Ive just replaced my reg rec, (mc21se)

New one is in place, but it seems to get real hot, im worried im gonna blow it (again)

I have done as much research on the situation prior to replacing the RR, including battery tests(still showing 13.5 V from the over boiling - rooted RR), short finding (none to be found)

how hot is too hot, i cant even touch it when its been idling for 10 mins...
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They do get very very hot (its how they work after all). I wouldn't want to be touching any after a bikes been running.
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If I have to take the carbs off once more...

I recall hearing that the TYGA subframe mod could cause some probs with the Reg / Rec. Does anyone have any direct experiences?
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Rich
MC21 Track Bike / RS250 NF5 'Spencer', NX5 'Cadalora' & NXA 'Aoyama' / RS500 / Two Brothers Racing RC30

never had any probs with my old SP with tyga tail..
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MC21SP - Roth-tax
CBR400 - track
MC21R - sold
MC21SP - sold

I can only imagine that the problem could be that with the TYGA seat unit the reg rec doesnt get as much air as normal or the position of it on the TYGA sub frame isnt as solid as the OE one.

Either could be helped by bolting the reg rec onto a fair sized peice of alloy then fitting that to the subframe to act as a larger heat sink.
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If I have to take the carbs off once more...

The regulator part works by short-circuiting the excess voltage... anyone who's ever short-circuited something 12V by mistake (or even on purpose! ) will know how quickly the wires or component gets hot and eventually melts, or even explodes... allegedly!

The reg/rec is squeezed into a very compact housing, and the rectifier components themselves also generate heat while converting the AC generator current to DC. Both parts are generating heat as soon as the motor is running, which is why it gets very hot, very quickly, and why it needs a good heatsink and preferably unobstructed airflow around it.

There's a surprising amount of energy that comes out of a small motorcycle stator.
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Andy.
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Kubira, if you can't touch it after idling for 10 minutes, there's some kind of problem. Mine will get hot to the touch but that's after a day at the track. In the past I had used an electrolux(?) uprated unit. I believe it was from a VFR750. It has large heatsink fins on it and ran much cooler.

Andy wrote:There's a surprising amount of energy that comes out of a small motorcycle stator.

yeah, when the old RR was installed the stator was crankin out 16.3 V
Now thats a lil too hi eh.

scottvor wrote: Mine will get hot to the touch but that's after a day at the track.

You prolly strip it of electrical components i assume? Maybe i should have gone the extra mile and put in a finned version, i know of a few that will work now..

I have installed a small heat spreader on the rear side (battery box side) of the RR mount. Hope this helps
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..so do we have a list of RRs, different than stock that is, that people here has used with success?

It seems that this problem can not be eliminated by the NSR community...

Dexter wrote:..so do we have a list of RRs, different than stock that is, that people here has used with success?

It seems that this problem can not be eliminated by the NSR community...

Speak for yourself! I think it's been well solved in previous posts.

The problem seems to be more that people can`t be bothered to look up the info for themselves!

Believe me this subject has come up many times (even before you signed up )

Solutions reported are:

1.Buy the finned version for newer Honda models
2.Relocate for better cooling

(maybe I m getting old and I don't remember any more solutions mentioned)

That doesn't really help when buying for a new one does it?


So help an NSR-buddy out Lizard and tell me what are the solutions mentioned in previous posts?

Well how many more solutions do you want? Buy a finned one and mount it correctly!

5 clicks from this page to this:-

http://www.electrosport.com/products/product-detail-620.php

Wasn't hard to find, and if you've been around that long, surely it would be just as easy for you to find as it was for a newbie like me?!

I want a specific pt. number for a finned Honda OEM Reg/Rec, or even a bike model that came with the Reg/Rec in question.

I want the related experience from the people that used it.

I don't want the search police

The link you provided is useless, as I don't want to use a non-OEM part.

5 clicks from this page you can find the whole internet (5 times).

Finding anything through phpBB a search engine is pretty much hit and miss...

Newbies can do it too...

Really, how bloody difficult is it? There are plenty of topics on this, with a number of them referencing cross-compatible parts from other Hondas.

The Electrex page I linked to has details on compatible Honda part numbers, and this website`s Parts Manual shows 31600-MV4-000 as an MC21 reg/rec part number.

All that cross references against itself, and the OEM numbers that come up on the Electrex site can all be checked at Honda.

Christ! Do you want me to buy you one and come and bloody fit it too?

I`ve seen it written before, "the site helps those who help themselves", and I see what they mean now. Short of listing each and every CB/CBR/VT/VFR etc that these reg/recs fit, what more do you want?


Last edited by NSR-lizard on Thu May 07, 2009 2:14 am; edited 1 time in total

Is it possible to identify any issues that relate to the RR operating too hot

Im happy to assume my RR just simply packed up , and that my new one will run (with heat spreader assisting cooling) for a few thou K's.
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