Hi all. First off, thanks for the constant help with my CBR woes. Today, I was hoping that someone might be able to say, "Yeah, I know exactly what that is. That happened to me a couple years back." So here's what's up...

I'm a college student right now. I commute year-round on my F2 and have racked up about 60,000 miles so far. On the 4th of July I was heading home from a weekend away when my bike died while riding down the freeway. I tested and found the issue to be the rectifier. I replaced it with a low-miles F3 rectifier and have been riding fine ever since.

Two weeks ago I didn't ride one day. The next day I rode to campus, went to classes, and at the end of the day when I started my bike it turned over very weakly. I have a 3 mile ride back home and while waiting at the light just before my road I could feel the bike beginning to lose power. I held the revs at 2K while waiting for the light and then rode home. I shut the bike off and then tried to start it again, suspecting that it wouldn't. It barely turned over for a couple seconds and then refused to do anything more.

15 months ago I put a new YUASA battery in the bike. Having bought it locally I took the battery out and over to the shop I bought it from. They load tested and recharged it for me and said that everything checked out. I reinstalled the battery and checked output voltage at the battery. It was good at 13.5-15.0 through the revs. I rode it for a week without issue, and then yesterday I spent Halloween with my wife and kids and didn't ride at all.

Today the exact same thing happened. I got to campus and shut off the bike. When I got out to ride again it was VERY weak and barely managed to start. I rode home and again, at the same intersection, it tried to die. Unfortunately this time I didn't catch it and ended up pushing it the one block home.

So with that back-story, has anyone had this kind of issue? Any direction would be appreciated.

Thanks in advance, everyone.
- Mark

 

I've had a very similar thing happen. It turned out to be a reg/rec that worked intermittently. Sometimes it would charge. Ride the bike a while. Test again and it wasn't charging. Then the next day it would work fine again. Replaced it with a new Honda reg/rec and fixed the problem.

The original epoxy filled reg/rec are prone to failing due to heat. I've had the epoxy melt out of them before. Honda completely redesigned the reg/rec a while ago, no epoxy, the new one have heat fins built in. New one are much better. They are a bit expensive, but well worth it unless you like chasing charging issues.

 

Thanks Phil! I'll look into that. I've seen on here that a lot of folks swap out the reg/rec with gixxer recs. Any thoughts on that?

 

Most people don't know how to do electrical work properly. I can't even count the number of times I've helped people fix there bike and it turns out the problem was cause by something they did and didn't do correctly. Wire nuts and electrical tape is not correct, neither is solder or many crimp connectors. Unless you know what your doing, I never recommend cutting up wiring harnesses or cutting off stock connecters. Yes it can be done, but people usually do it cheap and quick, not correct.

I prefer to get the honda one. The are plug and play. If you have to buy a reg anyway, why not get the right one. It's how I've kept my bike running with as many miles as it has.

 

+1000

 

Phil, one more question. Which new ones are compatible? Are you talking about a reg/rec for like an F4i or 600rr, etc? I like the idea of replacing with factory but want to make sure I'm hunting for the right piece.

Thanks again.

 

I'm talking about the one specifically made for the F2. Honda redesigned it and gave it a new part number. It probably fits F3 and a few other too but I didn't cross reference it. Honda part #31600-MV4-010. (~$140 online)

I've put in half dozen of these and it's made the charging system rock solid every time. Problem is a bad reg/rec can also fry your battery or stator. So many time people replace those, fix the symptom, but not the real problem.

 

Great information. Thanks so much! I really appreciate all the help

 

Ordered a new Honda rectifier. I'll let you know how it works out.

 

So I swapped out the rectifier and couple months back and the issues I wrote about are all sorted out. BUT (there's always a but, right?) my bike is acting like there's a parasitic ground. If I don't ride it for 2 days and then start it up, it's obviously week. I've ran my multimeter in series with the ground cable and battery on multiple occasions to check for a draw and constantly get readings indicating that there is no draw on the system. Any advice on this new issue?