Author Topic: End float fluctuations  (Read 516 times)

Online Minto

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End float fluctuations
« on: 05.04. 2021 21:23 »
Hi all, I'm confused as to why I'm getting such fluctuations in the readings on my crank end float. I've read a bunch of threads and tried a couple of different methods, and am now at the point of laying the lump timing side down on some blocks, putting all the bolts and nuts back in and using a lever under the timing side end of the crank to measure with a dti set up on a magnetic clock stand on a  sturdy lump of angle iron clamped across the drive side case. This has proved a tad more consistent but still got a read of 0.1mm last night, 0.09 this morning, and without touching anything got 0.082 this afternoon. The lump is cold, as is my garage so I doubt it's being affected by temperature.
With putting only four bolts in the cases I was getting even more differences.
Every time I take it apart and reassemble (without changing anything on the crank) the readings are way different.
Multiple readings taken at the same time are all consistent, but differ from all the other times.
Any ideas??
52 A10 plunger
Aprilia RSVR

Online berger

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Re: End float fluctuations
« Reply #1 on: 05.04. 2021 23:08 »
minto I wouldn't worry to much about 1/2 a thou, even my brain surgeon can't get the same reading twice on me *whistle*

Online chaterlea25

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Re: End float fluctuations
« Reply #2 on: 05.04. 2021 23:28 »
Hi Minto,
Bring everything indoors and let the temperatures stabilise
then measure gain

John
1961 Super Rocket
1963 RGS (ongoing)

Online Minto

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Re: End float fluctuations
« Reply #3 on: 06.04. 2021 08:33 »
Thanks guys
Bringing the lump into the house isn't an option I'm afraid, not even going to ask. Putting bits of it on the barbecue raised an eyebrow!
But if it's really the slight temperature variation that's doing it I can live with it, just thought there might be something amiss with my methods.
Cheers
Jase
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Aprilia RSVR

Online Greybeard

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Re: End float fluctuations
« Reply #4 on: 06.04. 2021 09:55 »
You may be overthinking this. The end float needs to be close to zero.

Online muskrat

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Re: End float fluctuations
« Reply #5 on: 06.04. 2021 10:55 »
G'day Minto.
I always install all the case bolts and nuts up to torque and install the primary drive and cush nut to take the measurements.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Online Minto

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Re: End float fluctuations
« Reply #6 on: 06.04. 2021 18:44 »
Hey Muskrat
I think it was your instructions from an earlier thread that I was following, though I've not assembled the cush drive as I have read that it has no effect on end float, and I wasn't up for the fight to put 65ft/lb of torque onto the crank with nowt to stop it spinning.
Cheers
Jase
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Aprilia RSVR

Online RDfella

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Re: End float fluctuations
« Reply #7 on: 06.04. 2021 19:13 »
Don't understand this. The cush drive / nut etc is an important part, ensuring the bearing is tight against the crank. As for nowt to stop it turning, aren't the cylinders off?
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online berger

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Re: End float fluctuations
« Reply #8 on: 06.04. 2021 19:15 »
as I understand it if you put all the bits on and tighten the nut, it pushes the bearing tight against the crank web , then measure the end float,  you don't need 65ftlb to get the bits tight, that is the end of the build figure to try and stop it all loosening.  or is your bike not a roller bearing drive side *conf2*

Online Minto

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Re: End float fluctuations
« Reply #9 on: 06.04. 2021 20:40 »
RDFella/ Berger,
Thanks for your insight. Yea, barrels are off, as are pistons and rods. I'm no expert in this, or anything, so just learning what I can as I go from here. I think I must've misunderstood something somewhere.
I'll put the cush drive on as well tomorrow and take another reading, might mean I don't need to do anything else to it as the bearing looks good and the end float ain't a million miles off as is. The tightening of the cush drive assembly might bring it within the right numbers.
Cheers
Jase
52 A10 plunger
Aprilia RSVR

Online Colsbeeza

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Re: End float fluctuations
« Reply #10 on: 07.04. 2021 00:04 »
Hi Minto,
When I did mine recently (with cush sleeve and nut on tight), I also could not get consistency. I was concerned that levering the crank back and forth may have been moving the crankcase (which was clamped in my 4" vice, as I don't have an engine stand and I hadn't made up a bracket for the DI) and was giving me errors on the Dial Indicator, which was mounted on the tail of the vice slide. As the crank was rotating easily, I tried rotating the crank by hand and pushing it back and forth gently, each time ensuring that the crank was hard up against the end.  I did have to allow for the shaft end not being perfectly circular. ie. stop the crank in the same vertical position each time. That gave me much better consistency. Sorry the Set-up photo is a bit blurred.
It would have been much better to mount the DI on a bracket bolted directly to the crankcase. I'll make one up next time.
Col
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Online Minto

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Re: End float fluctuations
« Reply #11 on: 07.04. 2021 02:05 »
Hey Col,
That's something I discovered too, that the crank end isn't totally flat. As I was levering the crank it was rotating a few degrees and altering the reading by quite a bit. Whod've thunk!!
Cheers Col
Jase
52 A10 plunger
Aprilia RSVR

Offline UKlittleguns

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Re: End float fluctuations
« Reply #12 on: 07.04. 2021 12:03 »
Hi Minto,

Only one comment.  Fit your rods now.  There is nothing worse than getting the job cock on and then having to pull it apart again!

Len 

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Re: End float fluctuations
« Reply #13 on: 07.04. 2021 14:15 »
Jase,
I also found that a very sparing application of Hylomar on the Crankcase Faces added about a 1/2 thou.
Col
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Online Minto

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Re: End float fluctuations
« Reply #14 on: 07.04. 2021 15:35 »
Len, sound advice. Had been thinking about this earlier, got to order some bits over the next day or so, but defo.
Jase
52 A10 plunger
Aprilia RSVR