Help: Yamaha Alpha EX

[asburrou]

I just recently won a Yamaha Alpha EX off of Ebay. The seller was not able to provide the right string for the bow(nor is he knowledgeable of the bow) and I've had a horrible time finding the appropriate string to use. Here are the specs for the bow:

23" Riser
Medium Carbon Ceramic Limbs

Approx: 67.5" in length unstrung.

Have tried the following strings: 62" -- too short
63" -- too long

40 lb draw

Has the following written on the bottom limb:
SH 66 40#
LH 68 39#

Have no clue what those mean, neither did the people at the local archery shop.

I'm new to the world of Archery, having only shot for 5 months. It has been very difficult to obtain any information on this bow as Yamaha no longer is in the Archery business. Anything would be most appreciated.

[rei14]

Sounds like its a 66 inch bow if its a 23 inch riser. So at 66 its 40# and at 68 (on a 25inch riser) its 39#. I have a hoyt nexus 23 inch riser with medium limbs (66) and hoyt recommends a 63" string. I'm new to archery myself (started 4 months ago)... you can also get a flemish string and twist it down to 62.5" . I've used at 61" string and 63" string on my bow and I havent notice anything... just that its easier to take off the 63" string. How do you know if its too short or too long? Maybe someone else can chime in.

[Steve N]

Rei is correct, how do you know the string is too short or too long? String length sets your brace height, the distance from the back of the grip at its deepest point to the string. I don't know what that should be on a Yamaha, so maybe someone else on here can help. I would guess it should be between 8 1/2" and 9 1/2" as a starting point. Proper brace height helps make the bow quieter, and aids in shot consistancy.

If a string is too long, simply twist it to make it shorter. You can twist until you start to put kingles in it (those little tight twists that don't pull out when the string is under tension). After that point, you need to get a shorter string. You want to avoid shooting a string with no twist in it. The strands will balloon out on release, affecting string speed, arrow speed, consistancy, etc.

Buy a bow square, and measure your brace height every time you string your bow. Once your nocking point is set, changing string length will move the nocking point, therefore brace height, which will affect arrow flight.

Remember, archery is a game of boring repetition. Do the exact same thing the exact same way every time, and the result will be the same (negating wind, rain, etc.). The fun is in learing to do the exact same thing the exact same way every time.

Please fill out your profile completely. There may be someone on here close to you that can help.

[archeryal]

SH = short handle, LH is long handle. At one point, Yamaha marked its limbs at 26" rather than the AMO standard of 28, but that may not be the case on this later bow.
I don't know if their short riser is exactly compatible with standard 23" Hoyt riser, for instance, but it should be approximately the same. Most of these came with metric fittings (button, stabilizer, etc.) so check this out before you force fit anything.

[asburrou]

I know it is too short at 62" because the string does not fit into one of the grooves that is at each end of the limbs(the limb is bent too far). As for too long, the 63" string is almost right, but it just seems to be a little too close to the riser. I actually shoot the bow better with the 62" string, the 63" just really dosen't seem right. I'm also using dacron string if that makes a difference. I read somewhere that Yamaha made everything in metric, which I'm wondering if that would make a difference. If the bow is 67.5" in length the string should be 63.25", but the 63" is too long. If the marking on the side indicate that the bow is measured as 66" then the string should be 62"--which is clearly too short. I could try a 62.5" string, but I was wondering if someone knew something I didnt before I went ahead.

[skybowman]

Originally Posted by Steve N

If a string is too long, simply twist it to make it shorter. You can twist until you start to put kingles in it (those little tight twists that don't pull out when the string is under tension). After that point, you need to get a shorter string. You want to avoid shooting a string with no twist in it.

Steve N has the right answer for a too-long string. Twist it until it appears correct. How many twists do you have in the string now?

[massman]

As you are new I'll explain twisting up a string.

A string should have a min of 12 twists. Maximum being around 40 twists. The 63" string is most likely the correct length. Put the string on the bow with the loop at the top sliding down the top limb and the bottom loop on the bottom limb tip. Now remove the string on the bottom tip and spin the string adding twists to it. I'd try 20 twists to start. Without loosing any of these twists, replace the bottom loop on the bottom limb tip. String the bow and using a "t" square or ruler, check the distance between the grip (at it's deepest point) and the string. For a 66" bow I'd suggest around 7 1/2 to 8 1/4 inches for this measurment. If it is more than 8 1/4", unstring the bow and take some twists out and restring the bow and measure again. If it is lower, unstring the bow and add twists. This is called Brace Height. Once you get the brace height within the range indicated above, you will measure this dim every time you string the bow, adjusting up and down to keep this measurement consistent.

BEST Regards,

Tom

[asburrou]

so I've gotten the following:

Brace length with 63" string: 5 3/4"
Brace length with 62" string: 7 1/4".....

The 62" is clearly too short as I mentioned before the string is coming out of the grooves on the end of the bow.

I'll take some pictures tomorrow. Hopefully that will help.

[Steve N]

Per Massman's post, you are close to the low limit of brace height, but still 1/4" too low. That means the 62" string is the correct length.

Please post pics of both limb tips strung with the 62" string. Focus on the string/groove area. If the string is coming out of the groove in the limb, it has nothing to do with the string being too short. It could be that either your limb alignment is off, or the limb tip is twisted.

[asburrou]

Here are some pic. Tell me if you need more:

[asburrou]

More:

[Shinigami3]

You have some kind of HUGE tiller problem on that bow- check and make sure the plastic tiller blocks in the top and bottom pockets are the exact same.

