flywheel nut size and thread pitch

[spamoo123]

Hey guys just got my first atv, the legendary yamaha blaster. The flywheel nut is missing!
It would be greatly appreciated if someone could help me out. What is the size nut and thread pitch for the flywheel?

 

[sicivicdude]

M12 x 1.25 I believe (best I can recall from memory). You have to make sure you get a flange nut for it though because a flange nut has a 14mm drive hex and the regular jam nut has a 17mm drive hex and a 17mm socket won't fit inside the flywheel.

 

[spamoo123]

Thanx, so u think I can pick this up at an auto parts store?
I found 1 on eBay but I don't want to pay $13 for a nut

 

[sicivicdude]

Thanx, so u think I can pick this up at an auto parts store?
I found 1 on eBay but I don't want to pay $13 for a nut

I bought mine at Ace Hardware locally. I took a spare junk crankshaft in with me to confirm the size.... but yes, it can be had for less than $13.

Oh, if you're missing the washers behind the nut, check out the "machine thrust washers" if your Ace hardware has those in stock. They're steel flat washers basically but they have a small OD compared to a relatively large ID and the ID is exactly what's stated not a "nominal size" flat washer. I've stacked two of those before together and they worked GREAT!

 

[spamoo123]

I'm kinda running off subject but is there a way to flush the cr
ankcase without pulling the halves apart? The clutch cover was repaired with jb weld maybe?
Anyways it was done over paint and the inside was not roughed up to accept the jb in and now I got litthe bits of it all over inside I'm sure

 

[sicivicdude]

I'm kinda running off subject but is there a way to flush the cr
ankcase without pulling the halves apart? The clutch cover was repaired with know weld maybe?
Anyways it was done over paint and the inside was not roughed up to accept the jb in and now I got litthe bits of it all over inside I'm sure

Pictures of what you're talking about. You mean the transmission area between the center halves? The crankcase and transmission case are physically separated (although cast in one piece and look like one big piece from the outside) The transmission area is not easily flushed from the outside but the good news it, the transmission area and clutch cover share a drain when you pull the drain plug out so you can flush the case chemically and drain it back out. A small amount of marvel mystery oil maybe? down inside and then start the engine up and let it circulate around to work all the crud to the bottom. I wouldn't throw that fluid out either. I'd use a funnel with a screen in it to "clean" the fluid and flush it several times until no more crud came out THEN put that transmission fluid into the recycle jug and pour fresh fluid into the transmission to run.

 

[spamoo123]

I have been looking all over the internet for the nut size specified but I can only find it in a 17mm and that's not gonna fit right? Anybody got any ideas?

 

[sicivicdude]

You're not going to be able to find it on the internet. It's going to be a metric bolt bin at a hardware store. My local Ace hardware has them in stock.

If you don't feel like doing any legwork, order a new nut and washer from Cheap Cycle Parts and they'll drop it off at your house gift-wrapped.