Author Topic: cam grinding? (Read 5177 times)

Bigbo1234 · « **on:** August 01, 2011, 07:56:25 PM »

tonight i tore down an extra cb750 engine and was looking online @ the price of cams, to save some moolah i was wondering if i could have a machine shot re-grind my cam to different specs, or am i going in the wrong direction? there is a few local machine shopspthat are pretty good.

the technological J · « **Reply #1 on:** August 01, 2011, 08:41:23 PM »

i have heard of people doing this but other than that run a search on it here

MCRider · « **Reply #2 on:** August 01, 2011, 09:05:45 PM »

Quote from: the technological J on August 01, 2011, 08:41:23 PM

i have heard of people doing this but other than that run a search on it here

To modify a stock cam, you grind the base circle. About all you can accomplish with this method is an increase in lift. By reducing the diameter of the base circle you will increase the load on the rocker arm. This method was used at the beginning of the CB750s production, as proper regrinds or billet cams weren'ta available.

They were very soon after however. A regrind is usually welded up with more material so you have more to grind down. You can increase the duration and lift.

Better yet is a fresh stick from billet, if that's the proper word.

For the price of a proper billet cam, <$200 can't see the draw to the first option. And the second option may be even more expensive.

Flying J · « **Reply #3 on:** August 01, 2011, 10:48:01 PM »

who sells these billet cams?

phil71 · « **Reply #4 on:** August 02, 2011, 12:22:20 AM »

Do you know what lift, duration, lobe seperation and/or installed centerline angle you want?
Will you be increasing the compression ratio? Changing displacement?
There were plenty of hot cams for CB750s (mostly with big bore kits) from back in the day, but they're all a waste of time if you haven't modded the engine some other way. What are your goals for a cam change?
Adding a lump of metal to a stock cam seems like a good way to dump said lump into your running engine.

Bigbo1234 · « **Reply #5 on:** August 02, 2011, 03:09:27 AM »

yes i will be boring out to 836, also goiong over the head. not exactly sure what type of lift and duration, but that what im looking for, info to help me with my build along the way, phil71 what is your suggestions. im looking for a bike that has a little for getup and go but not something that will cost so much my childeren wont be eating. i dont know if its possible but i would like to build this bike for less that $1000 total. any advice it considered.

MCRider · « **Reply #6 on:** August 02, 2011, 06:03:20 AM »

Quote from: ffjmoore on August 01, 2011, 10:48:01 PM

who sells these billet cams?

By billet, I mean "new".
Forum Sponsor APE http://cbrzone.com/sohc.html
WEBCAM http://webcamshafts.com/index_blank.html?pages/vehicle_search.html
DynoMan has them: http://www.dynoman.net/bikepages/sohc/cams_dp.html
All the usual suspects.

phil71 · « **Reply #7 on:** August 03, 2011, 08:54:44 PM »

Under $1k?! Leave it stock and add 2 teeth to your rear sprocket , you'll be able to do power wheelies all day, if it's tuned right. If you wanna go up against some CBRs, you're kinda outta luck no matter what you do.

MCRider · « **Reply #8 on:** August 03, 2011, 09:22:06 PM »

Quote from: Bigbo1234 on August 02, 2011, 03:09:27 AM

yes i will be boring out to 836, also goiong over the head. not exactly sure what type of lift and duration, but that what im looking for, info to help me with my build along the way, phil71 what is your suggestions. im looking for a bike that has a little for getup and go but not something that will cost so much my childeren wont be eating. i dont know if its possible but i would like to build this bike for less that $1000 total. any advice it considered.

Under $1000? Think outside the box. I'd go with stock displacement. Have the head ported and nice valve job. That will maximize a mild cam. Get a good pipe, not a Mac. Anything left over put it in suspension parts.

Tews19 · « **Reply #9 on:** August 03, 2011, 09:28:30 PM »

Quote from: MCRider on August 03, 2011, 09:22:06 PM

Quote from: Bigbo1234 on August 02, 2011, 03:09:27 AM
yes i will be boring out to 836, also goiong over the head. not exactly sure what type of lift and duration, but that what im looking for, info to help me with my build along the way, phil71 what is your suggestions. im looking for a bike that has a little for getup and go but not something that will cost so much my childeren wont be eating. i dont know if its possible but i would like to build this bike for less that $1000 total. any advice it considered.
Under $1000? Think outside the box. I'd go with stock displacement. Have the head ported and nice valve job. That will maximize a mild cam. Get a good pipe, not a Mac. Anything left over put it in suspension parts.

You say get a good pipe, not a MAC... DO you suggest to stay away from MAC 4-1? What is a good pipe?

