Voltage Regulator Improvement Mod.

On the 5 gen VFR's, if you notice the voltage reg is mounted flat against the tail frame to a thin steel plate. Kind of choking off the air on it's backside. Heat is your regulators worst enemy. So, the next time you have the tail fairing off, get a couple of regulator bolts 1/4 inch longer than stock and two 1/4 inch thick OD spacers. OD meaning the outside diameter of the spacer is larger. 3/4 inch OD would be great. The reason for the OD is it will help to better support the regulator. If would can't find spacers, stacking fender washers to a 1/4 inch will work. Fender washers have a larger OD than a standard washer. Spacing your regulator out will get some more air to circulate around it's backside improving it's heat disipation, greatly improving it's reliability. This is a very easy mod and well worth the added benefit. Ride Safe

 

Do you have proof of this? Honda or any manufacturer could have easily done this, so why haven't they?

It's my understanding the R/R mates to a large piece of frame expressly to dissipate heat through conduction much the same way a heat sink on a computer processor must contact the processor. In fact, a popular mod is to use heat sink grease on the backside of an R/R. The outside fins meanwhile use convection for heat dissipation.

On my fourth gen subframe opposite the R/R, Honda dished out the frame and suspended the fuel pump with a rubber strap so it can get air flow on all sides. They could have done the same for the R/R but didn't.

 

I have to agree with photomoto, I've been doing alot of r&d on this subject,the common sense thing would make you think spacing the regulator would make it run cooler,however Honda dissipates the heat away from the regulator via the heat sink mode which uses the metal frame to pull heat away from from it. I
have not installed it yet,but I recently made a 1/4" thick aluminum plate the same size as the regulator,in hopes of making the current system more effective. eddie cap:wink:

 

yea i wouldnt recommend this option, all you are doing is contributing to overheating the r/r. If you want to help dissipate the heat, get some Arctic Silver (a paste that is applied between a computer's CPU and heatsink) and apply a THIN coating on the back of the r/r. This will help transfer heat to the subframe.

 

C'mon guys, Honda didn't intend to make the subframe a heat sink. Steel is a very poor dissipater. Even worse when painted. The contact area of the fins to the subframe is very minimal any way. Eddie is on to something with thick alum. plate which equals larger heat sink. Anybody call an ignition mfg tech like MSD. Better yet experiment with a point & shoot infrared temp gun and see what you think. Ride Safe

 

Sorry, but photomoto, eddie cap & rev are correct on this one Bodrodz.

Just last weekend I had to put on a new RR on the 97 and my father in law is an electrical guru of sorts. He did the wiring mods that supposedly assist in keeping the RR alive longer. Anyway, we discussed the heat sink and he explained it would be a very bad idea putting spacers behind the RR keeping it off the metal plate. Besides, the heat fins do not touch the heat sink, the flat metal backside of the RR does. The subframe is aluminium too if memory serves.

Appears Honda got that part correct with the RR.

BZ

 

OOPS! I am so sorry, I completely lost my head. I'll go back to minibikes and working on the F117.

 

Bodrodz:

You have 4 people questioning your RR modification. That's all it is and nothing more. We would like some kind of proof that it works before we attempt the same modification. I was just sharing some 'knowledge' passed to me from someone I trust that has electrical know-how.

So if you have information or experience to back up the logic this modification works, then expalin it to us instead of being a pompous asshole with the statement "I'll go back to minibikes and working on the F117".

BZ

 

Yeah Mello Dude... you get a beefier RR unit, aluminum backing plate, and longer bolts.
You can still fry an egg on it after a big ride, but working well at 14.5V.
I'm still looking for an R1 unit, they are pretty scarce around here, coz I know this thing will not last me forever.

One thing I did notice is just how much hotter the subframe becomes with the new backing plate. My old RR {when it died} was very hot, but the subframe was much cooler. I'm happy to have heat go to the frame, as long as it's going somewhere other than the RR unit. For me... mounting the RR unit "off" the frame would spell a quicker death.

 

yes, the bigger R/R unit, seems like it weighs about a pound more than the original one, and the alum. backing plate helps to transfer additional heat away, so at least for now I think we have this problem solved !
P.S- I saw an interesting mod on the R/R where the guy used a small computer fan to help cool the unit.

