Discussion in 'Triumph (Classic)' started by Esmerela, Jan 5, 2019.
Lookin good !
Hope the move went smoothly.
If as you say it turns out to be a Big D 867 motor , would you know what pistons they were using ? Back in the 70's we experimented with 71mm t120 pistons, fag packet mathematics make that 831.
Thanks, it's a pain but almost straight now.
sorry to be of no use here, when I was looking for some pistons it was because a mate had some barrells but no pistons for an 867, I phoned Big D and they told me they were having difficulty sourcing pistons so I didn't bother. Since then however Pat Brown in the USA has been making an 867 kit. His outfit is called Triplesrule, look them up on the internet, he might have some advice for you. My bikes use a stroked crank and are 990 Beadling kits.
you are right about the T120 pistons, that's what Norman Hyde was using for his 830.
The big D 867 may use RCC pistons. I got hold of a kit once off of John Anderson that had RCC pistons but in the end I didn’t use it because I thought the pistons were just too heavy.
Like Sam, I went the Beadling route, I had a Beadling 850 and a 898. Both performed faultlessly.
Not being an engineer myself, I'm very impressed.
Thanks for the information I will see what google throws up in response.
Dropped the inlet stubs in for anodising this morning, collected them this afternoon happy days
Well it was never going to look original with Morris mags and Mickunis so I went with the red
Good job on the inlet stubs, what bolt hole spacing did you end up with for the inlet stubs, I have measured my T160 head and they look like the holes are 1 7/8" & 5/32" off center?
The three original T160 inlet stubs are marked 'L', 'C' and 'R' (and have different part numbers) as the outer stubs are blended internally to match the inlet ports.
The T160 stubs are angled to set the carbs vertical. Hopefully, the Hinckley carbs (centre carb) will fit under the frame with those straight(?) inlet stubs?
The centre Mikuni BST carb clears the frame nicely on my T160. On my carb stub which Esmerela used as a pattern, the carb mounting flange is set at a slight angle compared to the stub, but it isn't easy to see on the pictures. I don't know what the angle is though?
The only slight issue that I had was the datebox air filter that I fitted was just touching the frame at the rear edge and so I put a slight depression (dent) in it to clear the frame spine.
A nice stand out colour.
I am pleased with the way they turned out. Your Ok on the imperial dimensions. We worked in metric to suit our tool path sofware 48.2mm centre to centre and 4.3472 offset. I turned the stubs on a manual lathe and milled the flanges on the CNC . I can let you have an stp , igs, fxf of the flange, should you want it send me a pm with you email address.
Apparently It's all sits fairly close to the frame but does clear and as Reggi said the air filter will be a wiggle.
I found these photos of the Green meanie in the tol gallery.
OK. They looked as if they could have been 'straight' inlets in the photos so I thought I'd mention it but as Reggie has said the flanges are angled then all is well.
That's my mate Steve's bike.
It looks and goes great !
I've just had a look at my manifolds again, and in fact they don't appear to be angled unlike my statement above , but what are angled are the o.e. Triumph Hinckley fitment carb mounting rubbers. The thick buffer in the middle that butts up to the inlet manifold on one side and the carburettor flange on the other side is approximately 3mm wider at its top outer edge than at the lower edge which of course alters the angle slightly that the carb sits at.
Esmerela has measured and machined copies so I suppose she would know categorically if they're straight.
Sorry to talk bollocks.....old age is cruel, but I knew there was a slight angle change somewhere.