Honda VFR 800 Service Guide [Oil, Filters, Spark Plugs] 2003 VFR800 VTEC Rough Running Solved | 02
I changed the spark plugs, oil, oil filter, and air filter on my 2003 Honda VFR800 VTEC and solved a problem with the low RPM running.
Oil Filter Socket Set: ebay.us/dgw5cE
VFR800 Spark Plugs NGK IMR9B-9H: ebay.us/JFClkc
VFR800 VTEC HiFlo Air Filter: ebay.us/hFj20C
VFR800 VTEC HiFlo Oil Filter: ebay.us/flrfnr
MOTUL 10w-40w Motorcycle Oil: ebay.us/cVXXI8
I am very pleased with my VFR800, apart from one thing. The engine isn’t as smooth as I expected, and the slow running, below 4.5k rpm, is not confidence inspiring. Having looked on forums it would seem that slow running can sometimes be an issue with these engines. There are a lot of suggested remedies, here is the list that I intend to follow.
Throttle play.
Italian tune-up over a couple of tanks of fuel
Fuel additive to clean the injectors.
Service, although nobody seems to say this is a cure for the low-speed running.
Balance starter valves.
PAIR system delete.
The main thing with the slow running is that it seems inconsistent, in that not only does it feel a little rough, the throttle seems to give a different response for the same amount of twist. So when you are going slow, and only want a little more acceleration, you can’t be sure how much you will get. It’s fine if you just crack the throttle open and set off, but if you are trying to modulate your speed around one of our lovely little roundabouts, on a mucky country road, with a pillion on it can be a little unnerving!
There also seems to be something that could be described as surging, although it isn’t so pronounced that you can really feel it. It seemed worse when you let the motor slow down to around 2 - 2.5k rpm then opened the throttle to increase the speed slowly. It wasn’t quite bucking bronco, but you get the picture.
I knew that the bike had only done around 1000 miles since it was serviced with the book being stamped when it was sold from a Honda Dealer 4 years ago. And over the last 2 years it had only done around 130 miles. The PO said he had also had it serviced when he had the last MOT, which was around 18 months before I bought it, but didn’t have the book stamped or a receipt. And it had only done around 30 miles since then.
Working through my list I adjusted the throttle play, although there didn’t seem to be any obvious issue with it so it didn’t take much. I added some RedX, which is more common in the UK than Sea Foam. Then did a few hundred miles giving it a few fresh tanks of E5, 99 Octane fuel. None of this seemed to make any difference to the slow running.
According to the service schedule, the plugs should be checked at 16000 miles and changed at 32k. This bike has around 23k on it, which is backed up by MOTs and service book so the plugs wouldn’t need changing on mileage, but I felt they should because of the age of them. It has very specific iridium plugs and they are very expensive compared to others that I have bought.
They are reasonably easy to change, but awkward to get at, the rear ones need the tank raising, and the front ones involve grovelling on the floor. :) Using the plug spanner from the Honda toolkit, they came out and went in pretty easily.
To change the air filter that tank needs to be raised, and Honda have made this pretty easy. The air filter did not seem as clean as I expected, so I think that this may have been missed on some of its previous services. But it wasn’t completely blocked.
To change the oil and filter you need to take the left side of the fairing off the bike. It isn’t too difficult but does seem to be an additional faff to get in the way of a service. The oil filter isn’t easy to get at, because it is behind some coolant pipes. Luckily we have recently bought some filter sockets so it came off quite easily. The oil filter was the same brand as the one I was replacing it with, which implied to me that it wasn’t done at the Honda dealer who I would expect to use OEM filters, so it may have had an oil change at the last MOT like I was told. But it definitely didn’t get a new air filter.
Anyway, once I had completed the service I took the bike out for a ride so that I could check for any leaks and the oil level once it was warm. I could tell straight away that the bike was running much better, and as time and riding has gone on it has felt better and better. I have never known a standard service to make such a difference to a bike, or car. The engine is so much smoother and the slow speed pick up is fabulous.
I will balance the starter valves and still intend to look at the PAIR system in the future. But for now I am totally happy with how this bike is running. I just wish I had serviced it a little sooner.
For more helpful how-to guides and restoration project logs, visit our blog: www.spannerrash.com/
#vfr800