Tacho Problem

[Kiwi_XZ]

Hi all.

I've now done 1000 kms and feel like I'm comming to grips with most of the teething problem (oil leaks, coolant leaks, stutter etc...).  One problem I haven't been able to solve is the tacho, RPM has dropped off on at least three occassions.  It appears to be only indication, it doesn't feel like I'm loosing a cylinder and it only occurs for a few seconds. 

Today I'm cruising along at about 100 km/hr (55 mph) at about 5500 rpm in 5th gear and when I glance down the needle is jumping down to around 1000-2000 rpm and then back up to 5500.  I blip the throttle and the bike accelerates OK.  I don't feel I've lost the rear cylinder (although I don't know what that would feel like anyway, I assume I would really feel it).  After a few seconds it all comes right and for the rest of the trip all was OK.

I did 250 km today and it only occurred the once, the other two times I noticed it the drop was only around 1000 rpm.  I've done a resistance check on the coils, both are OK and cleaned the TCI connectors.  Are there any other connectors in the system, under the tank?  Up the front?  I have had the connector behind the battery box apart when I did the stator.  Maybe another clean of that one?

Any other thoughts or pointers appreciated.

Cheers - Shane

[Extent]

It might just be a bad connection on the back of the guage it'sself.  Just pop the back cover off and check out the connections for the tach, make sure they're clean and that the screws haven't backed out or loosened any.

[kiawrench]

 I agree, check your connections at tach, but also check for ground issue.

    I had a lot of little needle spooks when i was building my bike after tha Deal's Gap fiasco, but found that by adding additional grounds, a lot of problems went away,ie bouncing tach needle, flickering lights, periods of no lights on dash panel .

[QBS]

The tach receives its signal from one of the low voltage connections at the spark coils.  One of the coils has a 12 volt feed wire that splits off and goes to the tach.  I think the wire is grey.  This tells the tach when that coils' electromagnetic field has collapsed and thus, when that coils cylinder has been fired.  The tach then figures out what RPM that data translates to.  Clean the your coil feed 12 volt conections and see what happens.

[Kiwi_XZ]

Hi all.

I think I may have found the problem.  I removed the instrument cluster and found the orange (every manual and wiring diagram says it should be gray but on my bike it's orange) wire terminal loose.  It wouldn't tighten.

I opened up the instrument cluster and removed the tacho mechanism and found the threaded right angle terminal on the board had cracked and had opened up.  Managed to carry out a solder repair to the terminal and throw it all back together.

It all works OK but I won't know until I've done a couple of 100 kms, as I explained I it only occurs every once in a while.

Shane

[louthepou]

I've always thought that a tach on a bike like our Vision is not quite essential. When it's getting cold, the one on my red V gets quite slugish, thus rendering it useless until it warms up; that just helps me keep my eyes on the road more!  :D

Lou