| Hi, This has been one of the best threads for a while. Must i agree with lads who said building it yourself is 1/2 the FUN, although probably more than that for me, engine building has been my thing for a long time.
Mid 130s bhp motors? I must agree with Ains et al,likening them to a hand grenade with the pin 1/2 way out or a tune to far. Great FUNif someone else is paying for the upkeep. Having said that both Neil and Rob B wisely used latter/stronger cases/motors.
When Raymond Roach won his WSB champinship, it was said that they got through 30 YES 30 sets of c/cases!!!!!!!!!
With this in mind i set about tuning my "92 851 strada.I wanted sp4 type power with a broader spread and peak below 10,000rpm.
Despite all the bhp claims for these models,the real world figure is around 82rwbhp! (still enough for 150/1 or 2 mph).
A 916 set of heads....same valve sizes,but better/cleaner ports,
916 barrels,
853 pistons-lighter than 888/916 items,
851 steel Pankle rods-lighter/stronger than 916 items,
Ballanced 916 crank,better oil feed to the l/hand side of the motor,as in it's got some!!!!!
916 water pump-same 888/926/955 corse item,
916 oil cooler,
Alloy flywheel*,stm slipper clutch + plates,1/2 time wheels (sp4/5),V-TWO vernier adjustment camwheels,
V-TWO 604 cams-996sps rip-offs,
54mm single green top feed injectors,
Feul pressure bumped upto 4.5 bar,
Inlet stubs matched to suit,
Full 50mm spaghetti GIA-CA-MOTO high rise spaghetti system,
955 corse roller main bearings (not to sure about these now),
Full blue print,
FIM 916 open pipe chip-fim 061?,
Dyno set up by Steve "H" at Moto Rapido.
So how did i do???
All work by myself except Dyno set up and crank,pistons and rods.ballancing....J+J's of Swindon-----Very GOOD!!!!!!!
Well i said i would be happy with a strong 110bhp and i would be over the moon with 115bhp...........Well i'm not over the moon,but she made the base line at 7,100rpm,100 at 8,400,105 at 8,800 and 110 at 9,500 hanging on to that till 9,800 then tailing off to 105 at 10,700rpm.a dead straight line from 3,000 to 9,500rpm! Max Torque 65.5 at7,250 with a good spread till 9,250
Not the star ship enterprise......but i'm quite chuffed!This was with a standard 851 airbox....Top removed, ITG foam filtre
The mk2 is now on the bench...Sp5 heads o/size valves 35/31, long stroke 900ss crank,Ti Pankle( 748sps) rods and 748 close gearbox,works carbon airbox and "x" shape runners.955 pistons giving 984cc.
Well that's the short version....2 other Dukes to keep going and 6 children and ONE very understanding wife.
Steve Robins S.W.
Last edited by Mr.R : 11-Jun-2007 at 23:21. |