cam timing for race cam.

[bevel bob]

I need to determine what cam is fitted to my 250, I'm told its a green-white but to be sure i need the figures also checking and running valve clearances,is it practical to use this race cam on the road?.

[Mr.R]

Hi Bob,
Didn't I read that you've already bought some parts from Nigel Lacey?
If so why not give him a call, there's not much if any that he doesn't know about the singles.
He did say to me over a pint or three that fitting a race cam to my 250 Desmo, (which has the 40mm inlet valve as standard) wasn't a good idea for the road.

Steve

[bevel bob]

Hi Mr R. Engine in bits, wobbly valve guide to be sorted, fitted with 40mm inlet 10.2 cr piston (borgo) and very knobbly cam,C.B. said to fit roll pin in end of cam to restrict oil to gear end,Is this a racing mod to increase pressure to cam and big end ?With this spec its bound to be a handfull, but I'm up for a challenge.Thinking of fitting additional spark plug to improve combustion and allow reduced advance.

[Mr.R]

Hi Bob,
The flow needs to be constricted at the end of the cam so that most of the (topend)oil goes to the valve gear and not straight down the bevel tower.
All of my V Twin cams and the cam on my 250 Desmo are partially blanked at the bevel gear ends, with what appears to be solder which then has a very small hole drilled through it.
These motors run on very low oil pressure as the bigends (being needle rollers) don't need to float on a film of oil in the way that plain shell bearings do.
Off the top of my head I recall the pressure relief valve blows at about 16lbs per sq inch on the big V Twins.
Nigel Lacey told me the 250's don't need twin plugging, he fits twin plugs to the bigger singles.
I'd asked him wether it was worth fitting it to my 250 as I'm a big fan of twin plugging and use it in my big motor but that uses either 87 or 90mm bores, for either 882 or 950cc.
I don't know Chris B but know who he is and that he has a lot of experiance with the old bevel bikes, but for tuning or tuned Ducati bevel motors in my opinion Nigel is 'The Man who knows', I'd be very suprised if Chris B dissagreed with me on that point.
I have a shed load of experiance with the big bevel V Twins, but have only rebuilt a handful of the singles over the years, which's why when I bought my little project 250 I turned to the guys who know for advice.
I've known Tony Brancato and Brian Silver (MotoMariana) for many years now and was lucky enough to be introduced to Nigel Lacey by Brian over dinner one evening, I said "I know who you are Nigel, don't worry I won't spoil your meal with an endless stream of questions" he replied that after the meal we'll take a walk to the pub and you can ask me anything you want...
I've met him again 2 or 3 times since and he's always been helpful and friendly my wife says that he's a complete gentleman after he quessed her weight at at least 2 stone less than she is when he was giving (free) advice on suspension units and spring rates/settings.
If I could afford it I'd happily give my motor to him before anyone else in the world!

Steve

[bevel bob]

Hi Mr R, Thanks for info, Just got back from driving round italy,Magic!!.As soon as Valve gear sorted I'll be back in saddle.Nigel has been very helpfull.Thinking about a big bevel, may have to sell the Norton!