# Cam and Half Tuning: Javi or Dudley Method



## alanmcdonley (May 15, 2009)

Looking for comments on Javi versus Dudley method of tuning Cam and Half.

Dudley: 
1)Twist up buss till DL is close with bottom limb between the performance limit marks on bottom cam (Assumption: If DL cannot get close stay in limits.)
2)Twist/Untwist control to sync bottom stop and top cam - (over rotated=twist, under=untwist, also adjust buss if no longer in performance limit) 
3) Fine tune DL with string twist

Javi method is in sticky thread.

When I follow Javi method, if I go 1/4" long on ATA per method, I can't get cam ref holes to sync, and if I put ATA right on and get perfect cam ref hole sync, the cam is so over rotated, that adjusting the stop timing destroys the cam ref hole sync and usually ends up with the bottom cam outside the performance limits.

The Dudley method ended up inside perf limits, with ref holes close, but DL 7/8" long, so I'm going to go shoot this tune. (Third tune attempt today.)

I'm starting to think there are just too many variables on cam and halfs.

Alan


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## hrtlnd164 (Mar 22, 2008)

Try this, 
1 Bottom out limbs
2 Remove some twists from your string so it isn't affecting a-a specs.
3 Twist buss cable to get your peak poundage. ex 60# for a 60# max bow. This should also get your a-a close to spec. Remember a-a and brace specs are listed as approximate.
4 Twist the control cable to set stop timing.
5 Twist string to fine tune draw length.
6 Let your tiller dictate your synch, if you're even you're good.

If after this is done and you lose your max # then add a couple twists to your cables while keeping the timing correct. Or reverse if your max # climbs too high. Everything else will fall into place. The timing marks on the cams are very open as far as where to set them and different marks are used for different bows.


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## SonnyThomas (Sep 10, 2006)

I believe you don't understand what sync and timing is per the methods. Look in the Hoyt manual. Timing marks/points (holes, lines or whatever) are only reference points. You draw stop time and it's timed. Snycing is keeping the cams movement in relationship. As such you may have the cable to the top cam a bit to the inside of it's reference point and the cable to the bottom a bit to the outside of it's reference point.


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## alanmcdonley (May 15, 2009)

@hrtlnd164 - Thank you. I used your method this morning bringing my weight to 49.5# (40-50# limbs), exact sync, and DL 1/2" long. It came from the factory 1/2" long, and I didn't think I should put anymore twists into the string. It is at exactly 1t/inch. With it 1/2" long, I shoot it in the "E" position making it 29" AMO DL actual.

ATA is 1/4" lower than "tune chart", and BH is 3/16 longer than tune chart. If forgiveness is related to BH, I certainly don't mind BH being as long as it wants to end up.

Your tune method is very straight forward. I like it the best.

@Sonny: I now understand "sync" as you stated. In the "Javi" tuning thread, he says that cam sync and stop sync are distinct and separately adjustable. His method has you get the cams in sync, then supposedly keeping that sync, adjust the draw stop timing. Perhaps I was misinterpreting him. 

I found this statement in the Hoyt manual that finally "releases" me from expecting those ref holes to match: "some 2005 and later models are optimized with the cables slightly off the reference holes." Also, with careful reading about the "performance marks" I found: "For all other bow models equipped with Cam & 1/2 Plus, the limb should lie between the round marks." VOILA - my limb is between the round marks, so I feel good about my tune now. I'm at the desired weight, with cams in sync and now I just have to work on *ME*.


Thank you both for helping me to tune my bow and feel that the tune is correct. Both are very important to shooting well. Thinking that I would have to send this off to someone to get it done because I cannot understand it was weighing a bit heavy on my ego. (And I didn't want to be without a bow for who knows how long.)

Alan


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## red44 (Apr 11, 2005)

Don't forget to check what position on the module your bow is supposed to be in to set it to specs to start with.


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## alanmcdonley (May 15, 2009)

*I prefer Mark's Method over Javi or Dudley Method*



> red44: "Don't forget to check what position on the module your bow is supposed to be in to set it to specs to start with."


I did that, but I don't think it matters for Mark's methodology. I think his method allows tuning the bow at the desired module setting, which could be better than tuning, changing, and then fine tuning.

The mechanics seem much simpler using Mark's (hrtlnd164) methodology :
a) Get string out of the picture, [untwist 10t]
b) Bring bow to max DW with buss cable
c) Get sync'd with control cable [over-rotated: twist, under-rotated: untwist]
d) Restore max DW without messing up sync by equal twisting of buss and control.
[DW low: twist both, DW high: untwist both
revisit c) if equal twisting messes up sync a little]
e) Twist string to be at desired DL delta​
(Mark also says "Let your tiller dictate your synch, if you're even you're good". I am guessing that if after d) the tiller is not even, make it even by adjusting limb bolts and go back to c) )

Javi states "the string is for all practical purposes, just along for the ride. 
and nuts&bolts manual states "most string builders build for 1 twist per 1.5".
I infer from these: 

if you have to shorten the string to the point of changing the DW, the string is too long.
 The perfect string length will be at spec DL with one twist per 1.5 inches of string length.

