Author Topic: How to adjust valves on a 350 twin?  (Read 2536 times)

0 Members and 2 Guests are viewing this topic.

blantonator

  • Guest
How to adjust valves on a 350 twin?
« on: September 18, 2007, 08:34:32 PM »
i hear what appears to be some valve noise and figure the valves need to be adjusted.  How do i do it?  what tools do i need?  Also i've heard people talk about the cam tensioner... what is this?

Thanks

Offline dustyc

  • I don't know why anyone would call me an
  • Expert
  • ****
  • Posts: 1,141
  • 1977 CB750K
Re: How to adjust valves on a 350 twin?
« Reply #1 on: September 18, 2007, 09:18:51 PM »
CB/CL250 - CB/CL/SL350  Shop Manual: http://www.mediafire.com/?5jygmwxxzoc

pg. 33 of the manual (pg. 46 of the PDF)
1977 CB750

Offline mikedialect

  • cbjunky
  • Expert
  • ****
  • Posts: 769
    • Mike's Metric Vintage Honda
Re: How to adjust valves on a 350 twin?
« Reply #2 on: September 18, 2007, 09:53:05 PM »
definitely get the manual.

Adjusting the valves is pretty easy. I prefer to have the tank off, though.

SOHC4 Member#44153  
www.mikesmetric.com | www.mikedialect.com

Offline mikedialect

  • cbjunky
  • Expert
  • ****
  • Posts: 769
    • Mike's Metric Vintage Honda
Re: How to adjust valves on a 350 twin?
« Reply #3 on: September 18, 2007, 09:55:10 PM »
if you right click that image you can pick view image and see it in it's full size. The board makes it smaller.
SOHC4 Member#44153  
www.mikesmetric.com | www.mikedialect.com

blantonator

  • Guest
Re: How to adjust valves on a 350 twin?
« Reply #4 on: September 19, 2007, 05:17:31 AM »
ah good, doesn't look too tough, but where can I can get a thickness gauge?

also it says check that the rocker arm is "free".  what do they mean by this?

Offline mikedialect

  • cbjunky
  • Expert
  • ****
  • Posts: 769
    • Mike's Metric Vintage Honda
Re: How to adjust valves on a 350 twin?
« Reply #5 on: September 19, 2007, 06:31:07 AM »
ah good, doesn't look too tough, but where can I can get a thickness gauge?

also it says check that the rocker arm is "free".  what do they mean by this?

a parts store.

When you have it set for one cylinder, with the valve cap off, the rocker arm will move up and down.
SOHC4 Member#44153  
www.mikesmetric.com | www.mikedialect.com

Offline dustyc

  • I don't know why anyone would call me an
  • Expert
  • ****
  • Posts: 1,141
  • 1977 CB750K
Re: How to adjust valves on a 350 twin?
« Reply #6 on: September 19, 2007, 09:25:24 AM »
They might look at you funny if you ask for a thickness gauge at the parts store.  Most people call them feeler gauges.
1977 CB750

blantonator

  • Guest
Re: How to adjust valves on a 350 twin?
« Reply #7 on: September 19, 2007, 07:50:58 PM »
So i'm kind of stuck here. 

Well first of all three screws for the generator cover stripped (awesome) ... than when i got them off, oil spilled all over me (awesomer).

So i lined up LT with the top left marker and im left with a few problems.

I think i might done a few bad things... First of all i turned the generator clockwise... but turned it counterclock wise to line it up.  not sure if this a problem?

Second thing i did was i turned the rocker arm adjuster left and right more than one whole turn and don't know where orignally was.  I noticed that if i turned it in one direction the rocker would go up and than down.

What i can't figure out is, where am i measuring?  The feeler gauges doesnt seem to slip in anywhere?

Please help!

Ben

Offline mikedialect

  • cbjunky
  • Expert
  • ****
  • Posts: 769
    • Mike's Metric Vintage Honda
Re: How to adjust valves on a 350 twin?
« Reply #8 on: September 19, 2007, 11:16:49 PM »
So i'm kind of stuck here. 

Well first of all three screws for the generator cover stripped (awesome) ... than when i got them off, oil spilled all over me (awesomer).

So i lined up LT with the top left marker and im left with a few problems.

I think i might done a few bad things... First of all i turned the generator clockwise... but turned it counterclock wise to line it up.  not sure if this a problem?

Second thing i did was i turned the rocker arm adjuster left and right more than one whole turn and don't know where orignally was.  I noticed that if i turned it in one direction the rocker would go up and than down.

What i can't figure out is, where am i measuring?  The feeler gauges doesnt seem to slip in anywhere?

Please help!

Ben

You put the feeler gauge in between the rocker arm and the valve to measure the distance between them. If you turned it the wrong way you just have to turn it back to the proper spacing for that valve. At this point it does not matter 'where it originally was'. You just need to get them to spec. Take a longer read of that picture I posted up here- and as I've been saying to people in class lately- read it until you can explain it to me :) If you're still lost- let me know.
SOHC4 Member#44153  
www.mikesmetric.com | www.mikedialect.com

blantonator

  • Guest
Re: How to adjust valves on a 350 twin?
« Reply #9 on: September 20, 2007, 05:41:36 AM »
Ok well i figured out what the problem was.  When LT is 10* ATDC the left exhaust valve(the one i was starting with) is closed; hence the feeler not slipping through.  I moved LT approx. 90* and the valve appears to be open and i can easily adjust it with the feeler gauge.  Unfortunetly this seems to contradicted the manual, as it says the left valves should be open at 10*.   What gives.

blantonator

  • Guest
Re: How to adjust valves on a 350 twin?
« Reply #10 on: September 20, 2007, 07:34:37 PM »
well i finally figured it all out, and she is much quieter.  even feels a little peppier

Offline Gordon

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 12,114
  • 750K1, 550K2
Re: How to adjust valves on a 350 twin?
« Reply #11 on: September 21, 2007, 04:13:08 PM »
Ok well i figured out what the problem was.  When LT is 10* ATDC the left exhaust valve(the one i was starting with) is closed; hence the feeler not slipping through.  I moved LT approx. 90* and the valve appears to be open and i can easily adjust it with the feeler gauge.  Unfortunetly this seems to contradicted the manual, as it says the left valves should be open at 10*.   What gives.

You seem to be reversing the terms "open" and "closed" in reference to the valves.  When the valve is open, the rocker arm is pushing down on top of it, holding it open, so you won't be able to move the rocker arm or insert a feeler gauge.  When the valve is closed (it's resting state) the rocker arm should be able to move a little bit, and you should be able to insert the feeler gauge between the top of the valve and the rocker arm. 

Offline crazypj

  • I'm brill, me
  • Old Timer
  • ******
  • Posts: 4,467
  • first 100,000 miles. 1977 CB550F
Re: How to adjust valves on a 350 twin?
« Reply #12 on: September 23, 2007, 07:08:27 PM »
Easiest thing to do. rotate generator rotor counter clock,with valve adjuster caps off. watch the intake valve. It goes down, it comes up, your on you way to top dead center compression. set valves with feeler between rocker arm and valve tip,  2 thou intake and 4 thou exhaust. 3 shouldn't go in intake,2 should be loose sliding fit (3 and 5 on ex. side)
rotate crank and do same for other side.
PJ
I fake being smart pretty good
'you can take my word for it or argue until you find out I'm right'