Author Topic: Adjusting tappets / valves Help (Read 8786 times)

Garryk · « **on:** April 19, 2013, 05:35:40 AM »

Hi,im looking to set tappets/valves through the tappets hole,i was wondering if anyone could give me a step to step guide on how to set them.
1975 CB750 K5
Ride safe and Enjoy

70CB750 · « **Reply #1 on:** April 19, 2013, 05:42:36 AM »

If you dont have it, download a manual. Follow instructions in the manual, that's the easiest way.

Manuals:

http://forums.sohc4.net/index.php?topic=17788.0

ekpent · « **Reply #2 on:** April 19, 2013, 06:22:41 AM »

It really is quite easy if you follow the manual,easier with the gas tank off also which is also easy to remove. Very nice looking bike by the way. Welcome to the fun.

Dream750 · « **Reply #3 on:** April 19, 2013, 06:39:13 AM »

Garry, Welcome to the forums.

Here’s how the Honda owners manual shows valve adjustment on your 750 K5 and it's done on a cold engine:

70CB750 · « **Reply #4 on:** April 19, 2013, 06:56:11 AM »

Offset 10mm wrench helps a lot.

Garryk · « **Reply #5 on:** April 19, 2013, 07:39:35 AM »

Many thanks to everyone for their help.
Dream750,just wondering what manual you got the instructions from,i own a Haynes manual but its only seems to show how to strip the bike down,hope I can following your instruction ok :
Respects to you all for your help and kind words.
Garryk

70CB750 · « **Reply #6 on:** April 19, 2013, 07:45:51 AM »

Quote from: Garryk on April 19, 2013, 07:39:35 AM

Many thanks to everyone for their help.
Dream750,just wondering what manual you got the instructions from,i own a Haynes manual but its only seems to show how to strip the bike down,hope I can following your instruction ok :
Respects to you all for your help and kind words.
Garryk

Honda CB750 SOHC CB 750 K F Service Repair Shop Manual 1969 - 1978 from the link I posted above.

Dream750 · « **Reply #7 on:** April 19, 2013, 08:02:20 AM »

Quote from: Garryk on April 19, 2013, 07:39:35 AM

Many thanks to everyone for their help.
Dream750,just wondering what manual you got the instructions from,i own a Haynes manual but its only seems to show how to strip the bike down,hope I can following your instruction ok :
Respects to you all for your help and kind words.
Garryk

The instructions come from the Honda Owners Manual which is found under the seat in a separate compartment. It’s circled in white in the first photo. Honda originally equipped your bike with the owners manual and tool kit. Many are now missing.

Reproduction owners manuals can be found on eBay as in the second photo, lots of good info found in those manuals.

richvageologist · « **Reply #8 on:** April 19, 2013, 08:05:31 AM »

When I did mine the first time, I read the manual and also found this website to be useful.

http://www.salocal.com/sohc/tech/vlvadj/vlv.htm

MCRider · « **Reply #9 on:** April 19, 2013, 08:13:47 AM »

Quote from: 70CB750 on April 19, 2013, 06:56:11 AM

Offset 10mm wrench helps a lot.

Where'd you get that wrench? Cute!

Looks like it fits the hand better than a standard box wrench.

70CB750 · « **Reply #10 on:** April 19, 2013, 08:21:14 AM »

Got a whole set from Sears, it works great with the valve cover hole.

MCRider · « **Reply #11 on:** April 19, 2013, 09:17:20 AM »

Quote from: 70CB750 on April 19, 2013, 08:21:14 AM

Got a whole set from Sears, it works great with the valve cover hole.

Thx!

iron_worker · « **Reply #12 on:** April 19, 2013, 09:32:41 AM »

It's a simple process.

1) Remove the gas tank (not necessary but does make it much easier)
2) Remove the 8 tappet covers
3) Remove the points cover
4) Using the large hex (17mm? 19mm?) turn the engine over clockwise until you see the T-F 1-4 marking and line up the marking to the "T".
5) Both pistons 1 and 4 are now at top dead center (TDC) and you must detmerine which one is on the compression stroke. To do this you can either look at the cam (if the lobes are both down it is on compression stroke ... if they are both up it is on exhaust/intake stroke). If you can't see the cam then just wiggle the rocker arms with your hand. The cylinder that has both rocker arms loose is on the compression stroke. - Adjust both intake and exhaust valve clearance to the values given in the manual using a feeler gauge to measure.
6) Turn the crank over 360 degrees clockwise (always clockwise) until the T lines up again on the T-F 1-4 mark. If you adjusted cylinder 1 in the previous step then you can now adjust cylinder 4 or vice versa.
7) Turn the crank clockwise again until you see the T-F 2-3 mark and line up the pointer with the T.
8.) As per step 5, check which cylinder is on the compression stroke. Adjust valve clearance of the cylinder that is on the compression stroke.
9) Turn the crank over 360 degrees clockwise (always clockwise) until the T lines up again on the T-F 2-3 mark. If you adjusted cylinder 2 in the previous step then you can now adjust cylinder 3 or vice versa.
10) Ensure all locknuts are tight. Replace all tappet covers.
11) Replace fuel tank and reconnect fuel lines.
12) Enjoy

For actually adusting the clearance of a tappet:
1) Loosen locknut
2) Slip in feeler gauge of correct size (as per manual specification) between valve stem tip and rocker arm tip.
3) Use flat blade screwdriver to adjust the rocker arm tip until there is only a very slight drag of tension on the feeler gauge
4) Lock the locknut
5) Recheck that the feeler gauge still has a slight drag when inserted between the valve and rocker. Sometimes tightening the locknut can disturb this.
6) Repeat 1-5 until the the feeler gauge has slight drag of tension when pulled between the valve and rocker tip when the locknut is tight.

IW

Garryk · « **Reply #13 on:** April 19, 2013, 03:39:56 PM »

Read all your info and have taken everything in,cant thank you all enough for your help,plus the time you have all taken to answer this thread

.
Just bought my CB750 few weeks ago and want to fine tune her.
Respects
Garryk

Garryk · « **Reply #14 on:** April 21, 2013, 11:37:32 AM »

I set the clearance of the tappets today,bit tricky trying to work in such small a space to check with feeler gauges,just hope ive done them correct,well started the bike and let her run a while and notice a small decrease noise from the engine,still gives me a peace of mind knowing I tried

.
Thanks everyone for your help
Garryk

mikejorg · « **Reply #15 on:** April 22, 2013, 09:26:49 PM »

What kind of noise is coming from the engine?

flybox1 · « **Reply #16 on:** April 22, 2013, 09:55:12 PM »

Probably a slack cam chain. You'll get to that point. Move on to timing and advance chec/adjustments.
Many noises quiet with the final step...vacuum sync.

neilc · « **Reply #17 on:** April 24, 2013, 05:00:58 PM »

i have no points plate cause i have a old electronic ignition,with no markings,that i can see threw the window,can i just rotate the crank till tappets go up all the way then adjust

dave500 · « **Reply #18 on:** April 24, 2013, 05:14:46 PM »

with no index marks you can watch an inlet valve as it closes when you rotate the engine,then with care insert a screw driver or other probe into that cylinders spark plug hole,continue turning the engine over and watch the screw driver rise the last little amount untill it stops rising and sarts to fall again,that position is then tdc compression for that cylinder,set your tappets here.

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Author Topic: Adjusting tappets / valves Help (Read 8786 times)