Sometimes you wonder...

[GregT]

Okay. Feeling a little better so got out and made the shell measuring jig I'd promised myself. Very simple, a 1/2in dia ball bearing welded to the end of a short piece of tubing. Held upright in the vise with a magnetic base DTI coming down onto it from above. The DTI has a good sized dial - 2 in plus - so the divisions are good and large. Works surprisingly well and seems repeatably accurate too.
I've been able to quite easily separate the pile of shells into four thicknesses. Interestingly - and a bit worryingly - the thinnest and thickest shells are both unused greens....

I wasn't enormously happy with the bigend clearances when plastigaged - all were just greater than .0017in. So put those shells over the jig...Two rods didn't have matching shell pairs even though the numbers are the same. Colours are long gone.
I have enough thicker shells of usable quality to redo the bigends and get them down to .0016in where I want them.

Worth doing - and that jig is going to see more work in the future...

[GregT]

Moving along. Happy with the bottom end clearances now. Trial assemblies done using #1 and #2 pistons less rings to establish cam timing. Both banks within 2 degrees of each other. It appears that the kit cams lobe centers are the same as the road versions - 100 inlet, 105 exhaust. Not where I'd have put them but there's no adjustment possible. Put in an inlet and exhaust valve and did valve to piston clearances. All good there and checked the high points on the pistons too against the chamber - don't have to trim anything.
I can't build the heads until the new head bolts turn up. Assembly sequence is - spring seats, stem seals, head bolts in. Then put the cam carrier on the head - which traps the head bolts. Then you can assemble the valves - which traps the cam carrier on the head....Honda......

Made a guide plate to put the pistons in the bores. Much better than ring compressors. Worked out which way round the rods go by checking for centrality in the pistons. Once i'd sorted that it was apparent how they were supposed to go. Judging by what little wear marks there are, they may have been wrong way round. The manual is contradictory of course. Happy they're right now anyway. Assembly lube generously spread around and the rods torqued up. New piston circlips of course - suzuki actually, lol.

Washed and inspected the gearbox shafts. They look like new - the dogs are practically virginal. But I had to buff some strange jointing compound off the OD of the bearings. Looked like a contact adhesive. Not Loctite bearing mount anyway.

Cases will go together tomorrow. Then it's the ancillaries, oil pump etc etc...

[nvr2old]

It's really refreshing to watch someone work meticulously on such a rare and historically important engine as one of these are. I'm sure your client is grateful.

[GregT]

It's really refreshing to watch someone work meticulously on such a rare and historically important engine as one of these are. I'm sure your client is grateful.

As long as that is expressed financially....

Found yet another sting in the tail. Started cleaning the oil pump pickup - which resembles an oyster, only just open - and realised it was half blocked with fabric...You needed to shine a strong light into it to even see there was anything there. Not like our own, familiar, open and easily checked GS pickups....
A LOT of scraping and high pressure solvent washing got it out eventually.
The sump appears to be an aftermarket deep one. It has a baffle cast in behind the pickup - so it can be wheelied without sucking air...Bonus.

I still haven't decided just how it got to this point. Was it a project which got past the owners engineering capabilities ? Was it someone's collection of parts which they decided to loosely assemble and sell when they realised they'd never finish it ? So many questions - and so many mistakes found in it.
The guy doing the chassis has found almost as many problems too.

The primary gear on the crank has a spacer taking up the distance the starter clutch would have occupied with the ignition trigger rotor outside that. The spacer is very loose on the crank so a replacement will be machined up. What's there has at least 1mm clearance on the shaft...

[GregT]

The head bolts turned up on Saturday. They are same length and will drop in perfectly. But they use a modern six point splined recess to tighten. Like a Torx - but straight sided splines so not a Torx...Anyway, went to town to a specialist tool shop and found the correct long bit for them. It came in a 10mm hex 1/2in drive socket so it got driven out of that - and will be used in a long 10mm 3/8 drive socket which matches my torque wrench...
Next problem was that the access holes in the cam carrier through which you tighten them were about 8.5mm dia. I machined the hex shank of the trick bit down to 10mm OD- leaving enough hex at the top to engage the socket. Then bored the holes in the cam carrier to 10.5mm...
Those holes are hidden under the outers of the ball and roller bearings the cams run on. Deburred them and I can now look forward to a couple of days building the heads and shimming them.

The end is in sight - for the engine anyway. Last I heard they were still looking for a rear axle - the one in the bike is cracked...

[GregT]

Heads assembled, front one shimmed and on - to get it off the bench.
Pic shows what I've been talking about re the head bolts and the poor access
If Honda had made the lower cam carrier two piece - as they easily could have - it would have been so much easier.
The latest problem to overcome was the shim stack under the carrier - .013in of them - which had to be trimmed to clear the bigger key for the bolts....

I've never done one but I'm told the later RC45 isn't much better. The lower cam bearings are part of the head which means you can't adjust the gear mesh if you cut the head or block...And compression changes have to be done with the pistons.

[GregT]

My bit's finished. Here it is in all it's scratched and scarred patina....You might see some writing on the heads - "Hallam Boyz" and some japanese characters.
We thought initially it may have been one the Hallams ran in the day in Australia, but I've since been told that they did several sets of heads. The japanese characters were translated by a kiwi who works at HRC as "brown eye racing", LOL. So it may have aussie history...
Yes, that's an extra breather outside the alternator...why ? Don't ask me, I wouldn't have done it.

Whether the bike will be completed in time to be sorted before shipping to Philip Island is another question which I can't answer.

Tidying up some loose ends and packing up spares, I thought I'd better test the thermostat before it goes away...The housing is empty. No thermostat - which in a race engine isn't too unusual - although I'm told this one has the extra lower radiator, and an oil cooler...But in addition the bleed hole for the thermostat housing is epoxied shut....I've passed the information on anyway.

[GregT]

Handed it over to a racer who was down from the North Island for a meeting this weekend. He'll take it to the door of the workshop where the frame's sitting.

By a coincidence there was another RC30 at the track too. Not racing, on his way to a classic revival meeting down South. Just stopped at the track to see the bike's regular rider. I know the owner and of course we swapped notes....as you do. His is much better than this one, never blown up for a start, LOL. It's got all the fruit incl Keihin FCR's and late short-port heads. But he says it makes about 124hp at the wheel...I was a tad shocked. The last one I built was a jap home market one which we went through thoroughly. With a locally made tailpipe and an unrestricted ignition box it made 118hp at the wheel....
This guy's race bike is a seriously good RC30, I'd have expected more.

[Spyder]

Very cool build. Thanks for sharing it with us. Please, keep us posted on it's progress if you can.

[GregT]

Very cool build. Thanks for sharing it with us. Please, keep us posted on it's progress if you can.

I will. I'm told it's in the frame already. Apparently a "just fit" due to the decked block and the accurate hole drilling in the frame for the top bolts...
They're not the usual 10mm bolts in a 12mm hole....