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Fast, Reliable But Not So Cheap - 1380 BMW K1200 EFI
https://www.ausmini.com/forums/viewtopic.php?f=5&t=96193		 Page 5 of 11
Author:  jpodge [ Sat Jan 11, 2020 12:16 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
timmy201 wrote:
Looking good Joe, you'll learn a lot rebuilding the gearbox! The Haltech will be a great bit of gear, hopefully once it's tuned it'll go really well and have a good cold start


Thanks Timmy - learning a lot already and enjoying it. Spent a couple of hours in the garage this morning with a coffee and and a tutorial video from Classic Mini DIY on the reassembly. Awesome content for anyone who hasn't checked it out made by an honest and modest enthusiast.

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I could only get so far while I wait for the 1st/2nd Synchro hub replacement part to arrive. Selector forks and reverse gear installed in the casing, and half of the main shaft assembled with new bearings after a deep clean of 43 years of schmutz.

After reassembling the 3rd/4th synchro hub I thought i would see how it felt with new springs going back and forward from it's respective seats. I learnt pretty quickly to be careful when doing that as I shot a bunch of springs and ball bearings around the workshop. Good thing I knew I was going to do this and bought extras!

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Author:  timmy201 [ Sat Jan 11, 2020 12:26 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
I can also recommend the videos by minimania and guessworks. Also having a gearbox guru around the corner helps (thanks Justin!).

You’ve got a centre oil pickup too?
Author:  winabbey [ Sat Jan 11, 2020 1:15 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
Some more info here, although mainly for a 3 synchro box - viewtopic.php?f=2&t=97472&p=1037989
Author:  TK [ Sat Jan 11, 2020 3:18 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
you are going to clean the gearbox case aren't you?

EDIT: Use 5 Star degreaser and a brush. It will come up like new.
Author:  9YaTaH [ Sun Jan 12, 2020 5:30 am ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
those cracks in the centre web look worrying...
Author:  jpodge [ Sun Jan 12, 2020 8:35 am ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
TK wrote:
you are going to clean the gearbox case aren't you?

EDIT: Use 5 Star degreaser and a brush. It will come up like new.


Yep I did notice that it could use a clean with a wire brush. I had already hit it with a high pressure hose and degrease but it has since come up slightly better after some wire wheel-ing. I am not worried about anymore schmutz that's embedded in the pores of the casting.

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9YaTaH wrote:
those cracks in the centre web look worrying...


hmm. Perhaps - but in my mind this is just the quality of the casting back in the day? There are no cracks along the middle of the center web. I can't see any cracks that look like fatigue cracks. Happy to be proven wrong by the SMEs though. Let me know what you guys think!

back side
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I am unsure what those grinding marks are though???

front side
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Author:  TK [ Sun Jan 12, 2020 10:51 am ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
I just used 5 Star and a old stiff paint brush. Gets the casing like new. I'd be looking at another gearbox case anyway.
Author:  jpodge [ Mon Feb 03, 2020 8:20 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
Without wanting to turn this into a gearbox rebuild thread I'll keep this post as short as I can and then we will get back to twinky specific stuff, I promise!

Firstly thanks to all of you guys for your advice - gearbox and diff have come up a treat. Cross pin diff is a cool bit of kit!

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I've changed the input shaft bearing and race. Thanks to some previous posts on this forum i got the idea to run a mig weld bead on the inside of the bearing race to shrink it to allow it to fall out. I was skeptical, but it worked a treat and doesn't look like it's caused any damage to the flywheel cover, except for one little pit. Either way, the new bearing race went in as it should.

new race installed (the circlip wasn't installed correctly in this photo but has since been seated properly)
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Trying to fit up the flywheel cover to the gearbox so I can check idler end float has proven difficult. I can't for the life of me get the bearing to seat properly in the race. I've checked that the bearing still fit in the race before pressing it onto the input shaft, and i've also checked with a spare race that the bearing still fits, so it must be an alignment issue - one that is so damn close. Anyone seen this before and or got any of those old school tricks up their sleeve?

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I highly doubt that it's warped the flywheel cover when I welded the old bearing race. I think the next step might be to remove the studs from the casing and see if the bearing fits in the race or if the race is no longer circular. if it fits maybe it just needs a chamfer filled into the race.... This new bearing seems to not have the chamfers on both the race and bearing rollers that the old one had. A naff issue that is frustrating me either way

Next photo you guys will see will hopefully be a picture of the box, block and head all together!! Woohoo!
Author:  9YaTaH [ Tue Feb 04, 2020 6:39 am ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
Re the gouges/grind marks...I suggest it was someone trying to see how deep the cracks went or trying to smooth them to stop them propagating further or just to clean up/hide the look of them! (maybe!) :D
Author:  Scoop [ Wed Feb 05, 2020 7:49 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
Hi Joe, try putting some vasoline or grease on the bearing to hold rollers in. The build is looking good so far, keep up the good work.
Cheers Scoop
Author:  drmini in aust [ Fri Feb 07, 2020 4:28 am ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
The dowel position in these flywheel housings can vary. This gives problems if you mix and match them with gearbox cases.
I have rebuilt 2 remote 4 synchro boxes over the years that needed the bottom dowel left out to avoid your problem.
Author:  jpodge [ Tue Mar 03, 2020 9:00 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
Thanks Scoop and Doc. Got it to fit with the grease in the rollers and the dowels removed. And what's best, the end float of the idler was spot on!

Before I mated the box and the engine, I thought I'd make sure that the top and the bottom end were in perfect harmony - everything looking and turning over nicely although the belt between the top cams seems kind of loose - but then again I've never worked on belt timed engines....

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Author:  jpodge [ Sat Mar 07, 2020 6:33 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
Bit more progress this week and I took plenty of pictures. Hope you guys enjoy the pictures as much as I did putting it all together.

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Flywheel not torqued down in this pic (and the lock washer was around the wrong way which I've just realized BRB)
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For the first time rebuilding a clutch on a mini I'm happy with how it went. If anything looks not right please sing out!

Getting pretty keen now as I'm not too far from putting the new donk in the car!! Times like these makes me realise that if it was being run on carbies i'd probably be driving it be now :P
Author:  FNQ [ Sun Mar 08, 2020 8:29 am ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
hi

looking good. Was the clutch all balanced up? I couldn't spy any of the usual A,B,C s present
Author:  jpodge [ Sun Mar 08, 2020 6:05 pm ]
Post subject:  Re: Cheap, Fast, Reliable - None of the above... yet!
FNQ wrote:
hi

looking good. Was the clutch all balanced up? I couldn't spy any of the usual A,B,C s present


Thanks! I didn't get the clutch assembly balanced - just the flywheel. All new parts though.Would these normally be dangerously unbalanced? It is a bit difficult to see in the photo, but the diaphragm "A" mark is lined up with the mark on the flywheel.

I also was missing the spacers that sit under the clutch straps in the above photo that are needed when using one of the minisport ultralight flywheels - they've since been installed so the clutch straps are sitting flat and under no tension.

Got the egg plate installed today and hoping to have the head on tomorrow.
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