Honda VFR400 NC24

Honda VFR400 NC24RJ-lll

I saw this advertised in a local shop window and bought it for £350 an hour later. It was scruffy and had obviously been thrown down the road but apart from a bent subframe didn't look so bad. The exhaust was badly corroded and I assumed that if it was too bad that I would be able to get a used or new replacement. I hadn't done my homework, firstly it’s a discontinued part and decent second hand collector boxes are almost impossible to find. Secondly it’s not possible to remove / replace the collector box and exhaust pipes without removing the engine from the frame. An additional problem is that the NC24 model was intended for the Japanese market only, consequently there's very little printed material in English.

Fortunately I very quickly found the 400Greybike forum which was an invaluable source of information. In a short time the bike was completely dismantled, cleaned, degreased and the parts sorted into plastic storage boxes with a photographic record particularly of the wiring for future reference.

neglected VFR400 NC24
Plenty of siezed bolts
Badly corroded NC24 collector box
Rear hub evidence of crash damage
Bent fairing bracket crash damage
NC24 Engine poor cosmetic condition

The frame, wheels and replacement subframe (from eBay - where else?) together with the engine covers were powder coated by Triple S Powder Coating in Bingley. New bearings and bushes were easy to source and replaced where necessary.

The exhaust collector box was too badly corroded to weld and at the time a replacement was impossible to find. The odd one appeared on eBay but they all looked to be in poor condition. Eventually I discovered MLB Manufacturers in Taranaki, New Zealand who were manufacturing copies and I bit the bullet and ordered one. The fit wasn't perfect but it was a good starting point and it did the job.

The inlet rubber mounts for the carburettors were rock hard and cracked so new ones were fitted. There’s definitely a knack to fitting the carbs on the rubbers. I've found the best way is to lightly smear red rubber grease on the inside of the rubber mounts.

While searching around the 400Greybike forum I found details of the hydraulic clutch modification for the NC24 which seemed worthwhile. A VFR750 master cylinder, NC21 hydraulic slave unit and sprocket cover were all found on eBay. The NC21 pushrod was a little harder to find and eventually I obtained one from a 400Greybike forum member - tip of the hat to Neosophist. Fitting was simple and the clutch action is light and progressive.

The electrics were in surprisingly good condition except for the HT leads and plug caps which were definitely past their best. A new set was hard to find and eventually I got some made up with some nice leads and plug caps by Rick Oliver. The entire wiring loom was checked for damage and all connections carefully cleaned as some were showing slight signs of corrosion.

The standard regulator has a poor reputation for reliability and R6 regulators seem to be a popular alternative. Fitting details are well covered in the 400Greybike forum and I also found this guide intended for VTR1000F which was helpful. I was initially looking out for a connector off an old R6 wiring loom but found a new connector plug kit for £3. Its very important to solder the connectors rather than crimping them on. The regulator was a tight fit and I had to file two rounded slots in the fins to make room for the ht leads which are routed below it.

The old fairing was beyond repair so a new one was obtained from Skidmarx and painted in Lucky Strike colours by Dream Machine.

Yamaha regulator rectifier

Yamaha R6 regulator - 5 pin and not the 6 pin version.

I noticed during the rebuild that the polymer bush on the fork anti dive mechanism had worn but had been unable to source a replacement - another discontinued NC24 part. The hardened steel piston collar (also discontinued) which fits inside the bush had cracked causing it to be slightly wider where the snap ring fits. Searching online I found plain bronze bushes (8x11x8mm) at £7 for a pack of 5. It was an easy job to press out the old worn plastic bush and fit the bronze bush. I've since had some replacement piston collars machined from a prehardened alloy steel which I'd expect to be a significantly more crack resistant than the free cutting steel originals. Please note that this modification is the way I carried out the work and should not be understood as the official or necessarily the correct way.
Anti dive piston original collar and bush
Anti dive piston original worn bush
anti dive piston with replacement bronze bush
The images show the cracks in the original collar and the worn plastic bush. I have two sets of forks and both were like this. The last photo shows the replacement bronze bush in place.

Fork servicing can be tricky if both legs are dismantled and the parts mixed or if they have been previously reassembled incorrectly. Some internals of each leg are different and unfortunately there isn't (to my knowledge) an English manual as the NC24 is a Japanese import. However they are very easy to work on and only needs a few minutes study of the online parts microfiche or the Japanese parts and workshop manuals. Firstly the stanchions are different lengths and the shortest fits in the antidive leg. The oil dampers are different too but are easy to identify from the microfiche and I've shown them in the photo below. The source of most confusion seems to be the alloy oil lock piece which should fit on the antidive side with its flange down. Again this is clearly shown in all the microfiche and manuals but many people seem to assume this is a printing error and install it the other way. The fork springs are installed with the tightly wound section uppermost. The images below show the lower fork leg components

NC24 lower fork components
NC24 oil lock piece and leaf springs
NC24 fork oil lock orientation
The bike in its Lucky Strike scheme is shown in the following slide show.

VFR400 NC24
VFR400 NC24
NC24 Speedo
NC24 headlight cowl detail
NC24 front wheel
NC24 rear hub
NC24 front brake caliper
NC24 hydraulic clutch conversion

2017 - 2018 Winter overhaul
I was happy with the Lucky Strike scheme for a while but I've been collecting panels and fairings etc for some time with the intention of taking it back to is original factory colour scheme. The last and hardest part to obtain was a decent fuel tank and I finally got one from the Netherlands - I wanted to sell the old fairings, panels and tank as a set.

After a little homework I phoned Clive White at Rapier Paintwork in Hull for a chat about my requirements and following a short discussion drove over with my parts. One of my concerns I had was whether he would need the bike to align the graphics as I wanted to do some other work on it. Thankfully he reassured me that there was no need and that it would all line up when fitted. I'd noticed that some paint had started to flake near the bottom of the fuel tank exposing some filler and unfortunately we later discovered that the tank was in a far worse condition than I'd thought. Corrosion and dent free tanks are becoming more difficult to find and this one had been previously welded up badly and filled - but well enough to hide it. Fortunately Clive was confident that the tank was repairable by brazing and lining.

True to his word the parts lined up perfectly when I got them back and the paintwork quality was impressive. I'm really happy now its as Honda intended.

VFR400 NC24
Fairing panel
NC24 side panels
Nc24 seat cowl
NC24 tank and panel
Previous tank repair
Brazed tank repair
Repaired and filled
Repaired tank ready for painting