Some very nice bikes here. I can tell a couple of relevant stories too... Some years back, I did the engine and repaired the frame of a Mach one being restored by a guy my wife was working for. I'd actually sourced the bike for him too - from the estate of a friend. Turned out very nice. I'd pointed him at the painters/polishers/platers I usually used. He'd sourced various bits incl a repro wiring harness. Once I'd increased the dwell on the early type points cam, it started better and ran really well - on 6V. Won best bevel and peoples choice at the annual NZ Ducati club rally. He pointed another owner at me to sort the electrics on his one. It'd been wired by a "professional mechanic" friend. When I saw that all the wire in the harness was one colour I told him to take it back to his mate.... I was at the Pukekohe meeting the year that Sammy Miller brought the Guzzi V8 out. The best it did was run on 7 for about half a lap... Sammy and the owner - young Todero I think - were walking in the pits and stopped at the Aermacchi I was looking after. One of my replica frames. Sammy and I discussed the frame business and I asked after the V8. Is it still on points and 6V ? Yes. So I asked if he'd ever used Pertronix points replacement modules. He was interested and actually wrote down the details. About a year and a half later I saw that they'd done something unspecified to it and it was now running reliably on 8...
Just a fairly accurate copy of the Macchi race frame. The side "hockey sticks" are mild steel, profile cut then CNC machined both sides to replicate the oe forgings. Straight top tube using a bit bigger OD. That's hidden under the tank anyway. Mild steel. the major junctions TIG welded, rest bronze. I've done 15 of them. Sold to NZ, Aussie, Canada. Not interested in doing any more now. While the supply of ex road HD Sprint engines hasn't dried up, the enthusiasm for racing them has died down a bit. And they're time consuming to do. Sammy was interested - good business, lol - but in the UK there were at least two suppliers already. I was undercutting them easily.
Cool, this one I assume. Even someone in Thailand playing with one. https://www.globaldimension.com/2017/06/reverse-engineer-aermacchi-crtt/
Ha - Two frames went to canada. One to Paul Brodie and one to John Cooper - at the time, editor of Cycle Canada, Paul on-sold his one at I assume a profit. John when last heard from hadn't started his build yet. And yes, 26 degree head angle, lol. The pic is the late flat sided fairing. We have moulds for the more attractive double-bubble fairing here.
Nope... twin Turbo I believe... with Intercooler and injection basically like the pic below... at least from the article anyway. Unless of course this was going to be their GP bike engine...
Nope... the twin turbo was apparently designed to compete against the 500's but when Honda proposed they use a 250 with Turbos apparently the other manufacturers got a bit concerned.. they were apparently getting 150 plus PS at 18,000 rpm from the NR250TC (code name) in testing... Honda applied for approval with the Ministry of Transport but were knocked back for production... wimps lol So it never reached production stage... apparently the road going version would have had a single Turbo under the front cylinder.. doubt it would work without both exhausts hooked to it though.. still looks a nice compact bike.
OIC, so we just need 2 of these and a VTR250 https://turbochargerspecs.blogspot.com/2013/03/garrett-gt06-gt0632sz-32-trim-80-hp.html
Why wouldn't a single turbo work on the front cylinder alone? Would not be able to extract as much power, but 53bhp seems reasonable even without an intercooler. The front cylinder would work a bit harder than the rear, but thats probably ok as it is likely to be better cooled.
That will do... I think the specs I found showed IHI made the Tiny turbo and boost (for the race bike anyway) Apparently the race bike was a touch peaky with boost starting around 7500 and peaking at 18000.. really... lol
Exhaust scavenging would be entirely different for a start so intake pulses would vary as well and loading on the internals would vary too I suspect... you never see multi-cylinder turbo's running the turbo from only 1 exhaust.
There's plenty of turbocharged Spadas and VTR250s if you search the web, but I've seen seen a VT250F Turbo. I think they put the turbo at the front and only running off the front cylinder because there is ZERO room to put the turbo and plumbing anywhere else on the VT250F. Nice find Blair.