Random Cutting Out/Hissing

Hi guys, hope you are all doing okay.

I've recently passed my bike test, and have bought a lovely Honda VFR800 A9 in Candy red. The bike seems to ride beautifully, but on a 120 mile ride today I noticed an issue. I will take to to the garage , but thought I'd ask here if you don't mind in case it is something I can check myself, with your help.

Early on into my journey I pulled into a petrol/gas station to fill up with fuel. I started the bike in the usual way, but then heard a hissing sound and noticed a small amount of vapour rising out of the O/S fairing - this immediately followed by the engine cutting out. Went to restart, and whilst it was turning over fine (starter turns over fast), it failed to start on three occasions. Having switched off, I moved it away from the pump, and tried again and it fired up immediately, and rode with no issues.

This was until 40/50 miles later, the hissing noise happened again, and the engine cut out while I was riding along. I pulled over, and it restarted, and got my the rest of the way home. I think I heard the hissing noise once or twice.

The engine temperature seemed quite normal, between 75 in free air and 85-90 in slow traffic/queuing.

I have checked the coolant level, and while it was between Min and Max cold, when I returned today the level was at the Max line.

I've noticed that the throttle response appears sometimes snatchy, and sometimes smooth. This might be me.

I had disconnected the air flap (mod), but have now reattached it, in case this is the cause.

Recently fitted a Quad Lock system, with charger unit that was on Auto, so if the charge goes below 12.4v it ceases to charge the phone (saving the bike battery).

In the past year, the history shows the plugs, coil packs, and reg/rec have been renewed.

Any suggestions would be much appreciated.

 

When you did this, did you block off the vacuum line? If not then that would explain the hissing sound and possibly the engine dying due to an open vacuum line.
See how you get on with the system fully restored and operational.

 

Thanks Grum, I wound a screw in the end of the vacuum hose. But I've reconnected it, and see how goes.

 

The hissing seems unusual; I wonder if you have a blockage or restriction on the fuel tank air vent? That is the smaller hose that connects to the underside of the tank. It should be open to atmosphere, and directed to the front right of the crankcase. You should be able to blow air into it with the fuel cap open and have no resistance.

 

I've connected the air flap pipe, and checked under the tank to try and ensure no pipes are trapped. I'm wondering whether the cutting out could be linked to the Quad Lock charger when it cuts in and out on the auto setting. It didn't seem to cut out before I fitted it. The last time it cut out, I removed the phone (ready to call recovery), and it didn't cut out for the rest of the journey. But I still remember hearing a hissing noise, which maybe is a blocked breather.

Regardless I'll take the bike out for a run tomorrow and see what happens!

 

Well, no unsurprisingly it happened, I broke down today! Left home and noticed the ABS light illuminated, and a little further all dash lights disappeared, the lights dimmed, and about a mile from home it cut out completely.

Recovery guy came out, checked the battery which was 11.9v (not too bad) but when started and increased the revs, it dropped steadily down. He told me its the reg/rec.

I also noticed the battery fitted is a TTZ12S, when checking batteries I found that this battery is NOT a suitable replacement for the correct YTZ12S.

 

Hi Simon and welcome to the forum.

When you get time please add a post and a photo of your VFR in the Introductions forum and say Hi to the rest of the folks on here. You may also want to update your forum profile to include an approximate location (County/town - is ample) so it appears with all your posts and if you need help with a problem you may find someone on the forum lives nearby and is willing to swing by and offer advice or pick up a wrench especially if you have a well stocked beer fridge.

I am not sure if you have been alerted to the charging system weakness which sadly affects many 6th gen models and earlier gens. If not this link will show just how many other have encountered charging system problems.

https://vfrworld.com/threads/how-to-fix-common-regulator-stator-failures.39277/

Given your latest breakdown I suggest you or your garage starts by carefully checking the charging system as the most recent failure has all the symptoms of charging system problems.

It is important to see the charging system (loom RR Stator and Battery) as an interdependent system so a fault in one component can also damage some or all of the others. Sadly the charging sytem was not made by H it was bought in and made to a budget. As you are well past any warranty period, I guess the manufacturer has fulfilled his remit even if it has left you stranded.

Depending on what diodes fail inside an RR this can see volts drop through the floor draining your battery or even send AC or 60+ volts into a system designed for a nominal 12vDC which can quickly cook the battery. Could this be the source of the hissing sound you heard if so you probably need to check for other damage like blown bulbs

Sadly too many people stop checking once they find one defective component (oblivious to the risk that damage may have already been sustained by other elements of charging system - melted wiring connectors - cooked batteries and shorted Stators).

Important - If the volts on your battery are low they can give misleading testing results. So start with a healthy charged battery, then do the tests outlined in post #9 in the thread linked aove. If you need help post up the results.

Good luck - let us know how you get on.


SkiMad