Tacho Stops at 4000??? WHY

[jawsap]

Hi all,
This is my first post on the forum.
I am the proud owner of a 1991 Model FZR600 which i purchased new.
My question is about the tacho it has recently stopped going past 4000rpm no matter how hard the engine revs.
The bike is going fantastic and can still lay down some pretty respectable numbers but the tacho just wont read above 4000.

Does any one have any ideas why, as far as i know the tacho signal come from the CDI, which appears to be ok with the running of the bike.
The old girl can still push that 150mph mark with the standard gearing (not that we go quite that quick these days, well not as often as we used to anyway) i have her geared lower now to keep up with the more modern bikes off the mark and up to at least 3rd gear.

Would appreciate any ideas on this one even though i don't really need a tacho, i just like to know where the problem lies.

Cheers in advance.

[yamaha_george]

Hi all,
This is my first post on the forum.
I am the proud owner of a 1991 Model FZR600 which i purchased new.
My question is about the tacho it has recently stopped going past 4000rpm no matter how hard the engine revs.
The bike is going fantastic and can still lay down some pretty respectable numbers but the tacho just wont read above 4000.

Does any one have any ideas why, as far as i know the tacho signal come from the CDI, which appears to be ok with the running of the bike.
The old girl can still push that 150mph mark with the standard gearing (not that we go quite that quick these days, well not as often as we used to anyway) i have her geared lower now to keep up with the more modern bikes off the mark and up to at least 3rd gear.

Would appreciate any ideas on this one even though i don't really need a tacho, i just like to know where the problem lies.

Cheers in advance.

j,
Welcome aboard, I think that this topic of iffy readings on Tacho's has been covered and even that one bright sparks repaired the tacho.

It may be in the WIKI or do a search thro the past posts.

[reelrazor]

First thing I would check is running voltage.

The tach acting hinky is quite often the first indicator of a voltage regulator/rectifier gone bad.

[yamaha_george]

First thing I would check is running voltage.

The tach acting hinky is quite often the first indicator of a voltage regulator/rectifier gone bad.

I would also look at the connectors associated with this circuit. I have seen some grotty ones cause havoc as ell but as RR said VR first look

[jawsap]

Cheers for the quick responce,
I had a feeling it may be the VR but wasnt sure its charging at just on 14volts.
Its not the first reg to go if its the case i have replaced it once before and this time i will do the mod and put in a YZF or R6 unit.

Thanks again ill let you know how it goes>