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Discussion Starter · #1 ·
Last time I introduced this thought on the web it was largely ignored . The time before that it was flamed by ignorant know it alls . I present it here just because I was bored or wanted donate a peculiar thought to the forum . You be the judge . :D

Suck Squeeze Bang Blow
or for the politically correct and exacting but humorless engineers '
Intake Compression Power Exhaust

There are two major pressure changes in a four stroke internal combustion engine , when you light the fire which is easy for you youngsters with your electronic ignition and when you let go of it . You go to people like Falicon with your cranks and A.P.E. or Branch with your heads . Pistons are weight matched within 1/8 gm or less .Even intake and exhaust ports are cc'd .Combustion chambers are volume matched within 1/4 cc or less . Some spend thousands on dyno time getting the perfect jetting or fuel map .
Then you adjust valves with a feeler gage ?
The valve clearances suggested by the manufacturer are just that a suggestion to keep you from holding a valve open or beating your valve train to death . Until Yamaha recently decided to experiment with 90 degree cranks all the inline fours used a flat (180 degree) crank with #1 and #4 at TDC and #2 and #3 at BDC . each pair firing alternately . Until the CBRXX no one thought to balance out this rocking couple but that's a story for another day . The point is why would you want to introduce any further variations in balance by scattering major pressure pulses over as much as 10 degrees of crank rotation ?
Use a positive piston stop to establish TDC and adjust the degree wheel to match a pointer . Insert the correct feeler gage between one exhaust valve and the rocker and adjust till there is a slight drag . So far this is basic a valve adjust . Now place a dial indicator on the spring retainer of this exhaust valve and preload it at least 0.060" . Pick some arbitrary lift distance like 0.030" and mark it on the dial . Rotate the crank until that valve has opened 0.030" and mark the degree wheel . If you started with #1 now go over to #4 and adjust the exhaust valve so there is that slight drag on the feeler gage and move the dial indicator to that retainer and preload it . When it has moved 0.030" look at the degree wheel . It should be 360 degrees out from #1 AND ON THE SAME MARK . Unless lady luck intervenes it won't be . Variations in cam indexing and tolerance as well as deformation of the top of the valve make it unusual in the extreme for all this to work with simply a feeler gage .
In the end all exhaust valves should be opening at the same place in degrees plus or minus 180 degrees at 0.030" lift and be within specified lash limits . If you have gone this far then repeat for the intakes even though the effect on the engine is not nearly as dramatic and closing more critical than opening .
Now of course when confronted selective shim valve adjustment you are limited to just how close you can get to ideal . Or are you ? If you have enough experience to have adjusted valves on an 8 valve kawasaki , Suzuki or other then you remember they came in half millimeter sizes ie 2.30 , 2.35 etc . I have sizes in 2.325 , 2.375 . If you think this is overkill imagine what you find in a factory race team's box of shims . I don't have to imagine it , I've seen it .
I do have a curious and humorous way of doing this that I have used to demonstrate the principal in a classroom and as a garage joke with friends . I'll set up the degree wheel ahead of time and expose the valve adjustment . I found a hose that just screws into the spark plug holes rather than continually removing the valve from my compression tester .
To the end of the hose I attach a rubber , yes a prophylactic , un-lubed , with a rubber band . The compression stroke inflates the "balloon" and the exhaust opening rapidly deflates it .If you really want to drive yourself crazy try the above procedure with the dial indicator and then repeat it with the balloon . I recommend a very little light oil on the seat . Now observe what a change of just 0.001" (insert a feeler guage between the rocker tip and valve or the cam lobe and "lifter" ) does in relation to opening in degrees . Then for those that obsess try just a 0.00025" or 1/4 thou change and record the difference in degrees at actual opening *. This "shade tree" device , with a little practice will also give a indication of low pressure cylinder sealing that a leak down tester will not unless equipped with gages costing several hundreds of dollars .

I'll attempt reason without anecdote or explanation .
If your cam specs are @ 0.040 lift and intake opens 19 degrees BTDC and closes 46 degrees ABDC and exhaust opens 34 degrees BBDC and closes 16 degrees ATDC ....
ALL exhaust valves are opening at 34 degrees before bottom dead center for their respective cylinder AND staying within acceptable valve clearances ( .007" to .010" ).
The lash or static clearance has far less impact on engine performance if kept within the manufacturer's specified limits than does adjusting the exhaust valves to open at a specific point in crank rotation .
I lifted representative specifications from an older megacycle 493-x1 cam

So it's up to you . Call it lazy to use just a feeler gage and get out simple tools and take a little extra time and get it right or use just a feeler gage and get close .

