Stock cam alignment issue
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2nd Gear
Joined: Mar 2020
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From: California
Stock cam alignment issue
Rebuilding my 88 twin cam and my rear cam sprocket spacer is now .030 short of the drive sprocket alignment. I am using all the original parts except for the cam plate bearings. I split the cases and did not have any issues getting anything back together. Flywheel and counterbalance all fit like a glove. Pistons, cylinders fine. Everything seemed good until I checked the alignment on the cam gears. I even pulled the cam plate back off and reset the bearings again, but that was not the problem. Not sure why or how the drive shaft could have moved over .030 upon reassembly. And I dont see how the cam plate bearing could be the problem unless it's different than the original. I did purchase a new OEM bearing from Harley so it should be the same. I would just purchase a larger spacer but it concerns me that something has changed when I'm using almost all the original parts. Plus they dont make a .347 spacer.
HDF Community Team
Joined: Jun 2006
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From: san antonio
AFAIK, the HD cam spacer kit PN25285-08 includes six spacers ranging in thickness from .307 to .357 which does include a .347 spacer. Those spacers each have a PN and can be purchased individually. The PN for the .347 spacer is 11889.
Don't have an answer as to why you need to shim the rear cam sprocket but I wouldn't be too concerned about it if everything else checks out. You did split the cases and if an early model with the Timken crank bearing, the crank had to be shimmed for proper clearance. Did you need different shims to set the crank clearance on re assembly?
Don't have an answer as to why you need to shim the rear cam sprocket but I wouldn't be too concerned about it if everything else checks out. You did split the cases and if an early model with the Timken crank bearing, the crank had to be shimmed for proper clearance. Did you need different shims to set the crank clearance on re assembly?
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2nd Gear
Joined: Mar 2020
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From: California
There was no need for shims because I didnt install the timken aftermarket crank bearings. I replaced the original roller bearings with the same OEM roller bearings. Everything should be lined up like it came off the assembly line. I dont believe it was running before with that type of misalignment because I would think I would see signs of wear on the sprockets and chain. .030 seems like a lot to me. Apparently they do have the spacers I would need and I can run them, but I'm still concerned about why this misalignment suddenly occurred. Pretty sure I wouldn't be able to close the crankcase if the flywheel and shaft were not seated properly and off by .030
HDF Community Team
Joined: Jun 2006
Posts: 12,763
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From: san antonio
Don't disagree with anything you have said; just providing information on the availability of spacers to correct the alignment.
You don't know for sure that the mis-alignment has always been there. I know .030" sounds like a lot but I could see it running that way. Did you look at the wear pattern on the outer tensioner; maybe that would be a 'tell"? Anyway, once aligned all should be good.
You don't know for sure that the mis-alignment has always been there. I know .030" sounds like a lot but I could see it running that way. Did you look at the wear pattern on the outer tensioner; maybe that would be a 'tell"? Anyway, once aligned all should be good.
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From: poway
There was no need for shims because I didnt install the timken aftermarket crank bearings. I replaced the original roller bearings with the same OEM roller bearings. Everything should be lined up like it came off the assembly line. I dont believe it was running before with that type of misalignment because I would think I would see signs of wear on the sprockets and chain. .030 seems like a lot to me. Apparently they do have the spacers I would need and I can run them, but I'm still concerned about why this misalignment suddenly occurred. Pretty sure I wouldn't be able to close the crankcase if the flywheel and shaft were not seated properly and off by .030
No Tinken? Was the primary assembled. Mainly did you have the motor sprocket on and nut tight? Did you replace the crank?
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Joined: Jun 2017
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From: Granville New York
Do you really believe every bearing or part is exactly the same regardless of it being the same stock part or not. Manufacturing equipment gets set up and broken down many times for various runs on different parts...sometimes it's not exactly the same as the last. Doesn't take much for a tolerance to build up to where you notice a change. Trust what you're measuring and use the right shim
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2nd Gear
Joined: Mar 2020
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From: California
Maybe I'm getting confused on the shim advice. Are you guys talking about shims used on the inside of the crankcase to center the flywheel and crank? There were never any shims on the original setup and I measured the new OEM roller bearings and they were exactly the same. I think the timken bearings you're talking about are upgraded ones where you have to alter the case and theres more involved with adjustments.
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From: poway
Maybe I'm getting confused on the shim advice. Are you guys talking about shims used on the inside of the crankcase to center the flywheel and crank? There were never any shims on the original setup and I measured the new OEM roller bearings and they were exactly the same. I think the timken bearings you're talking about are upgraded ones where you have to alter the case and theres more involved with adjustments.
I think that the shim the others are talking about are the shims that set the cam to pinion gear spacing. There really isn't any shims to center the crank in the case. 2 washer on the either side of the left side roller bearing set the crank spacing in the case. They are fixed size.
Without a compensator installed the endplay is in tenths of inches on a roller bearing bottom end, so the thought on not closing the case if there was a minor .030" problem isn't necessarily accurate. With the comp installed, if the endplay is correct and it rotates freely, I would not lose sleep.
Did you push the components to position them for measuring as directed in the manual? If it's assembled and being measured properly, I would trust the measurements. .317 is one of the most popular shims, but they make all the sizes for a reason.
Did you push the components to position them for measuring as directed in the manual? If it's assembled and being measured properly, I would trust the measurements. .317 is one of the most popular shims, but they make all the sizes for a reason.