bent timing belt sprocket


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joecoolsuncle
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bent timing belt sprocket

Post by joecoolsuncle »



So, I have searched near and far using all sort of different terms and cannot find anything relevant. my problem is after removing engine to replace stator, the engine fell off the motorcycle jack a distance of about 6 inches and landed on cement. It appeared to have hit on the left side sprocket on tumbled over. I inspected and though all was ok, continued with stator repair, and when i started the engine, I was watching the area of impact closely for any issues. I noticed a slight wobble of the sprocket.
I found a parts bike nearby, and pulled same pulley from it. Installed used pulley and it too was bent. Went back and pulled the right side pulley from the parts bike and it too, was bent. I have no indication the belt covers had ever been off the parts bike, it had been sitting up forever with a locked engine. It is an SEI.
Question/poll: Has anyone else notice a very slight wobble on their cam sprockets? Odds are that three out of three would have a wobble! If so, has anyone straightened a bent cam sprocket?

Thanks in advance!


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Re: bent timing belt sprocket

Post by DenverWinger »

I think the cam sprockets (at least the ones on my 1100) are Cast Iron and then machined. They would break rather than bend.
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joecoolsuncle
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Re: bent timing belt sprocket

Post by joecoolsuncle »

thanks for the reply. these are definitely bent. you can see it with naked eye. spoked instead of holes like yours.
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LAB3
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Re: bent timing belt sprocket

Post by LAB3 »

You might want to check out the Springfield, Mo craigslist ads for motorcycle parts, there's a guy over by Mountain Home that has a few old Goldwings around he's selling parts from.
I'm selling good clean fresh hay. If you want some that's already passed through the horse, that comes a little cheaper!
joecoolsuncle
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Re: bent timing belt sprocket

Post by joecoolsuncle »

will do, lab3. mountain home, ar? but the question is because i have bought two used ones already, and both are bent. my guess is they bend during the pulling process? i used two different ways of pulling, the last being a small slide hammer that hooked into the center portion of the pulley. so, either the pulleys are not true from honda, or they were already bent (i know i bent the original by dropping it) or i bent them when removing them, which is unlikely but possible.
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LAB3
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Re: bent timing belt sprocket

Post by LAB3 »

Yes, Mountain Home Ar. I'm in Branson and noticed you weren't too far from there which is why I offered it. Have never actually met the guy but have communicated with him on a couple of things, retiree with a good amount of experience working on Gold Wings. I've never pulled a sprocket either, maybe he has.
I'm selling good clean fresh hay. If you want some that's already passed through the horse, that comes a little cheaper!
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Re: bent timing belt sprocket

Post by WingAdmin »

If you dropped the bike and the sprocket now has runout when it turns - and OTHER sprockets installed also show runout when mounted, then I might suggest that perhaps the problem is that the camshaft end itself was damaged - and that's why it's wobbling? Do any of the sprockets wobble if they are mounted on the other cam?
joecoolsuncle
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Re: bent timing belt sprocket

Post by joecoolsuncle »

LAB3 wrote: Sat Nov 20, 2021 12:49 pm Yes, Mountain Home Ar. I'm in Branson and noticed you weren't too far from there which is why I offered it. Have never actually met the guy but have communicated with him on a couple of things, retiree with a good amount of experience working on Gold Wings. I've never pulled a sprocket either, maybe he has.
ok, thanks again. you can never have too many leads on parts! i will keep an eye out for him on craigslist and also snoop around mountain home to see if anyone knows him.
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Re: bent timing belt sprocket

Post by joecoolsuncle »

WingAdmin wrote: Sat Nov 20, 2021 5:13 pm If you dropped the bike and the sprocket now has runout when it turns - and OTHER sprockets installed also show runout when mounted, then I might suggest that perhaps the problem is that the camshaft end itself was damaged - and that's why it's wobbling? Do any of the sprockets wobble if they are mounted on the other cam?
thanks. i thought about that, but thought honda would never build a cam softer than the pulley. i will not discount that idea though. i have not switched pulleys on the other cam to see yet. if cam is bent, do you know if SEI injected cams will interchange with aspencade cams? i suspect the profile will be different. thanks again for replying.
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LAB3
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Re: bent timing belt sprocket

Post by LAB3 »

I'd be inclined to compare part numbers off the parts fiche to find out.
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joecoolsuncle
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Re: bent timing belt sprocket

Post by joecoolsuncle »

thanks. i dont have a fiche, but i did find used cams on ebay and they list compatability. they show 84-85 same and others are different. i did make a redneck truing stand yesterday and the original (obviously bent), and the first one i pulled from parts bike are bent for sure. put a crescent on the worse one and gave it a tweak. they are very flexy, springy lol. the other one i pulled is on the engine and u can see the slight runout at idle.
i am still not discounting a bent cam, but if three sprockets have varying amounts of runout then odds are the sprockets bend easily. i have no way of checking cam runout and there are no real machine shops around here. maybe i could make a pointed stud to screw into the cam end and fire her up! lol.

thanks again for yalls help
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LAB3
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Re: bent timing belt sprocket

Post by LAB3 »

joecoolsuncle wrote: Sun Nov 21, 2021 9:23 am thanks. i dont have a fiche
Try this, it's what you're looking for.

https://www.hondapartshouse.com/oempart ... ycle/parts
I'm selling good clean fresh hay. If you want some that's already passed through the horse, that comes a little cheaper!
joecoolsuncle
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Re: bent timing belt sprocket

Post by joecoolsuncle »

great link! works and is easy to use!
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Re: bent timing belt sprocket

Post by joecoolsuncle »

took a short video with phone. it is not the best, but you can see the wobble i am concerned about. this is the best of the three pulleys i have tried. the one that was on the engine when it fell is much, much worse. the first one i pulled from donor is about twice the wobble.
do yall think this one would be ok to run? maybe im being anal? quit flappin my piehole and ride the darn thing?



