Author Topic: 1976 yamaha yz125x crank width  (Read 1893 times)

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Offline jimg1au

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1976 yamaha yz125x crank width
« on: October 15, 2014, 07:18:24 pm »
can anyone tell me the width of the yz 125x crank
mine is toast after 7 laps (a while ago) after a full rebuild by a mate(that will teach me)
jim

Offline Freakshow

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Re: 1976 yamaha yz125x crank width
« Reply #1 on: October 15, 2014, 09:38:49 pm »
probally same as the early 125s.  do you want  to know the width as they sit in the cases assembled, or just the width of the one of the half to source a similer one ?
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Offline jimg1au

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Re: 1976 yamaha yz125x crank width
« Reply #2 on: October 15, 2014, 10:15:42 pm »
as they sit assembled please

Offline matcho mick

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Re: 1976 yamaha yz125x crank width
« Reply #3 on: October 15, 2014, 11:04:05 pm »
freaky MX125 A's 56mm (+0.05 -0.10),Jim/me need X's assembly width, :P
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Offline William Doe

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Re: 1976 yamaha yz125x crank width
« Reply #4 on: October 16, 2014, 05:47:23 am »
can anyone tell me the width of the yz 125x crank
mine is toast after 7 laps (a while ago) after a full rebuild by a mate(that will teach me)
jim

Same thing happened to me Jim with a YZ 125A crank , I don't think the rod had enough lateral clearance so a crank width of an assembled one would be great .
Its only old bike racing FFS get over yourselves





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Offline OverTheHill

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Re: 1976 yamaha yz125x crank width
« Reply #5 on: October 16, 2014, 09:14:07 am »
what i'd do [not always right lol] is build it up to a 'rod' side clearance incase of slight variations with say an aftermarket rod kit or thickness of washers. I just slide a feeler blade in & press [tap tap tap under press pressure when near the mark]. Then--ummm, [been a while] measure across the webs where the bearings but up & then somehow measure between bearings in the case with cases clamped together then calculate the difference [another then--] decide if you need to space it over from the primary side only to get rod in the middle as it's held tightly towards that side by the crank nut--then--now i'm confused but that's the guts of it. Good luck. ps, i wouldn't blame your mate [unless an obvious mistake] as i'm sure he did his best and possibly other [unknown forces] things came into play--was it new bits or 'best of the rest' etc. Hope the rebuild goes to plan. Cheers.

Offline sleepy

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Re: 1976 yamaha yz125x crank width
« Reply #6 on: October 16, 2014, 10:42:09 am »
From my records it should be 56mm. Most important thing is the side clearance, minimum .20 mm.
Do you know what brand of rod kit was used and what type of failure is it? Also what type of oil do you use and what mix ratio?

Offline Davey Crocket

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Re: 1976 yamaha yz125x crank width
« Reply #7 on: October 16, 2014, 10:58:12 am »
And how hard did you belt the crank fitting it....LOL.... :)
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