I'm currently balls deep in a build that I will call a “TT2 Tribute” rather than a “TT2” or “TT2 replica” as it is not going to be anything near the real thing other than in cosmetic appearance. It will most likely be built and registered (historic rego) as a road bike and taken on occasional weekend outings and the odd track day. Given that the TT2 has never actually been a road bike, I would like to build it as a lightweight, powerful (relative to 1986) and good handling bike but I don't care if it is unruly, uncivilised, uncomfortable and hard to live with as a daily commuter because it never will be.

It sadly all started when a friend had to clear his garage after a marriage went bad and I ended up buying his '86 750 F1 race bike. What was a cheap price soon became more expensive when I found that it had been sitting outside for the better part of 15 years collecting rainwater. The front cylinder poured water out when I removed it and the Nikasil lining looked like this




and the carbs looked like this



I've started on a tidy up and and accumulating bits and pieces which I'll post up when I get around to it

First things first…stripped everything down and ordered some 90mm Pistal hi comp pistons to take the engine capacity up to 780cc



Sent the barrels off for rebore



Bought a Verlicchi TT2 frame from Steve Munro



and a 750SS aluminium swing arm from Ed Milich



Bought a friends wrecked Triumph 675R so I can use the wheels (3.5x17” front and 5.5x17” rear), ohlins forks and TTX shock

Thanks for taking the time to post here. It is fun to see someone build. This will be a good save.

I will not ask how you will manage to title this (frame number). But, can we see some photos of the Pistal pistons? And, where did you get them? Finally, do check the fitting of that swingarm inside the frame; I guess you are using a later engine with the small pin.

Have fun,
MikeV

I have a plan for the frame number and registration...possibly not the most robust plan but a plan none the less. Probably good not to ask...

I will be using the F1 engine and I've manage to sort the swing arm pin diameter problem. I bought two roller bearings for each side of the engine case. OD to fit in the case, ID to fit on the swing arm pin (can't remember the dimensions just off the top of my head). Oil seals need to changed to the appropriate size too. To stop the roller bearings working their way inwards along the pin and dropping into the case, the engine needs to be split and a shouldered shaft machined to the appropriate size with the swing arm pin running through it. Hope my description makes sense?? It's less complicated than it sounds...didn't take any photos unfortunately but if I end up back inside the bottom end, I'll snap a few pics.

The foot peg mounting position on the frame needed to be "spread" a little for the swing arm to fit in. Didn't need to be spread much...probably about 10mm each side. I tried a "cut and shut" method (unsuccessfully) before just cutting them off completely and relocating them slightly wider.

Will rustle up some photos of the pistons and post them up

Just realised I do have some photos inside the engine block. My swing arm spacer can be seen here



And a few other random photos

Hey jr...
Will the shouldered shaft allow a sufficient amount of oil past, to keep the swing arm bearings lubricated? Or is that a none issue?
Regards...
Flattop

Hi Flattop,

To be honest I hadn't even thought of that! But it's all pretty loose fitting...plenty of room for the oil mist in the engine case to work its way in there. Anyway, it's got to be better than the original large diameter pin turning in those brass inserts or whatever they are

Pistal HC pistons 90mm



Measuring piston to head clearance using 1.6mm soldering wire. I measured at 8 places around the perimeter of the piston and took the average. It worked out at 1.03mm on the front and 0.86mm on the rear. Not sure why it is so different but it's easily fixed with a 0.2mm base basket under the rear cylinder.





Nice big valves...43mm inlet, 37mm exhaust

And finally, got my Ducabike slipper clutch to fit

I can't wait to see this one!
Paul

Those Pistals are nice pieces! It is really hard to judge from here, and I am sure you have cleaned the heads and valves. Looking at that shiny ring around part of the center of the exhaust valve makes me think they ever so lightly touched the pistons --- at the 106 degrees or so lobe centers you found. Did the pistons have any missing carbon on the valve pockets in the same place? If they seem close again I would consider going for the 103 degrees to move away from late closing on the exhaust. Or, you could start cutting away on those nice hunks of Pistal! MikeV