Topic: cb750 cylinder stud woes - buyer beware.

[timdhawk]

Boy, where to begin: Short version of long story...

4 yrs. ago I bought 16 APE "heavy duty" cylinder studs from a reputable dealer we all know. I installed them back then and had one stud snap off under the nut during the torque sequence before I reached the set torque. The reputable dealer was nice enough to send a replacement. Changed it out and ran the motor for 500 miles before this happened:






After I catastrophically went kaput on the highway, I pulled the valve cover and found the tip of the stud laying next to the valve spring with no nut in sight. (see first pic)  I found the nut in the case bottom all chewed up.
I called APE for a replacement stud and when it got here I noticed the thread length was different than my others. I pulled the rest out of the case to scrape the gasket and double check those as well and found another one of my original ones was also threaded short.
The first one is the newest (uninstalled) replacement stud.
The second one is one of the original ones but the only one of the group not threaded the same.
The 3rd one is the one that caused all my woes. And you can see that the first 2 are not even threaded the same in comparison to the rest.



I called APE and they, rather testily,  insisted that they have been cutting studs the same way from the same specs for 35 years.
Needless to say, the reputable seller that I bought them from no longer sells APE stud for "quality control" issues. Given all the other APE "issues" I've read about on other boards, I'm fairly certain the reputable seller is the more believable one in all this.

Moral of the story: Be cautious of APE studs. Your mileage may vary.

[KRONUS0100]

geez id be really pissed off and sending those pics to an attorney.  not for sure what exactly, but id definitely be talkin to one.  thats ugly, and could have been way uglier

[Jerry Rxman Griffin aka MuthaF'er]

Sorry you've had problems. Mine are fine. I torqued mine 20 - 22 ft lbs using new Honda washers and nuts. Same with my lower case studs.

[kmb69]

I called APE and they, rather testily,  insisted that they have been cutting studs the same way from the same specs for 35 years.

And over those 35 years, there are many stories of their studs breaking. Even when properly torqued. They roll the threads AFTER heat treat and the hardened material is developing micro cracks. A thread is rolled on a diameter pretty close to the pitch diameter of the thread. The rolling process pushes the root diameter in and causes the displaced material to flow up to the major diameter. Could be caused by "trash" on the rolling head but I think they should be rolled BEFORE heat treat while the material is more malleable. IMHO. We roll many threads in our shop to Customers' specifications. They all specify rolling threads prior to heat treat on high tensile strength material.

wiseGEEK says:
...
The deformation of metals involve changes to the makeup of the material itself. For example, metals that undergo this process of plastic deformation experience a condition known as dislocation. As stress of some type is exerted on the metal, the material reaches a point known as the yield strength. When this point is achieved, the pattern of the molecules that make up the metal begin to shift. The end result is that the molecules realign in a pattern that is shaped by the exterior stress placed on the object.
...
The speed with which the plasticity takes place is also important. In situations where the stress causes changes rapidly, there is a chance that the material will be unable to conform to the pressure and may break. For this reason, plastic deformation as it is used in the manufacture of goods involves carefully controlling heat and pressure, allowing the structure of the material to adapt to the new conditions and incrementally bend until the desired shape is achieved.
...

[tlbranth]

Many years ago, my engine was frozen from lack of use. I disassembled the top end, fixed things up and managed to strip out several spots where the head bolts threaded in even though I torqued them. I Helicoiled those spots and decided on studs instead of bolts. I got them at Tacoma Screw but to my knowledge they were jive studs - not hardened. I didn't know any better. Never had a problem though. If I'd bought specially hardened studs made just for this application and they broke like that, I'd be after the 3@57ards who made them. If there are a lot of complaints, maybe a class action would work. These bikes are worth too much to let it slide.

[754]

Kmb69 do you want to make some?
 Are they really heat treated after, or do they use a HTSR 4140?

[KrautKoffin]

I feel like I'm being told half of a story. Who is this 'reputable seller'?

[dave500]

im not a 750 guy but do the stock ones fail?

[Retro Rocket]

Stock ones are weaker Dave, they don't take the higher torque loads a hipo engine needs to stop oil leaks. I have had an APE one break as well but to be fair it had been in the engine for 30 years and only broke while being re-torqued, I'm going to use the Kibblewhite ones CycleX sells now, they are expensive but that really doesn't bother me at all....

http://www.cyclexchange.net/cycle_x_super_studs.jpg

http://www.cyclexchange.net/Engine%20Parts%20Valve%20Trane.htm

Half way down the page....

[timdhawk]

Does anyone have any APE studs laying around that they could measure the overall length of the threads on both ends for me? The more I read and the more I think about it, the more I wanna push this a little harder at APE HQ.

[Big Jay]

If someone says they had a stud fail, we simply send them replacements without asking for proof that they were ours. We are not the only one making these.

