Major Malossi Mismatch

[Wheelman-111]

Greetings:

How smart I thought I was! I ordered a spare rear tranny cover off EBay. The seller said it was from a 1986 Aero - close enough. It got here today.

Pulled out the Malossi 16/32 with new driveshaft and... It doesn't fit. The Malossi shaft measures 17 mm according to trusty HF caliper.




The ID of the case bearing is 14.5.



There's not enough grease in the world for that to press in!

I have not disassembled the '87 Aero's tranny so far to check its size. If anyone has one lying open and feels like measuring, please let me know. The cover is similar but not identical to the one depicted in the Service Manual, which covers 1985 to 1987. Running change? Anyone recognize this particular cover from these Chitty pictures?





Wrong kit? Wrong cover?? Is there another bearing with the same OD & a larger ID that can serve to adapt the shaft to the cover? Sheesh, this may be more trouble than it's worth. Too late now, but I'm a little bit smarter...

[scooterwerx]

according to the ol trusty mitutoyo digimatic, the main OD of the axle shaft is 17mm, the ends are 12mm. the other gear that is replaced is ID 15mm. the malossi gears are exactly the same, they pressed in with no troubles, i know the 85 has different parts, dunno about the 86...leads me to believe its the wrong cover...

[Wheelman-111]

Greetings:

I suspected something like that. It's good to have the details. Maybe someone else will avoid this mistake. Thanks for your generous help!

[chevyguyjay]

ive got an extra 86 cover wheelman. ill mic it when i get home from work and send a few pics of it.

[chevyguyjay]

now to be honest, i dont know anything about the sizes of the aftermarket gears and shafts, but i would think that the 85 and 86 covers are the same. must be the bearing ID size. heres a couple of pics.....

[Clivester]

Hey Chevyguyjay:

Haven't you heard - Honda have gone metric

[chevyguyjay]

yep lol. u do the math. its not that hard.

[Wheelman-111]

Greetings:

The cover I received was from a 1985. There are obvious casting detail differences, but I think the centerlines are the same. Without an '86 or even my '87 out for side-by-side inspection, I can't say if the bearings' ODs are different or just "skinnier" bearings.

The metric-Imperial math is only combersome if you're oversizing by 0.0025 mm. Here we only need purdy close.

Metric or Imperial, you Chevy guys (and the rest of this Forum ) rock! Thanks.

[mousewheels]

The cover I received was from a 1985. There are obvious casting detail differences, but I think the centerlines are the same. Without an '86 or even my '87 out for side-by-side inspection, I can't say if the bearings' ODs are different or just "skinnier" bearings.

Partslist confirms bearing and case differences. But the case you have looks to be from an '84 Aero. '85-'87 use the same bearing. Between the 2 covers, bearing OD will be different too.

'84 - 6202 bearing -- 15mm id x 35mm od x 11 thick
'85 - '87 -- 6203 bearing -- 17mm id x 40mm od x 12 thick


1984 Aero transmission partslist



1985 Aero transmission partslist

I'm not posting the 86 and 87 images, but they are the same.

[Wheelman-111]

Greetings:

That is some useful information! You went to a great deal of trouble to help me out and I appreciate it. I admire your ability to manipulate the data and get it to post in the Forum. How tha heck did you do that?!

The seller of the spare Tranny cover seemed certain that it was off a 1985, but I think you're right. Otherwise how do you explain the clear differences between the bearing sizes? The cover I received is not exactly like either of the partslist depictions but surely Honda-san had several molds in operation. What matters is the size of the bearing "nests" and those resemble the '84. With so many running changes and Honda model name overlap, confusion is easy to understand.

Thanks to all the helpful Forum Scooterpersons once again, I have something to go on. The eBay seller mcpartman0jsq98 was
very apologetic, even offered to send me another cover for free, but he would not know if he had one until he purchased a couple of donor scooters in 2 weeks. He's been a good guy all along, and I acknowledge it was my mistake, not his. (well, maybe a little his...)

BTW, MW - how did you determine the bearing sizes (6202 and 6203) ? Is there a specs table somewhere or good old-fashioned measuring. Special thanks to you for your post.

[mousewheels]

You went to a great deal of trouble to help me out and I appreciate it. I admire your ability to manipulate the data and get it to post in the Forum. How tha heck did you do that?!

Wheelman - Your're most welcome. There's very little behind the curtain. I capture the windows in Paint, cut/paste to condense, save as a .jpg and post....

MW - how did you determine the bearing sizes (6202 and 6203) ? Is there a specs table somewhere or good old-fashioned measuring. Special thanks to you for your post.

The 6xxx bearings cross to industry standard sized bearings, so it is easy to get basic dimensions. Here's a link to NTN just type in the bearing number '6202'

http://www.ntnamerica.com/interchange.h ... [/quote]

[z50r-ghost]

NICE work, mousewheels... definitely a good post!! thanks for sharing the NTN info.

later, j