APE cylinder studs & nuts, a good investment?

[Pat Conlon]

When rebuilding your motor, I wonder if folks have had any experience with replacing their oem studs with APE cylinder studs and nuts.
When looking at the APE site, I note that it mentions that these cylinder studs (CS1100FJ) fit the "late" FJ1100's, I wonder about that.
http://yamahazone.biz/studs.html

I have the early FJ1100 motor, so I wonder if the later FJ1100 motors ('85 etc.) use a different cylinder stud than the early FJ1100's.

Thanks folks.   Pat

[craigo]

http://www.fjowners.com/index.php?topic=479.msg20551#msg20551

I read to stay away from the ape studs and use OEM ones.  See the thread above.

Cheers,

CraigO
90FJ1200

[Travis398]

+1 for oem

[RichBaker]

I'm pretty sure RPM randy says to use the stock stuff...

[Pat Conlon]

Ok thanks guys, I remember that thread now. APE studs are out.

FYI  I noted in the Zanotti online microfische that the 84/85's use a different part # than the '86 thru 90's and yet a different part # for the '91's to '93's.

'84/85's  use # 10441; 10442 and 10443 studs

'86-90's use # 10481; 10514 and 10515 studs

'91+    use # 10561; 10562 and 10563 studs

I wonder what the difference is?   Thanks again!   Pat

[rktmanfj]

Ok thanks guys, I remember that thread now. APE studs are out.

FYI  I noted in the Zanotti online microfische that the 84/85's use a different part # than the '86 thru 90's and yet a different part # for the '91's to '93's.

'84/85's  use # 10441; 10442 and 10443 studs

'86-90's use # 10481; 10514 and 10515 studs

'91+    use # 10561; 10562 and 10563 studs

I wonder what the difference is?   Thanks again!   Pat

The '91s are a bit less 'studly'...             

Randy T
Indy

[racerrad8]

That is the three different lengths used in all generations. We will have to determine which studs you need to use by the block and head. We might also want to think about installing Heli-Coils in the old case with those new part you are talking about...

I replied to your email as well...

In reference to APE studs; NO!

Randy - RPM

[andyb]

Oh!  I found a lovely picture of what happens when you use the APE studs!  Let me look for it a minute....


There's a few others over there as well.  Some familiar names posting over there.

[VMS]

Wondering what that has to do with APE studs? I just read the thread, and he said the crank broke, and the APE studs are the only thing left that was holding the engine together.

"This motor was blown up while racing a dwarf car. I actuall drove it back to the trailer like this! When i tore it apart, as soon as I pulled the cyllinders off the studs, the motr felll in two!  The head studs were the only thing keeping the pieces together."

I've used the APE studs and nuts on my Legends motors and not had a problem. I also sell them and haven't had a customer come back, just my personal experience.

[andyb]

The cases are weakish at the #4 area, the stronger studs will crack the cases at that area.  Not really a common problem unless you're running really high compression or a power adder (i.e., a turbo setup, nitrous, or a dragbike running alcohol).

The crank broke because it's poorly supported, really needs another bearing in there someplace.  In an overrev it's a pinch fragile!

I guess it's down to designing in weakness to where you want it.  For my build I'm using stock studs, because I'm expecting to see an honest 10.5:1 compression ratio and then building it to run as much as a 75 shot of nitrous in addition.  If the extra pressures within the cylinder become more than things can handle, the stock studs will stretch a pinch and I'll blow the headgasket.  Easy fix within the frame, and assuming I catch it in time the damage to the head will be minimal (nevermind that I've got a pair of spare heads).  With the stronger studs, the force would get transmitted down to the bottom and at best pull the threads out.  Once those have been reinforced/repaired with a timesert or the like, the next area to break is the cases themselves.  I'd much rather blow a headgasket, myself. 

Further, I'm going to use sidegapped plugs of the wrong heat range for the application (too hot, rather than a cold plug) so that with luck it'll just melt the ground strap off if I get detonation or screw my tune up (or have a fueling failure, too high of bottle pressure, etc).  Once I've seen things with an AFR on a dyno, then I'll look at getting the proper plugs involved, but again....where do you want the failure?  Swapping a torched plug is a matter of five minutes at the track, swapping a holed piston (or cracked cases, or headgasket, etc) is a more involved job to be done in the garage.


Randy can probably elaborate more on broken cases from overly strong studs.  The pictures I linked was just an example, the crank let go first, the question is why (probably a fatigue/overrev situation, I'd imagine).  I couldn't find good pictures of the cases failing first.  Also, there's a possibility that what happened in that guy's case is that the cases let go first, cracked, which allowed the crank to flop around, leading to flexing and eventual destruction of the crank itself, which then let everything go to bits.

[VMS]

Ahhh, so its you crazy 3 second nitrous turbo bike guys.
Gotcha.
Thanks for the explanation Andy. Explains why I never had a problem.

Jim