Motorcycle Repair: High Rev Cut Out, yamaha fz1, exup valve

Question
Mark

I have a 100% stock 2002 Yamaha FZ1 that has acquired a bad habit.  At high revs, starting around 8K but varies, the engine sputters/stutters.  It kind of feels like a rev limiter kicking in pre-maturely.  I had read that the EXUP valve gets sticky and needs maintenance so I adjusted the cables by tightening them up a bit.  After tightening the cables the tachometer started a strange sequence:

Step 1: Reflect the actual engine RPM
Step 2: Go to Zero
Step 3: Go to exactly 7K

This sequence will repeat for a bit and then stop until I turn off the engine and re-start.  The exact sequence will repeat again.

Any ideas?  Is it connected with the EXUP or am I way off base there?  I originally thought it was the EXUP because this happened to me about 4 times one day last year (but not again for the balance of the year) and it occurred exactly at 7K which is where the FZ1 gets a step function power surge under hard acceleration.

Please advise.


Answer
Hi Gary,

I don't have access to tach trouble codes. I think you're on the right path with diagnosis. Try the following links and post same question here. Someone should offer assistance.

Respectfully,
Mark Shively

http://www.angelfire.com/ia/z/FZ1sitemap.htm

http://www.yamahafz1oa.com/index.shtml

http://www.yamahafz1oa.com/forum/index.php?s=e6a1e219b59768827339b08652554683