We sent this guy a replacement and it did not match what he had. We have made ours the same since the 70s.  Not sure what the guy had.

Always try to help.

[madmtnmotors]

I feel like I'm being told half of a story. Who is this 'reputable seller'?

+1

[MCRider]

I feel like I'm being told half of a story. Who is this 'reputable seller'?

+1

Just asking. I bought mine direct from APE. Didn't know they had dealers. I had another set from a dealer who didn't disclose to me who the actual maker was. Came in a nameless plastic bag. They were all too short.

APE's came on an APE card/blisterpak, with APE written all over it.

[Retro Rocket]

I feel like I'm being told half of a story. Who is this 'reputable seller'?

Considering he actually bought these studs elsewhere and has shown no proof that they were APE's studs, I would like to see some proof as well. I have had dealings with Jay and everything went a smooth as it could possibly go, even went out of his way to do things he didn't have too. I think if your going to trash someones  reputation {or try too} then at least detail all the facts, you've named APE, who's the dealer..?

I called APE and they, rather testily,  insisted that they have been cutting studs the same way from the same specs for 35 years.

Well they have and they are industry leaders and have been for over 35 years and use state of the art equipment, the more i see of this thread the more i think you've been screwed by your "dealer". Like Ron said, these studs come in a blister pack and it would be glaringly obvious if the studs were of a different composition....., Again, who's this dealer you bought them from and why didn't you take up your problem with them...?

[dave500]

maybe they were non ape studs?sold as ape studs?like unbranded jt sprockets in plain packs sold as jt sprockets?

[bwaller]

Jay is a member here and is good to stand by his products. What kmb69 descibes about rolling the thread first before hardening makes sense to me. I have heard of actual Ape studs breaking, although I haven't had the problem. I wonder what process APE uses.

[Big Jay]

Even if they weren't ours, but the guy thought it was, we don't care, we send him a replacement anyway. We have had people over tighten ours and pop the top off in the past, so we just take care of the guy.

Jay

[kmb69]

Kmb69 do you want to make some?
 Are they really heat treated after, or do they use a HTSR 4140?

Thanks Frank, No. I don't want to be in the cylinder stud business. And I didn't really mean to be baggin on Jay. It's just that you frequently read about somebody breaking an "APE" stud. maybe they are and maybe they aren't. I have used them without any mishap. If you are not there to do clinical failure analysis, it's hard to identify the root cause. Maybe the "Torquer" did not apply oil to the threads. Maybe the "Torquer's" wrench needs calibration. Maybe it's a defective part. Jay has probably sold tens or even hundreds of thousands of his studs. Kind of like the 50% divorce rate that gets to be 100% if it's you.

If someone says they had a stud fail, we simply send them replacements without asking for proof that they were ours. We are not the only one making these.
We sent this guy a replacement and it did not match what he had. We have made ours the same since the 70s.  Not sure what the guy had.
Always try to help.

That's standing behind your stuff right there! Hats off to Jay! He also openly publishes his process on his website:

"Heavy duty cylinder studs are necessary to prevent head gasket leakage in high compression and turbocharged engines. Stock studs are made from poor material that will stretch and allow gasket leakage. APE studs are made from heat treated chrome moly, centerless ground, and have rolled threads after heat treat for maximum strength. APE originated heavy duty studs for performance motorcycles and today is recognized as the industry's leading manufacturer. We supply studs to all of the top engine builders. No matter whose parts you have in your engine, join the top names in racing and insist on APE studs to hold it all together."

Heat treating after thread rolling would definitely drive the cost up as they would need to be heat treated in a vacumn and back filled with gas to prevent oxidation. Most of the threads we roll prior to heat treat are on tooling parts made from VascoMax 300 and stainless orthopedic medical devices where failure is not an option. Maybe the chrome moly is a different animal.

[KrautKoffin]

So who is the dealer and did they come in the blister pack when you bought  them originally?

[timdhawk]

EDIT:

ya know what... after writing a long diatribe and then doing a lot of searching and thinking on this... I think I'm gonna back away from it and apologize to APE at this point. I bought the studs over 4 years ago and I can't prove or say with 100% certainty that they were APE studs even though they were billed a "HD Studs" and my memory says they were but, I've bought a lot of #$%* in the last 4 years and could very easily be transposing memories.


So I'm just gonna say #$%* it and chalk it up to a head scratching learning experience and drive on.

Big Jay/APE - my apologies for disparaging your studs. I would have sworn they were your studs, but after doing more research I can't say I'm as sure as I was 2 days ago.

[Don R]

Anyone using an older ft lbs torque wrench on these is asking for a problem. 
Not saying that was the case here but it has been a problem in the past. Just saying.

