Tachometer not working properly

[b_racuda]

I went for a longer ride with my Vision. This started with the tachometer needle just not being stable, it was shaking a bit. On the way I noticed that my idling revs are quite high but engine does not sound to have so much revs. Well I turned the bike off and the tachometer did not come back on zero revs. It shows 500 - 1000rpms also when the engine is not running. Is the problem in the tachometer or in the TCI? Is this sympton for something bigger to happen in the near future, for example TCI going to break down? I assume that tachometer is getting the data from the TCI and the rev limiter gets data from the tachometer, is that correct? Also sometimes the bike starts with one cylinder only and after a while the other comes alive. This is not happening every time, sometimes starts fine.

I don't know if this is related to tachometer somehow. Today I was overtaking a car and the revs went over 10 000rpm and after that the bike was not taking revs at all (under load). When putting the clutch on (not under the load) the bike rev normaly but if I let the clutch off the bike was not taking revs. It lasted about 5 minutes and suddenly the bike was normal again. Perhaps the the tachometer is telling the TCI to cut spark or something? Or the TCI is going to break down? Or the pickups? Or coil going to break down? Or just some junk moving in the carburetors?

EDIT: I did wash my bike yeasterday and and the first start was tomorrow morning. I have also a list of things allready done within last 3000 kilometeres which are related to TCI/ingnition:
- changed the fuse box (blade fuses)
- cleaned all connections (all wires are checked because the bike was totally apart last winter)
- changed the stator
- removed the bad connector from the stator wire
- changed rectifier (to a model from CBR 600)
- changed the spark plug wires and caps
- changed the spark plugs to iridium (because is was hard to start after standing a few days)
- all ground connections are clean (last winter cleaned all)
- new battery last month

[b_racuda]

I did find a old post where was great link http://www.jetav8r.com/Vision/IgnitionFAQ.html After reading that I probably have a broken TCI (symptons in the tachometer, the ignition problems don't last long and they show up occasionally). So time to order Sparker TCI from IgniTech.

Just in case, are the pickup coils prone to fail? I have to check them also when I have more time to go deep into this.

Maybe next summer I can just ride and not to repair...I think I have had all the common fails that Vision is known of. The bike was quite cheap to buy but I have spend at least same amount of money to get it running reliably...or just to get it running.

[Rikugun]

Just in case, are the pickup coils prone to fail? I have to check them also when I have more time to go deep into this.

Maybe next summer I can just ride and not to repair...I think I have had all the common fails that Vision is known of. The bike was quite cheap to buy but I have spend at least same amount of money to get it running reliably...or just to get it running.

I don't think the pickup coils are prone to failure on this bike but that's no guarantee. Once you get the bugs worked out you'll enjoy more riding and less repairing!  :)

[jefferson]

Have you removed the rev limiter wire from the ecu? Might be worth doing. If I remember right it is the black with a yellow tracer.

[b_racuda]

Actually I don't know if the rev limiter wire is removed. Have to check. Nevertheless the new TCI is now ordered from IgniTech and there is no revlimiter included in their Sparker TCI.

Last evening when I was driving home from the work I noticed that there is some sparks missing, so some of the cylinder is cutting down. I haven't notice this before. Maybe best to let the Vision stay in the garage until new TCI is arrived.

[QBS]

The tach gets its' signal from the spark coil gray wire.  Check a color coded wiring schematic to be sure.

[mshowe]

Ok, I was going to create a thread very similar to this, but thought I'd just add to this one.  I have a very similar issue.  I couldn't find my original post.  However, my problem happens (which is very similar to what is described here) after I come down from a wheelie.  As soon as my front tire lands, it starts running on one cylinder.  Similar to what is described here, occasionally it starts running correctly.

I was down for 2 years on this one, I finally decided to bring it into a shop (first time ever), and they called a few weeks later "Runs great and we couldn't get it to act up".  What?!?!?!  For two years, I never once had it run correctly.  I haven't been driving it BTW.  I thought "Well, they don't know what it's supposed to run like, apparently???".  So, drove my '93 Venture up there (40 miles away) and sure enough, it ran like a champ. 

Ok, cool.  I got it home - it was half torn apart when I took it up to the shop (imagine their joy in seeing it arrive) so I put everything back together.  In the process, changed antifreeze, cleaned air filter, oil change, gear oil change, and installed a fuel shut off valve.  Oh, prior to taking to shop, installed new Rick's repair stator and new oem R/R purchased from ebay a few years ago.

So, in my prior post, there was argument on whether it was carb or electrical.  I was wondering about coil pickups.  But, I am getting the same behavior, but this time - I am getting a very steady stream of fuel coming from overflow (coming out bottom of bike).

[QBS]

Fuel from overflow indicates a malfunctioning float bowl needle valve.

[fret not]

Steady stream indicates significant flow, stuck needle, debris holding it open, or maladjusted or broken float.  A lesser flow might be the O ring that seals the float valve barrel (seat).