Author Topic: 78' CB550 cracked casing causing gear selection problem!  (Read 926 times)

Offline Hudson.

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78' CB550 cracked casing causing gear selection problem!
« on: May 29, 2017, 01:08:38 PM »
Hi guys,

A while back I made a post about the issue i was having selecting first gear, seen here

http://www.sohc.co.uk/index.php/topic,9195.msg63727.html#msg63727

I've only just gotten round to taking a look at the bike (bad I know), anyway I removed the clutch cover and found a chunk of alloy laying in the bottom, removed the clutch assembly and upon closer inspection have found part of the lower casing has 'chipped' off around the gear shaft plug at the end.

I made a post on a CB550 facebook page and one guy in particular had also had this issue with gear selection and described the exact same culprit being a cracked part of the casing in the same place. The bit thats missing was retaining the shaft meaning there was no endfloat, however now the casing has cracked it means the shaft can move in sideways axis approx 3mm and this causes gear selection issues.

Stole this picture from the internet to show you guys the bit i mean, this is what i should look like:




And this is mine!:




Has anyone else ever had this issue? If so how did you go about fixing it? The guy on facebook didnt have any reference pics but said he'd tapped the casing with M6 threads, made a plate/bracket up and put shims behind the retain the shaft.

Before i have a go at it, i was wondering if anyone on here had seen it before and knew of any alternative solutions?


Thanks in advance!

Rich

Offline Bryanj

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Re: 78' CB550 cracked casing causing gear selection problem!
« Reply #1 on: May 29, 2017, 02:19:38 PM »
That has been caused by poor assembly on rebuild as there is a hardened steel pin that locates that bearing both radially and longitudinally via a hole in the casing of the bearing and a hole in the crankcase. Proper repair would be new casings but it might hold with a new pin and bearing plus the repair you describe but not just the repair you describe, sorry for the bad news

Offline Bryanj

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Re: 78' CB550 cracked casing causing gear selection problem!
« Reply #2 on: May 29, 2017, 03:06:39 PM »
Good spot on the broken hole oddjob, missed that, I agree and always build in the top case, no problem with selectors or pins and the primary shaft locates easy through the sump hole

Offline Trigger

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Re: 78' CB550 cracked casing causing gear selection problem!
« Reply #3 on: May 29, 2017, 03:13:36 PM »
Some nasty person has been in there before, common sight on 500's and 550's. Can be repaired but, a bit of a tricky job.



Offline Colonial-Clive (yindi)

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Re: 78' CB550 cracked casing causing gear selection problem!
« Reply #4 on: May 29, 2017, 08:58:38 PM »
i have a set of cases only cost postage or you can pick them up.

Offline Hudson.

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Re: 78' CB550 cracked casing causing gear selection problem!
« Reply #5 on: May 30, 2017, 05:04:10 PM »

Thanks very much for your input guys, shame its happened! I guess the previous owner bodged it enough to work for the meantime, then I started having issues with it! I had noticed that pin/dowel 'modification' too, no idea why I didnt mention that!

Not the end of the world though, I had planned to refresh the engine as theres a stripped thread in the barrels if i remember correctly and also the previous owner managed to round the splines off the kick shaft with a loose pedal.

i have a set of cases only cost postage or you can pick them up.

Those cases would be very much appreciated thankyou for the offer! I'll send you a message now!

Seeing as i'll be needing to strip the lot down, can anyone reccomend a rebuild guide or some good material to have at hand for when I start putting it back together? Im fairly competent, just very paranoid at the same time haha.

Again, appreciate the help!

Thanks



Offline Bryanj

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Re: 78' CB550 cracked casing causing gear selection problem!
« Reply #6 on: May 30, 2017, 05:37:55 PM »
Genuine Honda manual and parts list, I have them on cd cheap

 

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