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1963 LI125 Engine Rebuild - It's A Runner - With Vid!

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1963 LI125 Engine Rebuild - It's A Runner - With Vid!

Postby Cosmic Wizard » Tue Oct 31, 2017 11:04 pm

Evening all,

I hope this is okay in here, if not, please move to the appropriate section ;)

I thought I'd start a thread about the rebuild of mine & my mate's LI125 engine and gearbox.
We recently bought and recommissioned the scooter and got it on the road. The engine ran okay, but there were some faults - clutch slip and poor running/idling. Anyway, the other day, the clutch gave up, and last Sunday, out came the engine lol.

We have already been buying the parts in preparation, but like any project, the more you dig, the more you find.

Fortunately, everything has come apart quite nicely, unlike my other engine which looked like it had been sitting at the bottom of a river for 30 years :shock: I will start another thread for that one.

Plans for this engine are a full stripdown, vapour blasting of cases and a rebuild to 150cc with new SH1/20 carb, new crank, clutch and clubman exhaust.

All that is left to do on the stripdown is dismantle the gearbox. I'll do that this Saturday, then it's off to the vapour blaster's next week :)

Here are some pics:

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Last edited by Cosmic Wizard on Sun Dec 10, 2017 8:12 pm, edited 7 times in total.
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Re: 1963 LI125 Engine Rebuild

Postby Covboy » Wed Nov 01, 2017 10:05 am

I like threads like this... Keep the posts coming....
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Re: 1963 LI125 Engine Rebuild

Postby Toddy » Wed Nov 01, 2017 1:23 pm

Agree keep the updates coming :D
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Re: 1963 LI125 Engine Rebuild

Postby TurboTrev » Wed Nov 01, 2017 1:32 pm

Yes, very interesting, don't think we've had an engine rebuild thread. 8-)
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Re: 1963 LI125 Engine Rebuild

Postby LuiLui » Wed Nov 01, 2017 9:23 pm

Also agree, always nice to follow a journey. Good luck.
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Re: 1963 LI125 Engine Rebuild

Postby ToBoldlyGo » Thu Nov 02, 2017 5:11 pm

Agreed. Keep them coming. Not sure you would gain anything by using a Clubman exhaust on that set up to be honest. It would be a much better motor with a standard exhaust. Mind you, I think I'd be inclined to find an Indian 150 barrel and have it bored out to 175 myself.
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Re: 1963 LI125 Engine Rebuild

Postby Knowledge » Fri Nov 03, 2017 8:36 am

There is something very odd about that head gasket. It looks too big. The carbon deposits around the gasket face on the barrel is also unusual and supports the idea that the gasket is too large. Messy.

Any thoughts, folks?
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Re: 1963 LI125 Engine Rebuild

Postby Cosmic Wizard » Fri Nov 03, 2017 9:34 am

Thanks for all your comments, I will definitely be keeping you all updated. :)

@ ToBoldlyGo
It's funny you should say that, my mate suggested standard, but I wanted to go Clubman lol.

I have a Clubman on my 125 and also rejetted the carb. It has helped the engine rev better, but I also plan on making more engine mods in the future.

This is an original standard scooter, so a standard pipe might have to be done. I do like the sound of a standard pipe.

The bore out to 175 sounds interesting. Does the 175 share the same stroke as the 125/150?

@ Knowledge
Ha-ha, I wondered if someone would notice :D

I thought exactly the same as I removed the head. I will take a measurement tomorrow as I forgot last week. The head looks like it has been replaced too.

The scooter seemed to go quite well I thought, but it did have its problems, hence the stripdown.

Thanks again & more pics/updates tomorrow ;)
Cheers
Jim
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Re: 1963 LI125 Engine Rebuild

Postby ToBoldlyGo » Fri Nov 03, 2017 6:54 pm

CW, not entirely sure on the jiggery pokery side of things. All I can tell you is that I run a 175 with a standard exhaust and 20mm carb, and I find it a perfectly balanced engine. Hence the reason I'm not keen on a Clubman exhaust. It's more volume to fill to get your power and you lose a bit downstairs. A standard exhaust puts the power where you want it, usable across the range, and to be honest it goes at a fair lick as well.
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Re: 1963 LI125 Engine Rebuild

Postby a.lo » Sat Nov 04, 2017 1:10 pm

Knowledge wrote:There is something very odd about that head gasket. It looks too big. The carbon deposits around the gasket face on the barrel is also unusual and supports the idea that the gasket is too large. Messy.

