Page 1 of 1

NH80 - Removing drive gear for crank seal replacement

Posted: Sun Mar 15, 2020 1:18 pm
by breaze
Hi all, working on an 83 Aero NH80 and I'm inside the leftside engine cover. I'm trying to work on the kick start mechanism but also notice a little oil/fuel mix inside the case, so I thought I would change the crank oil seals while I'm in there. It looks like the drive gear will have to come out in order to get to some of the kick start components and also to get to the oil seal.

My questions: Anyone ever pull one of these? Pullers available at Autozome? Which puller did you use and was there any problem pressing the gear back on?
drivegear.jpg
drivegear.jpg (579.93 KiB) Viewed 8699 times

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Sun Mar 15, 2020 2:27 pm
by breaze
Argh, thought I found the perfect work-around tool. Just bends the hinge and strips the threads - that gear is on there. Heard those guys at Autozone all have Corona virus so trying to stay home. Maybe I heard they like to drink Coronas, not sure...
drivegear2.jpg
drivegear2.jpg (461.6 KiB) Viewed 8694 times

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Sun Mar 15, 2020 3:19 pm
by bonesv
Use some heat to expand the gear. Also, get a proper tool before you do real damage.

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Sun Mar 15, 2020 4:51 pm
by breaze
Thanks, good advice on both fronts. The proper Honda tool in the manual is a little out of my price range but I found this post which suggests a tool: http://hondaspree.net/phpBB3/viewtopic.php?f=3&t=32108
I'll remove the engine and give it a try with heat.

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Tue Mar 17, 2020 4:17 pm
by harleyracer59
use a steering wheel puller. and maybe a little heat. they press on to a slight taper. like the 83-84 aero 50. theres no keyway to keep them from spinning.

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Tue Mar 17, 2020 4:25 pm
by harleyracer59
question for anyone with a good explanation.. why were these aero 80's, first gen aero 50 ab07, and I believe the aero 125's a non-splined crank output shaft and work fine and don't slip yet the second gen aero 50 af05e splined crankshafts slip, strip the splines and become useless?

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Tue Mar 24, 2020 9:22 am
by breaze
Well, I worked on it for 2 days - tried heat and 3 different pullers but nada. Started making some calls to find someone to do it for me and ended up with a recommendation for 2 guys who work on these old 2 strokes in Lawrenceville, GA. About 30 mins out of Atlanta, back in the woods on a hill off the highway, dog on the floor, garden in the back. Brian and Dan from "Motorcycles and Trikes".

This is one of the things I love about working on these - the people you meet. Dan recognized the engine (had it out of the bike and in my truck) and immediately knew it was an NH80 - imagine that. He went in the back while I waited in the waiting room - 2 chairs, 1 occupied by a skeleton with a sign above saying "waiting room for disgruntled customers". In a few he came around the corner grinning with the drive gear in his hand - never said how he got it off and I didn't ask but he made sure the threads were fine and the nut came on and off easily. When I asked how much he didn't want to take any money, then accepted $25.00 when I insisted. You meet the nicest people on a Honda.

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Tue Mar 24, 2020 12:35 pm
by bonesv
Now you gotta drive back up there and have it pressed back on. You might have asked him how to go about that on your own.

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Tue Mar 24, 2020 1:00 pm
by breaze
I did ask him about it, and as he was showing me how to make a slide hammer oil seal remover out of a screwdriver, he explained that it would go back on fairly easily. I used a ceiling fan tube to knock it back on without needing a lot of force and it is working fine. Are you gonna chastise me about that also?

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Tue Mar 24, 2020 5:29 pm
by harleyracer59
that sounds like an interesting trip. glad to hear you got it handled. and that's cool you gave him a tip anyways. im sure that was a good move, probably why he had no problem showing you how to pull the crank seals by pulling yours. and im sure if you ever need to go back, he will be just as friendly. it pays to be kind and I like support local small shops myself. if we don't there wont be any left some day. hope you get this beast running soon! stay healthy!!!

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Wed Mar 25, 2020 9:14 am
by breaze
Thanks - good project for social distancing. I'll get there but having the same problems as always with these 83 - 84 NH80's. Almost impossible to polish the seat enough to seal and keep the carb fuel level below the top of the bowl and the control assembly/by-starter/choke which has to be cleaned and tested again. Sure wish they had put removable seats in the carb like on my CT90's, I hate having to replace the top part of the carb when the seat gets worn out. Right now the choke control box is pulling thru the air intake when cold (should be only pulling thru fuel intake) so I'll be soaking it overnight - don't mind sorting these out though because once they are working, my experience is that they really perform well.

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Wed Mar 25, 2020 4:05 pm
by harleyracer59
do these carbs have an electric bystarter or that goofy heater hoses to and from the head setup? have you thought of swapping/ upgrading the carb for something newer, bigger, better performing, easier to get parts for? I know in Europe they make spigot adapters that'll bolt to the manifold and allow you to slip any number of carbs into the spot. just an option if the old one ends up NFG.

Re: NH80 - Removing drive gear for crank seal replacement

Posted: Wed Mar 25, 2020 4:57 pm
by motormike
breaze wrote: Wed Mar 25, 2020 9:14 am Right now the choke control box is pulling thru the air intake when cold (should be only pulling thru fuel intake)
so I'll be soaking it overnight - don't mind sorting these out though because once they are working,
my experience is that they really perform well.
....lol....good luck bu-u-u-u-u-uuuuddddy... :urban: