Replacement gears for a 550. [mild gearbox gore]

[Ecks]

Hey everyone,
Is there a good place to go for spare primary and countershaft gears?  I had a bit of a gearbox problem last October...

... Though the timing wasn't that bad, as I was planning on removing the engine for some paint work anyway.  Just means I get to learn how gearboxes work too.

Anyway, I had a look on David Silver, they only had one of the gears I'm after.  Is there any chance that one of you folks would have the following gears lying about that you wouldn't mind selling to me?  Here's what I'm after:

Primary 2nd/3rd gear (one unit)
Countershaft 2nd gear, 3rd gear.

I'm also looking for a countershaft bearing retaining clip (that thing that looks like half of a piston ring that fits in the groove on the big roller bearing that's on the right side of the image).

On a side note, I'm still not sure what caused the problem.  Going from 3rd-4th (or was it 4th-5th?), I  heard a sound that was very similar to what you hear when you don't quite get all the way into the next gear.  It's that rapid knocking noise, except much louder in my case, occurring irregularly, and continued as I braked to a stop.  The shift forks look fine, though I have yet to do any inspection beyond just furling my eyebrows as I look closely at them.  Has anyone had something similar happen?

[Bitsa (Ralph Wright - RIP)]

Welcome to the site Ecks as for your gearbox have you looked on csmnl.com? Often have them when DS doesn't.Failing that it will be s/h bits loads of guys on here are into the 550s.Cause probably fatigue and non regular oil changes.
All the best
Bitsa

[Ecks]

Thanks for the help guys, here's the part numbers of each item:

Primary 2nd/3rd gear: 23431-374-000
C-shaft 2nd gear: 23441-286-020 (or 23441-286-010 for non-UK model, unsure what the difference is)
C-shaft 3rd gear: 23461-286-030

The C-shaft 2nd and 3rd gears appear to share the same number between 500 and 550, but no such luck on the primary 2nd/3rd gear unit. 

I'm hoping I don't have to replace the whole assembly, that seems like a bit of a waste.  Then again, is there a good reason to do so?  Perhaps fitment or gear mesh reasons?  I'll be headed to the USA over Christmas, so maybe I can take some parts back with me.

Further disassembly revealed that some of the spacer/washers were installed out of order.  I can't be certain that had anything to do with the failure, but perhaps the misplaced washers pushed the gear assembly sideways enough to possibly cause one dog to occasionally engage before the other had completely disengaged.
 

[mickwinf]

check EBAY item gearbox and crankcases starting bid £28 item number

261337429021

[matthewmosse]

If you are struggling I have several 550 engines either ready dismantled or for parts. I warn you now, I am pretty disorganised so may need reminding and won't be what you'd call fast at digging bits out, especially honda stuff as I'm not that eager to part with it compared to say my bmw parts that I'm sick of the sight of. I do know there is a complete 550 gearbox that functions really nicely but has a crack in the crank cases after the engine dropped a valve. I put a differet head on after this and ran like that for several years so know the gearbox functions well.

[paul G]

HI,
                 I have both shafts with good bearings, just been taken from a 550 K3 77 plate.
PM me with an offer !!

Regards,

[Ecks]

Thanks everyone, you guys are kings! 

Good call Oddjob, I'll have a extra-long stare at them, assuming I don't just replace both shafts anyway.  I was quite surprised that there were only two sets of gears with obvious signs of damage, I would have expected such a shower of debris to cause more fouling.

[paul G]

Ecks,

               I should have pointed out the shafts are complete with all the gears and I do have the retaining clip that you were after.

Regards,