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Technical Help Forum
Started by CHIANGMAICXMAN at 05-21-2010 4:25 AM. Topic has 30 replies.
  
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 05-21-2010, 4:25 AM
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CHIANGMAICXMAN
 
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Valve Adjustment (again) but with a twist....hot vs cold
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OK OK already. I know this is probably going open a can of worms and all, but.....
The way I understand it, adjusting Cold at .08 and .10 mm allows for thermal expansion of the relative engine parts to create a tighter, i.e. closer tolerances. Probably the part to experience this 'expansion' the greatest, assuming the theory is correct, would be the Rods between the Cam Followers and the Rocker Arms themselves. Am I correct or at least semi correct on this point?
When DEAD COLD the tolerances are the loosest and when at normal operating temp (170 or so) the tightest and the Tappets (theoretically) should be just riding off the Valve Stems by a small amount and thus the sweet barely tapping sound we should expect. Has anyone actually measured the tolerance on a 'proper' engine? Would it be .06 and .08 or exactly what?
I ask this because in trying to isolate engine noise, I decided to adjust the Tappets while HOT HOT HOT. I tightened the tappets just tight to the stems and then backed them off about a 1/4 turn (inlet) and 1/3 turn (exhaust). They, the rockers, were still clicking/tapping just a bit against the valve stems. I buttoned things up again, started the engine and OH MY the sound was sweet. Previously, adjusting cold, things just got louder and louder as the engine warmed.
Still there was a bit of an odd sound out of the right head, but at least it helped to potentially isolate where a problem might exist.
Another related question: I realize tappets are hardened steel, but do they loose hardness as the wear down?
I anxiously await your responses.......
Mark
GL400 (79-83 bits and pieces)
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05-21-2010, 4:31 AM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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05-21-2010, 5:15 AM
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spanish bandit
Joined on 02-12-2009
southern spain
Posts 5,010
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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i would have thought,if you adjusted the tappets on a very hot engine,theoretically you are doubling the gap[when the engine cools] given in the manual.which is obviously wrong
when i feel the need,i do it,llego,ve 60,s
-----------------------------
2008.1982 honda gli silverwing [uk model ]
2010.1981 honda gli silverwing [uk model ]
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05-21-2010, 6:06 AM
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CHIANGMAICXMAN
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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 spanish bandit wrote: | i would have thought,if you adjusted the tappets on a very hot engine,theoretically you are doubling the gap[when the engine cools] given in the manual.which is obviously wrong
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Bandito--
Yes, agreed. If I adjusted the tappets to spec while hot they would, presumably, be way over spec when the engine is cold. However, if I recall correctly, the tappets have a 1.8mm thread pitch. Thus, 1 full revolution would create a gap of 1.8mm between the tappet and valve stem. I adjusted to 1/4 and 1/3 revolution inlet/exhaust respectively. That, at least in theory, should give me a gap of about 0.045 and 0.06mm. Correct me if I'm wrong, please....
Shep-
Yes, I know every manual everywhere says do it cold. I've done it cold many times and the engine starts out sounding fine then as I warms up it starts clattering badly. That's why I decided to take the unconventional route and do it hot.
As for the tappets wearing, I know they do. I'm just wondering if they loose hardness as they loose length because some just don't hold the cold 'spec' gap.
I am also aware of the potential of the Exhaust Valve burning syndrome and am watching temperatures carefully.
Thanks for the replies. I kinda figured this would possible open pandora's box.....
Any guestimates on what the gap(s) would or should be when HOT HOT HOT?
Mark
GL400 (79-83 bits and pieces)
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05-21-2010, 6:20 AM
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spanish bandit
Joined on 02-12-2009
southern spain
Posts 5,010
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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mark,id guess honda did their homework,both on hot and cold engines prior to production.
so,id guess on a fully warmed up engine[when brand new,not allowing a wear factor]...there would be no gap.
the metal rate of expansion would be a constant....therefore,its lodgical...gap when cold,no gap when hot
when i feel the need,i do it,llego,ve 60,s
-----------------------------
2008.1982 honda gli silverwing [uk model ]
2010.1981 honda gli silverwing [uk model ]
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05-21-2010, 6:25 AM
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Doward
Joined on 05-11-2008
Alachua, FL
Posts 814
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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Adjusting the valves when fully heated up is fine. You actually should have as close to zero lash when heated up as possible.
