The Bucket Foundry

**WilDun** · 7th April 2017, 21:51

Originally Posted by Grumph

Roberto Crepaldi. ........... John never did cases in CF for the single, I think an alloy test crankcase only - no gearbox - was done and used for dyno running. That was the motor John did a CF rod for - unsucessfully. ......... I did a little machining of the cast CF throttle bodies. Feather light. Black sooty swarf which got everywhere .......... my lathe covered in black shit....

Sounds much like when I was machining SG iron valves! - spent all night clearing out my nose (and lungs!) - didn't seem to hurt though!

BTW, Isn't it Crepaldi who still owns one of the Brittens?

**guyhockley** · 7th April 2017, 22:08

I've seen pictures of a Britten single, backward leaning top end, reversed head and triple(?!) inlets. Pretty sure it had a gearbox, or a sprocket that wasn't on the crank, anyway.
I used to work on magnesium castings on a turret lathe, piece work, so needed to go as quickly as possible to make decent money. One of the two big problems with the job was the fire safety bloke who would insist on swarf being cleaned up almost before it came off the bloody tool tip!

**Frits Overmars** · 7th April 2017, 22:41

Originally Posted by Grumph

I did a little machining of the cast CF throttle bodies. Feather light. Black sooty swarf which got everywhere and dulled HSS tips quickly. I'd come in of a morning and the nights free labour would have left my lathe covered in black shit....

I think the stuff should be treated like asbestos. John Britten might agree....

**guyhockley** · 7th April 2017, 22:44

These are on my hard drive - obvious where one came from, no idea about the other two, looks almost like a museum exhibit?

**husaberg** · 7th April 2017, 22:53

Originally Posted by guyhockley

These are on my hard drive - obvious where one came from, no idea about the other two, looks almost like a museum exhibit?

the others are from here
http://www.bikeme.tv/index.php/visit...-britten-1000/

**Grumph** · 8th April 2017, 07:39

Originally Posted by guyhockley

These are on my hard drive - obvious where one came from, no idea about the other two, looks almost like a museum exhibit?

I never visited the "museum" while it existed. The quakes put paid to the building it was in and while I know there was a "mission" sent in to recover what they could, I don't know how much they could get out. Two bikes certainly as they've been seen since. A couple of years back at the annual BEARS meeting here there was a gathering of as many as possible would come to NZ. Don't recall seeing the single engine there so it may not now exist.

**F5 Dave** · 8th April 2017, 07:50

Let's just say it was lost along with the 54.5hp 125 2stroke single.

**guyhockley** · 8th April 2017, 10:37

So was the Supermono a 5 (or 6?!) valver?

**Grumph** · 8th April 2017, 11:34

Originally Posted by guyhockley

So was the Supermono a 5 (or 6?!) valver?

Pretty sure it was six. The better Britten book quotes it as six. Cathcart quoted John as saying six.

AFAIK there was one set of 5 valve heads made for the 1100 version of the twin. John showed one of them at a club social night in ChCh.
It was very nice as you'd expect, but by that time I already knew what the advance curve for the FZR's looked like - and talking to John it was apparent that he didn't...When the 1100 blew I think it wrote off one head and it didn't make enough power to be worth persevering so the good head became a display item.

**husaberg** · 8th April 2017, 13:06

It should be noted that when the "Britten" heads were made they were designed and the inlet and exhaust port shape all the rest was fitted in arround these predetermined locations.
Jerry Branch a noted American gas flow expert was consulted with on a number of occasions.

**Grumph** · 8th April 2017, 14:33

Originally Posted by husaberg

It should be noted that when the "Britten" heads were made they were designed and the inlet and exhaust port shape all the rest was fitted in arround these predetermined locations.
Jerry Branch a noted American gas flow expert was consulted with on a number of occasions.

Yes, he was - but he was the main voice pushing for 5 valves.

The 4V head development was done by Hans Weekers in Auckland who had been introduced to John by Mike Sinclair. I believe Mike had met him in Holland.

Frits may have known him as he'd worked for Yamaha Motor Europe before emigrating to NZ.

**husaberg** · 8th April 2017, 15:50

Originally Posted by Grumph

Yes, he was - but he was the main voice pushing for 5 valves.

The 4V head development was done by Hans Weekers in Auckland who had been introduced to John by Mike Sinclair. I believe Mike had met him in Holland.

Frits may have known him as he'd worked for Yamaha Motor Europe before emigrating to NZ.

I was just meaning he 4 valvers.
From memory he flowed the head design with a port model, most likely made of Bondo (ie bog) and valves until he got the desired result.
Then progressed to the actual Head patterns.
They actually got very good results on the flow bench with the 5 valver ,but airflow was only part of the equation As you know it needs to be able to be burnt efficiently and in a timely manner as well.
The patterns for the cases (at least) were made with plywood sheets with each sheet template taken off cross sections of the engine drawings.
I always admired the bolt on nature of the ancillaries on the Britten. They never made anything they never really needed to.

**F5 Dave** · 8th April 2017, 18:46

So did Hans work for McIntosh? Think I sold him a YZF muffler.

**Grumph** · 8th April 2017, 19:37

Originally Posted by husaberg

I always admired the bolt on nature of the ancillaries on the Britten. They never made anything they never really needed to.

If you talk to the guys who did the work, they never got the opportunity to make it how they needed to...
John could never give a firm direction as to how something was to be done and in the early stages of design would not allow extra bosses etc for mounting ancillaries. Rob Selby told me he hated how the alternator mounting finished up. But there had been no provision made for it on the patterns so how it finished up was all he could do.
I walked in one day and was immediately asked where I'd put a starter motor - I assume it was when Indian were sniffing around. I pointed out a couple of options and we talked geared drives and decompressors. It was all feasible using available tech - but I was told the patterns couldn't be altered and John wouldn't like the locations I'd suggested. AFAIK no engine with a starter was built. I do know that others were asked too though.