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Author Topic: minor machine work on a 750 cam  (Read 3918 times)

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Offline bucky katt

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minor machine work on a 750 cam
« on: December 25, 2009, 07:46:20 PM »
someone suggested to me that i mill a little material off the heel of the cam lobes in my 750 to get some more lift. my question is what kind of cutter should i use and how to get it to a nice smooth finish? i am all alone tomorrow and if i can get around a little better i might go and cut some metal.
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Offline dragracer

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Re: minor machine work on a 750 cam
« Reply #1 on: December 25, 2009, 08:08:11 PM »
Quote from: bucky katt on December 25, 2009, 07:46:20 PM
someone suggested to me that i mill a little material off the heel of the cam lobes in my 750 to get some more lift. my question is what kind of cutter should i use and how to get it to a nice smooth finish? i am all alone tomorrow and if i can get around a little better i might go and cut some metal.

Just curious, how can you increase lift by taking the very same material away that gives you lift?
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Offline bucky katt

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Re: minor machine work on a 750 cam
« Reply #2 on: December 25, 2009, 08:12:18 PM »
if you remove material from the heel (bottom) of the cam lobe, you can run your adjusters in more so when the cam comes up under the lifter, you'll have that much more lift.
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Offline 754

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Re: minor machine work on a 750 cam
« Reply #3 on: December 25, 2009, 08:23:47 PM »
I think itwas me that suggested it... a bit tongue in cheek..

Drag racer, the heel does not give lift, that is where the valve clearance is set, the DIFFERENCE in height, then provides lift.

bucky, I have only thought about this briefly, I do know it has been done, and Burt Munro types have done a lot of this. The problem is it probably requires a bit of experimentation.  Does your RT have minutes on it or seconds or how fine can you break down the degrees?

 Basically I think that on the low part, you take cuts across (ball end cutter), then as you hit the ramp you have to taper off in small increments, then polish it all up to finish... a bit of work. I dont think stock cams are too hard, could be wrong tho..

 I have no doubt that in the early days (of hotrodding), a few people measured cams and tried to copy them , themselves if they were low on cash. Because a stock came is narrower on the lobes, ie looking from side, the lesser duration makes it appear slimmer, you have little to work with.. just some off the heel and try to blend the transition nicely.
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Offline bucky katt

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Re: minor machine work on a 750 cam
« Reply #4 on: December 25, 2009, 08:25:03 PM »
i have several cams i can experiment with, possibly. i've not ever done anything quite like this before.
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Of all God's creatures there is only one that cannot be made the slave of the lash. That one is the cat. If man could be crossed with the cat it would improve man, but it would deteriorate the cat.
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Offline voxonda

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Re: minor machine work on a 750 cam
« Reply #5 on: December 26, 2009, 01:42:18 AM »
You will have to grind it of, to keep a smooth surface. We used to call it a 'poor' mans cam. But it can work, but keep your valve piston clearances in mind. Do not overdo it.

Rob
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Offline Soos

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Re: minor machine work on a 750 cam
« Reply #6 on: December 26, 2009, 09:23:28 AM »
If trying this I would suggest a grinder as well.
However you CAN use a carbide cutter if you have to. I had a problem when I tried cutting with a HSS cutter.

I've done this to 1 cam..... and regretted it. Never ran it, I F'ed it up before I got a chance.
Gave up the thought of doing so once I found out 650 cams are worth a small fortune to 550/500 riders wanting a up in power.
:)
Money VS power.......



Good luck though!!



l8r


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Offline Yoshi823

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Re: minor machine work on a 750 cam
« Reply #7 on: December 26, 2009, 11:49:18 AM »
Quote from: voxonda on December 26, 2009, 01:42:18 AM
You will have to grind it of, to keep a smooth surface. We used to call it a 'poor' mans cam. But it can work, but keep your valve piston clearances in mind. Do not overdo it.

Rob

I tried a Yosh R/T cam on my modified 750 (823 pistons etc) but found the carbs a bit wanting. So I took a standard F2 cam to a specialist who grinds the base circle to a given specification as set by a profiler, so's to get all of the inlets and all of the exhausts exactly the same.

I just googled this...http://www.google.co.uk/search?client=firefox-a&rls=org.mozilla%3Aen-GB%3Aofficial&channel=s&hl=en&source=hp&q=camshaft+specifications&meta=&btnG=Google+Search
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Offline HB-1fan

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Re: minor machine work on a 750 cam
« Reply #8 on: December 26, 2009, 03:13:07 PM »
Noticed this company on that google page that Yoshi listed and was interested if any of our members in the pacific northwest have inquired with them about custom cam work?

http://www.oregoncamshaft.com/cam-specs.html

HB
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Offline Old Scrambler

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Re: minor machine work on a 750 cam
« Reply #9 on: December 28, 2009, 09:29:58 AM »
My thoughts are you would get similar effective flow through the valves by grinding the seats, polishing the valve flute, and then think about duration instead of lift on the cam for max performance with retained durability.
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Offline bucky katt

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Re: minor machine work on a 750 cam
« Reply #10 on: December 30, 2009, 01:57:14 AM »
i've decided to leave it alone and wait until i can find an affordable 750f cam.
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Offline honda3303

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Re: minor machine work on a 750 cam
« Reply #11 on: December 30, 2009, 12:39:37 PM »
how much lift you looking for?  I have many cams just laying around.  Tell me what it's worth to you and I'll see if I can find what you are looking for.  I've been wanting to get rid of the piles of honda parts I have laying around.  Well, except for the stuff i might use.
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Offline bucky katt

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Re: minor machine work on a 750 cam
« Reply #12 on: December 30, 2009, 10:25:13 PM »
really, i'm just looking for better performance than the 75 750f cam gives. i've found a few 750f cams available but for another 100 dollars on top of that i can get a new cam from web or megacycle. i'm just going to have to leave it be for now. i got it insured finally so i'll be happy with that for the time being. the main reason i was looking at machining a stock cam was the fact that it would have been free.
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Of all God's creatures there is only one that cannot be made the slave of the lash. That one is the cat. If man could be crossed with the cat it would improve man, but it would deteriorate the cat.
Mark Twain - Notebook, 1894
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