~kop
 

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55,500 miles and counting
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Hi and welcome Kop, don't worry, we have several sad techno freaks here on site who will soon come along and discuss your theorys with you.

do you know much about diodes and resistors in relation to amplifiers too ? if so chainsaw and you will get on famously, he can send me to sleep within two paragraphs with his electronic drivel.

you could liven it up with some colour photos for those of us who are struggling to picture what the hell your talking about and some links to good porno sites for those of us who are'nt quite as interlectual as you and are starting to get a little bored.
 

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Discussion Starter · #3 ·
Pete , don't get me started . I dug for ever trying to find my prized photo of Willie's XS explosion . I was impersonating a corner worker that day for reasons that really should .....


Yeah for you comic book and Pr0n mag educated heathens I can muster up com creative photography to illustrate my interest in women half my ... I mean all things mechanical . I don't have a lot of time as of late but occasionally I'll make it by and at the very least donate a few words in exchange for all the great bike pics I've found here ...


~kop
 

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Pete , don't get me started . I dug for ever trying to find my prized photo of Willie's XS explosion . I was impersonating a corner worker that day for reasons that really should .....


Yeah for you comic book and Pr0n mag educated heathens I can muster up com creative photography to illustrate my interest in women half my ... I mean all things mechanical . I don't have a lot of time as of late but occasionally I'll make it by and at the very least donate a few words in exchange for all the great bike pics I've found here ...


~kop
you know Chainsaw willie :eek:hmy: it figures :wallbash:
 

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:wallbash:
 

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Moving at the speed of...
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I have just printed of this thread. I have been suffering from insomnia lately and though if I read this it will help.

Anyone else with tendencies to show off their technical prowess please feel free to post here and I will print those off too so I have some fresh soporific material every night. :whistle: :whistle:
 

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Discussion Starter · #9 ·
But.....


Won't the engine have to be at operating temperature for this method to be accurate?
But.....

Won't all the cylinders/valves be at operating temperature and the variations due to heat be similar ? :D
Actual practice is that a "fresh" unfired setup/build/tuneup will "move" a bit so an engine is run in with nominal valve clearance for a short period of time prior to getting out the dial indicator and degree wheel .

~kop
 

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Hey, kop, if you want to get a bigger and more enthusiastic following, you should include rude photos of near naked ladies and links to really hot porn sites in your posts.

Works for me....
 

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KNEE DRAGGER
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Interesting stuff. I do agree with your theory, but let me pose a few more questions and comments. I have built my share of engines so I am quite good with doing numbers, I have tons of half size shims and so on...

1. If you assume there is slight tolerances in total duration, by synchronizing the opening position does this not then cause a much wider tolerances in closing numbers? Yes it does, so this leads to question 2.

2. What is actually more important, opening/closing numbers or total duration? In cases where race rules do not allow aftermarket cams, I will sometimes shim my valves up tighter than the spec anyway, this gives slightly more lift but has a much greater effect on total duration time. If I tighten up my valve clearances an extra .12mm or .13mm I only get that much extra lift, but in some cases I will see an extra 5 to 6 degrees in total duration.

3. Overlap needs also to be taken into consideration, intake opening numbers and exhaust closing numbers then need to be scrutinized to see what the actual cylinder to cylinder variation there is.

4. Dynamic systems are way different that static based system, so it would be interesting to analyze this under running based condition to look at how the the variances change from static based measurements.

5. I have checked cam phase and piston phase on several bikes to see how close they really are to 90 degrees or 180 and so on. All but one engine was really really close.

6. Is there an actual difference on the dyno when preparing the valve train this way?

7. For a regular street engine this seems a waste of time unless there are significant gains in performance that can be measured. None of my customers at least street bike wise even want to set their cam timing, it cost too much for them and they do not get to see any new shiny parts like exhausts, or Penske shocks...

8. The measurement error also needs to be taken into consideration, left number error and degrees error will stack making a much large + and - variation. Is the accuracy of what is being attempted actually going to be a statically significant change? Eye balling the degree wheel can be tough. I use a rather large wheel when I can to help eliminate this kind of error.


