1999 VFR800 Unsolved Misfiring Problem

you can't own a honda long without being familiar with a multimeter, and checking resistance is easy.

 

Going to strip the plastics off and see what I can figure out, got myself a multimeter, hopefully youtube can teach me how to use it!!

 

How do you check resistance in a plug cap then?

 

Thanks Norcal, don't think my little cheapo voltmeter will be good enough for this job though.

 

^^ it's not that technical, so give it a try.

 

I have been fault finding on my newly acquired 1986 VFR750, and one of the four coils failed the resistance test to the plug cap end (as in, infinite resistance). All of the Honda plug caps I have examined have an internal resistor, and these are held in place by a screwed in cap plus spring that is also what clips to the spark plug end. A medium size flat blade screw driver will easily undo the cap. The resistior is a red cylinder about 25mm long and 5mm diameter. When I opened this faulty cap up it was apparent that water had entered and corroded the resistor end caps, and it was beyond saving. I ordered a universal NGK plug cap and was delighted to discover the same construction and a matching resistor, so I fitted that back into the OEM plug cap after cleaning up the end of the plg wire. Sorted that nicely.

 

Cheap insurance. If they haven't been swapped, they are over 20 years old. $50 + shipping and they came with the grommets.

 

Nice...and the red wires guarantee an extra 5km/hr top speed.

What was your source NCB?

 

Rick Oliver in the UK, he does all the work to get them cut to the correct length and also adds the grommets and the o-rings, which is a nice touch. He only does VFR/RVF400 stuff, but I got them in a package of other bits so the shipping was inexpensive to the US. They are readily available on Ebay and Dennis Kirk sells them in the US, minus the grommets.

 

I will see if he can do me a set of plug caps and leads for my 5th gen, worth changing just by age alone.

 

I emailed him so I'll see if he can supply caps and leads for a Vfr800, I had a run yesterday, the bike just feels to be running slightly 'off ' though I suspect most people wouldn't notice, I swapped bikes with a friend and he noticed nothing on mine but I could tell his vfr was running better, his bike is the same year and model.
at at steady 5400rpm she is sitting steady at 80mph, it's just low down I notice it, could just be one of those things, this bike was a 1 owner from new bike when I got her 2 years ago with low miles, I suspect she was never ridden very hard, I think she is just starting to loosen up and break in after 23 years!!

 

No joy getting plug leads and caps from Rick, he doesn't supply parts for the Vfr800,
this is probably a very stupid noob question but is there a cam position sensor on the vfr800 and if that's bad could it explain my issue? just something a car mechanic said to me today.

 

There is a cam pulse generator, but no cam positioning sensor.