Author Topic: Camshaft Questions  (Read 5592 times)

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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Camshaft Questions
« Reply #25 on: November 04, 2014, 10:05:56 PM »
If you aren't a patient information sponge it will get more expensive real fast and very time consuming.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

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Re: Camshaft Questions
« Reply #26 on: November 04, 2014, 10:34:57 PM »
I understand your mental dilemma. This scared the #$%* outta me too. Too complex/complicated it seemed after reading all the instructional gobbledy gook. After I did it it was a '#$%*, why did that need to SEEM so complicated?!' moment. HOWEVER you need to do this if you're using a high performance cam. I lucked out my first time when I just slapped that Yoshimura Daytona cam in and aligned it like the stocker. No valves hitting pistons but it probably would have run that much better had I done it the RIGHT WAY!

Get that degree wheel Bodi says from Dynoman, APE, etc. A piece of coathanger is what I used for a pointer. Bent a loop and stuck it under a 6mm bolt. At TDC the pointer should be bent to read '0' on the degree wheel. I got a dial gauge and a magnetic base from Harbor Freight. I used a 3" L shaped metal corner shelf brace from Lowes to mount the magnetic stand on. I attached it to the top of the head using one of the valve cover holes and a 6mm bolt. Put the stand on the brace and the dial indicator on the stand. Position it as close as possible parallel to the valve stem above the spring keeper and it's 'pointer' touching the keeper to measure the lift of the valve. When the valve starts to open that is zero on your dial gauge which should correspond to 37 degrees BTDC on the degree wheel. You should have the lash set correctly at this point. You'll rotate the cam shaft slotted sprocket to make the adjustment of the cam to crank to obtain the beginning opening at 37 BTDC. ETC. ETC. ETC. Lock down the 2 bolts in the cam sprocket then rotate it 2 turns and recheck everything. If not on the money do it again. You only have to do this on one cylinder!  :)

Use this, Bodi's explanation and the instructions you have and just play with all this until it starts to sink in to your way of thinking. I'd bet that Dynoman's instructions are Webcam's? If not go to their site also to study. Do NOT get in a hurry. This is probably the most complicated procedure you'll have to do BUT when you get it and look back you'll probably say 'that was a pain in the ass' AND 'that was really much easier now that I see WTF I'm doing'.

Bodi says to use the degree wheel on the alternator rotor. I used the points shaft on the other end. Either will do, just depends on the hole size in the wheel. What you are attempting to do is to set the timing of the cam with the crank so the cam opens the valves the correct amount at the right time so that the valves don't kiss the piston and you get the most performance from your engine.

Lot easier the second time  ;D

This explanation is definitely a step in the direction of me understanding Degreeing. Thanks again Jerry!

Looks like I'm going to have to just jump into this and pound my head against the wall until I have that "eureka" moment.

I am wondering why a new hp cam made for this specific engine would have the timing notch marks on the end, like the stock cam, if you end up having to degree the cam yourself thus making those marks obsolete?





The factory markings indicate the point at which the piston is at tdc and the valves should be closed for cylinder #1.
It's the starting point for installation. If the cam is installed a tooth off one way or the other, the mis match of the
marks will be glaringly obvious. Once you do the actual adjustment to "time" the lift events of the valves according to the
cam manufacturer's specifications, you may notice that the factory timing marks are still fairly close. A few degrees difference
in when valve events occur can make a BIG difference in the way the engine behaves.

Offline PeWe

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Re: Camshaft Questions
« Reply #27 on: November 05, 2014, 03:04:47 AM »
I timed a cam for first time last year. Earlier head lifts during the 80's I mounted the cam sprocket according to marks my local tuner had done in sprocket and cam. No timing needed.

The timing process took rather long time when I double checked the result to be very sure about the correct procedure. I think my new pistons broke in manually during this process. It's much easier now when I have timed some times the last year.

The photos below show timing since I have mounted the restored head. Check cam sprocket bolts, if it is close to cam holder head.
Next time without removing the carbs.
Tank off
Frame kit off (I had no coils in first session, did it later without removing the coils.)
Head cover off
Free access to cam. Change cam is easy.

This need carbs off:
Remove head, cylinder, pistons or whatever needed without draining the oil ::)
« Last Edit: November 05, 2014, 12:51:41 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Lazerviking

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Re: Camshaft Questions
« Reply #28 on: November 09, 2014, 11:36:23 AM »
Alrighty, so I'm feeling a little more confident in this procedure and I ended up biting the bullet and purchasing a proform universal degreeing kit that should be here midweek. I'm sure I'll have more questions when I get into it but right now I'm wondering what other components will need to be adapted because of the hp cam I'm installing. Such as my carbs? I've been told I'll need to jet my carbs to get the proper fuel mixture. Is there anything else that will need some attention because of my cam?

Offline 70CB750

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Re: Camshaft Questions
« Reply #29 on: November 10, 2014, 04:06:05 AM »
Great illustration PeWe!

Only thing, I would use the alternator side nut to turn the engine to make sure I dont bend the little bolt on the right side.
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