The problem is, if your engine ever runs any hotter than the exact temperature your engine is at when you adjusted the valves, you'll have a 'hanging' valve that won't completely close, and thus will lose power.
Optimally, you'd want to do it on the hottest day of the year, and block off the radiator so that you slightly over-heat the engine (get it up to 200-220F) and THEN do your hot adjustment! That would seriously reduce the risk of you not having enough lash on a 115F day, lol
Besides, no OEM wants to deal with the lawsuits of idiots grabbing a hot exhaust and claiming OH THE MANUAL SAYS TO DO IT WHEN HOT!
*edit*
Spanish, that is correct - but Honda has to think about the guy overheating his CX in the middle of the desert, as well.
What I do is set lash when cold, run the engine up to temp, and re-check. I don't adjust when hot, I just check.
1978 CX500 motor + 1980 CX500C frame
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05-21-2010, 6:27 AM
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CXSarnia
Joined on 01-11-2008
Sarnia, Ontario, Canada
Posts 2,623
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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Spanish Bandit wrote: "I would have thought,if you adjusted the tappets on a very hot engine,theoretically you are doubling the gap[when the engine cools] given in the manual.which is obviously wrong"
The way he has suggested it, if he adjust the valves while hot, he's doing it to the point where the rocker just barely sits off the valve stem. (not to the recommended setting) but very much less. Thus, when the engine cools, it should return to the cold engine settings - or at least close to it. He then knows that due to the differences in engine components, he HAS the best clearance when the engine warms back up. This however, may be a problem if the engine ever OVERHEATS. If the hot tolerances are too close, they may then leave a valve open if overheated causing all kinds of problems.
2009 DN-01 Spakin' New!
1982 CX500 Turbo & Parts bike
1981 SL185 Yamaha Exciter
198? V45 Magna
1979 CX500 Deluxe
1982 CB750K Daily rider September 1999
1982 CX500 Custom - project Originally bought April 1982 safetied and on the road 09/2008
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05-21-2010, 6:38 AM
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spanish bandit
Joined on 02-12-2009
southern spain
Posts 5,010
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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loosing compression and possibly burning a valve out,its risky
when i feel the need,i do it,llego,ve 60,s
-----------------------------
2008.1982 honda gli silverwing [uk model ]
2010.1981 honda gli silverwing [uk model ]
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05-21-2010, 6:53 AM
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ramprat06
Joined on 03-22-2006
Vancouver WA USA
Posts 361
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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*insert scratch-the-head smiley here* Maybe my coffee hasn't hit full song, but here is what I don't get from the OP ""Previously, adjusting cold, things just got louder and louder as the
engine warmed."". If you set the gap when cold, then assume the heat will tighten the gap tolerance, why in the world would the tapping noise become more pronounced?? Shouldn't it become less, as the gap has supposedly closed to near nil due to the expansion??
Joel in the Couve
May the multitude of wheels in your head always control the two wheels between your legs.
1982 CX500 custom. 99% stock.
3rd owner
New to me, Spring '03 ~7k miles
Now, ~23k miles
Age 55
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05-21-2010, 6:58 AM
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chicagorandy
Joined on 05-28-2007
Chicago, IL
Posts 414
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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It is not a question that is answerable I'm thinking.
Decades of smarter folks than me have written manuals for all makes of bikes advising cold valve lash setting, using a feeler gauge, not 'turns' of the nut.
It is always possible that you are in fact wiser than them and have made a new engineering discovery.
Or not.
In the end it's your engine and you get to maintain it as you decide.
2003 Ural Tourist - 80,245kms to date
1982 Honda GL500 Interstate 12,800 miles since 05/30/07
"Down the highway of life at smiles per hour, with special attention to ignorant and blind cagers"
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05-21-2010, 7:26 AM
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CHIANGMAICXMAN
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| ramprat06 wrote: | *insert scratch-the-head smiley here* Maybe my coffee hasn't hit full song, but here is what I don't get from the OP ""Previously, adjusting cold, things just got louder and louder as the
engine warmed."". If you set the gap when cold, then assume the heat will tighten the gap tolerance, why in the world would the tapping noise become more pronounced?? Shouldn't it become less, as the gap has supposedly closed to near nil due to the expansion??
