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Crank Runout, How to check?

Sheepdogmarine

Sheepdogmarine

Active Member
Now that I have decided to keep my bike, I am looking at several upgrades.

I am looking at an engine kit that has gear drive cams. I am pretty sure it may be easier to install the conversion kit and run a roller chain, but there are more cam choices with the gear drive.

My question is this? How far do I have to disassemble the engine to check crank runout? Looks like I can remove the right side cover and maybe the oil pump and then check it. If it checks good, then the gear drive is the way for me. I don't mind doing some work to see if a gear drive is doable or not. I know the runout cannot exceed .002". I don't mind being down a couple days, just don't want it to be a couple weeks and then have to send back parts and change plans.

So what is the easiest, quickest way to check runout?

Thanks,

Eric
 
Thanks, the video shows me what I needed to know. Looks like they even left the oil pump on.

The second link is a good link, but it says it cannot download until they upgrade their bandwidth.

Thanks for the help. Maybe one day, I will learn to search first.:52:
 
Hey TQ - I also couldn't get the second link to do anything and the video doesn't really show all that much. I want to get this checked before my basic warranty runs out if it doesn't require too much disassembling of the engine. What exactly has to be taken off to get to the point where this can be measured? What is the tool called that measures the runout? Any idea what it costs?

Thanks!
 
Dr. Doolittle said:
Hey TQ - I also couldn't get the second link to do anything and the video doesn't really show all that much. I want to get this checked before my basic warranty runs out if it doesn't require too much disassembling of the engine. What exactly has to be taken off to get to the point where this can be measured? What is the tool called that measures the runout? Any idea what it costs?

Thanks!
Click to expand...

Dr. D,

Sorry about that. I did not realise that second link was not working. Attached is some info from Andrews. Unfortunately it is not a full step-by-step procedure for doing it, but you may get enough guidance out of it to help you. See the last page.

Harley Davidson Community

See here too:

The Flywheel's Crankpin Is TIG-Welded - Hot Bike Baggers Magazine


TQ
 
Thanks TQ. The second link actually has better photos and a brief explanation of what's going on in each picture. Looks like you have to drain the oil and open up the right half of the motor to check this runout? I'm not experiencing any vibrations or any other symptoms to make me think I've got a problem but my warranty ends this coming February and it's one of those things I'd like to know more about before deciding on an extended warranty or not.
 
Dr. Doolittle said:
Thanks TQ. The second link actually has better photos and a brief explanation of what's going on in each picture. Looks like you have to drain the oil and open up the right half of the motor to check this runout? I'm not experiencing any vibrations or any other symptoms to make me think I've got a problem but my warranty ends this coming February and it's one of those things I'd like to know more about before deciding on an extended warranty or not.
Click to expand...

Dr. D,

You don't actually have to drain the oil. You will get whatever is left in the cam chest drooling out when you take off the cover either way. But yes, you do need to open up the cam cover and take off the outer sprockets or gears depending on your set-up. Then you measure the runout on the pinion shaft with a dial indicator. Make sure you rotate a full revolution, and record max. and min. You are looking for the total spread. If you rotate until you find the "lowest" spot, re-zero the gauge, and then rotate until you find the "highest" point, that will be your runout. The Andrews Products doc says this:

"If runout is greater than .003 TIR, Andrews Products recommends NOT installing gear drives without first re-truing flywheels to remove excess runout. Cam support plate MUST be installed for this test"

That is one of the reasons I went with roller chain conversion. The other was all the combinations of oversize, normal, and undersize gears that may be required for the gear drive.

TQ
 
TQ,

Thanks for the info. My problem is this. How much runout is too much and will cause damage to the oil pump? I would think if .005" will cause damage to the gear drive setup, it is still going to cause damage to the oil pump.

My bike has 35000 miles on it and it runs great and is smooth, but I am just wondering if I should go ahead and get a crank, already welded trued and balanced and just plan on doing the entire engine. I did speak to Andrews and they said .002" was the limit for the gear drive. But do I really want more than that causing other damage.

Just trying to think this through all of the way.

Has anyone checked and found no runout or are all Twin Cams doomed?

Eric
 
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