Topic: Replacement for Front Sprocket Washer/Spacer? SOLVED!

[burmashave]

I would have thought that someone else might have had this problem, but I couldn't find a relevant posting. This leads me to believe that mebbe my problem is the result of a new low in bike eptitude.

The previous owner of my bike must have lost the washer that sits between the front sprocket bolt and the front sprocket. I know that earlier models had a different arrangement; however, the '77 CB750K is supposed to have a single flat washer. It's listed as an 8mm washer.

Anyway, the previous owner cobbed it by using a pair of common washers. The first time I replaced the chain (about 5 years and 18k miles ago) I "improved" on his engineering by finding two normal washers (30mm width, 8.71mm hole, 1.97mm thickness) which fit slightly better.

I've got it apart again, and the washers are concaved only a tiny bit, on the other hand, it dawned on me that the 8.71mm washer hole must cause some wobble, given that the OEM is supposed to be 8mm.

My question, oh shade tree mechanics, what's the quickest way out? I rarely cob anything on my bike, but I'm doing a lot of work on it, and it seems that everything has become a pain. It seems the cheapo washers weren't overly stressed. I am blessed to have a bike boneyard 1hr from me, but I'm not keen on driving 2 hrs to see if they have the part and then bang it off if they do.

Bonus question: The back wheel is off, the clutch is dissembled, and I'd like to get the sprocket and clutch back together before the wheel (being relaced) goes back on. What's the best way to lock everything up so I can torque the nuts?

[burmashave]

I've had a time sifting through all the replies, but it seems to me -- given the extremely minimal deformation of the fender washers -- that the OEM washer does not sustain much lateral stress, so I'll go with option "D". In order to minimize vibration, I'll scribe a circle on the sprocket and center the washers as best I can.

[bollingball]

Bonus question: The back wheel is off, the clutch is dissembled, and I'd like to get the sprocket and clutch back together before the wheel (being relaced) goes back on. What's the best way to lock everything up so I can torque the nuts?

Cut a wedge out of a 2x4.

On the sprocket washer why not get the correct thickness and cut the correct center hole? Wait was that a concave washer oem??
Ken

[burmashave]

Thanks so much bolling, I was going to lock it up with the chain, but a wood wedge seems to be a more better idea.

I don't know what the correct thickness of the spacer is, but I'm guessing it is thcker and stronger than a regular washer. The original is not likely to be concave. The washers I used became ever so slightly concave probably from compression from the bolt head.

To belabor this more than I prolly should, The washers need to be in the 1 1/4 - 1 1/2“ diameter. Fender washers in that range are the ones with the holes slightly than the bolt.

[scottly]

Sorry for the late reply, but the stock washer has an 8.3 mm hole, is 40 mm OD, and is 2.2 mm thick. It is also slightly concave, probably due to the fact that the face of the shaft sits slightly below the face of the sprocket; it was probably flat until the bolt was tightened.

[burmashave]

Thanks so much for the info!