Joel in the Couve
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Joe,
That has had me scratching my head too. The only thing I can think of is the fact that the oil viscosity is near its maximum when cold and thus is dampening the sound. As the oil heats and thins, it has less sound dampening effect. You guys are a lot smarter than I, so I am just guessing. Perhaps something else is worn (cam lobes, followers) which when at N.O.T. (Normal Operating Temperature) is making the noise. I'm just trying to eliminate as many as possible one by one to get to and find that last noise.
The right Head still makes some noise, far better than before, but still some at between 35-5k RPM, perhaps its the Rocker Arm Shaft? I'll heat things up again and re-adjust the rockers to near nil gap and see where I am.
I knew this topic would spark some controversy........but I'm glad I did anyway.
Mark
GL400 (79-83 bits and pieces)
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05-21-2010, 9:17 AM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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Worn rocker arm bushes and rocker shaft will make it virtually impossible to correctly set tappets as will worn and incorrectly installed Cam-followers.
On two,"Basket Case" engines I've not only seen the cam-followers incorrectly installed but the,"Oil Orifice" installed upside down thus reducing the oil flow to the valve train causing premature wear of said components.
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05-21-2010, 11:56 AM
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CHIANGMAICXMAN
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| Shep wrote: | Worn rocker arm bushes and rocker shaft will make it virtually impossible to correctly set tappets as will worn and incorrectly installed Cam-followers.
On two,"Basket Case" engines I've not only seen the cam-followers incorrectly installed but the,"Oil Orifice" installed upside down thus reducing the oil flow to the valve train causing premature wear of said components.
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Shep,
Is there any way the ascertain the condition of the rocker arm bushings and/or shaft without removal of the head bolts? Twisting side to side, back and forth etc.? I've looked at your site and the swap of the shafts from inlet to exhaust may be an option if necessary.
I've looked down the rods at the cam followers, they appear to be installed correctly but I cannot tell the condition of the faces of either the followers or cam lobes. I assume it IS a heads off assessment, yes?
I have looked at the oil flow through the rockers during tick over and at low idle. I don't know what the flow amount should be, but it appears to be fairly liberal. I could post a video, if that would help. Is there any way to accurately gauge the oil pressure? Install an Oil Pressure gauge?
Finally, I am aware of the perils of adjusting the tappets while hot and others in this thread have pointed out additional issues/concerns to be aware of . I have been at my wits end to solve these noise issues and have turned to "thinking outside the box" and conventional wisdom to diagnose and rectify the issue.
I truly appreciate the vast knowledge and experience everyone brings to this forum to keep our rides running right.
Thanks again,
Mark
GL400 (79-83 bits and pieces)
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05-21-2010, 12:16 PM
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Mothman52
Joined on 09-23-2008
Berkeley, CA
Posts 785
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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Just curious...what is this mystery sound that you're trying to isolate? Is it anything besides tappet noise?
1982 CX500C in Metallic Black & Gray
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05-21-2010, 4:05 PM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| CHIANGMAICXMAN wrote: | | Shep wrote: | Worn rocker arm bushes and rocker shaft will make it virtually impossible to correctly set tappets as will worn and incorrectly installed Cam-followers.
On two,"Basket Case" engines I've not only seen the cam-followers incorrectly installed but the,"Oil Orifice" installed upside down thus reducing the oil flow to the valve train causing premature wear of said components.
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Shep,
Is there any way the ascertain the condition of the rocker arm bushings and/or shaft without removal of the head bolts? Twisting side to side, back and forth etc.? I've looked at your site and the swap of the shafts from inlet to exhaust may be an option if necessary.
I've looked down the rods at the cam followers, they appear to be installed correctly but I cannot tell the condition of the faces of either the followers or cam lobes. I assume it IS a heads off assessment, yes?
I have looked at the oil flow through the rockers during tick over and at low idle. I don't know what the flow amount should be, but it appears to be fairly liberal. I could post a video, if that would help. Is there any way to accurately gauge the oil pressure? Install an Oil Pressure gauge?
Finally, I am aware of the perils of adjusting the tappets while hot and others in this thread have pointed out additional issues/concerns to be aware of . I have been at my wits end to solve these noise issues and have turned to "thinking outside the box" and conventional wisdom to diagnose and rectify the issue.
I truly appreciate the vast knowledge and experience everyone brings to this forum to keep our rides running right.
Thanks again,
Mark
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So long as the oil flow seems ok then don't worry about that but no there's no way of inspecting the rocker bushes and shaft without loosening the head bolts which 99% of the time will crack the head gasket seal.
