Hey everyone! I'm a newbie posting but I've been checking out some of the threads here for a few weeks on various issues. Thank you to the developers for providing a great portal for CBR enthusiasts to come together and keep our bikes screaming down the road. 🤪

That being said, I need help. 🤔 Bought a '97 600F3 about 8-months ago and right away had to change the stator out w/ a new Caltric (also voltage regulator). Very much enjoyed 100mph+ no problem riding for several months and then started to have what seems like a common problem from what I've seen here: fuel system cutoff after running for a while. The bike would suddenly shutdown like it was running out of gas, but at first I just just had to wait an hour or so and the bike would fire back up...

Then the bike shut down and wouldn't restart, so I changed the fuel pump out (Caltric) and the bike fired up, 100mph+ no problem; however, it shut down again two weeks later. When I disconnected the outlet hose the pump was obviously not pumping any fuel and I couldn't hear a "click" at the cutoff relay when power was engaged through the ignition/engine kill switch, so I changed the fuel pump cutoff relay and the bike fired right up, you guessed it, 100mph+ no problem.

Then on a day I rode over 90-miles many of which were 100mph+ (no problem &#128521, the bike shut down 20-miles away and I had to have it towed back home; same exact symptoms. I did some tests and sure enough the relay was not supplying power to the pump, so I ordered a new one (relay), put it on and the bike fired right up - pump' a pumping - 100 mph+ no problem. Rode the bike all weekend to the beach and the store, then rode it to work last Tuesday (Monday was Memorial Day). Rode a total of just over 80-miles and the bike shut down again, same exact symptoms. 🤨 Had it towed back to the house (the tow truck driver laughed &#129325, ordered a new, more expensive relay from a different manufacturer and put it on. The bike fired right up, rode all weekend 100mph, blah blah blah...

That brings us to yesterday (June 6th, 2022). I rode the bike to work and kept it below 75mph like a girl (no offense girls) and as soon as I got a few blocks from work the bike shut down and I had to have it towed back to the house again (3rd time in like 12-days @ $100/tow &#129324. I took the tank off and changed the petcock out with a brand new one I had ordered and then tested the relay: 12.2v in, zero volts out. When I inspected the relay more closely I noticed the housing was bubbled up on the top. When I checked the previous one I changed out the week before I noticed it was bubbled up in almost the same place and the housing was cracked. So, I'm asking you, what is going on? What is causing my brand new cutoff relays to go through a complete meltdown? The bike is made for extreme (track-worthy) riding, but am I pushing it too hard?

Is it possible the voltage regulator is supplying too much voltage (15v-17v I figure)? Can the primary coil (which I understand supplies power to the fuel pump) supply that much voltage through the whole system without blowing other components (like the 10amp fuse) or melting down wiring? 🤔

My boss says if I can't get to work by the end of the week I'm fired, so please help me get this figured out. Thanks in advance! 😀

 

Hi and welcome to the forum. Post some pictures of your relay and the fuel pump. Does the fuel pump look just like the OEM? Does the top black cap come off and does it have relay contacts in it just like the OEM? If your R/R is charging with over 15v, then you've got a problem for sure. Put a meter on your battery and check the voltage at 5k RPM.

 

Not sure if I'm doing this right (responding to your message). I'll take a couple pics tomorrow morning but, yes, the pump appears to be a match to the OEM as well as the relays. When I got the bike to start from residual fuel in the bowls there was a 13.3v @ 3,000 RPM reading at the fully charged battery.

Should I run a hot/ground directly to the pump from the battery to do a 5,000 RPM test? Do I need to add an inline (10 amp) fuse for that?

 

No, just measure across the battery terminals while revving to 5K RPM. Just to make sure you there is no issue of over voltage. Fuses are only going to blow if something draws too much current. This usually only happens when something is shorting the circuit to ground.

And, yes you did it right.

 

Got a little frustrated yesterday with the repeated relay meltdown situation on the F3. Decided this morning to install a new subwoofer in my truck instead and ordered a new fuel pump cutoff relay for the CBR online. It will be here on Friday and I'll run some voltage tests then to see if I can isolate the source of the over-voltage.

What's the most likely source?
> Voltage regulator/rectifier
> Primary coil> Other (what?)​​​​​

 

I received the new fuel pump cutoff relay yesterday and installed it around noon today (PDT); the bike fired right up.

Ran voltage tests first on the battery (indicating charge voltage) and the result was 14.2v @ 5,000 RPM. Shut the bike off and checked relay voltage, engine cutoff switch "on" and the result was 12.2v in, zero volts out. Started the bike again and the multimeter said 3.1v in and <1v out @ 5,000 RPM.


Does the R/R control voltage to the fuel pump relay or is that managed by the ECU? I changed the R/R out when I changed the stator over 6-months ago and it wasn't too long after that I started having this relay meltdown problem, but I'm not sure there's a correlation. It seems the stator is supplying sufficient power to charge the battery, but it may be hard to detect voltage surges in the system while the bike is operating @ 100mph.

I think I understand that over-voltage or surge voltage (under voltage/excessive amps?) is what's causing the brand new relays to meltdown, but what supplies power to the relay? Is it the 1/3 Primary Ignition Coil? What controls the voltage input/output @ the relay?

Help!!!

 

Great photos, thanks for posting. The R/R only converts the AC voltage that the Alternator (Stator) is producing into DC voltage and tries to keep it from going too high. The reason you can't get a good reading on the voltage going from the Fuel Cut relay is that it's only on for short periods of time. The relay is provided 12v, but is only grounded for the amount of time that the ignition coils are being grounded (producing the spark). The typical digital multimeter is not able to capture those short duration pulses. You need to have a Peak Voltage adapter that can capture voltages that only last for milliseconds. Then you would see the 12v going to the fuel pump.

This is the first time that I can think of where anyone was actually having a problem with the OEM Fuel Cut relay. They are solid state (no moving parts) and are pretty much bullet proof. Do you still have the OEM one your bike came with?

 

No, I've just kept a couple of the aftermarket relays that have melted down. Why are the relays generating so much heat they are failing? I haven't bought an actual Honda OEM replacement relay because of the significantly higher price. I don't hear of anyone else having meltdown problems just because they are buying aftermarket cutoff relays.

 

For it to be melting, it would typically be 1 of 2 things, high voltage or high current. You bike is only generating 14.5v so it's not voltage. The current draw is based on the fuel pump. How much current does that fuel pump draw? If it was drawing too much you'd think the fuse would blow. Like I said, I've never seen any of these relays go bad. I'm at a loss here.

 

Yeah, me too. Three melted down relays in less than 90-days, three $100 tows in just over two weeks and fired from my job, but the fuse never blows, and I put a new relay on and the bike fires right up until the new relay melts down once again. Never heard of such a thing.

Pardon my French but WTF?!