Author Topic: APE studs too short, what am I missing? CB750K (Read 2754 times)

brazwell · « **on:** February 25, 2015, 03:35:40 PM »

So if there is a thread clearly addressing this problem I haven't found it, so I apologize in advance if I'm beating a dead horse. Im doing the top end in my 73 cb750. Ive torqued my APE studs to 8lbs. Now with my heads on, I have approximately three threads left between the top of the stud and top of the nut after torquing with washers. I did a three step process and have the nuts torqued to 20lbs. I have emailed APE and verified they are the correct studs by measuring them. They have suggested that I "drop a 3/16 or 1/4" steel ball in the hole and screw the stud down onto it and tighten." This seems crazy. Any thoughts?

flybox1 · « **Reply #1 on:** February 25, 2015, 04:05:55 PM »

cylinders and head all the way down?
how thick are your gaskets?
on one, two, all?

pictures please.

brazwell · « **Reply #2 on:** February 25, 2015, 04:08:33 PM »

On all studs I have 2-3 threads left after torquing. They are all even in length, solvent in the holes and blew out, long end of threads in the case. New stock nuts with the original washers. Athena gaskets.

flybox1 · « **Reply #3 on:** February 25, 2015, 04:36:24 PM »

you should have 3-4 stud threads showing.
are you sure your cyl and head are all the way down?
did you get your knock pins in all the way if you took them out?

brazwell · « **Reply #4 on:** February 25, 2015, 05:05:04 PM »

Absolutely, Everything is sitting flush, cylinders flush with cases and heads flush with cylinders. Im at a loss...I cant imagine what else to check..

flybox1 · « **Reply #5 on:** February 26, 2015, 06:56:25 AM »

If you and APE have ruled out the possibility of short studs...it could very well be the stud hole depth.
did your PO ever mention a rebuild?
were the original studs in there when you tore it down?
can you measure your stud hole depth, and possibly compare it to another case?
Im sure there are a few members here who can measure for you.

bytio · « **Reply #6 on:** February 26, 2015, 07:56:58 AM »

Did you put the studs in correct wAy, ? There is a long and a short end

MCRider · « **Reply #7 on:** February 26, 2015, 09:34:50 AM »

I had a set of studs of unknown origin that did this. I replaced them with a set from APE, on APE blistercard, and they were fine. The APE's were longer.

Interesting.

The idea that they had about the ball spacers indicates to me this problem has occurred before. I'd do it and go on.

Airborne 82nd · « **Reply #8 on:** February 26, 2015, 10:37:47 AM »

Quote from: bytio on February 26, 2015, 07:56:58 AM

Did you put the studs in correct wAy, ? There is a long and a short end

Quote from: brazwell on February 25, 2015, 04:08:33 PM

On all studs I have 2-3 threads left after torquing. They are all even in length, solvent in the holes and blew out, long end of threads in the case. New stock nuts with the original washers. Athena gaskets.

BPellerine · « **Reply #9 on:** February 26, 2015, 11:23:07 AM »

read somewhere that mreick installs with height of studs not torque as the the governing factor.shoot him an email.bill

MCRider · « **Reply #10 on:** February 26, 2015, 11:28:17 AM »

Quote from: BPellerine on February 26, 2015, 11:23:07 AM

read somewhere that mreick installs with height of studs not torque as the the governing factor.shoot him an email.bill

If so, and I don't doubt it, that would indicate there is a quality control issue amongst those who actually make the studs. They are likely to not be the same people who ultimately stick their name on the pkg for sale.

Common practice.

brazwell · « **Reply #11 on:** February 26, 2015, 06:20:54 PM »

I have thought about expanding to see if i could get a measurement of my hole depth in the cases. No PO, copped the bike for a few hundred bucks from someone who nothing about it. The ones I removed appeared to be originals. APE has been unhelpful to say the least.

calj737 · « **Reply #12 on:** February 26, 2015, 06:37:46 PM »

Seems the only way to ascertain the problem is to remove the head and jugs, extract 1 stud and compare overall length to the stock ones you removed. That will also allow you verify the installed studs are threaded fully into the block (no extra threads showing).

Retro Rocket · « **Reply #13 on:** February 26, 2015, 07:39:39 PM »

Quote from: brazwell on February 26, 2015, 06:20:54 PM

I have thought about expanding to see if i could get a measurement of my hole depth in the cases. No PO, copped the bike for a few hundred bucks from someone who nothing about it. The ones I removed appeared to be originals. APE has been unhelpful to say the least.

