RVF Engine Build Project

[DAC]

RVF Engine Build Project

About three years ago, I bought a couple of RVF race engines in a state of stripdown from a member on this forum, to realise the dream of building a special engine for my NC30. I've owned the bike for over 15 years and have enjoyed all aspects of riding, maintaining, repairing and especially modifying it over that time. The bike is an '89 Type 1, though all that remains of the original is the frame, swingarm & loom. The original engine, having been round the clock yonks ago through commuting, countless rideouts, a tour of Ireland, John-O-Groats, a weekend thrash to LeMans, loads of trackdays, the Estonian Tallin circuit, trips north and east from Moscow & back to Red Square and an astonishing ride from Sarajevo to Mostar and on to the coast, is still going strong. Its fate is to undergo a forensic examination to see just what the bearing surfaces and other internals look like after such a life and still being capable of turning in this level of performance & reliability. God bless it :)

So this is the timeline of the engine build project .....

Jan 2013 picked up RVF engines

Easter 2013 cleaned and fettled the chosen engine casings :
Removed all internal burrs and casting blemishes
Honed cylinder bores, which were fabulous anyway
Drilled lower casing for UK style oil cooler passages
Drilled upper casing to accept second VFR pickup coil
Forgot to drill upper casing to thread mounting point for VFR chassis
Did this later with engine in frame, yes, easily managed.





Spring 2013 sourced NC29 HRC option B gearbox cluster from a guy on this site after many many fruitless attempts to source an NC30 HRC set



Summer 2013 ordered new shell bearings from Japan, to begin the blueprinted build. This took FOREVER but was well worth the lead times, plastigauge bill and repeated torquing etc for the sheer delight at a set of nominalised main bearing figures, to complement the beautifully balanced crankshaft, whose journals are like new.



Then of course it was time to repeat the process on the big ends, to complement the balanced polished rods.
This also took FOREVER but was equally satisfying.



Everything has been micrometered, verniered, slip gauged, plastigauged, weighed, spun, fettled, honed & polished to be on nominal.

Easter 2015 (Yes I know, life happened) assembly of engine casings. Major assemblies being ready, crankshaft, conrods, pistons, rings, gearbox, selector gubbins etc.

The NC29 HRC gearbox parts with the exception of 1st gear, have been transferred to a set of VFR shafts, fitting snugly in the RVF casing.



The original RVF gearbox, sold on to somebody on this forum.

Summer 2015 engine casings finally assembled with all major assemblies carefully checked. I was particularly keen to check the gearbox selection action and so contrived a method of driving the clutch basket, loading the output sprocket with a torque limiter and checking for reliable gear selection up and down the gear range over a period of about two weeks until totally satisfied



Then assembly of the remaining engine ancillaries proceeded

Generator, going to re-route the wire which in standard form crosses the bike twice. Still tempted by the GSXR upgrade.

Water channels, and new feeder hose. I have modified the water pump cover to link to a donut heat exchange unit behind a shorter oil filter.



Clutch saga - OMG - eventually decided to use an RVF basket and have lopped off the lugs from one of the inner friction plates to create more slipper effect on overrun.



The clutch actuation has been hydraulic for ages, since a trackday at Cadwell when the thing got so hot that the clutch dragged with the lever fully in.





NC24 oil pump with extra chamber for external circuit. At this stage the external cooler route was completed using a short length of suitable hose awaiting later inclusion of an external radiator.





VFR pickups fitted utilising the newly machined and tapped mountings. Clearances against starter clutch lugs checked on feeler gauges.



Autumn 2015

With the short engine now complete and having incurred a broken collarbone, attention turned to the cylinder heads during my recuperation period. These had already been ported and polished in the airways and then skimmed.





There were a couple of sets of shims for the camshaft holders and the shafts themselves had been relieved of their quietening gears and modified to be slotted in order to individually adjust the valve timings. The valves were in fine condition, but I removed them all to lap them onto their respective seats. Thorough sonic cleaning to remove all traces of grinding paste and I replaced the thrust washers under the valve springs, as these compress and flare on extended life engines. Then assembly onto the engine casings. Some calculations and a fair bit of experiment with shim washers of varying thicknesses eventually produced a set of backlash figures which I was happy with for the entire camshaft drive gear train on both heads.



The cassettes have also had their antibacklash gears removed, so these required shimming onto the heads as well. New gaskets fitted and then both heads torqued down. Camshaft backlash minimal, but enough to allow for expansion of parts when in use.



