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XT/TT/SR 500 Camshaft

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Since my current camshaft is hosed and needs to be replaced, looking for thoughts on a replacement.

Bike is an SR500 (street tracker), 540cc, HD valve springs w/alloy keepers, ported, Mikuni 38 mm roundslide, Supertrapp exhaust, etc.

I have a megacycle cam from my old roadrace XT -- don't know the model number but it was the most radical they sold back then (25 years ago). The guy who built that motor drag raced it, but for roadracing, it was too peaky -- had one hell of a top end, but the guys with milder cams would kick my ass accelerating out of the turns. That bike had stock bore but high compression piston, and ran with open megaphone and 38 mm Mikuni roundslide.

I am tempted to give this cam a try on the SR, although I expect I will still find it too peaky. But maybe the extra displacement will give it enough midrange that I would find it acceptable?

If I get a new cam, what recommendations would any of you have. Have been away from old thumpers for quite a few years and don't know what is now considered the hot stuff.

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what lift are the lobes ?, i grind a few of those from .240" up to .320" lift @ the lobe with a little or a lot of duration for short track or trail ridiing....got any specs ? crower

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I would have to measure to be sure.

The White Bros cam in the motor now is their "performance grind" whatever that is.

The Megacycle cam has visably higher lift and lots more duration.

Do I need to measure the lift with a dial indicator (which I don't have), or can I get close enough by just measuring with a ruler or something.

Hard to tell just how much of the cam has been worn away. There are some pretty serious gouges in the peak of the lobe. At what point is the cam no longer able to be reground?

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it sounds like it might be regrindable with a custom lobe selected for whats left on your core......you would be surprised at what regrinding can fix , like new sometimes if the bearings aren't completely fried. send it , or check the lobe height with calipers.measure from nose to heel and then the heel only and subtract the difference, and walla thats your lift....... we need to know that #on both lobes.

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Your Megacycle cam may have engraved numbers on it somewhere,but im sure you have already looked.Check out the Megacycle website,(www.megacycle.com),they give a breakdown on the different cams and a brief explanation too,you can also look at the J2 and J3 cams by www.johnsoncams.com,(google it i am not sure).

Megacycle cams are available from www.thumperstuff.com,speak to Mark he is a helpful guy.

Good luck,

Brandon.

South Africa.

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