APE are members of the forum {big jay}, I have dealt with them {from Australia} and have nothing but the best service i could imagine....What do you expect them to do...?
Measure the length of the studs and post here, do you have any old original studs to compare size to..?

mick7504 · « **Reply #14 on:** February 27, 2015, 02:55:52 AM »

For your reference mate, the stock stud lengths are
Long Stud - 195mm OAL
Short stud - 160mm OAL

Installed height
Long Stud - 170mm
Short Stud - 130mm

First image shows stock studs on APE HD studs for comparison

Second shows the stock stunds installed - 170mm and 130mm height from top of case.

The best thing to do now is to Loctite the studs into the case and set the heights (above) as evenly as you can.
It doesn't have to be a micro measurement, just get them as close as you can by eye with a steel ruler.
The warning here is, don't flood the stud threads with Loctite.
Lightly coat the threads in the case with a toothpick and then screw the studs into the case.

Reasons being that too much liquid runs the risk of "hydraulicing" the stud in the threaded hole and secondly and most importantly, there's every chance that the oil galleries that let oil feed the top end will be blocked solid.
If that happens, you'll be pissed off big time.

PeWe · « **Reply #15 on:** February 27, 2015, 03:26:47 AM »

I could remove my HD studs after lifted the head only, cylinder still mounted. I had over torqued APE studs. Bought new Kibblewhite studs that went in. No problem since I had used the bike very little.

The head gasket might be very thick, will be better when tíghten the nuts?

mick7504 · « **Reply #16 on:** February 27, 2015, 05:08:10 AM »

He's saying that he's got 2 to 3 threads exposed on the nuts.
At 1.25mm pitch, thats 2.5mm/3.75mm exposure.

I don't know why, but its either that every stud is too short which would be a short straw or, for reasons unknown, the studs have screwed too far into the case which is where my bet is.

754 · « **Reply #17 on:** February 27, 2015, 07:18:09 AM »

APE told him how to fix it by using spacer balls.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #18 on:** February 27, 2015, 09:54:30 AM »

Are the case threads 'interference fit' or whatever it's called when they are a tighter fit than normal to allow a tighter grip? Did the threads get chased? or otherwise reamed out a little allowing the APE studs or even the stock studs to go deeper into the threads? I might surmise this being the case if there is room at the bottom for a steel ball.

Thanks for the fitted length measurements! I will be doing this soon too.

PeWe · « **Reply #19 on:** February 27, 2015, 11:17:53 AM »

I mounted my studs all the way in the case until the bottomed, torqued 8 ft lb
The stickout was much more than a few threads. The case holes might be deeper in the TS case.
Below photos when head had slipped on and later when higher HD nuts (std DIN6331 nuts) are on. Most of the nuts cover threads. I used thinner washers when the flange nuts had thick flanges.

brazwell · « **Reply #20 on:** February 27, 2015, 05:28:39 PM »

Does anyone else feel like dropping a steel ball in the hole and torquing may run a high risk of cracking the cases? Ive removed them completely and retorqued but ended up with the same results. I have the correct length studs.

Retro Rocket · « **Reply #21 on:** February 27, 2015, 05:32:58 PM »

Quote from: brazwell on February 27, 2015, 05:28:39 PM

Does anyone else feel like dropping a steel ball in the hole and torquing may run a high risk of cracking the cases? Ive removed them completely and retorqued but ended up with the same results. I have the correct length studs.

So are you saying that the old studs that cam out were the same length...? Interesting.... I don't think you'll risk cracking the cases as the studs themselves shouldn't be torqued tight into the cases, they are there to torque down the head, so the pressure on the bottom of the studs is upward, not downward...

brazwell · « **Reply #22 on:** February 27, 2015, 05:43:14 PM »

I actually don't have the original studs...funny little thing, I tore this motor down several years ago and became preoccupied with another motorcycle and school. Poor decision making in hindsight.

Retro Rocket · « **Reply #23 on:** February 27, 2015, 05:56:08 PM »

Quote from: brazwell on February 27, 2015, 05:43:14 PM

I actually don't have the original studs...funny little thing, I tore this motor down several years ago and became preoccupied with another motorcycle and school. Poor decision making in hindsight.

Thats a shame, but also you weren't to know...

BPellerine · « **Reply #24 on:** February 27, 2015, 07:29:51 PM »

put ape studs in my engine and they were a snug fit in the cases,and more than a couple threads showing at the head,were your ape studs a good fit in the cases ,or loose going in?as stated someone may have run a blind tap down the holes and taken the taper out of the holes letting the stud go down further??if you are worried about the bearing fix you could always make some spacers out of round stock.just some thoughts.bill

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Author Topic: APE studs too short, what am I missing? CB750K (Read 2754 times)