With this "perfect" string length, 

you can go up to 1 twist per inch of string length to shorten DL by 1/4", or 
 down to 1 twist per 2 inches of string length to lengthen DL by 1/4".

Brad at 60x says he prefers to lengthen a short DL setting than to shorten a long DL setting. Since my bow came from Hoyt 1/2" long perhaps Hoyt agrees.


So ultimately:

buss length controls DW
 control length controls sync
 string length controls DL delta from module DL setting.

Regardless of what the tune chart says ATA should be at the "spec" point, it seems the limbs need to flex what they need to flex to get you max DL, and regardless of what the spec says the string needs to be the length to put your DL in spec based on the actual ATA you end up at.

From all this, I infer that my string is way long (how much I don't know).

Also I think Mark's method refutes the statement by Javi:


> The cams need to be in synchronization and in draw stop timing; these are two entirely different issues but interconnected. It is possible to have the cams in sync, but not in time and visa versa.


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## JAVI (Jun 19, 2003)

alanmcdonley said:


> I did that, but I don't think it matters for Mark's methodology. I think his method allows tuning the bow at the desired module setting, which could be better than tuning, changing, and then fine tuning.
> 
> The mechanics seem much simpler using Mark's (hrtlnd164) methodology :
> a) Get string out of the picture, [untwist 10t]
> ...


You are correct.... I was wrong and know nothing about tuning a bow..

In fact I repeatedly asked that the offending thread be pulled several times because it was all a lie, I've never even shot a Hoyt bow in my life.


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## alanmcdonley (May 15, 2009)

JAVI said:


> You are correct.... I was wrong and know nothing about tuning a bow..
> 
> In fact I repeatedly asked that the offending thread be pulled several times because it was all a lie, I've never even shot a Hoyt bow in my life.


Woah Javi, please, I started this thread to understand and to discuss the two methods I had found, not to malign your credibility. I apologize for how this came out. 

I should have expressed my statement as a question about me: 
"How can I resolve the apparent difference between my implied mechanics model of Mark's method with my implied mechanics model of Javi's method?"

and 

"How do I diagnose what needs to change when following Javi's method to the best of my understanding does not result in an in-sync, timed, max DW, at spec DL?"​
From before I purchased my bow in 2008 till March of 2011 when I gave up, you were "the god of Hoyt tuning" to me, the only person that understood the process of finding the optimum point where the crossing of quadruple cam shapes (control and buss have one cam shape each, string has two cam shapes) with four/five variables (control length, buss length, string length, one limb bolt/which bolt). A system of four equations controlling four "solve for" variables (DL, DW, force curve, nock travel) with two limits (bottom stop, and top cam flat). 

For the first year or more, I didn't dare change the way the bow came from the factory. Eventually, I needed to change the string, so bought a press, ordered a string/cable set from a reputable maker, and with a summary of your methodology next to the press, I embarked on finding my "optimum" point.

I failed. I could not achieve bow tune nirvana, and my tournament scores were unchanged, despite more hours of trying to understand the signs to know what to tweak and how much to tweak than working on my mental game.

I came to the point of thinking all my research, all my engineering training, all my experimenting was not going to get me there, and I was going to have to send my bow and some arrows off to some "Hoyt god" with a hooter shooter to perform magic that I am incapable of doing for myself. I didn't want to be without a bow for a month, so I started thinking of buying a second bow to shoot during this process, and what should I buy? Another Hoyt with exactly the same complex tuning, or perhaps a bow that I might be successful with. And if that was going to be the case, why tune the Hoyt at all, just sell it and join the "non-Hoyt bow of the month fan boy club". (I've been shooting Hoyt since 1969, and stuck with Hoyt for sentimental reasons, not because I believed I would shoot better with Hoyt than with brand Y.)

So Javi, this whole thing is about me - not you. I am sorry that I offended you. I am hurting. I discovered one day that if I stopped trying to pull into the wall like the general wisdom was telling me, that my NAA indoor score shot up 25 points. In one day! Now that was a sign but there was no prophet around to help me interpret it, or to help me retune to bring that nirvana point to the wall point.

I started looking for a new religion. I found one that said "it is alright, I can sin a little on the specs, and still be "in tune". Life is simpler than I was making it." 

So Javi, back off on the sarcasm and ego. 

