HELP - CBR F4 Regulator/Rectifier Issue | GTAMotorcycle.com

HELP - CBR F4 Regulator/Rectifier Issue

K

k2p2

Active member
Forum Sponsor
Hey guys

My CBR F4 started having what seemed to be an electrical problem at the end of last season. It would start up fine and ride fine until I'd get stuck behind a red light and the fan would come on. RPM would then drop, the bike would stall and would not start back up (had to be bump started). I did some research online and found out that a lot of F4s have regulator/rectifier Issues so this year when I was having my carbs cleaned, I also had the R/R replaced and got a new battery as well. The bike's been running amazing all season .... until last week. It's not as bad as it was last year but I can tell it's getting there. After a long ride (15-30 min highway) my RMP starts twitching when the bike is idling and the fan comes on, the horn sounds like it has bronchitis (low voltage?) , and the backlight gets dimmer than normal when I apply the horn.
Here are my questions:
1) I've read online that one of the solutions to this is to replace the R/R with another bike'r R/R that doesn't have the issue. If this is true, what are my options and how labour intensive is it if I wanted to do it myself ?
2) Another side solution online is to replace the battery with a more powerful one. Again, what are my options and can I do it myself ?

Any feedback would be much appreciated.

Edit: one more thing. I've also heard that you can replace the fan with a lighter one that doesn't put as much strain on the battery when it comes on. Is this true and if so, what are my options ?
 
Last edited:
I can't see the battery helping much if your charging system isn't working well. If you only took short rides and kept the bike attached to a battery charger and ran the system full-loss, sure it may work for a while, but your best bet is a new RR (try to locate where it can get air flowing over it to keep it cool).
 
Do you have a service manual? If not PM me and I will get it for you (May be an F4i one, but same charging system)
If so they have a section for testing your charging system to see if it is your Battery, R/R or stator.
 
I Do have the manual.
When the bike was at the shop at the start of the season, they tested the r/r and it tested weak and that's why I replaced it. I just don't want to have to put in a new one every season if the F4 r/r's are crap and have to be replaced frequently.

jeffjones said:
Do you have a service manual? If not PM me and I will get it for you (May be an F4i one, but same charging system)
If so they have a section for testing your charging system to see if it is your Battery, R/R or stator.
Click to expand...
 
Replacing the R/R isn't tough at all. You just need to know how to cut and splice wires.

Replacing the battery won't matter if your charging system can't charge it.
 
k2p2 said:
I Do have the manual.
When the bike was at the shop at the start of the season, they tested the r/r and it tested weak and that's why I replaced it. I just don't want to have to put in a new one every season if the F4 r/r's are crap and have to be replaced frequently.
Click to expand...

I will look into it but a certain year GSXR R/R fits and is supposed to be much better.
 
huh!
so you think keeping the r/r cool could actually help ? Anyone else can attest to this ?

GreyGhost said:
I can't see the battery helping much if your charging system isn't working well. If you only took short rides and kept the bike attached to a battery charger and ran the system full-loss, sure it may work for a while, but your best bet is a new RR (try to locate where it can get air flowing over it to keep it cool).
Click to expand...
 
Why not repalce it with the one from F4i? I never had problems on my F4i so far.
 
k2p2 said:
huh!
so you think keeping the r/r cool could actually help ? Anyone else can attest to this ?
Click to expand...

When the R/R gets hot is usually when it fails, I have seen people put computer fans on them in the tail to disapate the heat faster.
 
That's very interesting because the stalling issue would get worse and kick in way quicker on very hot days. Thanks for the info I'm gonna give it a try :)

jeffjones said:
When the R/R gets hot is usually when it fails, I have seen people put computer fans on them in the tail to disapate the heat faster.
Click to expand...
 
k2p2 said:
huh!
so you think keeping the r/r cool could actually help ? Anyone else can attest to this ?
Click to expand...

Yes. On newer GSXR's they fail due to being placed in a ****** spot.

If you move them and allow more airflow, it doesnt allow them to overheat and cause fires.
 
I know this is a stupid question but do you hook up the computer fan directly to the battery or have it run by a secondary battery ?
Anyone know a how-to website for this ?

you guys are awesome btw! It's hard to understand why people help others when they have almost nothing to gain from it; I guess BECAUSE they're awesome :)

jeffjones said:
When the R/R gets hot is usually when it fails, I have seen people put computer fans on them in the tail to disapate the heat faster.
Click to expand...
 
