Hi
Thought I would share a little bit of info about an F3 / TT replica that I am slowly putting together . Most of the major parts are here except the fuel tank & body work .




It started life as a std f3 the frame has been cut & new lower half subframe welded on . Rebuilt 38 mm Marzzochi forks with Sports Valves . new 18 " wheels . New 280mm disks & 08 calipers .



The engine is based on 400 f3 cases , 6 speed 620 gearbox , 620 crankshaft , 88mm FBF pistons , new barrels , 750 dry clutch , welded & ported heads with bigger valves , ST2 cams .


As you can see from the photos some of it has been trial assembled to see if it all fits together . Now the real work starts .


Hope that you enjoy .

Ducbill

Ciao Ducbill,

Nice conversion of the frame.
We're pretty sure You will dump that cast iron lug on the rear wheel in favour for something more exotique ?

After seeing quite a few cracked cases, aren't You afraied those right handside engine lugs are going to crack ?
Or are the later cases a better stronger version than the first Pantah cases ?
Is the 620 gearbox a simply "slip it in" job or is there machining involved ?

That's a lot of questionmarks, isn't it

Keep up the good work

ducadini

Hi
Thanks for the positive response to my post

The frame conversion was done by Glyn @ Sports Motorcycles in NZ then flown back to Brisbane as excess baggage !
There is a full floating caliper kit to go on but not a smaller disk at the moment .

I have heard about some engine cases cracking but I don't have any others so I guess I will take my chances with what I've got , It makes sense that later cases are stronger but I am not sure .

To fit the 620 gearbox I had to bore a small amount out of the right hand case & turn down a collar for one end of the shift drum . Then change the roller bearing on the left hand side of the input shaft . I am not saying that this is all there is to do as all have done so far is to trial assemble the g/box & make sure that it turns & changes gears .

The next hurdle is to fit the dry clutch , a quick set up shows that the output shaft is shorter , I tried a shorter spacer & gained 5 mm on the nut but I am still not sure if I have enough clearance between the pressure plate & the clutch hub for it to work .


I realise that I may be totally wrong & a 620 6 speed & a dry clutch combination wont actually work in early 400 cases . If anybody has any experience with this please share it with us .

Many thanks
Ducbill

Very cool!!!! Thanx for sharing!!!
For some reason those forks look bigger than 38's in the picture.....the triple trees look beefy too, what are they??

Keep the updates coming....

Good luck with the build,
Clay

It looks like you have a nice project there, and you know where you are going. I started to say that was a nice conversion on the rear of the frame, and then you said who did it --- I understand. RE: the six speed; not sure which one you are using, but all (vintage and modern) for the small cases were for wet clutches; the clutch shaft is short. Maybe you can turn down the very center of the inner clutch hub to get enough threads to make it work as a dry clutch.

Good Luck,
MikeV

Looking good Bill, nice to see new projects!
I used a set of 400 cases but stuffed them with guts from a 695.
I stayed with the wet clutch all worked well!
I believe mine were a newer version.
Paul

Well here we are 2 & bit years later & finally i got to roll it out of the shed & into the sunshine .

Its now a 750 with different wheels & a whole lot of hours put into it .

I tried to do at least 1 job a day to keep it rolling forwards but sometimes it just went backwards of it own accord .

Did a lot of fabrication learnt some new skills & did a heck of a lot do overs !

Happy with it now as it runs & i may get to take it around the track within a month .

Nice job

Thanks for the reply Graeme .

I got the stable mates out today for photos , not a TT or even close but it is belt drive .

Those both look great!!!
.......and lots of red and a little white is a hard color scheme to beat.

Clay