Rotor/Primary gear problem

[Nobby]

I'm rebuilding a Super Rat 93 motor and have run into a problem during reassembly. The clutch rotor gear is contacting the primarary gear when I titghten the clutch nut down. Everything spins freely on its own but it seems the rotor sits just low enough that it hits the primary gear during engine rotation. Does the primary gear have to go on a certain way? It looks symmetrical to me but I don't know. It only wants to go on one way, anyway. I'm thinking either the primary gear is sitting to high (but I'm positive it's fully seated) or the pinion gear is too low, causing the rotor gear to sit too low as well. Most likely
I'm overthinking it and it's something simple.
Any suggestions as to what might be going on? Thanks guys!

[hodakamax]

Hmm, is the clutch thrust washer inner 904016 in there?

Max

[Nobby]

Yes, it is. With the rounded side facing the engine.

[hodakamax]

There's an ice storm going on and I can't reach the Hodaka shed tonight. Let us look tomorrow, (if I have power!) I need to look at an example. Another thing to look at is the clutch pinion bushing might be crushed and a little short. Just guessing at this point. Check for flaring, maybe someone can give us a length on that.

Max

[Nobby]

Thanks Hodakamax. Good luck with the ice storm and be safe!

[matt glascock]

I may be off my rocker here, but according to the Wombat bible, there is a "sidedness" to the primary gear and therefore, it needs to be marked on the outer face so that it can be reassembled in the exact same way. I am assuming, hopefully correctly, that the 100cc line is the same. Have you tried reversing the primary gear? Just a thought.

[Nobby]

I don't think your off your rocker at all. I'm pretty sure the primary gear went on opposite of how I have it, but I cannot get it on any other way. The gear looks symmetrical, but there may be a subtle difference between the two sides. No matter how much I try, it won't even begin to slip on the splines from the side that I believe went toward the engine and I'm not sure why. But I think you may be on to something there.

[Nobby]

Ok, I filed the splines on the primary gear and was able.to install it as I believe it came off. Same problem as before. It's gotta be on the pinion side of things, I think. If the pinion gear sat a millimeter higher, there wouldn't be an issue. I thought that maybe when I installed new crank bearings, the bearing didn't fully seat, but that's not the case as there is no gap between the outer bearing shell and the boss on the case. Worn thrust washer maybe?

[matt glascock]

I'm with Maxie. If I was you, I'd dig a little deeper. Remove the clutch basket. Be CAREFUL here, the holding nut is a left-handed thread "righty loosey lefty tighty" affair - don't ask me how I found that out. Deep to the pinion gear is the pinion bushing. It might be mushroomed from wear or more frequently, overtorquing. That will cause misalignment of the pinion gear with the primary drive gear. If you don't have one, invest in the official expanded Hodaka Workshop Manual - the one that features detailed information on maintenance of the Ace 90, Ace 100, and Ace 100 Super Rat. Best money I've ever spent. It gives step-by-step instructions on everything from routine maintenance to complete motor rebuilding in an understandable way for anyone with reasonable mechanical skills. It also has a comprehensive list of all torque specs which I follow to a "T" without exception. It and the companion Wombat Workshop Manual are used continuously here.

[hodakamax]

Ok, I'm awake and still have electricity. Funny, I woke up thinking about this first thing. There is also a 904015 washer that sets inside the 914002R clutch rotor gear. It doesn't show well in the diagram as it is on the other end of the clutch pack and against the clutch hub. Make sure it is there as shown. Keep us posted.

Max

[Nobby]

I finally found the problem and I'm ashamed to admit it was my mistake. I have a spare Ace 90 engine so I popped the clutch off of that and compared the two setups. Turns out I had the rotor gear on upside down which made it sit way too low and interfere with the primary gear. After a few dope slaps to my head, I put it together and it works as it should. Wow, I can't believe I did that! Anyway, thanks you guys, for all the help. I really appreciate your taking the time to offer advice and ideas.

[hodakamax]

You are welcome, a mystery is always fun. If there is a wrong way to assemble something, I usually try that method first, so I understand.

Max

[viclioce]

Max! Been there, done that & Ed sent me the T shirt!