Next, the valve clearances were set to nominal using a selection of shims amassed from many broken engines over the years, plus a few specially ordered from Rick. Once initially set, it was intended to crank the engine on battery, without compression and allow the valves to settle and begin to bed in. The engine was filled with oil, by pouring over the camshafts and then an oil pressure light was jury rigged in order to check that sufficient oil was being circulated whilst cranking. All was well.








Spark plugs fitted, carburetors too, to ensure proper fitting the first time on their new rubbers.



The thermostat housing is best fitted once the engine is mounted. I chose to swing the front of the fame up on a pulley and then trundle the engine under from the front, lowering the frame down and minimising the mass being supported.





It is a simple job to mount the engine, followed by exhaust and loom connections, not forgetting the HT leads and then ready to fire it up.



I had previously sourced most of an Ethos system from Japan, but was missing a front pipe and a crucial Y piece.



Late in the day, I found a job lot of parts which had been on this forum and have adapted one of those to be a perfect solution to the problem.



After about a dozen flicks of the switch, the engine fired and ran, initially on the front bank only, but then on all four. What a buzz that was!

A brief spell of reluctance from cylinder 3 in consistently firing, but I suspect that was a pulled LT coil lead. The slotted camshafts are evident, but the whine is there so I'm happy and the induction roar and exhaust note are tremendous.

So then it was time for the radiators to be fitted, a recently purchased OEM stock-clearance upper and a huge triangular wedge lower from Liam



I'm riding the bike unfaired at the moment, checking carefully for leaks, drips and any other issues, the only one so far being a split in the rear camshaft cover gasket I chose to use, which dumped oil into the spark plug well and then out of the drain hole all over the rear of the engine. GRRR - at least there is plenty of oil pressure then!



Never before have I had difficulty warming up an NC30, to the extent that I have had to tape up part of the lower radiator just to get a reading on the HRC temperature gauge.





Now I am running the engine in and really enjoying the close ratio gearbox. Can't wait for the track. I need to re-jet though, as I am testing a tank I have had modified to bring air in from (potentially) either side, ducted from the front of the bike. Off to the Isle of Man on the bike at the end of the month for practice week.

Last week I finally ditched the standard subframe and fitted an alloy one from Rick, which is fabulous.



This project is nearing completion and I am delighted with the result. It has given me such enjoyment over many years and yet the biggest grin is always when the throttle is wide, the gears are whining and the pipe is booming, heading through the twisties

[VtypeV4]

Supreb fella, nice one!

[Dynamohum]

Astounding attention to detail great work

Did you do the rc36 rear wheel conversion or is that one of the ones done by a forum member from Northumberland a while back ?

[jim157]

Fantastic work Dave.

[marcus57]

Very nice and obvious to see alot of time and effort has gone into the build of your engine

[bikemonkey]

Needs a GSXR genny.....


Awesome work, super trick and really looking forward to seeing this modified tank!

[Yakama]

Excellent write up mate! It's guys like you that really keep these old bikes going!

Perhaps a write up on some of your other mods? Like the QS you made?

[Yakama]

Out of interest do you know which NC29 HRC gearbox you have?

CBR400RR NC29 % Drop
HRC Sugo

15-42 2.800
18-38 2.111 24.60%
20-37 1.850 12.37%
22-36 1.636 11.55%
23-34 1.478 9.66%
24-32 1.333 9.80%

52.38%


CBR400RR NC29 % Drop
HRC Tsukuba

15-41 2.733
18-38 2.111 22.76%
20-35 1.750 17.11%
21-34 1.571 10.20%
23-35 1.522 3.16%
23-33 1.435 5.71%

47.51%


CBR400RR NC29
HRC Suzuka

15-42 2.8
18-38 2.111 24.60%
20-36 1.800 14.74%
22-35 1.591 11.62%
23-33 1.435 9.81%
24-32 1.333 7.07%

52.38%


All of the ones I have been able to source are the suzuka ones

[Yakama]

So assuming yours is a suzuka too, this is it compared to the NC30 F3 HRC gearbox (Everyhting is the same apart from the 1st gear I think


VFR400R NC30 % Drop
F3

15-41 2.733
18-38 2.111 22.76%
20-36 1.800 14.74%
22-35 1.591 11.62%
23-33 1.435 9.81%
24-32 1.333 7.07%

51.22%



Using CBR400RR NC29
HRC Suzuka apart from 1st Gear

14-41 2.929
18-38 2.111 27.91%
20-36 1.800 14.74%
22-35 1.591 11.62%
23-33 1.435 9.81%
24-32 1.333 7.07%

54.47%

[CMSMJ1]

Top work Dave.