Bruce Reader Posted January 29, 2008 Posted January 29, 2008 G'day everyone. A while ago i had the Scura heads decked and the cam replaced due to some early wear and tear. The resulting dyno resulted in little to previous excursions and i suspect that a Breva V11 cam was installed-(yet to be verified). In the near future i want to check this and look towards changing the cam. Any ideas ? Not expecting 200 hp !! Different cam and dual plug heads ? (i Have the coils ready) ? Cheers Bruce P.S Mr Roper ! maybe i can bring the bike up late March for a bit of work and a bit of a fang with your new Scura !! Maybe sit in your local pub and talk squish bands !
Dan M Posted January 29, 2008 Posted January 29, 2008 Mike Rich has V11 cams. http://www.mikerichmotorsports.com/MGproducts.htm I don't know if any are "drop in", most would require additional work. You could probably expect a reasonable increase in top end power. The down side is low speed power and drivability will be hurt.
motoguzznix Posted January 29, 2008 Posted January 29, 2008 From the Mike ritch cam charts I would opt for the following: A) # 800-620x9 - Street Grind. 258° Duration, . 400" Lift # 800-620x10 - Biggest Street Cam Avail. 264° Duration, . 426" Lift The standard V11 cam has a duration of 270° at 1 mm lift and 0.415 lift. I remember my flow bench measurements on a V11 head here that show no flow increase above 8 mm valve lift. If your heads flow alike, I would use the cam with the shortest timing and good avcceleration off the seat to make good mid range power. A cam like this might eliminate th power flat spot at 4000 rpm. A higher lifting cam only contributes to higher valve train forces instaed of a better charge. If your heads flowed better, cam B could also increase the power wt high rpms. Brono Scolas OSS could be a good choice too. Lift is the same like Mike Ritchs B cam, but shorter duration. Every cam with more duration and lift would not show its benefits in the badly flowing standard V11 heads. No power advantage and less on bottom end with an even more pronounced torque dip at 4000. How did you deck the heads? By milling off the chamfer in the combustion chamber? Then you have the chance to get a real squish area. Shortening the cylinder barrels is the next step to bring the pistons on top. If all this is done, the valve to piston clearece has to be checked.
Greg Field Posted January 29, 2008 Posted January 29, 2008 The Mike Rich cams are megacycle x9 and x10 cams. We set up one V11 with an x9 cam and mid-valve heads from a Cali. The low-rpm and mid-rpm power were awesome. I never got a real chance to try out the top-end power.
jihem Posted January 30, 2008 Posted January 30, 2008 Brono Scolas OSS could be a good choice too. Lift is the same like Mike Ritchs B cam, but shorter duration. I have a Scola RS installed. Heads have been flowed, KN pods installed, etc...the bike is now very much more nervous and fast. But won't idle too well.
Mike Stewart Posted January 31, 2008 Posted January 31, 2008 Jihem, What valve lash are you using? Going to a larger valve lash (Raceco Specs.) will make your idle speed more stable. A larger valve lash decreases the duration of the cam. Worth a try! Mike I have a Scola RS installed. Heads have been flowed, KN pods installed, etc...the bike is now very much more nervous and fast. But won't idle too well.
Pierre Posted January 31, 2008 Posted January 31, 2008 I have a Scola RS installed. Heads have been flowed, KN pods installed, etc...the bike is now very much more nervous and fast. But won't idle too well. Mike sells the x8 cam as well. I got one from megacycle. It's the old Norris RR3 - then it became the megacycle 620 x 8. Requires sinking the valves. No idle problems. Excellent drive-ability and power. PCIII got it all working for me. Here's the specs on those megacycle cams. http://www.guzzitech.com/Files/megacams.pdf Don't know if they still make 'em - but as Greg said Mike Rich caries a few of 'em.
jihem Posted January 31, 2008 Posted January 31, 2008 What valve lash are you using? Going to a larger valve lash (Raceco Specs.) will make your idle speed more stable. A larger valve lash decreases the duration of the cam. Worth a try! thanx for the tip. except for the flowed heads, PC III and dynobench tuning, we didn't do much more to the engine, except using KN pods cos the frame/airbox of the bike couldn't breath no more. I'll look into the lashes !
luhbo Posted January 31, 2008 Posted January 31, 2008 .... It's the old Norris RR3 - then it became the megacycle 620 x 8. Requires sinking the valves. .... Cams requiring sinking of the valves are an improper solution. Sinking the valves spoiles most if not all of the effect that the extended lift should give. Just look how this changes the angles of the flow direction and how this influences the open area between seat and valve. What is left is stress and noise and reduced lifetime of the valve train. And some bucks for your "tuner", of course. Hubert
Skeeve Posted January 31, 2008 Posted January 31, 2008 Cams requiring sinking of the valves are an improper solution. Sinking the valves spoiles most if not all of the effect that the extended lift should give. Ah, but mine goes to eleven!
al_roethlisberger Posted January 31, 2008 Posted January 31, 2008 I have the 620x9 from Mike Rich. He seemed to think it was a good fit for those looking some mid-range power, without having to sink the valves. Al
leafman60 Posted February 1, 2008 Posted February 1, 2008 Al, I forgot to ask you in that other thread but how is your V11 running ???? I lost track of everything you did to it. Was everything worth the trouble??
Pierre Posted February 1, 2008 Posted February 1, 2008 Cams requiring sinking of the valves are an improper solution. Sinking the valves spoiles most if not all of the effect that the extended lift should give. Just look how this changes the angles of the flow direction and how this influences the open area between seat and valve. What is left is stress and noise and reduced lifetime of the valve train. And some bucks for your "tuner", of course. Hubert I think that kind of generalization over simplifies and ultimately misleads. Sure, there are issues created when valves are sunk, but they can be dealt with. I like to go to the Harley engine builders to read about what works - no air cooled mills are more heavily or more often modified than harley motors. Anyway, I got 92 RWHP out of my sport i using the RR3 and some modest "unshrouding" of the valve pockets. Milled head, sunk valves, unshrouded pockets and voila - real HP. There is no question motor work has to be organic - gotta' be approached that way. There are no "drop in" solutions - though a hotter cam comes closest. But the hotter the cam, the more "other" work needs to be done. High lift extended duration cam, sink the valves to gain valve to valve clearance, unshroud to preserve flow, mill to recapture lost CR - it's all good. 92 RWHP good. Adjusting valve to valve clearance is generally done by sinking the valve in the head, which is done by cutting the seat farther down. Sinking the valves hurts low lift flow, though, because it shrouds the valves. When we have to do it, we always "unshroud" the valve with a special cutter that removes chamber material around it so that flow is restored. The sinking and unshrouding of the valve then makes the chamber bigger, which in turn lowers compression unless the head is also milled. And milling the head introduces it's own set of issues, you really never want to mill a head any more than necessary. So sinking the valves excessively causes a chain of undesirable events; we often refer to it as "molesting the heads to make them work". Done in moderation, say up to about .050", sinking valves is manageable. Beyond that, it starts causing more issues than it solves and you're better off to seek a solution through a smaller exhaust valve, for example. http://www.nrhsperformance.com/tech_xlcaminstall.shtml 1
Bruce Reader Posted February 1, 2008 Author Posted February 1, 2008 Does anyone now how the standard V11 (2002) cam compares to these cams mentioned ? Which of the aftermarket cams is most similair to the original ? Does anyone know if these cams are readily available in Australia. Any good companies for overseas ordering ? Cheers Bruce P.S Has anyone else had expierience with premature wear on their cam?
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