I've got my Stage IV Clutch yesterday, and we tried installing it. Now, the Flywheel will not slide into the Crankshaft. My mechanic said the CS diameter is 1.679 I think he told me, and the Flywheel is 1.659. Not sure the exact numbers he told me, but I know for sure the difference was .020"
How can this be? I'll be calling Spec on Monday, and I wanted to know of any known issues like this from anybody here.

I've got two options here, one... have my old Mcleod FW resurfaced. Two...bore the Spec FW to fit my Crankshaft. Of course, I can call Spec and have them send me the correct one.
Could this have been a machinist error?

When I measured the Mcleod I have, it came up to 2.0560. Maybe I my caliper is out of whack or something...

 

Well, just a quick update. My mechanic was in a hurry, and didn't zero out the caliper. The exact measurements, still came out short. The crank shaft is at 2.065 and the FW is at 2.059. I called SPEC, and they told me to send my flywheel back for inspection, if it comes out like I said, they're going to upgrade me to an aluminum flywheel for free. I don't know if that's a good thing or not, but I think I'd take the aluminum flywheel if there's a benefit from it.

 

This is just out of sheer curiosity, but why did you go buy a SPEC 4? Did something happen to your street twin?

 

Well, my ST was down to its rivets. It was slipping, and was already scoring the flywheel. I could've sent it back for rebuilt, but because I'm in a hurry to get my car back, and the deal I've got on the SPEC IV, I decided to give it a try.
I don't know why my ST didn't last as long as I've seen others last. Maybe because the car sat for 2 years, and the elements may have deteriorated the discs. I don't know.
I still have the ST. I'm going to send it back to be rebuilt by MCleod. This won't be for another month or so, that way I will have another spare clutch, should the SPEC IV have problems. For what I've been told, the stage IV is a pretty durable a good clutch. We'll see what it comes out of it.

 

I am having a little trouble with my spec 4. How did your MCleod perform when it was in good shape. Can it be used on the street????

 

The ST is a wonderful clutch. I really liked it. Good street manners. Clutch pedal is a little strong, but you'll get used to it. Good clutch all around.
I never had any problems with it on the street or anywhere for that matter. Grabs like crazy. Good stuff.

Let me ask you about your SPEC IV. Is it as aggressive as advertised?
Some people say I'll be fine, some other vendors' opinion is that it will be too aggressive for the street. I'm taking my chances. Even if it's too aggressive, that goes with what I'm looking for. How aggressive? I don't know yet.

 

I run a ceramic stage 4 and its pretty agressive. Running street tires at the track i chirp 4th at ~95mph. When i first got it broken in, i side stepped 2nd. With the stock clutch i would spin pretty good, but with the stage 4 i went sideways into the other lane. No slip to that thing.

Its my estimation that when the clutch pedal is all the way out, this thing will NOT slip unless it has an insane amount of power thrown at it.

I daily drive mine, and only problems i have ever had was in rush hour kansas city stop and go traffic on the interstate, the clutch began to heat up. It started to groan and be very grabby. I got off the road and let it cool down for about 30 mins, then it was fine again.

 

i just dropped in my new 383, and a spec stage4 at the same time........havent driven it yet, but did not have any fitment problems. i put in a new stock flywheel also.

 

I'm getting my new flywheel tomorrow. I'll find out about how this one fits. I'm sure the first one was a machinist error in the specs. We'll see.
-Goose