Last edited:
k2p2 said:
I know this is a stupid question but do you hook up the computer fan directly to the battery or have it run by a secondary battery ?
Anyone know a how-to website for this ?

you guys are awesome btw! It's hard to understand why people helps others when they have almost nothing to gain from it; I guess BECAUSE they're awesome :)
Click to expand...

Have it run via a switch you can turn on and off. That way if you get stuck in stop n go traffic you turn it on. Out on the highway its off.
 
There is a new OEM version that replaces the original. I've had r/r problems with my f2, f3 and current f4.
The ideas about a small cooling fan, and reducing the load are all effective but they are workarounds. On my f3 I had a toggle switch for the headlight.
Many aftermarket r/r have heatsinks to help and I'm pretty sure the new Honda one does too. I don't have the part number handy, but if you done some research already, you may have been close to it. the CBRforum will have it. Since there's a brand new post about the issue there, I'm guessing it could be you asking about it? You'll get flamed for not searching, but you'll get the part number ;)
I switched to a Shorai battery late last year, and I had previously switched to an aftermarket (rick's) R/R. It turned out I didn't need to switch that, I was just having a battery problem. I switched back to my OEM regulator and it's been fine.

It's easy to switch, but check the connections before you order. If everything is burned, you'll want a new end for your harness too.
 
Thanks.
One more question: since I've already noticed my aftermarket r/r which was installed just 3 months ago is starting to give the same symptoms as my weak OEM one, does that mean I should replace it and then think about adding the fan ? Or do you think I can just install the fan on top of the cooling fins of current r/r and things should work out ?

Emefef said:
There is a new OEM version that replaces the original. I've had r/r problems with my f2, f3 and current f4.
The ideas about a small cooling fan, and reducing the load are all effective but they are workarounds. On my f3 I had a toggle switch for the headlight.
Many aftermarket r/r have heatsinks to help and I'm pretty sure the new Honda one does too. I don't have the part number handy, but if you done some research already, you may have been close to it. the CBRforum will have it. Since there's a brand new post about the issue there, I'm guessing it could be you asking about it? You'll get flamed for not searching, but you'll get the part number ;)
I switched to a Shorai battery late last year, and I had previously switched to an aftermarket (rick's) R/R. It turned out I didn't need to switch that, I was just having a battery problem. I switched back to my OEM regulator and it's been fine.

It's easy to switch, but check the connections before you order. If everything is burned, you'll want a new end for your harness too.
Click to expand...
 
I have a 1990 honda cb-1 also known for crappy regrec's I just replaced it with a Mosfet regrec Shindengen FH020AA (you can buy it as a kit and install it, and is probably one of the most popular regrec upgrades) http://www.roadstercycle.com/
is one place to get a kit, once installed mine has stayed at room temp consistently and delivers a solid 14.3 V at idle to the battery.
 
k2p2 said:
Thanks.
One more question: since I've already noticed my aftermarket r/r which was installed just 3 months ago is starting to give the same symptoms as my weak OEM one, does that mean I should replace it and then think about adding the fan ? Or do you think I can just install the fan on top of the cooling fins of current r/r and things should work out ?
Click to expand...

I would replace it, and not worry about the fan. If the one you have is failing, it may already be too late to fix it by adding something that draws more current. If the one you have is failing, it may not have been good enough in the first place. When I replaced the ones on my f2 and f3 I never had another problem. When I replaced the one on my F4, it didn't last more than a couple of months of daily riding. If you read the multiple threads on the cbr forum about it, it seems you can't go wrong by just replacing it with the updated and upgraded Honda part.
 
Hey guys

Quick question: Would having HID headlights have anything to do with what I'm experiencing? I've heard that LED lights can cause these kinds of issues.

I got myself an ohmmeter so I'm gonna test out the r/r and stator and will report.

Thanks for your feedback.
 
k2p2 said:
Quick question: Would having HID headlights have anything to do with what I'm experiencing? I've heard that LED lights can cause these kinds of issues.
Click to expand...
For sure LED lights won't cause it.

HID headlights have a very high power surge when they fire up. I'd imagine that could put stress on your R/R, and/or some of the cheap china ballasts are very "noisy" and wouldn't be crazy to think they could cook your R/R.

Do your HID's fire up as soon as you turn your key on? If they do, that's bad. Either put them on a time delay relay, or there might be a trick you can do with your starter button that will stop them from coming on until the bike is running.
Forum Sponsor
 
Last edited:
You must log in or register to reply here.

Back
Top Bottom