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The OBSERVED Valve Clearance thread
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beardyweirdy@me.com Offline
Running Like a Top

London
Posts: 395
Joined: Aug 2014
Post: #21
RE: The OBSERVED Valve Clearance thread
I left it as is. The fact that the next morning was the first sunny day in ages and I'd arranged a burn out with my mate, who'd just bought a new Bonnie T120, might have had some thing to do with it ;-)

I have to agree with 736, as well as Ulvetanna. Not worth the risk and a tad loose isn't such a bad thing.

I'll see if they move any more next year...
02-17-2018 03:19 PM
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Ulvetanna Away
Road Warrior

USA
Posts: 1,696
Joined: Apr 2016
Post: #22
RE: The OBSERVED Valve Clearance thread
(02-17-2018 03:19 PM)beardyweirdy@me.com Wrote:  I left it as is. The fact that the next morning was the first sunny day in ages and I'd arranged a burn out with my mate, who'd just bought a new Bonnie T120, might have had some thing to do with it ;-)

I have to agree with 736, as well as Ulvetanna. Not worth the risk and a tad loose isn't such a bad thing.

I'll see if they move any more next year...
Sounds about right, see what they look like next checkup.
02-17-2018 08:21 PM
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max Offline
Road Warrior

Auckland New Zealand
Posts: 1,545
Joined: Sep 2017
Post: #23
RE: The OBSERVED Valve Clearance thread
Clearance at 17.000 km ( first time check ) cb1100 2010 japan import with 7.500 after 7 years.
Used 300 cc. oil over 5.000 km but has used 75 cc since last change ( both times full synthetic ).
Everything looked pristine and shiny, no oil deposits anywhere, very clean inside.
There is a bit of residual oil stuck between the cam lobes and the buckets that has to be good for first startup lubrication, nice bonus, and the cover went on much easyer than taking it out, the coil spade connectors rubber boots go much easyer on with a little grease on the inside of the rubber boots and protect the connectors from water over the little edges on the coil terminals.

spec; ex 0.28 in 0.15 +/- 0.03 mm.


#1 - exhaust .28,.28 intake .16,.17
#2 - exhaust .28,.28 intake .15,.16
#3 - exhaust .27,.27 intake .18,.18
#4 - exhaust .28,.28 intake .16,.15

No adjustment needed.

max

sometimes i get lucky, and the more i practice the luckier i getCool
and; It's always something simple......just not always simple to find.
2020 cb1000r chromos red
2010 cb1100 candy red
2006 cb919 hornet black
1977 cb550 k3 1st owner
(This post was last modified: 05-10-2018 01:37 AM by Cormanus.)
03-14-2018 07:35 PM
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DaSwami Offline
Running Like a Top

Northwest Montana (again!)
Posts: 467
Joined: Jun 2015
Post: #24
RE: The OBSERVED Valve Clearance thread
OK, I have a question. People refer to these measurements as "loose" or "tight", assuming that the larger measurements mean loose and the smaller mean tight. I always assumed that meant the valve didn't open very much when tight and opened more when loose. However someone explained to me the opposite is true, what we are measuring is valve LASH, the distance between the tip of the lifter or cam lobe and the rocker arm? So that a wider gap means the valve opens LESS because the lifter/lobe has to move further before it contacts the rocker and moves the valve. A smaller gap means that the lifter/lobe contacts the rocker quicker and therefore opens the valve MORE as they move through their travel. Does this make sense?
03-15-2018 03:28 AM
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jimgl3 Offline
High Mileage

Covington, Ga
Posts: 790
Joined: Apr 2015
Post: #25
RE: The OBSERVED Valve Clearance thread
Ult, can't the shims be fished out without pulling the cams? or is that not possible with this motor?
03-15-2018 04:44 AM
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redbirds Offline
Been There

Patterson, GA, USA
Posts: 4,591
Joined: Jan 2014
Post: #26
RE: The OBSERVED Valve Clearance thread
(03-15-2018 04:44 AM)jimgl3 Wrote:  Ult, can't the shims be fished out without pulling the cams? or is that not possible with this motor?

In this motor the shims are under the "buckets" atop the valves. The cam shafts must be removed in order to access. On an engine with the shims on top they are removed easily by compressing the valve spring and pulling them with a magnet.

