While reading this thread I also looked at the description of the PV adjustment procedure in the tuning section:
If I understand that correctly the PVs are fully opened already at 2500 rpm? Is this true? Does that mean that above 2500 rpm there is no difference in behaviour to an engine that has PVs stuck in the fully open position?

If the PVs only have an effect below 2500 rpm, I wonder why Honda cared to design such a system.

Which part is it that I don't understand?

gepe.

The power valves open fully at 2500 rpm for the purpose of set up. They then close again and do not start to reopen again until around 7500rpm, and are fully open at 12,000rpm.
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If I have to take the carbs off once more...

I have a question that is directly related to this post...and then some. I would really love to get an answer.

I have just re-set my PV's using the method in the workshop manual...eg. Run motor up to around 2500rpm until the PV motor rotates to it's maximum open point (clockwise). I then, as the manual suggested, puy an M3 bolt into the hole in the cable pulley and lightly tightened it to stop it revolving. I then adjusted the cables at the power valves so that the indication marks were aligned (I could also put a dowel through the two holes). Then I slackened the cables slightly to allow a little slack..as per the manual.
I have not yet had a chance to run the bike but when I turn on the ignition I noticed a faint buzzing from the PV motor. It appears that the cables are 'just' a little tight when the ignition is just on.

Now originally I used the TPS plug method to set the PV's but this method gives a different setting as the PV motor pulley is not rotating clockwise as much as the 2500rpm then kill switch method.

Which is right?

Mike
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I don't mind dying...I just don't want to be there when it happens!

The servo motor shouldn't buzz. If you can feel the buzz or hum through your fingers if you put them on the pulley then they are either misadjusted or the cable on one side is too tight.
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If I have to take the carbs off once more...

StephenRC45 wrote:The servo motor shouldn't buzz. If you can feel the buzz or hum through your fingers if you put them on the pulley then they are either misadjusted or the cable on one side is too tight.

Thanks, that is what I thought!
So that is with the 'workshop manual' set-up. Would it be best to still use the 'Workshop Manual' (2500rpm) set up but just go for a little more play on the 'tight side' or revert back to the 'TPS unplugged' method?
In my own (tiny??) mind I think that the 2500rpm method to be more correct.

Help please?

Mike
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I don't mind dying...I just don't want to be there when it happens!

The official Honda workshop manual way is that show in the tuning section of the main site, and how we've always set the MC21s up.

If you refer to page 24-36, you will even see a photo of the TPS disconnected.
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Andy.
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I'm curious, does a pgm4 with hrc 030 card generally operate in a similar way? I 'm referring to what rpms it opens.

With the greatest of respect Andy, what is the workshop manual that I bought from this site if not the 'official Honda' one. That is what I imagined it to be
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I don't mind dying...I just don't want to be there when it happens!

I don't have a copy of it, so that question should be directed to Charles. Charles's version is his [unofficial] translation; the official manual is Japanese, as sold by Honda.

I only keep the Japanese versions of all the manuals; workshop and HRC, and the official manual clearly shows the TPS disconnection method for the MC21. That is what we use when setting standard bikes up, and what's outlined in the tuning section.
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Andy.
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Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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