Author Topic: CB750 Shift Mechanism identification help  (Read 2034 times)

Offline AshimotoK0

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CB750 Shift Mechanism identification help
« on: August 29, 2016, 06:18:11 PM »
My 750K0 & Richs (RGP750) were fitted with the sandcast shift mechanism but we both want to fit the later shift drum as described in Service Bulletin no40.

I want to find enough of the mechanism parts for both of us but all my parts are mixed up some K0,K2,F1 K7 . We need to determine the diameters or the two discs on the 'stopper' arms correct for the modified --300-- shift drum. Anyone got them to measure for us from the later mechanism?(see red outline in attachment)

Also a couple of videos useful for replacing the mechanism. OK Trigger this is old hat to you but not to us novices who have never fitted it  ;D ;D ;D

https://www.youtube.com/watch?v=qJd6NvhbCNA#ws

https://www.youtube.com/watch?v=ppg-sf7mvU4

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« Last Edit: August 29, 2016, 06:20:20 PM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline Trigger

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Re: CB750 Shift Mechanism identification help
« Reply #1 on: August 29, 2016, 08:49:34 PM »
They are that and a bit more and the smaller one is a little less ;)

Offline steff750

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Re: CB750 Shift Mechanism identification help
« Reply #2 on: August 29, 2016, 09:25:25 PM »
Quote
They are that and a bit more and the smaller one is a little less
and a little bit less on the selector drum outer washer  ;) trigger knows what i mean
(try and keep up ash you need too use the later washer with the notch init) lol

Offline Trigger

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Re: CB750 Shift Mechanism identification help
« Reply #3 on: August 29, 2016, 09:37:25 PM »
I had a spare 5 minutes so I had a look at the link to wankerweek and was wondering how he is going to get his final drive seal in, when he has already bolted the crank cases together ;D ;D ;D

Offline AshimotoK0

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Re: CB750 Shift Mechanism identification help
« Reply #4 on: August 30, 2016, 12:22:43 AM »
I had a spare 5 minutes so I had a look at the link to wankerweek and was wondering how he is going to get his final drive seal in, when he has alreadrwardsy bolted the crank cases together ;D ;D ;D

Weird because in another video he tells you to make sure you have the final drive seal in place before assembling the cases. Obviously, he realized afterwards and learned by his mistakes. Thought it was a pretty informative video myself. We all spout out about what we think we know on here but it takes guts to actually dip your toe in the water and put it on a video clip for everyone to criticize. Must admit though it makes me cringe when he rattles the conrods against the crankcases  ::) ::).
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline AshimotoK0

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Re: CB750 Shift Mechanism identification help
« Reply #5 on: August 30, 2016, 07:10:15 AM »
So if you look at this pic I have identified the K0/Sandcast shift-drum parts. I know that the end disc is notched on later drums. I just need to know which are the correct stopper discs for the later shift mechanism. There is one marked with two **'s that is different to all of the others. I think there may be ---392--- parts in there too and not sure how to identify them.

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“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline Trigger

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Re: CB750 Shift Mechanism identification help
« Reply #6 on: August 30, 2016, 09:04:04 AM »
I can Identify the banana ;)
Neutral stopper wheel is (24440) 11mm
Gear wheel is (24430) 25.90mm

Offline AshimotoK0

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Re: CB750 Shift Mechanism identification help
« Reply #7 on: August 30, 2016, 05:50:27 PM »
I can Identify the banana ;)
Neutral stopper wheel is (24440) 11mm
Gear wheel is (24430) 25.90mm

It's all driving me 'kin bananas  ;D Just trying to help a forum member out with some missing parts !

I have 3 that are 25.9 mm

but the three small ones (neutral stopper)are almost 12mm (11.92 to 11.99 mm)

oh and one that's 17.95mm (perhaps that's sandcast early K0 dunno)

Anyone?
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline RGP750

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Re: CB750 Shift Mechanism identification help
« Reply #8 on: August 30, 2016, 10:05:01 PM »
Hi Ash
I'll measure mine when i get home tomorrow.
Triggers 11mm and yours up to almost 12 i wouldn't worry about, the diameter isn't that critical at all
considering what it does.
Thanks for putting up with all of this stress on my account :-[
Rich
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline AshimotoK0

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Re: CB750 Shift Mechanism identification help
« Reply #9 on: August 31, 2016, 07:44:04 AM »
Hi Ash
I'll measure mine when i get home tomorrow.
Triggers 11mm and yours up to almost 12 i wouldn't worry about, the diameter isn't that critical at all
considering what it does.
Thanks for putting up with all of this stress on my account :-[
Rich

No worries Rich ..you do plenty for folks on here.

Do you have this pin  (PIN SHIFT RETURN SPRING) I found another one if you need it ..it was still in some old F1 cases as was another in some K7 cases. The K7 is different though and is the same part as the 400/4 but the F1 ( and F2 according to CMS)  is the 300 original part.

The original part is 24652-300-000 and the K7 / 400/4 is 24652-035-000 (original is 12mm hex later looks like 14mm)

---035-- is a Honda S65 centre part no. !!  More useless anorak info.

Anyway if you need  the peg I have one

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« Last Edit: August 31, 2016, 08:08:33 AM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline AshimotoK0

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Re: CB750 Shift Mechanism identification help
« Reply #10 on: September 01, 2016, 08:35:22 AM »
Think I have bits sorted for Rich now. Basically shift drum modded as in SB40 to give better shifting but still a ---300--- part. 'Birdcage' as Yanks call it at end of shift drum changed after K0/sandcast and also the stop roller setup changed . Later e.g K7 used ---392---shift drum with larger end spigot and thicker 20mm washer with hole in it that pegs to shift drum with 4mm pin. Confused? Never give a kid a drum to play with  ;D ;D

MY THREE SHIFT DRUMS

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K0 SHIFT ROLLER PARTS

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SHIFT DRUM BIRDCAGE BITS AFTER K0

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K0 DRUM WITH BIRCAGE BITS INSTALLED

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« Last Edit: September 01, 2016, 08:38:51 AM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline AshimotoK0

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Re: CB750 Shift Mechanism identification help
« Reply #11 on: September 01, 2016, 09:20:00 AM »
---392----  spacer washer  after 1975 K5 onwards

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 90436-392-000 20 mm thick pegged to shift drum  washer K7 (discontinued)

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“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline RGP750

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Re: CB750 Shift Mechanism identification help
« Reply #12 on: October 02, 2016, 06:53:14 PM »
Thanks for all of your efforts Ash, i'm up and gear changing now.
I have a few bits to send back when i send the 175 ears.
Cheers Rich
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline AshimotoK0

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Re: CB750 Shift Mechanism identification help
« Reply #13 on: October 02, 2016, 08:05:46 PM »
Got another  full drum including the end pins plates etc last weekend for 3 quid ..so no worries. Glad it all worked out.
 Thought I had stuck gold as he had a 009xxx bottom end but it had a funny prefix mark and was a much later engine .. wasn't bad at 60 quid though but I passed as I am de-junking!
« Last Edit: October 02, 2016, 08:10:51 PM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

 

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