HondaMan · « **Reply #10 on:** August 03, 2011, 10:20:00 PM »

Quote from: Tews19 on August 03, 2011, 09:28:30 PM

Quote from: MCRider on August 03, 2011, 09:22:06 PM
Quote from: Bigbo1234 on August 02, 2011, 03:09:27 AM
yes i will be boring out to 836, also goiong over the head. not exactly sure what type of lift and duration, but that what im looking for, info to help me with my build along the way, phil71 what is your suggestions. im looking for a bike that has a little for getup and go but not something that will cost so much my childeren wont be eating. i dont know if its possible but i would like to build this bike for less that $1000 total. any advice it considered.
Under $1000? Think outside the box. I'd go with stock displacement. Have the head ported and nice valve job. That will maximize a mild cam. Get a good pipe, not a Mac. Anything left over put it in suspension parts.

You say get a good pipe, not a MAC... DO you suggest to stay away from MAC 4-1? What is a good pipe?

Do I feel an oil thread coming on?

Bigbo1234 · « **Reply #11 on:** August 04, 2011, 03:20:08 AM »

well so far ive got 2 bikes for free and 60 into the other. im thinking with some scrounging ill be able to do it less than 1000. i have a knack for finding things free or cheap. ill post later if i actually accomplish it or not.

Quote from: MCRider on August 03, 2011, 09:22:06 PM

Quote from: Bigbo1234 on August 02, 2011, 03:09:27 AM
yes i will be boring out to 836, also goiong over the head. not exactly sure what type of lift and duration, but that what im looking for, info to help me with my build along the way, phil71 what is your suggestions. im looking for a bike that has a little for getup and go but not something that will cost so much my childeren wont be eating. i dont know if its possible but i would like to build this bike for less that $1000 total. any advice it considered.
Under $1000? Think outside the box. I'd go with stock displacement. Have the head ported and nice valve job. That will maximize a mild cam. Get a good pipe, not a Mac. Anything left over put it in suspension parts.

is porting something i can do in my own shop? what about a valve job?

Hinomaru · « **Reply #12 on:** August 04, 2011, 08:11:15 AM »

From the SOHC (UK) forums:

http://www.sohc.co.uk/index.php?topic=2730.0

Perhaps this is an option for you if don’t have any luck finding a CB750 camshaft regrind service in the USA?

Bigbo1234 · « **Reply #13 on:** August 04, 2011, 02:17:51 PM »

hey thanks for that link, were they expensive? ive heard that grinding the base circles makes a diff but doesnt last too long?

Gearheadgreg · « **Reply #14 on:** August 04, 2011, 02:59:28 PM »

Give American Customs Cam a call, he has a lot of spec's for anything you want, We just had him do cams in my neighbors Valkyrie, $200 bucks for 2 camshafts,, Bike runs like a scalded dog! http://www.americancustomcam.com/

HondaMan · « **Reply #15 on:** August 05, 2011, 11:33:20 AM »

Quote from: Bigbo1234 on August 04, 2011, 03:20:08 AM

well so far ive got 2 bikes for free and 60 into the other. im thinking with some scrounging ill be able to do it less than 1000. i have a knack for finding things free or cheap. ill post later if i actually accomplish it or not.
Quote from: MCRider on August 03, 2011, 09:22:06 PM
Quote from: Bigbo1234 on August 02, 2011, 03:09:27 AM
yes i will be boring out to 836, also goiong over the head. not exactly sure what type of lift and duration, but that what im looking for, info to help me with my build along the way, phil71 what is your suggestions. im looking for a bike that has a little for getup and go but not something that will cost so much my childeren wont be eating. i dont know if its possible but i would like to build this bike for less that $1000 total. any advice it considered.
Under $1000? Think outside the box. I'd go with stock displacement. Have the head ported and nice valve job. That will maximize a mild cam. Get a good pipe, not a Mac. Anything left over put it in suspension parts.
is porting something i can do in my own shop? what about a valve job?

My book outlines how to port these heads.

Bigbo1234 · « **Reply #16 on:** August 05, 2011, 04:22:28 PM »

i would love to get that book, but thats more $ than my bike!!! not doggin you but i cannot afford that. if you have an older used copy that i might get for much less, ide be up for that.

phil71 · « **Reply #17 on:** August 06, 2011, 09:47:37 AM »

how expensive is it to ruin heads?

Bigbo1234 · « **Reply #18 on:** September 11, 2011, 06:47:49 PM »

not that expensive, ive got a few laying around.

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Author Topic: cam grinding? (Read 5177 times)

Hinomaru