cams cams cams!

TripleKing · Posted: July 21, 2007, 12:46 am Post subject: cams cams cams!

so is there any consensus on a top grind for these bikes?

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

I f your staying with the stock displacement of 650CCs,then you'd be best to use a camshaft with either mid 240 or 250 degrees of duration at 40 or 50 to maintain good streetable characteristics of torque and hp cuz anything around 265 degrees and performance will suffer...............Jack

natemeins · Posted: July 9, 2009, 6:31 pm Post subject: Re: cams cams cams!

Maybe I haven't done a complete search here yet but I'll throw it out anyway. I noticed when I received my performance cam from Mike's that the spec sheet called out for a .006" running clearance for BOTH intake and exhaust, whereas the stock setting is .002" intake and .004" exhaust. Is there any reason for this big of a jump from stock settings? Seems to me it would make less valve opening and shorter duration, not to mention noisier in the valve "clinking" department running down the road. I admit I was a bit reluctant of these numbers, so I've set them at .004" and .006". Seems to run fine, but I'm wondering if I'm losing out on some performance because I'm not at .006". I know this is the kind of cam that takes lots of revs to make its power, but I generally dont rap the ole' gal up that high. Anyone else running this cam and would like to chime in? By the way, my engine has the 750 big bore kit, 34mm mikunis, boyer ignition, and iridium plugs, if it makes any difference. Thanks for all y'alls help.

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Mikes XS Performance camshaft has very aggressive ramp profiles,the same as the Megacycle profile and those clearances are needed to prevent the rocker arm from digging in or gouging the cam lobes coming off from the base of the cam and are also the key to the timing events of the cam during opening and closing of the valves. DO NOT EXPERIMENT WITH TIGHTER LASH SETTINGS BELOW THE CAM MANUFACTURES RECOMMENDATIONS,YOU CAN WIPE OUT THOSE CAM LOBES QUICKLY!,I know,I've been down that road using a billet camshaft.

yamaman · Posted: July 9, 2009, 8:11 pm Post subject: Re: cams cams cams!

Interesting reading here on Mikes cam:

xs650temp.proboards.co...042&page=1

Better too much lash than too little for sure! If you can't hear them, they're too tight!

Also, I don't know what Yamaha were thinking when they said .002, but thats generaly accepted as being way too tight!

xsjohn · Posted: July 9, 2009, 8:18 pm Post subject: Re: cams cams cams!

All this makes me want to go out and give my absolutely great running 8-1 a big hug....... Cool

xsjohn

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