crank shaft nut size?

[dshaw340]

I have an 82 of which I am attempting to rebuild.  The guy I bought it from was on the freeway and shut it down as he heard a noise.  Later he found a gasket had blew and all the oil had pumped out.  Anyway I suspect the main bearings need to be replaced.  I am almost to the point of splitting the crank case but need to buy yet another tool.  My question is what size nut is on the crank shaft behind the rotor pulley?  Roughly I measured it at 46mm but my method was crude.  Also, any tips on purchasing one?

[louthepou]

Hi there dshaw,

My advice for this one: find a used engine in good shape, keep the one you have for spare parts. A good engine shouldn't cost you more than some $200 US, and with a bit of luck shouldn't take too long to find one. It's going to be way cheaper than rebuilding one, especially if you're talking about the bottom.

Louis

[ozian]

A 46mm (1-13/16 ") crows foot spanner is mentioned in Haynes manual ( hope you have one ) . An air rattle gun is handy too loosen things up while not putting stress on other things while holding them to undo . Always & I mean Always check whether it's L or R hand thread by looking at the bit of thread sticking out before. It saves a lot of swearing, sweat skun fingers & red faces overall. Best of luck  Ian

[dshaw340]

Hey thanks guys.  I do have the Hayes manual .  I just went and looked at the tool list in the front of the book and duh, there lists a 46mm crowfoot.  Thanks Ian.   I'm going to attempt the rebuild unless the crank is chewed up.  I can get a gasket kit from PRO-FLO for about $120.  I'm going to call them today to confirm what all is in it.  Bearings shouldn't cost anymore than $20 or $30.  Then it's just a matter of slapping it back together I think.  Certainly I'll be out alot of time but it keeps me out of trouble.  So far everything else inside the engine looks in supreme condition.  I've never opened a motorcycle engine before and I have to say that it is truly amazing at how much thought and engineering goes into them.  Alot more than a car engine.  Very impressive.

Dan

[George R. Young]

<snippety-snip> . . .I've never opened a motorcycle engine before and I have to say that it is truly amazing at how much thought and engineering goes into them.  Alot more than a car engine.  Very impressive.
Dan

Yes, those 'crude' cars have their alternators outside the engine driven by rubber belts, no less.

But they stay cool.

My 'crude' Mazda Protege has 160000 km on its alternator and the stator hasn't melted once.

[QBS]

Be sure and replace the oil seal that lives in the clutch side engine cover and is penetrated by the end of the crankshaft.  If this seal fails or is damaged during reassembly there will be no oil pressure going to the bottom end. Be carefull. Cheers.

[dshaw340]

Thanks for the tip QBS.  I took a look at it and I see what you are talking about.  There is an oil passage that feeds into the end of the crankshaft behind the seal and if the seal were gone the oil would just pump into the cover.  I wasn't sure so I stuck a narrow screw into the end of the crank and sure enough the hole goes all the way through so I get what you are talking about. Cool...  I'll have to be careful putting the cover back on.  

I think I found a 46mm wrench in Florida that'll work. It was like finding a needle in a haystack.  I'm going to have more money into tools than what I paid for the bike.  Oh well.  anyway thanks everyone for all your help and insight.  

[Paul_Jungnitsch]

My 'crude' Mazda Protege has 160000 km on its alternator and the stator hasn't melted once.

Hah, my 'crude' Mazda B2000 has 370,000 km on its alternator and it has never been touched, no new brushes, no nothing.

[jasonm.]

46mm wrench. Heck, the tool place down the road has a box/open type on hand($25) or a socket can be ordered. But adapters are needed since it's 1" drive. I know I have both.

[dshaw340]

I did find a 46mm wrench off Ebay but that was after I went to my local Sears, Harbor Freight, Napa, and Schucks.  As far as a socket goes, I think it would have to be atleat 3" deep anyway as the nut is way in on the crank.

[jasonm.]

2 and 3/8" depth is all you need for the socket.

[dshaw340]

Just for conversation sake, I just went and measured and I get 2 3/8" from the end of the crank to not quite the beginning of the nut.  So if you add 2 3/8 plus say 1/4 (which is the depth of the nut) plus say 1/2" (which is the drive depth of the ratchet) I get a total of 3 1/8".

Do you measure different? :)