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LAB3
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Re: bent timing belt sprocket

Post by LAB3 »

I'd run it the way it is. If there where any concern you can always pop the cover off after awhile and look to see if there's any fraying along the edge of the belt which would indicate to me that it's riding along the edge of the pulley.
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joecoolsuncle
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Re: bent timing belt sprocket

Post by joecoolsuncle »

LAB3 wrote: Wed Nov 24, 2021 8:08 am I'd run it the way it is. If there where any concern you can always pop the cover off after awhile and look to see if there's any fraying along the edge of the belt which would indicate to me that it's riding along the edge of the pulley.
thanks. yes, i have inspected it several times and there is absolute zero evidence of fraying or other damage occurring. i have put about 140 miles over 7 test rides at 20 miles each (i have other concerns as well that i am sneaking up on). my main fear is that i will declare victory only to lock down at 80mph on a freeway somewhere in "not America". i would feel much better if the pulley ran as true as the other, or the other was sloppy like this one. lol
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Re: bent timing belt sprocket

Post by billball »

I just did the timing belts on my GL1100 and both timing sprockets ran 100% true.
I think you have something bent and will cause a vibration in the engine when started.
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Re: bent timing belt sprocket

Post by joecoolsuncle »

billball wrote: Sat Dec 04, 2021 1:48 pm I just did the timing belts on my GL1100 and both timing sprockets ran 100% true.
I think you have something bent and will cause a vibration in the engine when started.
thank you for that info! it is what i have been trying to find. for the record, the engine runs very smooth. but i am worried about harmonics, work hardening, etc: i fear a sudden catastrophic failure, but maybe i am paranoid? i have been trying to find a camshaft from a trustworthy source. no automotive machine shops around here to trust.
meanwhile, i just ride it on short tests rides to determine, repair, prove other problems. the list of to-dos is down to one page now!

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Re: bent timing belt sprocket

Post by terryt »

When the engine is running and you can see the cam pulley is not running true. Have a look at the bolt that holds it to the cam shaft to see if it is oscillating. As WingAdmin said its most likely the cam shaft bent
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Re: bent timing belt sprocket

Post by joecoolsuncle »

terryt wrote: Sun Dec 05, 2021 8:44 am When the engine is running and you can see the cam pulley is not running true. Have a look at the bolt that holds it to the cam shaft to see if it is oscillating. As WingAdmin said its most likely the cam shaft bent
well, you can't see the bolt running out of true. strange thing is, three sprockets all have varying amounts of runout. i have suspected the cam bent, and have not discounted mr. admins advice, have even mentioned i am looking for another camshaft. i have no way of checking the cam for true, so next step is to replace with used. you have to agree that with three bent pulleys (i know how the original got bent) in a row, i will not trust ebay for a camshaft. one also has to think that the factory would not have installed warped pulleys on the assembly line. i like to prove theory, and in this case, looks like i will have to become a billy bob, bubba deluxe, redneck parts changer to resolve! lol
Merry Christmas and thanks for your reply
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Re: bent timing belt sprocket

Post by joecoolsuncle »

Update! well, i found a used camshaft on ebay. i installed it yesterday, and guess what!? same @#$%^^% thing! i still have the same wobble! so the old cam was not bent or either i now own two bent left side cams, along with three bent cam sprockets. the question still remains......is honda quality control responsible or is it extremely probable that the sprockets are so very easy to bend/warp/distort?
always a silver lining! changing the cam did get rid of the irritating light tick i would hear at startup!

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Re: bent timing belt sprocket

Post by Sassy »

I think its time to find a machinist or someone with the equipment that can tell you exactly what is bent.
The odds that all that stuff is bent must be pretty high.
Enjoying the 2xDarkside
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joecoolsuncle
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Re: bent timing belt sprocket

Post by joecoolsuncle »

Sassy wrote: Wed Dec 22, 2021 12:18 pm I think its time to find a machinist or someone with the equipment that can tell you exactly what is bent.
The odds that all that stuff is bent must be pretty high.
thats what i been saying. it must be within tolerance as manufactured. the pulleys flex very easily which could be what i am seeing, but that would mean the wobble would be getting produced somewhere like the crank or an imperfection in the belt. there are no automotive machine shops around here, and i no longer have truing stand or vee blocks.
another camshaft was $24 so that is the direction i took. again, this may be perfectly normal and im just being anal. i wish i knew so i could move. this makes me feel like such a parts changer and less like a mechanic. know wut i mean?

i will try the next step after this weekend if it doesnt get too cold.
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Re: bent timing belt sprocket

Post by Rambozo »

Stamped sprockets rarely run perfectly true. However, if you have the machined versions they should. The video is gone, and you don't specify how much runout you have. If is not enough to rub on anything I wouldn't worry about it. If you do have a stamped sprocket, you can have a go at straightening it. These days you can get measuring instruments for cheap. While not the best, they will do the job for most hobby work.
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Re: bent timing belt sprocket

Post by Sassy »

I didnt read all the posts so maybe this has been mentioned.
Are the sprockets interchangeable side to side?
If so swap the know true sprocket to the other side and/or put a questionable spocket on the true side.

The side with the new cam try different sprockets and see if the run out is in the same place relative to the cam.
I understand,,,, lots a work but without proper equipment how else do you eliminate guessing.

Another idea, make a pair of wooden V blocks, take the "bent" cam and see if sprockets all wooble the same spot relative to cam.
Hope these ideas help you understand your problem.
Fred


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