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View Full Version : Bad day for crossthreading.



phidauex
04-01-2004, 02:09 AM
No, not crossdressing, crossTHREADING. ;)

I switched to a yellow contra spring today from the white spring, and I ran into a problem reassembling. Somehow the threads that the big huge nut goes onto to hold the clutch down got mangled, and when I took the nut off, it got worse. I switched to the yellow spring, and then I could not get the nut back on, it wouldn't thread. I didn't have a tap that big (geez, who does?) so I couldn't chase the threads, so I just used my impact wrench to hammer it back on, crossthreading or no. I need this scooter every day, so I went brute force.

However, the next time that nut comes off is the last time its ever coming off. Can anyone tell me what that part is called? I'll need to replace the nut, and the part it screws onto, sometime in the next few thousand miles. Is this the 'torque driver' that malossi offers? Or do I need an original aprilia part for this? The clutch and spring are fine, its just those threads which are horked.

Also, while putting the case back on the transmission, I somehow crossthreaded three of the bolts!! Damn. However, I did have taps that size, so I ran the taps through the holes to chase the threads out, and ran the bolts through the die, and it all reassembled fine. Sadly I couldn't do that for the clutch...

So be careful out there, guys!

peace,
sam

scootnfast
04-03-2004, 03:59 PM
Sam,

Hey whats going on... As far as that nut goes and the threads, the threads are actually on the end of the final gear drive shaft. Check out my thread on how to change your rear end gearing and you will see what I am talking about. If I were you, I would just go with the new final drive kit from malossi. It comes with the new shaft and nut.

OH, and even if you did have a tap die that large, the shaft is hardened. You try to run a tap on that thing and you are going to just break the die.

Good luck!

scootnfast
04-03-2004, 04:05 PM
Sorry, I just re-read your post and realized your talking about the BIG nut on the end of the torque drive pully. I think malossi sells a new supossedly "high performance" torque drive, but I am not really sure if they make them for the ditechs or not. But I am sure it will have a new nut with it.

TiminIndy
04-04-2004, 12:37 PM
Hey Sam-

Do you think the threading got screwed up by your method of tightening with the electric impact that you don't recommend to anyone else?

How does it go with the Yellow Spring? Are you still using the 6.0 g rollers?

phidauex
04-04-2004, 06:08 PM
Originally posted by TiminIndy
Hey Sam-

Do you think the threading got screwed up by your method of tightening with the electric impact that you don't recommend to anyone else?

Lol, as poetic as it would be for me to screw things up by the same method I tell other people not to use, I don't think thats what caused the problem.

On the clutch nut, I think the problem is that I was changing the spring by myself, and as the nut was sitting on the very last thread, I wasn't holding the clutch down hard enough, and the spring pushed the nut off before I could finish unscrewing it, meaning the last thread got munged, and the threads in the nut got a little bent too. My attempt to get it to rethread didn't work, and maybe just made it worse. What I really need is some sort of jig that will help me remove the clutch spring. I'm thinking a circular piece of plywood a little bigger around than the clutch assembly with a hole in the middle that is big enough for the nut and socket in the center. Then a pair of C clamps could grip the top of the wood ring and pull the clutch down against my workbench from both sides evenly, holding it all around, while I work with the nut.

Having a second person hold the clutch compressed while you undo the nut helps too, but I didn't have any helpers around and I forged ahead on my own.

For the transmission cover bolts, I only do those by hand with my ball-head allen wrenches. I'll admit it was late at night and I was a bit tired as I was reassembling the cover, so I probably wasn't as precise as I should have been. At least those ones were an easy fix. I get more use out of this tap and die set than I would if I were a better mechanic! ;)


How does it go with the Yellow Spring? Are you still using the 6.0 g rollers?

It goes quite well, actually. The hesitation at 30mph is gone, and the takeoff is more decisive. Top speed seems ever-so-slightly decreased, but I haven't had many chances to get it all the way up to top speed recently, so its hard to tell.

I have a feeling that it is overreving a tiny bit. It seems like I hit the powerband, then pass it by a little bit. This feels better than the white spring which, especially as it softens with age, seemed to lug the engine at around 30-35mph, only picking up again over 40mph.

I'm going to get a set of 6.5g weights, and do a half/half mix with the 6.0g, and see how that grabs me.

The yellow spring doesn't let me 'cruise' at higher speeds like the white spring did, but I appreciate the fact that power out of corners is much better delivered with the yellow spring. Its a bit of a tradeoff, but the ability to drop gear ratio faster is helpful for me.

All in all, it feels like an improvement, assuming I can drop the revs a tiny bit with some slightly heavier weights. At this point in my transmission tweaking, changes are very slight. The last few changes I've made have all produced pretty damn good results, at this point I'm just tweaking it to match my riding style.

peace,
sam

TiminIndy
04-04-2004, 06:51 PM
Originally posted by phidauex
I'm going to get a set of 6.5g weights, and do a half/half mix with the 6.0g, and see how that grabs me.

Do they sell anything between 6.0 & 6.5?? I was going to get one or the other with my Leo 'S', but it sounds like I may need both so I can do half & half.

phidauex
04-05-2004, 04:19 AM
Originally posted by TiminIndy
Do they sell anything between 6.0 & 6.5?? I was going to get one or the other with my Leo 'S', but it sounds like I may need both so I can do half & half.

I don't know, but I've never seen any in-betweeners for the stock variator. Or any variator for that matter. Of course, they might exist, just not where I can find them.

My gianelli NRX came with rollers that were already installed when I bought the scooter. When I pulled them out and replaced them, they weighed in at about 6.2 grams each, plus minus a little. They had some obvious wear on them, so they could have been 6.25g originally, or maybe 6.5g and the wear is just more than it looks, I'm not sure.

You might just want to get a set of 6.0 and a set of 6.5g. That way you have 3 settings to try, and extra rollers are always good for tweaking and playing with new hardware.

peace,
sam

EnergyDK
04-10-2004, 07:40 PM
The one with the threads is called "fixed half-pulley". The Malossi torq driver is the moving part.

jd0g1
04-14-2004, 11:17 AM
Polini makes a 6.3 gr.
Bought them right here from AF1 $12.99
They are red in color. The Polini weights use a color scheme to differentiate, unlike malossi.
No clue if that affects their resistance to wear. My guess, it would make them wear faster if it's like any other colored vinyl/plastic/ composite. I don't really care, because weights are cheap, thank goodness.