Oddball engines and prototypes

[guyhockley]

Apparently, the Lynton Imp was at the Classic Racing Club's festival. Wonder if it was just a static exhibit (with a pristine drip tray!)

http://www.crmc.co.uk/donington-2017/#&gid=1&pid=3

[Michael Moore]

There's more on the Can Am/Rotax 500 twin in this folder on my website:

http://www.eurospares.com/graphics/CanAm_Rotax

[husaberg]

There's more on the Can Am/Rotax 500 twin in this folder on my website:

http://www.eurospares.com/graphics/CanAm_Rotax

Classic bike did a 3-5 page write up on the can am laydown twin in the late 80's with Jeff Smith.
i have it somewhere.............
it was a very neat bike shame it was killed off.
If i recall correctly they made 4-or 5 including, i think, a racer prototype.

Michael, That 175 road racer is beautiful

[WilDun]

For those, like Wil, who don't realise what high tech, finely developed machines Harleys are...

https://www.hotbikeweb.com/removing-...utters-is-snap

The link itself kind of gives it away!

Progress is just never ending - we just keep on learning (over and over again) - I have seen many of these new innovations come and go three or four times (this one is particularly brilliant of course) - the key word here is "simplicity" - that word also might even apply to one or two of the riders! - I experienced about 3 seperate instances of rider stupidity on a trip to Tauranga and back on Saturday and Sunday. (not necessarily confined to Harleys of course).

I need to add that I do like the look of some of the Harley engines, I just don't like to see the bikes festooned with dumb add ons like ape hangers (and dumb Apes).

There is one thing that Harley genuinely excels at and that is marketing!


Michael / Husa - thanks for the stuff on the Rotax - I missed all that during a 20 or so year "lull" in my motorcycle interest!

[WilDun]

HUSA,
Couldn't find the stuff you were referring to on Smithy and the CanAm but here is a bit on the "Titanium" BSA anyway.



http://www.motorsportretro.com/2010/...-titanium-bsa/

[T.W.R]

Here's a couple of pics of Ray Pollards Imp powered sidecar unit done a couple of years before the Lyster
And a Pic of Art Sparks "Spartus" engine dohc 4v again done a couple of years earlier

[Grumph]

Imp powered outfits appeared very shortly after the Imp went into production. But that's the first inline layout I've seen. Conventional wisdom was lean the engine forward with carbs and pipes behind the steering head. To get your Norton gearbox to survive, you fitted the largest possible rear wheel sprocket and worked forward from that. The idea being to run the gearbox at the highest possible rpm to avoid exposing it to excessive torque....It sometimes worked...

There's a Post Classic Imp powered chair under construction in ChCh. I've donated the back half of a Z1 engine broken in two in a fatal. The edges will clean up for cover plates/mount plates and they'll have a box that will handle anything they can throw at it. The late owner would be tickled too, he loved oddities.

That thing of Art Sparks is very early 4V style. Honda copy wide valve angles - and slow burning too I'd bet.

[guyhockley]

Imp powered outfits appeared very shortly after the Imp went into production. But that's the first inline layout I've seen. Conventional wisdom was lean the engine forward with carbs and pipes behind the steering head. To get your Norton gearbox to survive, you fitted the largest possible rear wheel sprocket and worked forward from that. The idea being to run the gearbox at the highest possible rpm to avoid exposing it to excessive torque....It sometimes worked...

There's a Post Classic Imp powered chair under construction in ChCh. I've donated the back half of a Z1 engine broken in two in a fatal. The edges will clean up for cover plates/mount plates and they'll have a box that will handle anything they can throw at it. The late owner would be tickled too, he loved oddities.

That thing of Art Sparks is very early 4V style. Honda copy wide valve angles - and slow burning too I'd bet.

What's the primary drive going to be on the Z1mp?

[guyhockley]

Here's a couple of pics of Ray Pollards Imp powered sidecar unit done a couple of years before the Lyster
And a Pic of Art Sparks "Spartus" engine dohc 4v again done a couple of years earlier

I think the 500 was done with a very short stroke crank about 35mm if it's the one I remember.

[Grumph]

What's the primary drive going to be on the Z1mp?

I've suggested duplex chain. A guy in the UK trading as Andychain I think has come up with a source of very high quality duplex and is selling them for quite a few applications. I've had a couple off a stockist in Queensland for Laverdas. Very reasonable price too.
Anyway, the box is a crossover so they can juggle it's location to suit either the primary chain line or final drive. I can come up with the guts of a Z1 clutch too.

The project seems to be on hold at present as the builder has broken an arm...

[T.W.R]

That thing of Art Sparks is very early 4V style. Honda copy wide valve angles - and slow burning too I'd bet.