As per other post post a recording of the sound.
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05-21-2010, 6:05 PM
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Steve in WA
Joined on 08-02-2008
Port Orchard, WA
Posts 63
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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I't two bad that Honda chose not to use hydralic lifters in this engine design. That would have solved a lot of problems.
Steve
1982 GL500I
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05-21-2010, 7:23 PM
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BillRod
Joined on 11-09-2009
Richton Park, IL 33 miles SW of Chicago
Posts 350
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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I don't think you could run the engine at 10,000 rpm with hydraulic lifters or Honda probably would have done exactly that. Just a guess on my part. BillRod
71 years old (April 1939)
Richton Park, Illinois
Just bought 1982 GL500 Naked 13,000 miles
Never worry about theory as long as the machinery does what it is supposed to do.
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05-22-2010, 2:11 AM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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At the time these bikes were made hydraulic lifter technology wasn't up to the same standard as it is on todays machines and also Honda were trying to make a high revving push-rod engine.I for one am glad it's old technology.It cost a pal of mine over £1,000 UK to get his VFR Hydraulic lifters shimmed and serviced.I got two CX500s for well less than that!!
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05-22-2010, 2:14 AM
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CHIANGMAICXMAN
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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Shep wrote, "So long as the oil flow seems ok then don't worry about that but no
there's no way of inspecting the rocker bushes and shaft without
loosening the head bolts which 99% of the time will crack the head
gasket seal.
As per other post post a recording of the sound"
I'll post up another recording as soon as the very very welcome rains stops here.
As far as describing the particular noise, I'm trying to come up with series of definitions to cover the various anomalous sounds we might hear from our bikes, the taps, clicks, clanks, clunks, thunks, scrapes and grinds etc. Might be a good challenge that would help many members as well...
Mark
GL400 (79-83 bits and pieces)
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05-22-2010, 2:39 AM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| CHIANGMAICXMAN wrote: | Shep wrote, "So long as the oil flow seems ok then don't worry about that but no
there's no way of inspecting the rocker bushes and shaft without
loosening the head bolts which 99% of the time will crack the head
gasket seal.
As per other post post a recording of the sound"
I'll post up another recording as soon as the very very welcome rains stops here.
As far as describing the particular noise, I'm trying to come up with series of definitions to cover the various anomalous sounds we might hear from our bikes, the taps, clicks, clanks, clunks, thunks, scrapes and grinds etc. Might be a good challenge that would help many members as well...
Mark
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If there are any I can use I'll add them to my Web Pages,
http://www.pdsrecording.site90.com/cxgl500/noises.htm
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05-22-2010, 6:05 AM
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MotorcycleCommuter
Joined on 07-16-2008
Fairborn, Ohio
Posts 435
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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I've alwasy heard that as valves heated up the got looser. As the head of the valve heats up it expands and isn't able to seat as far into the head, effectively pulling it away from the rocker and adjuster. Additionally as the engine heats up the head expands pulling the rocker and adjuster up and away from the valve stem. A combination of the two creates more valve lash. The valve stem and push rod may expand and lengthen some but not enough to compensate for the valve pulling into the engine and the head expanding at the same time.
1983 GL650i, 49,000 miles
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05-23-2010, 9:46 PM
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CHIANGMAICXMAN
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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Shep and others....
Rain has stopped darn it...really, we need a lot lot more this year or
disaster will result. Potentially far worse that the political/terrorism BS we've
just had in Bangkok (had a very small amount up here in the North, nothing serious, but are still under a curfew).
But it allowed me to get the recording I was
looking for. It is in a video from this site:
COLD BIKE http://dl.dropbox.com/u/471388/Bike%20Diagnostic%20Cold%20002.avi
HOT BIKE http://dl.dropbox.com/u/471388/Bike%20Diagnostic%20Hot%20003.avi
Also,
here is a video of the oil flow through the rockers at start rpm's with
Kill Switch on. Both left and right are about the same volume of oil.
http://dl.dropbox.com/u/471388/Bike%20Diagnostic%20%20Oil%20Flow%20004.avi
The specific sound I'm trying to isolate would present itself at between about 3.5K up to 6K RPM and sounds like a metallic ticking or 'fluttering' that would change slightly with the RPM's. The sound was virtually non-existent with a cold engine. I have no idea what 'valve float' might sound like or how it would present itself, but that thought has crossed my mind. With the tappets tightened and backed off ever so slightly on the hot hot engine, the sound has disappeared.
