CG125 Loose main bearing in crankcase.. Normal?

[smallfrowne]

Just dropped the oil out of the cg, opened up the filter and was greeted with a random bit of epoxy type stuff. It was hard, brittle and non-metallic.

https://i.imgur.com/zyRTgR1l.jpg

This coloured me curious and prompted further investigation.

It seems it was slathered on to the right hand side of the main bearing, with the indentations in the epoxy matching someone's attempt at using a nail punch to stop the bearing spinning in the crankcase. (right hand side, clutch side). It's obviously come loose and the bearing does spin in the case. For the past few rides I thought I was picking up a little bit more vibration than usual too, but I wasn't sure if I was going mad. But then 'extra' vibes may still be in my head as there isn't any play in the shaft given a good hard wiggle.

https://i.imgur.com/PORR9Agl.jpg

Never had the bottom end stripped down before, so my question is: Should the bearing be free to rotate in the crankcase like this? I can push it round with my finger. I'm going for no, and tempted to split the cases and slather some loctite in there (sparingly of course)... would that even hold it short/long term?

InB4 "get a new engine theyz only liek 50 squid safe urself sum hassle. Pass your test get busa"

Cheers

[Polarbear]

If you mean the outer race turning, no of course not.

Dimpling is a standard way of trying to recover a bearing housing when the bearing has siezed and worn away the casing. Add in bearing fit from Loctite and thats what you have there.

I know because this is a standard Marine engineers bodge when you don't have a new bearing case to fit and you have to get the macinery working till you hit port.

The only proper repair is a new case/housing. You could get it built up with weld and machined but I would suspect that would be more expensive than a new part.

So in b4 new engine - Yes another engine will probably be your cheapest route.
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Triumph Trophy Launch Edition

[kramdra]

CG would not be worth the effort of a swap or strip. Sell it as repairs while its still running and get something decent.. NSR125 perhaps

[MCN]

You could clean it with brake cleaner and clash it together using Loctite High Strength Retaining Compound and a new bearing.

Or maybe sleeve the case.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[smallfrowne]

Thanks for the replies. Looks like there is already a steel liner. Hmmmmm

https://i.imgur.com/5v26Q5Il.jpg
I think I'll give it a good fettle with brake cleaner and paraffin next.

[kramdra]

If you are going to strip it anyway, get someone to mig a bead of aluminium around the bearing/punch marks. The bearing will need to be replaced, but it should not require any machining.

[Pete.]

Bearing retainer is the way to go. Loctite 603 is high strength and oil tolerant. If it's more than 4 thou/0.1mm loose then Loctite 660.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[smegballs]

[MCN]

[smallfrowne]

Ok, having gone to bed and re-read the haynes manual, it notes

"The crankshaft assembly can be lifted out of position. The use of steel inserts in each crankcase half means that the main bearings are a light sliding fit, and offer little resistance during removal. They will remain in position on the crankshaft."

... so all seems well and as designed by the big H? Haynes mentions nothing of added loctite or making an effort to secure the bearings in the cases.

But! Another issue is now clear.

Now I have the crank out and can play with the two main bearings I can see some slop in both, although they are still smooth running. Time to replace the buggers then, but seems like hard work to get them off the crank, and the left hand one has the camshaft drive gear/pinion. Any tips on this job? Haynes says to mark the gear relative to the shaft to aid reassembly - but is it so simple? Am I just to man up, line the marks up to within 4 thou and then whack it back on again or am I missing something? Surely an error here could knock the timing off and kill the high performance of the machine.

https://i.imgur.com/3zpvSZS.png

Also, just seen the extra reply from MCN. The stuff that was glued on looked like it was stuck on from the outside, using the punch marks as a key. No sign of it on the inside of the case anywho. This bike has seen some bodges, I'm not surprised.

[Pete.]

[smallfrowne]

Cheers Pete, yeah it must pull off, not that I have a puller (yet). The slightly worrying thing is that there is no keyway (I can see) and it's driving the cam. There is a punch mark to align with the cam gear when it goes back together. The primary drive is on the other side and slides onto splines.

https://i.imgur.com/XcO0a1U.jpg

The woodruff key in the exploded diagram (10) is for the alternator rotor. Why no key for the cam timing? Why big H, why?

https://i.imgur.com/Mzca5yt.jpg
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'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[MCN]

[smallfrowne]

Sounds like half a plan then

I have a decent propane torch, can get some ice ready (could stretch to a mojito to go with) and I have some gloves...

Looks like I'll need a puller for the bearings though, unless I can fanny the heat method to work on them too.. but any bearing puller recommendations for when I fail to master it? I've seen a 3 leg puller on the bearing king site (who are actually local to me and are a lovely bunch [/end non-affiliated passing comment]) but it's £130 ex. vat . Probably the crème of all pullers like but even so.

I'm going to try make some wedges out of steel strips with a ground edge to get it going as per the haynes.

The only issue with this whole procedure is that I'll struggle to get the pinion exactly back in place even with marks, what with it being an interference fit surely it'll be hard to adjust once it's on. I can see me wanting to heat it up and rag it round with some pipe pliars to get it to move and damaging the teeth. I hope the diagrams are wrong and there's a key and I'm worrying/whining about nowt.

Ah well, I'll dive in tonight and we'll see.
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'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[stinkwheel]

There is a special tool for pulling that gear.

I'm an enormous fan of special tools. Every one I've ever bought has made a difficult job easy.

I would assume if it's pulls the gear, it could also be used as an arbour to re-fit it.

Often the genuine Honda one is cheapest so if you have the workshop manual and it says the part number, plug it into David Silvers website. For example, I bought a honda flywheel puller a few years back. It was £10.50 and I proceeded to remove the flywheel off my H100 by hand pressure.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Pete.]

I wouldn't put a torch anywhere near that pinion. You risk drawing the temper on the teeth trying to heat up the hub. Just pull the beggar off.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[stinkwheel]

Oh, and cheap but... Cheap.
https://www.ebay.co.uk/itm/12-pcs-Bearing-Splitter-Gear-Puller-Fly-Wheel-Separator-Set-With-Box-Tool-Kit-UK-/191693394149?hash=item2ca1d110e5:g:rO0AAOSwKIpV-o1X
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Pete.]

Can't really go wrong for less than a round of beer. just make sure there's plenty of oil on the threads and grease the end. Perhaps put a small washer on the dimple to save marring the crank end.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good