cam specs

[flea]

im building a rephased motor/mikes 750 kit/5th odrive/primary high ratio gears/modified head..ported,titanium o/s valves springs etc/slightly milled/ceremic coated/vm34 carbs.will be to a performance cam grind on rephased cam.im looking for advice on the best cam grind (specs) for it.it will be for street/hway use only (no racing) and was looking for performance and relibility have already looked at the shell grind and the first 2 of megacyle cams in their catalog and im getting out of my comfort zone so any advice or suggestions would be great

[tonyc2me]

Mr. Riggs cam. Amember here and other site. $19 electronic ignition.

[flea]

im in australia and looking for spec suggestions only for a rephased cam i already have that i want to do a grind on,hopefully mr riggs or 1 of the many knowligible blokes here maybe able to help with advice as to what might suit this motor..thanks

[270xs650]

Hi Flea,
if you contact Daryl at Professional Motorcycle Tuning in Melbourne on 93304909 he can help you out with everything you need. He built both my engines and I couldn't be happier.
Thanks John.

[mrriggs]

There are others here with a lot more experience than me. I'd say the Shell #1 would be a good fit for that motor, but I really don't know anything about the Megacycle cams.

[slide]

I suggest you contact Hugh's Handbuilt as he specializes in rephrasing the 650 motor and will give you all the info you require on a strong street cam. If you haven't already done so, I also suggest you check out his PMA charging system. I'm installing one of his units this weekend. Top shelf stuff.
....Mel....

hughshandbuilt.blogspot.ca/

[flea]

megacycle cam lift 420/420 duration 272/272 lobe 110/104 running clearence .006" megacycle street cam lift 415/400 duration 250/246 lobe 104 running clearence .010"/.012" shell #1 lift 405 duration 258 lobe 100

[jack]

If you're looking a good streetable cam,then the shell #1 or the megacycle 250-20 would be suitable. The megacycle will pull slightly higher up top than that the shell due to it's 104 LC. The 250-00 cam will start flexing it's muscle around 4000 RPMs. Most of the megacycles with the exception of the 250-20 are one dimensional with power band coming in around 4000 RPMs

[flea]

thanks looks like ill go with the 250/20,the head deserves it.just needed a nudge in the right direction plus jacks explation helped

[jack]

That particular camshaft is called a "Reverse Pattern" with having less duration than intake and used for instances when the exhaust flow ratio is high and you want to combat this situation to prevent over scavenging. I don't know who ported your head but I generally for that style of cam,which I plan on using in my build up,will port the exhaust to yield the highest possible flow gains and with it,will yield very high port velocities,can't have one without the other when working the exhaust port. A member here,can't remember who,installed that cam and was very pleased how it pulled,so I think you made a good choice.

[flea]

so the 250-20 cam really only works well with a ported head??? and the 250-00 is better with a non ported head???

[jack]

All cams work better with ported heads and depending on the valve timing events,some will pull harder or you could loose Hp out the exhaust,that's why you generally port the head to the cam.If you're are individual who looks at the theoretical side of things,like I do, you take the time and effort to obtain that little edge to add a few extra HP.

You have nothing to worry about with that cam choice you selected for your ported head, as it's quite similar to the "256 " Reverse pattern and when even combined with a non ported head and decent carburetors,pulls real hard to redline. When you start getting into the single duration patterns or cams 30 and 40,then I feel one should pay particular attention to the flow ratio details cuz to much lift combined with a high exhaust ratio could spell disaster in terms of power falling off quickly higher up in the cams power band. Didn't mean to scare you ;D

[flea]

thanks, not a scare but a learning curve into something i havent delt with before.always found if you your not sure of something it never hurts to ask before puting spanner and dollars to work instead of just blundering ahead (no man can be a exspert in everything,some only think they are) which is why this site and others are a livesaver

[flea]

webcams street cam valve lift 395/395 duration 280/280 duration@.05"240/240---- racing cam .475/475 duration 302/302 duration@.05"266/266.... does anyone have the email address for megascycle and web cams as both only seem to list address and ph num

[imworks]

They're both pretty old-school. Not much internet, but tons of knowledge.

The woman at Megacycle really knows her stuff. She seems to be a hardcore Nascar girl, not a lot of love for the Japanese .

I think I had to pay her by cheque, as they don't use PayPal!

xs2ss.blogspot.ca/2012/09/start-with-one.html