Now then, IF the tappets do start to increase in gap again......what would that indicate? Rockers, Rocker Arms.....CAM and/or Followers.
Thanks
GL400 (79-83 bits and pieces)
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05-24-2010, 12:10 AM
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spanish bandit
Joined on 02-12-2009
southern spain
Posts 5,010
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| CHIANGMAICXMAN wrote: | Shep and others....
Rain has stopped darn it...really, we need a lot lot more this year or disaster will result. Potentially far worse that the political/terrorism BS we've just had in Bangkok (had a very small amount up here in the North, nothing serious, but are still under a curfew).
But it allowed me to get the recording I was looking for. It is in a video from this site:
COLD BIKE http://dl.dropbox.com/u/471388/Bike%20Diagnostic%20Cold%20002.avi
HOT BIKE http://dl.dropbox.com/u/471388/Bike%20Diagnostic%20Hot%20003.avi
Also, here is a video of the oil flow through the rockers at start rpm's with Kill Switch on. Both left and right are about the same volume of oil.
http://dl.dropbox.com/u/471388/Bike%20Diagnostic%20%20Oil%20Flow%20004.avi
The specific sound I'm trying to isolate would present itself at between about 3.5K up to 6K RPM and sounds like a metallic ticking or 'fluttering' that would change slightly with the RPM's. The sound was virtually non-existent with a cold engine. I have no idea what 'valve float' might sound like or how it would present itself, but that thought has crossed my mind. With the tappets tightened and backed off ever so slightly on the hot hot engine, the sound has disappeared.
Now then, IF the tappets do start to increase in gap again......what would that indicate? Rockers, Rocker Arms.....CAM and/or Followers.
Thanks
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might be my computor,but i cant play the videos
when i feel the need,i do it,llego,ve 60,s
-----------------------------
2008.1982 honda gli silverwing [uk model ]
2010.1981 honda gli silverwing [uk model ]
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05-24-2010, 2:47 AM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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05-24-2010, 4:38 AM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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05-24-2010, 11:23 AM
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CHIANGMAICXMAN
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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Sorry about the videos, can't play or too damn long to download...
Anyway, I extracted the audio from the video, here they are:
COLD http://db.tt/bprNh1
HOT http://db.tt/jiTmwI
Subsequent to these files, I did run the engine up to 190-200 degrees today and redid the right rocker tappets tight then backed off just a bit. It sounds so sweet I'll do it to the left head as well the same. I'll post an audio of the result in a day or two after running some temp and compression tests. Then I'll do Sheps Tappet Dressing for the final final audio.
Having done the HOT HOT adjustment a couple times now, I can attest to the safety/wisdom of doing it cold. I have slightly burned my wrist on the header turning the crank to get TDC....ouch. But if in the end this 'being outside the box' and having this superb forum available for admonishments and encouragement gets the end result, then so be it.
As an aside, I was parking at a local watering spot in Chiang Mai just last night. A Yank who had lived in Spain stopped me and said owned a CX500 in Spain and he had, believe it or not, OEM Mufflers in the box, here, and was wondering if I was interested in them. Small world ain't it?
Mark
GL400 (79-83 bits and pieces)
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05-24-2010, 11:28 AM
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spanish bandit
Joined on 02-12-2009
southern spain
Posts 5,010
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| CHIANGMAICXMAN wrote: | Sorry about the videos, can't play or too damn long to download...
Anyway, I extracted the audio from the video, here they are:
COLD http://db.tt/bprNh1
HOT http://db.tt/jiTmwI
Subsequent to these files, I did run the engine up to 190-200 degrees today and redid the right rocker tappets tight then backed off just a bit. It sounds so sweet I'll do it to the left head as well the same. I'll post an audio of the result in a day or two after running some temp and compression tests. Then I'll do Sheps Tappet Dressing for the final final audio.
Having done the HOT HOT adjustment a couple times now, I can attest to the safety/wisdom of doing it cold. I have slightly burned my wrist on the header turning the crank to get TDC....ouch. But if in the end this 'being outside the box' and having this superb forum available for admonishments and encouragement gets the end result, then so be it.