[PeWe]

I broke one APE HD stud in the same manner as yours. Stud snapped just under the nut. Torque was just before 22 ft lbs if I remember correctly. That specific stud felt different earlier during the torquing process, a soft feeling.

My old std OEM studs never close to snap despite 21 ft lbs in torque which I had done to them several times, 6 times if I remember all head off.

My package bought on eBay in the std package as everywhere else. I bought a new package here at my local dealer. Next time torqued up to 18 then almost 20, let it wait over night. Next day 20 hours later I re-torqued each nut one by one by release 1/4 turn and torqued to almost 20 ft lbs.

I regret that I did not replace all when I bought a new complete package when one snapped.

[Geeto67]

FWIW, there are a lot of "knock off" imitation products flooding the market these days. There are enough people buying cb750 studs to justify someone making a counterfeit set and selling them to those who think they are getting a deal.

[PeWe]

There are several old threads about snapping HD studs.....

[timdhawk]

Well, I broke down and bought a new set of APE studs - still in APE packaging and everything - and they do in fact look different than the ones that started all this that I bought from the "reputable" seller. So who knows... we'll see if these do the trick.
Oofda!

[PeWe]

My new set I bought locally here at the old tuner looked exactly the same as the set I bought on eBay contained one that snapped.

I'm worried anyway. I hope they will not snap when I torqued less the other time. Cometic fiber head gasket might be softer for the studs as well.

I'll replace them next time the engine is out. I saw that CycleX has HD studs manufactured by Kibblewhite.

[PeWe]

Important to not believe in excessive torque. Kibblewhite specifies max 22 ft lbs.
"Tighten the head nuts down evenly to achieve 18 lb ft minimum to 22 lb ft maximum"
http://valvetrain.kpmivalvetrain.com/Asset/999-101355.pdf

[KrautKoffin]

You should just delete this thread.

[Jerry Rxman Griffin aka MuthaF'er]

Even if they weren't ours, but the guy thought it was, we don't care, we send him a replacement anyway. We have had people over tighten ours and pop the top off in the past, so we just take care of the guy.

Jay

Not to say a stud broke or didn't break or whose it was BUT.... I'm a Jay backer (but staying out of this 'situation'). I can attest to the effort he goes to in order to make things right. We worked through a difficult, expensive and time consuming situation and he took great care of me! Thanks again Jay. These old Hondas are what he got started with and I'd BET he cares more for our bikes than the Busas even though his bread is buttered by Suzuki stuff. AND it's my understanding all the CB750 machining is done by no one else besides Jay.

[PeWe]

You should just delete this thread.

Why delete?
Information like this is very important on a forum where things are up for discussion.

Fact is that there are several threads about snapped studs, especially since 2009/2010. Your story ended up in a major engine damage nobody wants.  It can be very dangerous if the engine suddenly lock-up. I have HD primary chains that will withstand forces longer before release getting a worse situation with a nut locking up.

It can be seen that IF one stud snap, replace them all when it might be a bad batch or just something else....

I want to replace all mine since I read your story. I have snapped one HD stud when assembled the engine April 2013, replaced the only one that snapped. I cannot continue with the 15 other HD studs that might be bad and get broken engine if lucky when locking up.

I'll take the engine out when I need to double check o-rings under the cam towers. I have never forgot them before but I'm not sure this time.

The winter is here and I have time. I have to trust the engine when I have spent rather much on the bike the last 2 years.
I'll try the Kibblewhite next time, that's why I found the instruction and its max torque.

[PeWe]

Check torque wrench!
I snapped one HD stud as I wrote earlier. Replaced only the snapped one despite I bought a complete set. I had that in my mind since then which I have to cure.
I bought a new complete set of HD studs AND a new torque wrench when it is better than borrow from the mechanical lab at my job.

My idea was to replace stud by stud without taking head off. First step was to find actual torque with my new torque wrench. I had to tighten about 36Nm to make the nuts to move!! tested on several head nuts. I know that I torqued less 2:nd time after stud snapped, about 19- 20 ft lbs (25.7-27nm). Now almost 1 year later it should not need more to tighten it further. The torque wrench I used when stud snapped must have been way off! 36 instead of 26Nm is 10/26 over torque +38% !!

This means when I torqued ~21 ft lbs was in reality >28 ft lbs!  Instruction with Kibblewhite HD studs states 22ft lbs as max. I think APE has same limit.

I trust my new torque wrench. HAZET 5120-2CT  Made in Germany, calibrated Oct 2013 and has almost spot on at 36Nm.
Invest in tools you can trust, it can cost a lot to repair.

[Jerry Rxman Griffin aka MuthaF'er]

Very good point indeed. I have a Harbor Freight (cheap) clicker and an older Sears Craftsman pointer that I can compare. They are close. My cheap clicker is good when comparing and it's very handy as I don't have to watch a dial which makes me feel the clicker is actually the better of the 2.