Thread: crank bearing tolerances
10-10-2008, 12:33 PM #1
crank bearing tolerances
just wondering about the crank bearings (lower). is any play acceptable, I have one here with a tiny bit, can't see it but can feel it (maybe .002"). Normally I would go with a new one but until I land this new job things are tight.
10-10-2008, 12:44 PM #2
I don't even know why I'm asking.. I'm replacing it. Or maybe set up a crank rebuild press and V-blocks??
10-10-2008, 05:00 PM #3
- Join Date
- Oct 2006
- Cleveland OH
Up and down, no tolerance allowed
side to side: .016-.024" with limit being .026"
10-11-2008, 10:08 AM #4
- Join Date
- Aug 2008
- Wilmington, NC area
FLjoyrider, I need you to get in touch with me ASAP about those parts I sent for the XL800!
10-11-2008, 11:24 AM #5
I knew that. Haven't split the cases but looking at the crank from the intake doesnt look too good.
10-11-2008, 12:09 PM #6
got the job, rebuild crank is in order. anyone on here who rebuilds them want to give out their secret? I know its time consuming and tedious, and I'll need to build a jig for my press, but whats the big deal really, you put it on v-blocks with dial indicators on each lobe correct? then you start from one end to the other knocking it into place with a brass hammer?? making sure that all rods are 120* apart?
10-11-2008, 04:01 PM #7
- Join Date
- Jul 2007
- near Toronto, Canada
I think the domestic cranks need a 25 ton press, vs the smaller press that the Fuji cranks needed.
10-11-2008, 08:37 PM #8
good to know, ill make sure to have at least a 25 ton bottle jack. Think Im going to try this, have plenty of cranks to practice on.
10-11-2008, 09:31 PM #9
I just rebuilt a friend's Seadoo twin crank. It wasn't that bad as I had access to a full machine shop.
There are two things you have to check for when reassembling the crank. Truing it and making sure it is in phase. Try to scribe marks on the crank so when you press it back together, you can get it as close as possible.
Truing it involves spliting apart and pushing together the lobes of the crank. http://www.greenhulk.net/forums/showthread.php?t=38113
Making sure it is in phase requires pounding the crank with a brass hammer.
To verify the crank, put it on two V blocks and have dial indicators on each end. If the dial indicators move in the same direction, the crank needs truing. If the dial indicators move in opposite direction, the crank need phasing.
Hope this helps!
10-12-2008, 08:13 AM #10
thanks! it does. One other question.. do I need a surface plate or will a steel tabletop be fine? need to buy a good set of V-blocks, and the rods pins bearings etc. Anyone know where I can get the crank parts for reasonably cheap? also how about stick welding it into place, is that ok as long as you get the slag off without getting it in the bearings? oh wait all I need is a tank of stargon for my tig.. nevermind, no splatter will be nice.
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