As an aside, I was parking at a local watering spot in Chiang Mai just last night. A Yank who had lived in Spain stopped me and said owned a CX500 in Spain and he had, believe it or not, OEM Mufflers in the box, here, and was wondering if I was interested in them. Small world ain't it?
Mark
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real small world mark
when i feel the need,i do it,llego,ve 60,s
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2008.1982 honda gli silverwing [uk model ]
2010.1981 honda gli silverwing [uk model ]
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05-24-2010, 1:06 PM
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Shep
Joined on 01-30-2007
UK.2x1980CX500A
Posts 7,647
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| CHIANGMAICXMAN wrote: |
As an aside, I was parking at a local watering spot in Chiang Mai just last night. A Yank who had lived in Spain stopped me and said owned a CX500 in Spain and he had, believe it or not, OEM Mufflers in the box, here, and was wondering if I was interested in them. Small world ain't it?
Mark
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Whenever anyone uses the phrase,"It's a small World" in my game(Aircraft Painter) the usual reply is,"Yeh but I still wouldn't want to have to paint the B*astard" 
My Music
http://www.reverbnation.com/pauldouglas/
Join Just In Case :)
http://globalcxglvtwins.hostingdelivered.com/
Id quot circumiret, circumveniat
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05-24-2010, 1:10 PM
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spanish bandit
Joined on 02-12-2009
southern spain
Posts 5,010
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| Shep wrote: | | CHIANGMAICXMAN wrote: |
As an aside, I was parking at a local watering spot in Chiang Mai just last night. A Yank who had lived in Spain stopped me and said owned a CX500 in Spain and he had, believe it or not, OEM Mufflers in the box, here, and was wondering if I was interested in them. Small world ain't it?
Mark
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Whenever anyone uses the phrase,"It's a small World" in my game(Aircraft Painter) the usual reply is,"Yeh but I still wouldn't want to have to paint the B*astard"
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you do my head in
when i feel the need,i do it,llego,ve 60,s
-----------------------------
2008.1982 honda gli silverwing [uk model ]
2010.1981 honda gli silverwing [uk model ]
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07-20-2010, 5:16 AM
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cxer4
Joined on 08-20-2009
London, England
Posts 6
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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My 10c worth. Chiang you hit the nail right on the head, the only reason we set a gap at safe(cold) temperatures is so we get zero lash at working temperatures. As to noise, yes, I noticed this too & yes, it's due to thin oil at high temp. If you hate it, use thicker oil! Hard rocker/hard valve stems wear, slowly but more important is that they lose flatness so it is not possible to use a feeler gauge as it will skate over the low spots. There used to be a setting tool that was marked in degrees - So if you knew the pitch, the tool gave the correct gap. Flatness did not matter. 1/4 turn or 1/3 turn does the same thing, as suggested above.
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07-20-2010, 9:56 AM
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CHIANGMAICXMAN
Joined on 01-12-2009
Chiang Mai, Thailand
Posts 170
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Re: Valve Adjustment (again) but with a twist....hot vs cold
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| cxer4 wrote: | | My 10c worth. Chiang you hit the nail right on the head, the only reason we set a gap at safe(cold) temperatures is so we get zero lash at working temperatures. As to noise, yes, I noticed this too & yes, it's due to thin oil at high temp. If you hate it, use thicker oil! Hard rocker/hard valve stems wear, slowly but more important is that they lose flatness so it is not possible to use a feeler gauge as it will skate over the low spots. There used to be a setting tool that was marked in degrees - So if you knew the pitch, the tool gave the correct gap. Flatness did not matter. 1/4 turn or 1/3 turn does the same thing, as suggested above. |
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CXER4
Ya, know....thought I would not recommend the "hot" valve adjustment due to the proximity to the down pipes (I've got the scalds to show for it) but it worked for me. I had to eliminate all possible noises (cam chain, bearings, clutch etc) just to have peace of mind.
I ran it hard and got it hot as I could following the recommendations of others and adjusted the tappets to just touching the valves then backed off about a quarter to one third turn. That seems to have solved the problem. All seems good after nearly 2000 kilometers since the "operation" and I can actually heard that beautiful exhaust and just a bit of tappet tap now.
I should probably go in and actually measure to tappet gap while dead cold so I know what works...but....I'm having too much fun riding, even thought he rainy season is finally setting in (and we need it very much).
I'd love to find that tool you mentioned, but...oh well.
Cheers M8,
Mark in Thailand
GL400 (79-83 bits and pieces)
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