Heck, make sure the top and bottom limb serial numbers match too- something is VERY wrong there.

[asburrou]

Serial numbers on the limbs match. The plastic tiller blocks(or what I think are the tiller blocks as I'm new to this) look the same as well.

[mholz]

Measure your brace height to the pivot point, ie: the deepest part of the grip. I agree check your tiller. Check your limb bolts one or both may be crank too far out or too far in. My wife had a problem with some G-3s had to return for a new set. They were built wrong.

[asburrou]

well i can't return it. Yamaha stopped making these in 02. Is there a way to correct the tiller?

[mholz]

The tiller is adjusted by the limb bolts. I suggest you take it to a local archery shop for help. Unless it's an optical illusion it appears that one limb has more bend below the recurve than the other.

[mholz]

PM sent.

[Shinigami3]

It looks like at least a 4-5 pound difference top to bottom- are you really sure the limbs are matched?

[asburrou]

As far as I can be. They have the same serial and are exactly the same when put side by side. One thing to note that i've noticed. The riser angles the bottom limb at a slightly different angle than the top limb. This is not due to the tiller blocks but the actual design of the riser itself.

[Shinigami3]

Well, sorry to say, something seems VERY wrong with one of those two limbs.

I could see something like that happening in a cheap 12# set, but 40# Yamahas?

One thing though- Just occured to me. The limbs are a much newer type than the riser- like, 10 years difference. They look like Superfeels.

MAYBE they're not compatible? Yamaha had at least 5 different systems over the years, none of which were reverse compatible except for the very last one, and their "type-H" Hoyt dovetail copy ones.

Perhaps, a photo of the limb butt might give a good clue.

[asburrou]

Hope these are what you are looking for:

[Shinigami3]

OK. Maybe we are on to something here. Is the riser an EX, or EX Alpha?

Like I thought, those are superfeel limbs from around '95. They work in an EX-Alpha, Eolla, and SFF-1 or SFF2...

But, I don't think they'll work in an original EX, as far as I know. That bow is from around '82, and was replaced with the EX-Alpha around '87.

I COULD BE WRONG. It has been 20 years since I owned a Yamaha!

(Also I think I am wrong about my comment above about reverse compatibility- the change from the YTSL to YTSL2 to EX were all incompatible, but after that i think they all pretty much fit.)

Yamaha experts that didn't kill that brain cell please chime in?

[asburrou]

The Riser is an Alpha- EX

[Eolla]

Ok you have a Yamaha Alpha EX riser with the "Superfeel Ceramic" limbs. Very nice. Your bow is 66" (short riser Medium limb). You need to compare the small black plastic wedge shaped bloack in the limb pockets. Each one will be marked 1 2 or 3. These MUST be the same number. These blocks determine draw weight (#2 is the kimbs stated weight)

Next get an Allen key and insert it down the silver stabilizer hole and wind it all the way down then all they way up, counting the total turns from bottom to top. Wind the screw down half of the total turns, do each pocket. Refit your limbs and re-string your bow, then give the string a fairly good pluck (draw it 6" and let it go without an arrow. Now re-measure your brace height (from button hole to nocking point.

Those super ceramics have a camber adjustment on the back (its the small circular button with an allen ket holding it tight), the EX limbs did NOT have this button. Make sure the plastic blocks have a hole for the adjuster button to fit in. If they don't you will need to find a set of "Eolla" or "Superfeel" blocks, this could be your problem.

[asburrou]

Eolla: I'm about to do what you said. I just looked at the blocks. They are number 1s. Could that be the entire problem?

Gonna update this as I go.

Edit:
The blocks fit the adjuster button.

[asburrou]

wow! It worked. Pics:

[asburrou]

I noticed that I unintentionally used the limb that I had used on the bottom on the top this time. Is there a top and bottom limb or are they interchangeable?

[asburrou]

Well i tested it out. there is a slightly noticeable difference depending on which limb i use as the top and which as the bottom. Probably should have been the first thing I checked...

Thanks for all the help yall, I really appreciate it!

[Shinigami3]

The bottom limb is the one with the logo on the archer side of the limb- the one that says "super ceramics carbon" or whatever. Be sure you get it right or you'll have reverse tiller, which might not work as well as you like.

Brace height is still a bit too low, but that looks a lot better. Probably run that up to 8-1/2 or so, the Yamaha extra-deep "passthrough" limb grooves are deceptive.

Also I think you mentioned you're using a Dacron string. That limb is built for high-performance strings, Dacron will waste a lot of the bow's potential- kinda like running bald, bias-ply tires on a Ferrari

[asburrou]

I plan on changing the string as soon as I can. However when I use the limb with the logo as the top limb. It gets the pictures I just posted. When I use that limb as the bottom limb I get something kinda like the original pictures(just not as bad as before for some reason)

[Eolla]

IMHO Dyneema strings work better on a Yamaha than FF. Don't forget to adjust limb tiller with the allen key. Oh and yes the bottom limb is the one with the weight reference markings. I forget if #1 or #3 blocks are the thickest, if your bow came with all 3 sets use the thinnist or the #2 for the optimum shooting feel, I found the thickest blocks made the shot feel too harsh. DOnt forget Yamaha draw length is meaured at 26" not 28", they will load up rather quickly over 28.

Now get out and get shooting, its a great bow with what I consider the worlds best ever grip!!

[Shinigami3]

No doubt that's a great grip on those old Yamahas! Rumor is the new Hoyt optional grip is a lot like it. I am waiting for mine.