Just had a quick google but there's only seems to be reference to books on the guy & the sale of a apparently very rare investors prospectus for the Indy Car development racer.

Was looking for bits on the imp and stumbled into it, the magazine had another pic that they were requesting info on.....a privateer V4 triumph racer that looked almost like the supercharged AJS

I think the 500 was done with a very short stroke crank about 35mm if it's the one I remember.

I was hoping one of the later editions of the mag would've had some more info/pics but haven't found anything and there's big gaps in the issues

[Grumph]

Just had a quick google but there's only seems to be reference to books on the guy & the sale of a apparently very rare investors prospectus for the Indy Car development racer.

Was looking for bits on the imp and stumbled into it, the magazine had another pic that they were requesting info on.....a privateer V4 triumph racer that looked almost like the supercharged AJS

Art Sparks was one of the guys behind the Novi Indy V8 back in the day. He also produced what was probably the final development of the Offy indy engine - a narrow valve angle head. Very Cosworth....

That double Triumph - built in NZ ? I remember a magazine asking for details on one some years back. There followed some letters in subsequent issues where it was at first thought it had been built by Mo Haley but it was identified as having been built by another one of the sidecar guys back in the day.

[T.W.R]

Art Sparks was one of the guys behind the Novi Indy V8 back in the day. He also produced what was probably the final development of the Offy indy engine - a narrow valve angle head. Very Cosworth....

That double Triumph - built in NZ ? I remember a magazine asking for details on one some years back. There followed some letters in subsequent issues where it was at first thought it had been built by Mo Haley but it was identified as having been built by another one of the sidecar guys back in the day.

Interesting read that he was a stunt rider in his early years, the pic of him jumping the Harley over the canyon is a beaut....no fear in those days

Nah the Trumpy is a Pommy built thing apparently pic was taken at Snetterton in the 70s, the info request was in a late 70s edition of Motorcycle Sport

[guyhockley]

I've suggested duplex chain. A guy in the UK trading as Andychain I think has come up with a source of very high quality duplex and is selling them for quite a few applications. I've had a couple off a stockist in Queensland for Laverdas. Very reasonable price too.
Anyway, the box is a crossover so they can juggle it's location to suit either the primary chain line or final drive. I can come up with the guts of a Z1 clutch too.

The project seems to be on hold at present as the builder has broken an arm...

I've been told that the triplex Lav chain (pull that to flush?!) can be replaced by a duplex that is a Mercedes engine timing chain. Just paddock gossip, so no guarantees...
Reason I asked was because I also have a Kawa box for a future project. When Tigcraft where running their BOTT GPZ/EX 500 they supposedly ran a slipper clutch from a later sports bike in the original basket, so I was planning to see if the 500 clutch was an easy fit to my GPZ750 mainshaft so I can use a Morse chain prmary. Embarrassingly, all the bits are in the same shed but I haven't got around to it, yet.

[Grumph]

I've been told that the triplex Lav chain (pull that to flush?!) can be replaced by a duplex that is a Mercedes engine timing chain. Just paddock gossip, so no guarantees...
Reason I asked was because I also have a Kawa box for a future project. When Tigcraft where running their BOTT GPZ/EX 500 they supposedly ran a slipper clutch from a later sports bike in the original basket, so I was planning to see if the 500 clutch was an easy fit to my GPZ750 mainshaft so I can use a Morse chain prmary. Embarrassingly, all the bits are in the same shed but I haven't got around to it, yet.

I'd think that the early ZX7 slipper either will fit or can be made to fit. The GPZ fours have a gear driven clutch - and a morse primary. The GPZ twins have a clutch driven by a morse on the drum outer dia. Never felt the need of a slipper on the 500's till we supercharged one and effectively doubled the rotating mass - but the engine braking was very severe.
Yes, chain of choice is the merc duplex, made by Iwis.

I'm not a fan of morse chains for primaries. Very heavy in relation to load capacity IMO.
When i did a big XS Yamaha triple for local pre 82 racing I discussed with the owner converting it to the merc duplex. The OE morse is unbelievably heavy.
Didn't do it - $$$. In conversation with the Queensland Laverda guy I told him about the XS and he said he was looking at putting a morse on a race Laverda triple. I'm pretty sure I talked him out of that, LOL.

Never knew Tigcraft did a 500. I did two, still got mine in the barn, it won the F3 support class at the last WSB round held here. The other one was national F3 champ 2 years running - on big doses of nitro. The yanks warn that they break this that and everything else. Take the mass of the alternator rotor off the crank and you get rid of the torsional vibe problems and the crank lasts. Rods stood up to 18lb boost, no probs....