Alan


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## hrtlnd164 (Mar 22, 2008)

They are truly the same method, it's just that most folks new to this system put too much reliance on the reference marks and get confused when one thing affects the other. Javi's thread states:

"The reference marks or holes are there to provide a visual reference to cam synch not draw stop timing. I find that TILLER IS A MORE PRECISE indicator of cam synch. If the limbs are bottomed out, the tiller will reflect the position of the cams BETTER than the reference holes"

I do not believe the OP meant any disrespect with his comments, but was clarifying what he found by going through the process. Javi, your responses on archerytalk and other forums have helped tons of folks out, I for one would like to say Thanks for that...


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## JAVI (Jun 19, 2003)

alanmcdonley said:


> Woah Javi, please, I started this thread to understand and to discuss the two methods I had found, not to malign your credibility. I apologize for how this came out.
> 
> I should have expressed my statement as a question about me:
> "How can I resolve the apparent difference between my implied mechanics model of Mark's method with my implied mechanics model of Javi's method?"
> ...


No sarcasm... no ego... just the truth.. I don't know anything about shooting or tuning a bow.. I copied all of it from someone else.. 

And I really have asked repeatedly that the thread be removed... but to no avail..


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## SonnyThomas (Sep 10, 2006)

First off, glad to see you up and around, Javi. Hope all is well. 

Second, I respect John Dudley's and @hrtlnd164's approach to tuning, but having worked with Javi's procedure for so long I find that it is simple and will work with other bows. I, along with others, know any tuning needs finished through being shot in the person's hand and size of hands can effect the outcome. As such, some prefer the top cam to rotate a tiny bit faster than the procedure. And in tuning one must have good form, repeat everything. You change, bow reacts. Also see Creep tuning.

And then understanding what someone wrote up of tuning is paramount. Sorry Dudley and @hrtlnd164. Wording changes, more refined wording or instructions and order of? nuts& bolts? So he wrote a book or should I say someone put all his info in a PDF? Got one and then later one updated. I keep it on hand for reference as I do other things.


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## nomad11 (Apr 14, 2006)

??????????????????????? archers helping archers????


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## JAVI (Jun 19, 2003)

HaHaHa… guess I should be more careful not to leave my computer open on a web page and probably shouldn’t talk negatively about something to my co-workers if I do.. 

Truth is I could care less how any one chooses to tune a compound bow.. Probably the dumbest thing I’ve ever done is write that little post.. It has caused me more time spent explaining and defending the method than anyone can imagine. 

My little funny buddy got one thing right; I’ve asked repeatedly that the post be removed. When I wrote it the bows were conventional and not past parallel, so some things I said no longer apply. Several of you have tried to explain and help others with the method and for that I thank you.. 

I have not been involved with Hoyt bows since ’05 and for the past two years have been battling one illness or another and my shooting of any bow has been almost nil. 

My only reason for even being on this website is to sell my compound archery equipment as I am out of the game forever..


Thank all of you who have shared the sport with me, and good shooting..


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## MNmike (Dec 27, 2003)

JAVI,

Been a while.

I can understand your frustration.

I'm saddened to read about your health struggles and pray they get better. 

BTW I still use your chilli recipe.:star:

Peace,

Mike


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## SonnyThomas (Sep 10, 2006)

*Cam and Half Tuning: Javi or Dudley Method*

Javi, it's still Gold. I tuned a Hoyt Alphamax and the customer sent me a pic. Note the top nock. I'd sayit's close enough. He said it was his first ever.


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## Reverend (Nov 2, 2004)

marked for later...


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## Ches (Aug 3, 2009)

^^ Me Too ^^^


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## SonnyThomas (Sep 10, 2006)

I haven't "played" with the newer Hoyts to say all is still valid. Started working at a small archery shop and Hoyts were rare. Mostly Martins and Pearsons. One thing that does stand out, giving the little more quickness to the top cam. Some like it to touch just a hair before the bottom. In another thread ontarget7 noted something about within 3/16". I PMed him in asking of this and what I look for and has never replied.

The top cam on a Hoyt and a Martin, the cable lays in the module groove track. I guess this is also true of the fixed draw length cams of Hoyts. You can't see that cable lay flat, not really. You may think it does, but then prove it. One way is with a draw board (safety) and pushing on the cable to see that it is true laying flat in the groove. The other way is to draw the bow so the cables can be seen to bend. This is true of Hoyts and Martins. Once I noted such I've never had to give that extra half or full twist to the top cam.

Most always, timed as above, I have right at zero to no more than 1/16" nock high setting. 

On the Pearson Legend cams there is a tang on the module right out in the open. Okay, so open to view you can time the Legend cam with a feeler guage. So I had my bow timed. I shot it and it was good to go. I thought then to have the top cam touch a bit quicker and gave a half twist. Whoa! My bow didn't like that one dang bit. So I believe that extra half twist people give the Hoyt and Martin cams is making the correction that you can't see.

The other part of the tad quicker top cam thing, all people are different to one degree or another. Perhaps a half twist does work for them. Size of hands, grip, or whatever being the difference. One can only experiment.


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## Turkey165 (Aug 24, 2009)

tagged


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