engine system has a rev limiter at around 8700 rpm. If it's working, you won't be going faster. If it isn't working, you probably won't be going faster for very long. What's your goal?

Somebody here certainly is able to explain why the tachometer on a bike that has a redline and rev limiter at the values on the instrument face should be able to register beyond it.

[billday]

Thanks to the Kafe Kraze, K-bike instrument boxes are plentiful and much cheaper than they were in the past. Just find a new one.