This Forum is now CLOSED use the link to get more details viewtopic.php?f=3&t=13924#p102587
By Norm
#2323
I was looking at a 612 that is getting 42Hp on the dyno, nice bit of kit that one and sounds even better
By Robin
#25786
Hi Norm, how is this measured? Is this the power output at the rear wheel, or at the crank (=rear wheel output + approximately 15% for taking drive train loss into account)?
By simon
#25789
Love to see a little iPhone type movie of such an event if you ever have the chance. S:)
By Norm
#25809
Hi Robin, I believe it was rear wheel but I was pretty distracted by the bloke who had made the 8 spring clutch for it and he has nearly finished a 10 spring for it. It is quite a bit lighter than the Newby one and you can operate it with one finger. Simon it was something I wanted somebody to take a vid of it for utube, will have to get some vids of it, it just smoked the rear in second gear so easily. It has been raced at Daytona in the USA, Suzuka, Okayana,Mt Fuji and Tukuba in Japan and has had several outings at Broadford in Vic. It is ectremely competive in the open class even though is is way down on cc's
By Robin
#25821
Wow, must be highly tuned piece of kit for 42 bhp at the rear wheel!
By Paul
#25822
Just a thought... Now Hitchcocks are to provide servicing and workshop facilities I wonder if that will include 'upgrade' services? A fixed price for a 612 installation may be of interest to many that lack the facilities, time or confidence to do it at home. The classic iron Indian Enfields are slowly creeping up in value making it more worthwhile to spend a decent amount of money on them.
User avatar
By Barry N
#25829
Say Norm, is that the Speed Dog Racing bike? I would like to know more, have you any technical details? Enjoyed your dyno videos Paul!
By Norm
#25836
Hi Barry, yes it is the Speed Dog Racing bike, as for any tech info Guy offers as much info as he can but he has others in the background doing the secret bits. I might try sitting him down one day without other distractions and try getting him to detail all the good bits, but with his shed the way it is it is alkways hard. Must have 50 bikes in there and each one has a story
User avatar
By Barry N
#25851
I've seen pictures of the bike on their website - what a gorgeous (and potent) looking thing it is! I'd be interested to know how much packing (spacers plus gaskets) he is running under the barrel and the piston he uses. His ignition timing would also be of interest. I have the 3mm spacer plus 3 gaskets (4.5mm in all?) under my barrel with the Acralite and it took a lot of fiddling to eliminate pinking when accelerating hard around 4000rpm. I have it sorted now by using the best pump petrol with a drop of octane booster (Castrol Valvemaster Plus) and 107 pilot (middle groove) and 280 main in the 32mm Amal using the megaphone with baffle in place. My ignition timing, which I found to be critical with the pinking issue, is a gnat's todger BTDC (static) which I estimate to be around 25-26 degress fully advanced. (I set it to 28 degrees advanced with the disc when I built the engine, but I lost that setting when I had to change the points and have since done it by ear on the road). Whilst it has fantastic mid-range power, I don't think I am getting the best top-end performance out of it yet, which is why I am interested in other peoples' 612 set-ups. My gut feeling is that I might need to raise the barrel by another mm or so to enable slightly more ignition advance and at the same time smooth out the sharp edges (hot spots?) around the valve pockets of the Acralite. I am reluctant to retard the inlet cam by any amount (which is a possible course of action), because according to the spec sheet that came with the cams, the inlet already closes at 70 degrees ABDC (compared with 42 degrees for the standard cams). Anyway, that's the story so far with mine at 1350 miles - and I'm loving it! So how are you getting on with the 612's over there Norm?

Shop for accessories at Hitchcocks Motorcycles