Tranny issues with Quad

[Ottobon]

UPDATE:go to post #9

Hey guys, after a quick search of Local ORV areas i feel the need to get my quad running again. The engine runs pretty good, but sadly the transmission blew on when me and a few friends were riding it about a year ago. Anyways its a clutchless 4 speed, the model is a Yamaha Moto4 100cc (year between 88-92ish.)

EDIT:Inspected axle/driveshaft area and seems as though they are fine, the sound is coming from inside the crankcase. Read post 8 for rest

+ YouTube Video

VIDEO!! for your referencing needs!

PS: Does anybody know some good Yamaha or dirtbike/4wheeler forums so i can ask their as well?

[Spectre]

You probably snapped a shaft or something, or the centrifugal clutch is gone.

I'd tell you more, but all the places I'd send you to have at least one page with the dreaded Honda logo you hate so much.

[Ottobon]

I'm fine with Honda, its just YOU talking about them 5 time in every single post.

What should i take apart first? The sound seems to come from the rear so maybe i should take apart the rear axle?

For the record the damage happened all at once, i would think with a clutch it may have gone progressivly, so maybe a driveshaft?

[Spectre]

Well, disconnect the driveshaft(s) at both ends and see if the output shaft turns when it's in gear and running. If it is chain drive, take off the chain guard and look at the output sprocket and the shaft it is bolted to. If the output shaft turns, then you probably have a snapped axle (if the driveshaft wasn't broken or the chain wasn't snapped).

If that is so:

[Ottobon]

One more thing that i remembered that might come in useful (before i rip it all apart) Although their is no noise when in neutral, revving, and stationary, when i push it from place to place it makes a pretty consistent scrapping noise about every wheel rotation (nomatter which gear its in)

Thought that might help narrow the cause down, or could it still be any of those forementioned shafts? (no chain)

[Spectre]

Still could be a shaft. No way to really tell until you tear it down.

[CraigB]

I had one of these (though it was the smaller cc version) that the rear gears stripped out from lack of lubrication.

[Ottobon]

Going out now to tear it down as much as i can (might get stopped if one of the rusty old bolts strips on me), somebody mentioned it maybe being a Ring Gear, what do you guys think?

Personally i hope like hell that its a driveshaft, because those are all over ebay.

[Ottobon]

Driveshaft/rearaxle seems to be fine, their was a rubber boot between the engine area and the drive-shaft so i hand cranked both the engine and the axle to see if i could locate the problem. I tried locking up the axle area (right off the crankcase) and rotating the axle, when doing this nothing slipped, so i am pretty sure the rear and axle are fine.

Spectre: Would the output shaft be the shaft inside the crankcase?

I'm wondering if anybody knows which side of the block i should take apart? (engine side or tranny side?) Might just end up having to take the whole thing apart?

Also do i want the supplement service manual or factory setup/assembly manual?!? or that freaky microfiche one?

[Ottobon]

Well now that i've had some more time on my hands i got back to looking at the quad, and i think i found the problem, tell me what you think.






and for being nice enough to read this post, heres a cute picture of my cat





Right now i'm still stuck though as it seems nobody sells these parts used, and brand new the total price for both would be worth more then what i payed for the quad (something like $380)

[Spectre]

Differential bite the dust?

[Ottobon]

oh yeah, good news is there seems to be a place that has atleast 2 of these thing that (last checked) still had ass ends on them, and one exactly like mine, literally

They also had a FL250!! i forgot that thing exsisted, and now i can't stop thinking about them.

[CraigB]

That's exactly what happened to mine.

[Ottobon]

Originally Posted by CraigB

That's exactly what happened to mine.

And i'm starting to think thats whats happened to almost all of them, all the junkyards around here seem to have NO rears at all

[CraigB]

It did happen to most of them. Something about a seal leaking all the grease out.

[Ottobon]

Well i haven't fixed it yet, but if the axle i found is good then i'm much closer then i've ever been. I found out the 92+ Yamaha "Badgers" had the exact same ass-end as the YFM100s, so luckily for me i found a axle and I'm just trying to prod the salvage yard into getting pictures of the hypoid gears before i buy it, heres what i found out about this quad though

The ring & pinion gear in the rear differential unfortunately are prone to go bad. Especially if the kids ride them in muddy / wet conditions. The ring gear is pressed onto the axle and is not sold seperatley $$$. The newer Badger's are like the larger machines meaning they require a HYPOID gear lube. If you simply drain and fill it often you should be fine.
On the older models that have no provisions for gear oil changes or checking (badly designed to be greased during assembly then simply ignored I guess) I have seen countless that have required replacement ($$$) I have often disassembled the componet, drilled & tapped a 6mm hole in the top and simply installed a grease zert. A additional 6mm hole is placed in the bottom for draining and the problem is now cured as the unit can now be serviced easily.

The other Badger item is the driveshaft itself. It is designed with a weak point midway through the shaft so it WILL break if to much stress is applied to the machine. This is there to protect more expensive componets like the clutch, differential etc.
If heavy adults or very fat kids try to ride up a steep incline or you try to tow something with it the driveshaft can break quite easily, as it is designed to.

Master Technician & Former MMI Technical School Instructor. Master Technician Of Motorcycle, Automobile & Aircraft. Imported & Domestic.

#1 Central States Trial Bike Champion 1986/87
#2 1983/84/85

From the internets! I personally don't know if its just because the lube gets dirty, or if its because it leaks, (Mine seemed to have required amount of fluid in it) but i'm going to be changing my fluid as often as possible assuming this gear i found is what i need and I'm able to re-assmble the whole damn thing properly. I've been thinking about getting another quad, but considering i picked this up for $350 i can't find another deal as good, even when i factor in $200 dollars in repairs, plus i rather like my baby yammy!