Author Topic: 750 Cams, Valve springs and cam tower questions  (Read 1344 times)

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Offline Garage_guy_chris

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750 Cams, Valve springs and cam tower questions
« on: January 30, 2014, 01:05:03 PM »
I have been piecing together a 836 and I have been considering my cam and valve spring selection. I have noticed a lot of talk about heli-coiling the cam tower bolts and/or the custom valve covers with welded in hold down bolts.

My question is when these steps are required?
-at what point do you need to heli-coil the threads?
-at what point do you need to add a valve cover with hold downs?

Im thinking one of these cams:
-69 K0 stocker    < no need for any modifications
-F2 stocker         < no need for any modifications
-DP117KHD        w/ HD springs
-Webcam #41    w/ HD springs
-Webcam #41a  w/ HD springs
-APE H360          w/ HD springs
1971 Cb450 Cafe  (on the road)
1974 Cb750 Restomod (on the road)

Offline Bill/BentON Racing

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Re: 750 Cams, Valve springs and cam tower questions
« Reply #1 on: January 30, 2014, 01:51:12 PM »
Most time helicoil as needed. No threads or won't hold torque. I guess you could just helicoil them all, but I haven't found or thought that nessecary. Lot of setups out there without cam tower supports. You would probably be just fine without them.Bill
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
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1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
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Offline BPellerine

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Re: 750 Cams, Valve springs and cam tower questions
« Reply #2 on: January 30, 2014, 03:59:25 PM »
got an f2/3 stock cam if needed.bill
1978 CB 750K ard and webers
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Offline Garage_guy_chris

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Re: 750 Cams, Valve springs and cam tower questions
« Reply #3 on: January 30, 2014, 06:41:26 PM »
the existing threads in the aluminum are just fine there not stripped or anything. But in a few threads/posts sounds like some people are drilling out good threads and heli-coiling for extra hold down strength?

will i need to look for extra hold down strength for any of these cam valve sping combo's or will the original alumimun threads be sufficient

 
Im thinking one of these cams:
-69 K0 stocker    < no need for any modifications
-F2 stocker         < no need for any modifications
-DP117KHD        w/ HD springs
-Webcam #41    w/ HD springs
-Webcam #41a  w/ HD springs
-APE H360          w/ HD springs
1971 Cb450 Cafe  (on the road)
1974 Cb750 Restomod (on the road)

Offline Bill/BentON Racing

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    • BentON Racing
Re: 750 Cams, Valve springs and cam tower questions
« Reply #4 on: January 30, 2014, 08:18:15 PM »
They should be fine.
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
______________________________________
See our latest build 'Captain Marvel' CLICK HERE

Offline Don R

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Re: 750 Cams, Valve springs and cam tower questions
« Reply #5 on: January 30, 2014, 08:55:08 PM »
 I had an F2 in my 836. I liked it but was close on valve piston clearance and tagged a valve on a missed shift. (having a little too much fun) Anyway when it went back together I used a Kenny harmon F cam and springs, (lots bigger) I haven't ridden it much since then DUE TO WINTER but The honda F2 cam may have been better at lower rpm's.
No matter how many times you paint over a shadow, it's still there.
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Offline MRieck

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Re: 750 Cams, Valve springs and cam tower questions
« Reply #6 on: January 31, 2014, 01:24:01 PM »
the existing threads in the aluminum are just fine there not stripped or anything. But in a few threads/posts sounds like some people are drilling out good threads and heli-coiling for extra hold down strength?

will i need to look for extra hold down strength for any of these cam valve sping combo's or will the original alumimun threads be sufficient

 
Im thinking one of these cams:
-69 K0 stocker    < no need for any modifications
-F2 stocker         < no need for any modifications
-DP117KHD        w/ HD springs
-Webcam #41    w/ HD springs
-Webcam #41a  w/ HD springs
-APE H360          w/ HD springs
I helicoil the 4 long cam tower bolt holes for large cams, Inserts are 12mm long. It is a PITA to do the doweled holes. The studs need no attention.
Owner of the "Million Dollar CB"