Cheers
-MS
 

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C'mon, we're waiting for more... :bigclap:

D.
 

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Oh boy...
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Hi and welcome Kop, don't worry, we have several sad techno freaks here on site who will soon come along and discuss your theorys with you.

do you know much about diodes and resistors in relation to amplifiers too ? if so chainsaw and you will get on famously, he can send me to sleep within two paragraphs with his electronic drivel.

you could liven it up with some colour photos for those of us who are struggling to picture what the hell your talking about and some links to good porno sites for those of us who are'nt quite as interlectual as you and are starting to get a little bored.
You should thank people like kop for all he knows instead of telling him he's boring you. People like him are the reason we have fantastic motorbikes to ride. You perverted ole sob.(w00t)
 

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You should thank people like kop for all he knows instead of telling him he's boring you. People like him are the reason we have fantastic motorbikes to ride. You perverted ole sob.(w00t)
Well, he's only done 10 posts so far, I think he's just a flash in the pan.

Anyway, how do we know if what he says is true ? we can't understand anything he says and he claims to know chainsaw... now thats suspisious as I'm not sure if anyones ever seen Chainsaw have they ? For all we know, chainsaw is a 9 year old girl whos possesed by the devil or he could be a fictious charactuer made up by the FIB to spy on us all.

......and he never talks about sex, posts rude photos or nuff'n, I'm tell'n y'all, he aint normal. :eek:hmy:
 

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Pete's bike hauler
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I can see where he is coming from but what you have to ask is all this palaver worth going through on a road bike, where you might stand to gain .125hp? I think not! and that is why feeler guages are used, I have been known to rub down shims on bikes to get the clearances just so , I did it on my sv.
if it was a racing bike then yeah go ahead get out the pack of 3 and set the bike up but as to what is the best distance the valve should be depressed depends on many variables what octane fuel , overlap and endurance on the cams , manufacturing differences between lobes and their timings and what is the proposed rev regime that one is working with. If we are talking less than 10k revs then all this effort is really for nothing but if we look at the new 600cc racers then this becomes a more valid thesis.

It all boils down to the same old saying bullship baffles brains
 

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International dogsbody
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:agree: As we can't use all of the power we already have for most of the time surely there more to be gained in suspension set up than looking for marginal improvements in valve train set up?
 

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Oh boy...
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Well, he's only done 10 posts so far, I think he's just a flash in the pan.

Anyway, how do we know if what he says is true ? we can't understand anything he says and he claims to know chainsaw... now thats suspisious as I'm not sure if anyones ever seen Chainsaw have they ? For all we know, chainsaw is a 9 year old girl whos possesed by the devil or he could be a fictious charactuer made up by the FIB to spy on us all.

......and he never talks about sex, posts rude photos or nuff'n, I'm tell'n y'all, he aint normal. :eek:hmy:
(w00t)I hear ya! You just saw the title of this thread and got all half boned up...got in here read what it was actually about...got pissed and gave kop shit for it...(w00t)

The mental pictures you paint...you disturbed man.:bigclap::supsmiley:

Agree with what was said tho, minimal gain on a street machine. For racers it is probly something they already do.
 

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N of Atlanta
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The thread title reminded me of the '07 SV Rally T-shirt, lol.
 

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....I have been known to rub down shims on bikes to get the clearances just so , I did it on my sv....
I thought about doing the same when I adjusted my valve clearances. The Hot Cams shim set I bought for the job had shims spaced in 0.05 mm thickness. To get all the clearances exactly in the center of the recommended ranges I considered making some a bit thinner by a couple hundredths of a mm. But someone told me they may be surface hardened and if I did this the resulting shim may be softer and not hold the clearance as long. So I didn't bother I just got it as close as I could with the shims I had. Not sure if this is true or not about the shims being harder on the surface.
 

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Pete's bike hauler
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I thought about doing the same when I adjusted my valve clearances. The Hot Cams shim set I bought for the job had shims spaced in 0.05 mm thickness. To get all the clearances exactly in the center of the recommended ranges I considered making some a bit thinner by a couple hundredths of a mm. But someone told me they may be surface hardened and if I did this the resulting shim may be softer and not hold the clearance as long. So I didn't bother I just got it as close as I could with the shims I had. Not sure if this is true or not about the shims being harder on the surface.
They are hardened but the hardening is quite thick taking off a few thou has no ill effects
 
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