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Clubroom => Tech Talk => Topic started by: BJJ on February 03, 2009, 05:12:05 pm

Title: 73MXA Cylinder Nut - Which Socket?
Post by: BJJ on February 03, 2009, 05:12:05 pm: What type of long socket do you need to use for '73 MXA Cylinder nut?
I know it needs to be long, but what size is it?
Will have to buy one from a tool shop :-\
Thanks in advance
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: jimg1au on February 03, 2009, 06:09:16 pm: it 13mm you can use 1/4 drive sockets i have one if you get stuck but i bought mine from auto parts at meani
not sca
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: cyclegod on February 03, 2009, 06:41:24 pm: Quote from: jimg1au on February 03, 2009, 06:09:16 pm
it 13mm you can use 1/4 drive sockets i have one if you get stuck but i bought mine from auto parts at meani
not sca

Are you sure? my barrel nuts were 14mm, but the cylinder head nuts were 13mm
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: BJJ on February 03, 2009, 06:47:38 pm: It's the ones that hold the barell down onto the crankase. Down that deep hole. The sockets and extensions I have tried so far (mix of both size drives) don't seem to want to make their way down the whole.
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: BJJ on February 03, 2009, 07:15:08 pm: Hi Paul, I guess I better say this is a Yamaha MX, not a Montesa/Maico (although that Allen Head example looks like it could be universal). The heads of the nuts are hex, like this one:

http://cid-0970e1979402bd5b.skydrive.live.com/browse.aspx/MXA?authkey=2hZNJNNBJW4%24&ct=photos
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: jimg1au on February 03, 2009, 08:17:34 pm: i will check tomorrow as i am at work now
cheers
jim
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: BJJ on February 03, 2009, 08:53:34 pm: Thanks Jim
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: JC on February 04, 2009, 09:38:40 am: If they're the same at the DT (& I'd think they are) they're 13mm, but you MUST use 1/4" drive sockets - my 3/8" drive ones are simply too big OD to fit down there.
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: Freakshow on February 04, 2009, 10:13:22 am: can you crack them through the side ? and then use whatever you have to spin em around ?

actually forget that use the right socket :O0
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: BJJ on February 04, 2009, 10:44:49 am: Thanks JC (and freakshow for imagination). will give this a go. Will report back next days to the thread how I get on. Regards,
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: Nathan S on February 04, 2009, 12:09:50 pm: My 3/8" drive AWB/SuperWorks Gold socket set fits down the holes.

Been a damn good set of tools, despite the SuperCheap stigma - only ever broken one bit, which was the 14mm socket while undoing a Volvo head bolt, using a 5.5' length of pipe for extra leverage...
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: JC on February 04, 2009, 12:58:07 pm: Billjack,

the heads of the nuts round off fairly easily. (Unfortunately I speak from experience) Then you have a problem I haven't yet overcome.

Make sure yr socket is a good fit & don't force it if they're not moving. Maybe good idea to spray w Bolt-off or the like a while before you try
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: Lozza on February 04, 2009, 12:59:22 pm: Volvo's have worse stigma than Super Cheap so don't let that worry you :-* But those SWG tools are VERY good.
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: BJJ on February 04, 2009, 02:00:22 pm: Thanks guys, I am very impressed with the help I have got from this forum. Considering all the other bikes will be gone within the week (eBay). Then I see no other bike project for me to be dissalusioned with (is that a word).
Maybe that 600 thumper LOL.
I'll get to a tool shop in the next days and report back. Once again, thanks.
Any small information I know, in these situations is invaluable.
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: Freakshow on February 04, 2009, 03:49:35 pm: No probs im good with imagination.

P.S the 73 is just the MX the 74 speedblocker is the MXA
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: jimg1au on February 04, 2009, 04:37:01 pm: its the 13mm make sure you buy the right size that fits down the hole in the fins i have 1 that is too big 1/4 drive as well .
cheers
jim
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: David Lahey on February 04, 2009, 08:29:33 pm: I think can help with this. I've done quite a few of these as they are the same as on TY250A,B,C,D twinshocks. Yes there are 3/8 drive sockets that will fit inside the fin holes, but sometimes no matter what you do in preparation to loosen things up, there will be too much force required to undo the nut (with a high quality single hex socket, it just shears off the top of the nut)
To get the barrell off, a simple tubular steel drill guide that fits neatly into the fin holes will guide a drill so that you can drill the stud away to flange level without risk of damage to the cylinder.
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: JC on February 05, 2009, 06:18:20 pm: Dave,

Can you buy such drill guides or do you have to turn one up?
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: jimg1au on February 05, 2009, 06:30:55 pm: how do you get the barrell off if it is stuck as well i have a 250 that was tight to get the nuts off but the barrell is stuck fast and wont bugde.i broke 2 scockets undoing the nuts but they were cheep 1/4 drive ones
cheers
jim
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: Nathan S on February 05, 2009, 09:54:48 pm: Quote from: Lozza on February 04, 2009, 12:59:22 pm
Volvo's have worse stigma than Super Cheap so don't let that worry you :-* But those SWG tools are VERY good.

Remind me, which form member was talking about going to great effort and expense to fit Volvo parts to his Ford?
Title: Re: 73MXA Cylinder Nut - Which Socket?
Post by: David Lahey on February 06, 2009, 08:28:14 pm: Quote from: JC on February 05, 2009, 06:18:20 pm
Dave,

Can you buy such drill guides or do you have to turn one up?
Sorry JC I didn't follow this thread till today when I got your message.
I made the guide from a piece of round steel bar and drilled a hole through the middle the same size as the drill I used to drill away the stud. I can't remember what size drill but it was probably 0.5mm bigger than the stud diameter whatever that is.