Author Topic: Recommendation on valve springs and cam chain  (Read 1519 times)

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Offline Kickstart

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Recommendation on valve springs and cam chain
« on: September 03, 2012, 07:52:39 AM »
I'm doing my rebuild and I noticed that all my valves springs lean to one side.  (see attached pictures).

Looking for advice from others:

1. Should I replace these? 
The gap between the top of the springs and the square is approximately 1.2mm (as best as I can measure) for both the inner and outer spring.  I only measured the #1 exhaust springs, but they all seem pretty similar when I eyeball them.  Length-wise they are all above spec, so they're good except for the lean.

2. If I do get new springs, what kind should I get?
I'm going to be running either a stock cam or one that works with stock springs.  I assume the springs sold by APE and CycleX are "better", but will they increase valve train wear?  It looks like OEM is still available, so that's an option.

Also, similar question on the cam chain.  I'm planning of replacing mine and I'm wondering if the ones sold by APE,CycleX,M3 are they way to go.  I assume they're better, but is there any downside to using them over stock (maybe it weighs more... increase wear?)

I appreciate the feedback,
Chris
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline killersoundz

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Re: Recommendation on valve springs and cam chain
« Reply #1 on: September 03, 2012, 10:02:29 AM »
Personally, unless you're building a hot motor to run at redline all the time I'd reuse these.
My project thread:

http://forums.sohc4.net/index.php?topic=107447.0

My CB750K4 Starting up for the first time after a seized motor and rebuild!


Offline Kickstart

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Re: Recommendation on valve springs and cam chain
« Reply #2 on: September 10, 2012, 08:05:28 AM »
Just wanted to bump this...

Looking for spring recommendations (aftermarket or OEM?)
APE, CycleX, Dynoman, OEM....  what are others using and how do you like them? What are the pros/cons with using the aftermarket ones?

Killersoundz, I appreciate your advice, but I decided for peace of mind I'm going to replace the springs.

Thanks
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Recommendation on valve springs and cam chain
« Reply #3 on: September 10, 2012, 08:31:21 AM »
Use the Tsubaki cam chain. Inexpensive and stronger. That's probably what everyone you mention supplies. It doesn't say Tsubaki on the box, forgot  what it's labeled as.  Camilla I believe. They run around $35.

While Killers advice about springs is sound it doesn't take a hot motor running at redline to destroy an engine, it takes the vehicle operator. My 750F was very strong and only 1 year old when I missed a 1 to 2 power shift and floated a valve at maybe 12,000 rpms into my piston which destroyed the engine. Yes, I rebuilt and used high performance springs to better control the movement of the valve. ie close when it's supposed to close. It ain't happened since after an additional 25,000 miles of abuse and I also cammed it and punched it out during the rebuild. Don't worry about additional valve train wear as you will not likely put nearly enough miles on one of these to notice. I didn't mic mine before and after but it looked pretty good when I took it apart. I had one rocker that showed more wear than the others. Use a good oil and change it at the orrect intervals.

Good chance all the springs you mention are made by APE. Kibblewhite would be a good choice too. I have no idea what the compression rates of any of the springs are.
« Last Edit: September 10, 2012, 08:34:58 AM by Jerry Rxman Griffin »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline MRieck

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Re: Recommendation on valve springs and cam chain
« Reply #4 on: September 10, 2012, 09:40:18 AM »
Use the Tsubaki cam chain. Inexpensive and stronger. Use a good oil and change it at the correct intervals.

Good chance all the springs you mention are made by APE. Kibblewhite would be a good choice too. I have no idea what the compression rates of any of the springs are.
Zinc additve helps too.
Owner of the "Million Dollar CB"

Offline Rgconner

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Re: Recommendation on valve springs and cam chain
« Reply #5 on: September 10, 2012, 11:58:48 AM »
Rummaging around in the back of my head on this one, perhaps a wiser head will confirm or deny:

Stronger springs will wear the rocker arms faster unless they are also treated.
And those things are like hen's teeth to find...
1975 CB550K aka "Grease Monkey"

Offline MRieck

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Re: Recommendation on valve springs and cam chain
« Reply #6 on: September 10, 2012, 02:58:44 PM »
Rummaging around in the back of my head on this one, perhaps a wiser head will confirm or deny:

Stronger springs will wear the rocker arms faster unless they are also treated.
And those things are like hen's teeth to find...
Stiffer springs will have more of an impact on rocker arms, valve tips, guides and cam noses. There are many, many used rocker arms out there....I probably have over 100. New rockers are still available as well.
Owner of the "Million Dollar CB"

Offline Kickstart

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Re: Recommendation on valve springs and cam chain
« Reply #7 on: September 10, 2012, 07:46:23 PM »
How much increased wear are we talking about? 
Not sure if there's an easily quantifiable answer to my question.

I don't really want to give up much reliability/longevity with my build.  I want this bike to last a long time before I need open her back up. 

I do understand there's a trade-off with performance here.. I just want to make an informed decision.

Thanks!



- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline Kickstart

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Re: Recommendation on valve springs and cam chain
« Reply #8 on: September 12, 2012, 10:06:06 PM »
I guess Mike answered my question about 5 years ago:  :)
http://forums.sohc4.net/index.php?topic=27162.msg277759#msg277759

And, Jerry, from your post above, it sounds like you've been running the HD springs for a  20+ years with no issues.

OK... Mike, Jerry, I'm taking your advice and ordering the APE springs...

Thanks guys!
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA