How to remove the advancer unit on my 1981 CB 750?

Zoodles95

Zoodles95

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So,

My neighbour put in another starter clutch for me early in the season. I picked one up off of ebay. Now that one is working wonky. Turns out what I should have done in the first place was buy a starter clutch rebuild kit, rebuild the starter clutch and have it put back in.

So, got the rebuild kit.

This is the starter clutch that was originally in the bike. You can see how the springs are buggered and the rollers are not staying where they should.


Cannot remove the starter clutch off of the bike without removing the advancer unit first. The Clymer manual says to hold the "hex spacer" with a 24mm wrench and remove the inner bolt with a 12mm wrench. Unfortunately I do not have a 24mm wrench; my largest is a 19mm wrench. I am trying to use an adjustable wrench. However, the inner bolt is not budging at all and I do not want to bugger something up.


My neighbor (who has since moved) had a compressor. Could he have tightened the snot out of the inner bolt and that is why I cannot move it? Should it just loosen counter-clockwise and then I can remove the advancer to get access to the starter clutch?
 
Got to love Canadian Tire. :)

Great deal on these wrenches.


Now I have the starter clutch finally off the bike.


Now to rebuild the one that was actually in the bike.
 
I'm shocked how well my mastercraft stuff has held up over the years. The warranty is also a nice thing when you apply....exuberant force to something.
 
Okay. So, I rebuilt the starter clutch. :)





Remove the three 12mm bolts:




There are all the old parts out of the starter clutch:



Old spring on the left versus the new spring on the right. Shorter spring equals inconsistent contact with the rollers and inconsistent starting and "rattling" sounds out of the left crankcase and low rpm.



Now here is NOT what you want to do. The rollers will come out when you put it back together.



Wait until both parts are together before you put the springs, rollers etc in.



Bit of a pain. You have to hold the spring and pusher in place and the roller just fits in. Let the pusher go a split second too early and then the pusher is under the roller instead of beside it pushing it. Took me several times to figure it all out.



Now it is all together and ready to be bolted together.




Then bolted on and mounted on the bike.



With the advance unit back on.



And now it starts easier and does not have the horrible ratting sound from the starter clutch rollers coming from the left crankcase. :) Click on the video to hear how it sounds now...
 
Last edited:
Riceburner said:
Good write-up.
Click to expand...

Thanks. :)

The starter clutch had been an ongoing issue since I got the bike. Researching the bike there is a litany of people having starter clutch issues. I guess after 20+ years it is not unexpected that springs and rollers are going to fatique.

Probably saved myself $100 doing the job myself. Best of all I know my way around the left crankcase now and ended up learning about the pulse generator.

Next up is to replace the light bulbs in the instrument panel. Apparently I have to remove the headlight, instrument cluster etc to do this. Will document and post this one. My tach is no longer backlit. Fuse seems to be fine so odds are it is the bulbs (there are two for the tach). Will replace all the bulbs for now and a future project will be to swap out all the bulbs for LEDs to reduce draw on the old system.

After the instrument bulbs are replaced I am going to tackle putting in the new choke cable.

I am no backyard mechanic by any means and not particularly "handy". Feels gratifying to repair something though. :)
 
Nice! Good job bro. :)
Hey those old Hondas are keepers. Gotta keep 'em running...
(You're reminding me of my CB900F, purchased brand-new in 1981.)
L8R
 
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