Tight spot turning the crank

  • SWest
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Re: Tight spot turning the crank

01 Jun 2017 16:18
#763265
Is the crank well lubed while spinning?
Steve

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Re: Tight spot turning the crank

01 Jun 2017 20:05
#763273
VTEC wrote: Maybe I'm overanalyzing.

Maybe… but I can tell you that I have the same problem, it would keep me up thinking about it.
It would probably run many miles maybe vibrate a touch more but who knows . I am rebuilding a old dirt bike right know and I am trying really hard not to get to technical because like you I am compulsive , it really sucks.

Have someone else put it together then you can blame them ;) :laugh:

Did you ask Stan if he would run it???
I believe its called "Oppositional Defiance Disorder"

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Re: Tight spot turning the crank

01 Jun 2017 20:18
#763276
VTEC wrote: Guess I jumped the gun. Been spinning the crank and still feel a slight tight spot. It's random, not any particular number of turns. I put a dial inch pound torque wrench on it and the tight spot is only 5 or 6 inch pounds.

I'm getting a straight edge to check the line bore.

It's either the bore is off, a bad bearing I can't detect otherwise, or maybe just the .0025" run out at the center of the crank. The runout is within specs but new is closer to 0. I'm sure most people wouldn't have noticed it. Maybe I'm overanalyzing.

I spoke with Stan at grc cranks and he suggested swapping case and/or crank and see which fixes it. Wish I Had a few laying around.
I'll stand corrected but I can't see a crank or any major item out of alignment having a random tight spot, my crank was badly out when it twisted and it still spun freely, sounds more like a bearing nipping up once in a while. The other thing to consider is a cam chain, if it is not new or the link (if it is riveted) is too tight it might bind once in a while.
First Permanent ride the Z1R since Dec1977 (220,000km) as of June 2015
Second permanent bike 1989 FJ1200 dyno'd 140RWH, great bike.
Third ride is now the Frankenstein 1981 GPZ1100B1, 1983 fully recon motor fitted LOVE THIS BIKE
Forth my work bike FJ1200 1989 (same type as FJ above)
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  • VTEC
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Re: Tight spot turning the crank

02 Jun 2017 04:43
#763298
"I'll stand corrected but I can't see a crank or any major item out of alignment having a random tight spot, my crank was badly out when it twisted and it still spun freely, sounds more like a bearing nipping up once in a while. The other thing to consider is a cam chain, if it is not new or the link (if it is riveted) is too tight it might bind once in a while."

Chain is off, crank only. This crank spun freely in my previous case because the twisted crank enlarged the journals so the bearings weren't held tight.
KZ1000-K2
ZRX1100
XR400R

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Re: Tight spot turning the crank

02 Jun 2017 08:36
#763329
SWest wrote: Is the crank well lubed while spinning?
Steve

Yep. poured oil into the oil switch housing hole to lube and confirm oil at all bearings.
KZ1000-K2
ZRX1100
XR400R

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Re: Tight spot turning the crank

02 Jun 2017 16:53 - 02 Jun 2017 17:00
#763367
Man, It's only 5 inch/lbs. I bet most would have spun it and said it was fine. Hope I'm not chasing ghosts.

Spinning it fast you feel nothing, just slowly by hand.
KZ1000-K2
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XR400R
Last edit: 02 Jun 2017 17:00 by VTEC.

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Re: Tight spot turning the crank

02 Jun 2017 19:05
#763374
If it were me I'd put it together and ride the piss out of it.:woohoo:
Steve
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Re: Tight spot turning the crank

03 Jun 2017 16:56
#763447
Torqued the case and checked line bore. Couldn't get a .0015" blade under anywhere. Ordered another eBay crank to test. After all this work I just can't put it together knowing something's not right.
KZ1000-K2
ZRX1100
XR400R

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Re: Tight spot turning the crank

09 Jun 2017 14:19
#763966
OK. Test crank from ebay came in. Installed and no tight spot. Sending the first crank to GRC. Stan says he can rebuild it if the welds weren't extensive. This stuff never stops.
KZ1000-K2
ZRX1100
XR400R

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  • daveo
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Re: Tight spot turning the crank

10 Jun 2017 14:41
#764026
Don't worry, winter is a long way off... :whistle:
1982 KZ1100-A2

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  • rssuby2001
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Re: Tight spot turning the crank

29 Jun 2017 15:58
#765683
Hey Im doing the same work on a 750, I can only find the max clearence spec for the crank to main bearing. You guys have any idea on a min spec for the crank to bearing?? I currently have .002 . Thanks
Ken McCormick

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Re: Tight spot turning the crank

29 Jun 2017 17:46
#765691
The big fours use roller bearing cranks. I suggest you start a thread on it. Lots of smaller four guys here and good info.B)
Steve

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