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Morning All,

anyone happen to know the dimensions of the spark advancer retaining bolt for a '72 cb350?

And just to clarify and to be 100% sure, the index on the spark advancer should be pointing the opposite directions to the numbers at the top of the plate?

Cheers Fellas
 

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Hey Bigring, do you happen to remember where you found those dimensions? I'm looking for them now and not having much luck. Lots of bolts for sale, none with dimensions listed!
 

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Sensei
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Order these by part number....They are specifically hardened/graded for this application, and, Depending on year and model they could be spec'd as JIS or spec'd as ISO threads...
For instance, My CL 160 cam takes a 5 mm JIS bolt, While the nearly identical looking early CL 175 cam takes the 5 mm ISO......
 

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So my intention of running to the local Ace Hardware and grabbing an appropriately sized bolt was ill conceived? I'm shocked! Simply shocked. Thanks for the advice, I'll order the proper part right now. How about the washer? Is that ok to be replaced at Ace, or do I need an OEM washer as well?
 

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The washer isn't standard either, it's a bit small in outer diameter compared to a fender washer but larger than a 6mm flat, but with 6mm hole - and it's black, which might mean it's hardened a bit
 

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In the event that the OEM washer was listed on Ebay at $6+$6 shipping (reality), what would you do? I'm morally opposed to paying $12 for a washer unless the difference in diameter causes the entire bike to explode upon starting. Barring any instances of catastrophic failure, would you opt for the slightly larger fender washer, or the slightly smaller flat washer?
 

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You really have no options, as the standard (smaller) washer would probably let the advancer slip off the shaft... the larger fender washer might work fine but will be larger than the breaker cam on the advancer
 

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Well, the entire advancer unit actually, but the standard sized washer will only cover the inner shaft of the advancer, and the breaker cam - the lobed slip-on that actually opens the points and rotates on the advancer when the advance weights open up - can slip off the advancer center shaft with no washer properly sized to retain it. Generally a fender washer is larger than the correct outer diameter of the proper washer for an advancer unit
 

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I don't think you'll run any risks unless the larger diameter of a fender washer has some unexpected affect on the operation of the EI at the advancer, but I wouldn't think so
 

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Sensei
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To be clear, this washer's sole job in the world is to hold the breaker cam in place, correct?
NO, it also acts as a thrust washer , allowing the breaker cam to advance, and as such is specially sized and hardened.....
 

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So, Steve, you're saying that there is absolutely not in any circumstances a feasible work around or replacement BESIDES the Honda OEM washer specifically designed for that location? I don't mean what's "correct," what's "designed to go there," I mean what functions. I've posted in the WTB Parts thread, but if that doesn't produce the washer for me, I will be forced to buy one online. For some reason everyone wants $6-10 to SHIP the washer.
 

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Instead of getting grouchy and arguing with Steve, why not just take your chances and buy a random washer and report back?
I've got a funny story about this washer (or lack of one), but no time to share. Maybe ancientdad can assist?
 

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What indicated that I was grouchy or arguing? Not my intention. I'm trying to learn something.

In answer to your "why not" question, it's because I don't understand the part that I am inquiring about, hence the inquiry, therefore I don't understand the ramifications of improper action. If putting the wrong washer on causes the spark to not advance and I go "Oh, it didn't advance. I need to get the right washer" that's not a big deal. If I put the wrong washer on and it prevents something from moving which in turn fries the brand new electronic ignition and Dyna coils...that's a little bit different than "oops." So, if my tone seemed pressing, it's because I want to be fully aware of all possible outcomes of the decision I am making in advance of making that decision.
 

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Yes Shane, a different or generic washer would function provided it was the (or very close to) correct diameter, flatness, and smoothness....(I'm assuming the hardness spec is only to prolong its life-span...)... Most "hardware store" washers are stamped out of sheet and are neither flat nor perfectly smooth, but some stainless ones seem to be an exception.....IF you can find the right diameter hole and outer edge, it might be suitable for use.......
 
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