Mike's overdrive 5th gear install

[headcase]

I've seen one post about putting in this gear, and about how the case needs to be split. I'll have my engine on the bench soon to do the cam chain guide and a few other things. Will it really be that much extra work to pop the bottom off and install the gear? I'll be leaving the top end on (except what's needed to do the guide fix), but while I'm in there would I need any specialty tools or Mojo Guru advisor present to do the deed? I've griped about highway revs on a few other posts and this is a worthwhile $60 mod for me to make since I plan on some decently long freeway cruises in the future. But not if it means extensive surgery. What say ye, O Respected Elders?

[XS Rod]

Smiling here bro...
The case gets flipped upside down to work in the bottom end. Gravity will be an issue if you're partially disassembling the top end to replace the guide.
I'm answering from work so talking outta me arse... remove clutch, starter gears, kicker, ummmm... side covers of course, alternator housing and rotor (need puller), shift linkage...
You can leave in the shft drums and forks... replace seals on way out... yep that might be about it... just a tad bit more than "popping the bottom off" . Specialty tools... need one to tighten the clutch hub. For a more definitive answer I need to put down my Ouija Board and pick up my esteemed shop manual.

[headcase]

Sighhh...seems my tendency to overdo the 'while I'm in there' thing has struck again. I know I'll eventually do this mod, but I'd really prefer to get more comfy with knowing the innards better before tackling everything at once. The clutch will eventually be gone through when I'm motivated enough to get the tools and have the time to familiarize myself with that area. Same with the alternator, but I'm not prepared to tackle it all at once I guess. I'm sure I'll come up with another reason or two to pop the engine back out in the future. I just hope it's by choice, not necessity. Until then, a new set of Spacely Sprockets will have to suffice, along with Griz's seat mod idea. The bum buzzes enough as it is, I don't need the bike to help with that. But I digress.......
Thanks Rod, and careful with that Ouija board at work.

[XS Rod]

LOL on the OUIJA board bro. Don't be afraid... bag all parts and sort them out as you disassemble. The tricky part in the bottom, IMO, is the shift drum and dogs. You don't have to take them out. Plus you can get everything nice and sparkly clean inside and out.

[headcase]

This is one of those 'don't know where to stop' scenarios. Can't tell you how many times I've tried my best just to do a basic valve job on whatever beast I'm working on, and end up porting everything in sight. Or 'while I'm in there'....yeah a better cam maybe and good timing set etc. It's a curse, and the temptation to get into everything is almost irresistable. Gear will happen, but another time.
Also while we're talking cogs: I noticed when taking the chain off the front sprocket that there was a lot of side-to-side clearance between the chain links and the gear teeth. Is this normal? or could a previous owner have mixed up thick/thin parts? It's a 17 tooth gear and shows some decent wear on it, but I have no idea what 17k on an original sprocket looks like. I'll be getting a new set of either 17/32 or 17/30 gears, but is there much improvement over stock with the thinner setup? Friction, durability, smoothness etc.? Sorry for going a bit off subject, but while you have that Weejer board out I thought I'd ask.

[XS Rod]

Yep... I can relate headcase, cause it ain't done till it's overdone... story of my freakin, now I really broke it, life...
Dunno on the side to side chain thing... if I thought my chain and sprockets had 17,000 miles on em I'd replace the set... but then again reference above.

[headcase]

We have an old saying here in Michigan...if it ain't broke yet, break it so you can put a new one on. Well, it's an old saying in my house, anyways.

[kopcicle]

"if I can't fix it , it ain't broke"

You're not alone in this as the red bike is in deep overhaul , again .
Anyone seen NOS Shell 12:1 pistons lately ?

~kop

[grizld1]

Saw a pair just last week at the local machine shop, Kop. They were hiding under the milling table, biting and snarling, while the proprietor tried to chase 'em out with a stick so he could knock .030" off the crowns. Darn, they were nasty little rascals!

Headcase, there's no big drama to removing the bottom case half. With the top end assembled, hang the cylinders over the edge of the bench and support them with whatever's handy. Be sure to consult the manual and locate all the fasteners first. The cast numbers for the fasteners indicate assembly sequence, loosen in reverse sequence. It helps to clean the cases thoroughly and paint-mark the numbers first; they have a tendency to hide. You'll need a 12 mm. crow foot on your torque wrench for one of the fasteners, reduce the torque reading proportionally to the length added by the crow foot.

[headcase]

Isn't there a mating gear to the one being replaced? I would think if one side gets a few more teeth, the other would need less just to fit everything together nice and even, since everything is on shafts with other gears. Seems to me a larger gear on one would knock the shaft out of alignment without putting a smaller one in place of whatever it meshes into. I yet again have misplaced my handy dandy manual, so I don't have the layout here. Is this really as easy as dropping in one gear and zipping everything back up?

[doubleg910]

Headcase- I asked the very same question of Griz when I dropped mine in...no problem, everything meshes just fine.

To the new guy, I do as one poster said and mark everything...I use little tags on strings you can get at office supply store, If you need to write a lot of stuff to make it easier, get bigger tags....label however you can remember whet you meant maybe a year later..."long bolt, front left corner next to engine case..." you can even go to the Yamaha web site and find their Parts Catalogue under the motorcycle product section and just number the thing the same as their blow up for your particular area you are working on, along with a Clymer manual or the OEM manual, you should be ok.....just write lots of notes on your tags...put those things in baggies and the same box....then when you come back to your work you can just assemble in reverse order. .I think you can see a tag or two on my bike in the photo gallery.(79 Special II w/ seat Doh!)..like on the LR chain adjuster I think...it says "not torqued" or something like that...the very fact there is a tag hanging lets me know I'm not done with that thing...always tag your key "no oil" when you drain your oil, or tape the note over the ignition so your well meaning cousin does not fire up your project for a buddy..., you should have your battery pulled too, but you get the idea. Write me if I can help.
Cheers,
Double G

[XS Rod]

reassemble stuff as you take it apart and take your freakin time...
Nowadays , if your a bit of a tekkie, you can take
it's always easier if you build up your confidence along the way by being organized.

[650leo]

There's only one way to find out if can do something, thats to do it.

[headcase]

Recently scoped out the gear on Mike's again and noticed they insist on getting the mating gear as well. Would this be because it's different to better fit the OD gear, or do they just want to sell you a new one so you don't mix the old wear pattern with a new cog? The whole bag of noise has to come back apart this winter again because the cam chain is sawing through something inside rather ferociously, and I hope to throw the last pile of parts inside (OD gear included) for a long time to come. Git-r-done right and have a few seasons of hopefully trouble free riding after this.

[richard]

Gears are usually in matched sets. They will whine something fierce if you mix and match new to old. The OD gear would have a different pitch and ratio too so your kind of stuck buying sets.