Moving the R/R to the front

[mobikie]

My R/R packed a sad

It had been running hot since I bought it 18 months ago. I had fitted a CPU fan as suggested, but on a recent trip the R/R packed up and the charging current went high, probably very high, as the battery ended up looking somewhat balloonish. It was so swollen that I had trouble getting it out of the bike. I was lucky to get home.

I ordered a new R/R and VFRness from www.wiremybike.com and fitted them. The charging voltage returned to normal and all seemed well, except the R/R still ran quite hot, and I was concerned that it would remain a threat to my enjoyment of my 1990 VFR750.

As I had a new battery, a new R/R, a new VFRness, and time to do something about it, I decided to relocate the R/R to the front to see if it would solve the overheating problem. The VFRness is an excellent unit, and of very high quality. I felt that I could use parts of it to enable the R/R to be located at the front.

This shows the final result. Air can get to the oil cooler above the R/R, and it doesn’t significantly obstruct the air to the radiator.

The R/R sits in front of the forks on an aluminium support which attaches to two brackets, one each side. These brackets originally held the wings of the centre bottom fairing. I had previously cut them back to just above the highest bolt going into the centre fairings. You can see the cut-off fairing to the right of the fork in the photo.

This is the bracket I made from a square section piece of alloy I had. It was 2mm thick and 75mm x 45mm. An angle section is what you really want, but this was in my scrap box. The cutouts are for the forks - when turned. The little tabs at the back in the second photo limit the turn (up/down) of the bracket.

Before final fitting, I filed away the little lip under the R/R, on the right.

I used Artic Silver to ensure a good contact between the R/R and the aluminium “support/heat sink”.

I removed the existing wiring and built a new harness. There are two hard parts:

Getting the terminals out of the existing holders

I didn’t have new plugs so I had to reuse the existing plugs and terminals. To get the terminals out, try to see whether they have a small lug which springs up against a stop to hold them in. All my small terminals were this type. You have to use a jewellers screwdriver, pushed in from the front, to bend the lug in. Generally the terminal then pulls out. The two larger terminals connected the +12v and –12v cables to the R/R. I found that these came out if I compressed the inside round bits by shoving a file end spike into them while pulling. I held the wire in a vice as shown in the photo. Even the ones with the lugs needed this treatment.

Soldering the new wires on to the terminals

The problem here is that the terminals don’t have much clearance around them when they are fitted in their plugs, so you can’t attach the new wires close to the terminal otherwise they won’t fit into the plug. I cut the existing cables so that about 20mm extended beyond the end of terminal. I found it best to hold the soldering gun against the terminal to heat it, at the same time pulling on the outer cover (insulation) of the cable. After a while the insulation starts to move and slides off the wires leaving the bare copper wires attached to the terminal. I cleaned any remaining insulation off. I then stripped about 10mm off the new cable, and laid it into the existing wires. I then soldered the new wires to the original wires. If necessary, I used the Dremel to smooth sharp or protruding edges. It is not as pretty as Hondas original, but the cable is considerably larger, and the joint will have minimal resistance. The cables I used are 95/0.29 = 6.3 mm2 (~AWG 9.5) for the Battery runs, and 56/0.29 = 3.7 mm2 (~AWG 11.5) for the Alternator runs. 10 AWG and 12 AWG are satisfactory. These are a lot heavier than the original cables, so the R/R should be able to work efficiently. The weakest point is probably where the two bits of brass contact within each plug.

I left copper tails to attach my new wires to. This one was the first. I cut it a little short!

I guess you get the idea. Don’t forget to slide the heat shrink tubing on before you do the soldering…and keep it away from the heat. You need a 100w soldering iron for a good join, as there is so much copper conducting away the heat.

Wiring harness

I am using separate looms for the alternator, and the battery, rather than try to fit them into one larger corrugated tube. It makes them more flexible, and able to pass through a smaller cavity when trying to get from the front to the back. The corrugated tube can go on at last as it is split lengthwise. I taped over it to ensure it remained closed. Make sure all heat shrinks are on their wires before attaching terminals etc.

These show the details of the new harness:

I had to tape the bend to hold it in shape, so that it would sit correctly under the headlights. This is the end which goes into the RR. The negative cable was 1.5m long, with the positive cable a little less. There is a 20 amp fuse in the red sleeve. The Alternator cables are each 1m long.

This shows the path the harness took. I kept it away from hot parts, such as the radiator.

The new harness, starting at the battery, follows the route taken by the previous alternator cables. I attached it to the frame behind the middle fairing. At the front it is held to the instrument support by a couple of cable ties. This support also holds the brackets to which the aluminium support is attached. The ends of the cable ties still have to be cut off.

Having installed it, all that remanded was to try it

I did the voltage test first, and it was producing 14.6v across the rev range as required.

I went for a 3km run to Placemakers, and when I got there I felt the R/R. It was very slightly warm, and the heatsink (aluminium support) was cold. I didn’t have my lights on, and it is a cold day, about 10 degrees C outside. I put my headlights on for the ride home, and when I got home the R/R felt almost cold….it’s looking good.

I went for ride of 27km the next day, another 10 degree C day (the middle of our winter in New Zealand). I had my lights on all the way. The R/R remained at air temperature – cold. The water temperature gauge rose to its normal level. I can’t comment on the oil temperature however, but its radiator seems to be getting a good air supply.

So it is really the lack of cool air that keeps the RR hot when it is in its original position.

Shifting it to the front drops the temperature remarkably.

Put it in a good flow of air, and it should last forever….

[KanadianKen]

Nicely done!! Will have to keep this one in mind if I ever cook mine and have to do a fix! :fing02:

[FotoMoto]

On my modified 4gen, I hardwired a suzuki gsxr 7 wire unit into the harness and place it underneath the lower VTEC triple (w/F4i forks). I got lucky in that the ebay vendor sent the r/r's OEM bracket along also which matched up with mounting holes on the steering stem all ready provided my mother Honda.

[mrmatt]

Thanks, very good write-up. I might have to do the same on mine now

[Guest]

Nicely done!! Will have to keep this one in mind if I ever cook mine and have to do a fix! :goofy:

+1 to that, what a good post ,10/10.

Plasma.

[JZH]

Excellent write-up! :huh:

The correct "barbed" blade terminals are available from sources such as Vehicle Wiring Products in the UK, and (I would guess) Eastern Beaver in Japan (though he trades worldwide through the Internet). VWP also has thin-wall cable in dozens of sizes and colour combinations, for that true OEM look.

The Honda reg/rec repair kit (for the VFR800Fi, but fits the earlier bikes) includes a new plug, as well as short lengths of wires already attached, which would avoid a lot of the fiddly soldering you had to go through.

Ciao,

[VFRSuperfreak]

keep that 3rd gen running!.

mine 4th gen fried an RR + connectors, so yeah cut+slice+crimp a gixxer 1k RR + heavier gauges + extra pos+ and neg- lines and this:

5k miles later, all is still well.

[Guest]

Posts on forward R/R relo on VFRW including mine :

http://vfrworld.com/...8-r-r-move.html

http://vfrworld.com/...-r-r-front.html

[mobikie]

Just an update...it's June 2016 and it's still going well.