 

I replaced my fried RR on my 86 last week. Purchased an Electrosport unit. It has much larger fins and I relocated it so it would get some airflow. Very pleased with the results. I can actually touch it now without saying "sh*t" that's hot.

 

Hot topic lads, I'm gonna see how long the new beefier honda one lasts before I mod anything, perhaps by then the forum will have it sorted.

 

I mounted mine underneath the headlight on the right side of the fairing and it runs very very very cool.

 

Fast Freddie, Excellent mod. That's the best place for it. Out in the open with air flow over it. Did you make up a pig tail for the longer wire run or hard wire it? Ok, for the guys who don't want to space the RR out away from the frame. Check out some heat sink material on Ebay. Plenty of sizes. Cut out the size and mark where you want the RR to sit in the heat sink material, preferrably in the middle or close to, and have your friendly local machinist mill the area out so to sit on the floor of the heat sink. There's enough room under the tail fairing for a family of six so don't skimp on the size of the heat sink. Then mount it to the subframe.....and then space it off the frame . The subframe on the 2000 is steel. The RR body is aluminum. When you have two disimilar metals together and heat is radiating from the one with faster heat disipating coefficient, which aluminum has over steel by a long ways, the other becomes an insulator. That's a law of physics, can't be changed. So you end up with.....a hot spot where the two meet. My friend has a 99 with 42K. Went thru a couple RR's first 15K. Did this mod with no heat sink, ended his trouble. My 2000 only has 1600 miles, I'll let you know know long it survives. In the process of adding a heat sink now. If you don't want to reposition the RR up front in the wind, try increasing the heat disipating area with the same material. Don't forget maybe some well placed NACA ducts if you don't mind cutting some plastic. Good Luck, Wish you guys 14.5 volts forever
Stealth Mech

 

Yo Bodrodz; Placing the R/R out under the headlight assembly is pretty clever. Actually Harley Davidson has been positioning their regulators
out front near the bottom of the frame for some time. Think of it, HD in the forefront of technology! When you stated in your last thread that you had a friend that did the R/R mod. without using a heatsink and getting good life from it, exactly what mod are you referring to? To take this similar metals
data that you spoke about,to the best of my knowledge, there are several types of aluminum. I know of a few such as T-6. So how does this effect the rule that you mentioned? What if you mated two different types of aluminum, would you get the hot spot effect? Also what if the the R/R and the heat sink had different material tempers, would it give good heat transfer ? Anyway I would be interested in knowing. eddie

 

I have had one of the newer, bigger Honda RR's and heat sink plate on my bike for the last 10,000 miles and all is good. I did the PCU fan mod just to be safe. It was like $17 from Radio Shack and took 15 minutes to wire it up. It is still running as well! I live in Tucson where it is average 105+ in the summer. If I'm riding in stop and go traffic you can compound those temps, so I wanted air flowing over it constantly.

Nonetheless, the outside temp is still cooler than what my engine and RR is thus cooling them.

 

Eddie Cap, the mod he did was just mounting it off frame. As far as aluminum goes. There all different aluminums out there because of the different alloys that are added such as copper which is the 2000 series, magnesium and silicon is the 6000 series, the 1000 series is pure aluminum, and so on. The thermal conductivity is the same for all practical purposes. And the temper, T6, T3 and so on applies only to the metals hardness. Comes into play when selecting aluminum for structural purposes or workability when fabricating. Do a search on the net on metal thermal conductivity, there are some good sights that show the difference between different metals. Silver being one of the best in thermal conductivity. Zonaman did a killer mod with a small fan. Anything to pull the heat off the RR so you don't get stranded. The best mod by far is mounting the RR out in the open air. Good luck.
Stealth Mech

 

Hey Bodrodz and Zonaman; Thanks for the metallurgy review, Zonaman; when you bought the cpu fan for your R/R, did you have to buy one specifically for 12v DC , or are they designed to work on both 120v ac and 12v dc? Also did you run the fan wiring through your ignition switch or do you turn it on/off via a toggle switch? THANKS eddie