(03-15-2018 03:28 AM)DaSwami Wrote:  OK, I have a question. People refer to these measurements as "loose" or "tight", assuming that the larger measurements mean loose and the smaller mean tight. I always assumed that meant the valve didn't open very much when tight and opened more when loose. However someone explained to me the opposite is true, what we are measuring is valve LASH, the distance between the tip of the lifter or cam lobe and the rocker arm? So that a wider gap means the valve opens LESS because the lifter/lobe has to move further before it contacts the rocker and moves the valve. A smaller gap means that the lifter/lobe contacts the rocker quicker and therefore opens the valve MORE as they move through their travel. Does this make sense?

Exactly.

1 Cor 13:4-7 (NIV)
4 Love is patient, love is kind. It does not envy, it does not boast, it is not proud. 5 It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. 6 Love does not delight in evil but rejoices with the truth.
(This post was last modified: 03-15-2018 05:25 AM by redbirds.)
03-15-2018 05:19 AM
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SportsterDoc Offline
High Mileage

New Mexico
Posts: 1,447
Joined: Nov 2017
Post: #27
RE: The OBSERVED Valve Clearance thread
(03-15-2018 05:19 AM)redbirds Wrote:  In this motor the shims are under the "buckets" atop the valves. The cam shafts must be removed in order to access. On an engine with the shims on top they are removed easily by compressing the valve spring and pulling them with a magnet.

Succient explanation, redbirds.

Although a time consuming adjustment, when actually needed, the first link may help explain why Honda used the shim under bucket design:

https://paradiseracing.com/blog/why-shou...r-buckets/

The second link has a good comparison photo:

http://www.koracing.net/productimages/Buckets.jpg

23 Guzzi V7 SE 23 Yam XT250
18 Yam Bolt 22 Triumph St Twin 20 CanAm Ryker
14 Honda CB1100 18 Yam XT250 16 Guzzi V7II
17 Yam TW200 12 Triumph Bonnie 02 Sportster 1200S
03 Sportster 883 76 Honda CB750F 75 Honda CB360
70 Yam CT1 72 Yam CT2 72 Yam AT2
70 Honda SL350 70 Honda CL350 67 Honda CL160
67 Honda CB16062 Honda CA110
(This post was last modified: 03-15-2018 08:17 AM by SportsterDoc.)
03-15-2018 08:16 AM
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736cc Offline
Running Like a Top

NY
Posts: 322
Joined: Aug 2013
Post: #28
RE: The OBSERVED Valve Clearance thread
Shim under bucket has a MUCH less chance of “tiddlywinking” when over-revved.
Shim under bucket has MUCH less wear on associated parts which equates to not going out of spec for valve clearance.
Shim under bucket is MUCH more involved to adjust clearance.
Shade tree mechanics probably risk doing more harm than good and should not remove cams in super skillfully built professional factory built engines, and trusting someone else to do so has its risks as well. They are PERFECT from the get-go.
Only abused, over-revved, dirty oil, high mileage modern Japanese motors ever require valve adjustment. Even then, they won’t break or have catastrophic failure. Motocross singles are the exception, they need regular adjusting and rebuilding.
(This post was last modified: 03-15-2018 12:05 PM by 736cc.)
03-15-2018 11:52 AM
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Houtman Offline
Been There

NC USA
Posts: 4,481
Joined: May 2013
Post: #29
RE: The OBSERVED Valve Clearance thread
Thank you for saving us money .

(03-15-2018 08:16 AM)SportsterDoc Wrote:  
(03-15-2018 05:19 AM)redbirds Wrote:  In this motor the shims are under the "buckets" atop the valves. The cam shafts must be removed in order to access. On an engine with the shims on top they are removed easily by compressing the valve spring and pulling them with a magnet.

Succient explanation, redbirds.

Although a time consuming adjustment, when actually needed, the first link may help explain why Honda used the shim under bucket design:

https://paradiseracing.com/blog/why-shou...r-buckets/

The second link has a good comparison photo:

http://www.koracing.net/productimages/Buckets.jpg
My CBX's had shim over bucket (24 !) but I never had problems because I never over revved the engines , they were quite easy to change with the right tools.
(This post was last modified: 03-15-2018 02:03 PM by Cormanus.)
03-15-2018 12:40 PM
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Wisedrum Online
High Mileage

Germany
Posts: 1,063
Joined: Feb 2015
Post: #30
RE: The OBSERVED Valve Clearance thread
Here' s another article with good explanation and illustration.

https://www.revzilla.com/common-tread/wh...-adjusters


Wisedrum
03-15-2018 12:59 PM
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