I don't think a minor variance in the thickness of the two units matters.
I think 14.2 V at cruising rpm is too high.
Here is my working theory and practice:
Your charging system should function like a battery tendender.
Your cruising rpm (where most time is spent) voltage should be just above your batteries steady state full charge voltage. Batteries differ so I won't give a specific number. My Oem Batt was at 12.6 & 12.5 for 18 months. My new Westco has sat at 13.0 & 12.9 for 5 years. This is what they both measured after sitting on a battery tender (digital automatic maintenance charger) over night and then unplugged for two hours. That is what I call steady state full charge.
If your charging system is working right your battery should measure the same after a one or more hour ride at cruising speed ( no extended stop & go or low speed running)
and then parked for two hours.
When I put my battery on the tender it goes up to 14.2 briefly if it was loewer than its usual 12.9 0r 13.0 then settles down to a constant 13.2. If the battery was already at 13.0 it just goes right to 13.2 and stays there.
When you crank your engine or run your lights without starting for a few seconds you battery will be low and 14.2 or 14.4 can be expected when you first start up but should soon settle down to around 13.2 after a few miles at cruising speed as the battery returns to full charge. Variables such as RPM and accesorries use wil cause the charge voltage to fluctuate more than it does with the bike parked and on the tender but if you see either less tan OR more than .5 volt above your steady state voltage, you have a problem.
I don't really know about the monitor wire on the 2000+ bikes but I feel sure the above applies to all 12 volt charging systems. Just one other thing, be sure your battery tender is suitable for the type of battery you have.
After recieving all the help here, I think it's only right for me to update. Btw, mine's a y2k 5th Gen.I've ascertain that my stator is bad, and hence ordered an Electrosport one from somebody selling it off in this forum and (after hearing all praises) decided to get one from Ricks too. Here are the 2 stators:
Funny, it seems the Electrosport ones is narrower than the one from Rick's. Which one is correct though?
Then I open up my alternator and took out the old coil. I guess this is what you could call 'burned'. Anybody knows what can cause this?
Comparing thickness of alternator. The one from Rick's is of the correct dimension. I'll be keeping the Electrosport's one as a spare I guess. Anybody who had used Electrosport's stator coil can confirm that I got the correct coil?
Next, some readings with the new coil:
Bike at 2500 rpm: 14.68V
Bike at 5000 rpm: 14.68V
Stator AC voltage - 24VAC - 67VAC form idle to 5000 rpm
Voltage drop from batt positive to R/R black wire (voltage sensing): 0.287V (which fail the <0.2V requirement from Electrosport's fault finding guide).
Hence I wire the black sensing wire directly to the battery positive and obtained:
Bike at idle: 13.4V
Bike at 5000 rpm: 14.2V
I guess that's good news...until you guys are now debating the credibility of doing the black wire mod! Drats, I've already cut the wire from the harness side...