Any thoughts, folks?


looks like someone has bodged a 200 gasket on there as the stud spacing and bore is different!
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Re: 1963 LI125 Engine Rebuild

Postby Cosmic Wizard » Sun Nov 05, 2017 10:05 am

Morning all, as promised, an update :D

I spent yesterday afternoon stripping the rest of the engine down. I found the gearbox had far too much oil in it, the clutches were glazed, which explained the clutch slip and the kickstart pinion retracting pin was nearly sawn in half.

On a positive note, everything else seemed to be in really good condition and actually very clean.

I also removed the bearings and seals from the mag housing and removed the clutch arm etc. from the chaincase cover.

All the parts are now ready to go to the vapour blaster's this week :D I will update you all when they come back. Until then, have a few more pics ;)

BTW, thanks for the comments :)

Loads of Oil:

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A bit too big:

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WTF?! :

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Chaincase cover removed. This put up a fight as I don't think it's ever been off:

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Front sprocket removed and clutch removal tool ready to go:

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All the clutch plates looked like this. No wonder they were slipping:

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Clutch basket removed:

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Crankshaft removed:

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Endplate removal:

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Out of my 'box:

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Gear selector, output shaft and rear brake arm removed:

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This is going to be fun:

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There's always one:

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And out:

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It's getting hot in here:

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Output shaft bearing removal:

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My go-to socket for these jobs :) :

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All stripped including studs:

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Mag bearing and seals removed:

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Chaincase cover stripped:

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Hmm, caught that just in time I think:

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These circlip removers are Pony :roll: :

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Removing bearing track from crankshaft:

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A quick clean up after track removal:

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All ready for cleaning:

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Hope you like the pics.
Cheers
Jim :D
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Re: 1963 LI125 Engine Rebuild - UPDATE 5/11/17

Postby Danbretta » Sun Nov 05, 2017 6:32 pm

You've been busy Jim. It seems to be going well. You've made it look easy. I'm contemplating stripping mine down and checking it over. I picked up an Italian import earlier this year and have been tinkering with the body work damage before I look at the engine. I'll be following this thread for some inspiration and to learn something. I'm new to the scene and never worked on a lambretta before.

I look forward to your next update.

Dan.
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Re: 1963 LI125 Engine Rebuild - UPDATE 5/11/17

Postby andrewgc » Sun Nov 05, 2017 6:51 pm

great thread, many thanks for sharing
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Re: 1963 LI125 Engine Rebuild - UPDATE 5/11/17

Postby Nudger » Mon Nov 06, 2017 11:52 am

Yep - keep them pics coming!
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Re: 1963 LI125 Engine Rebuild - UPDATE 5/11/17

Postby Rich Oswald » Tue Nov 07, 2017 1:13 pm

Brilliant thread, thank you.
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Re: 1963 LI125 Engine Rebuild - UPDATE 5/11/17

Postby Cosmic Wizard » Fri Nov 10, 2017 11:02 pm

Little Update:

Just been sent this pic by my mate. He picked the casings up from the blaster's this afternoon :D

The other case (the really pitted one) is one of mine which will have its own build thread soon ;)

Stay tuned for an update on Wednesday as I'm at the NEC tomorrow.

As usual, thanks for the comments.
Cheers
Jim

Image
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Re: 1963 LI125 Engine Rebuild - Casings are Back 10/11/17

Postby Cosmic Wizard » Thu Nov 16, 2017 12:16 am

The rebuild has started :D

I spent an hour or so tonight fitting the silent mounts and cleaning the threads in the casing and all the studs. Not much, but it was a job that needed doing.

Stay tuned for the next update which will be at the weekend.
Cheers
Jim

Nice and clean:

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New mounts to be fitted:

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Studs prior to fitting:

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Studs and dowels fitted:

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Re: 1963 LI125 Engine Rebuild - Rebuild Has Started 15/11/17

Postby MickYork » Thu Nov 16, 2017 8:44 am

The casings look spot on.....who did the blasting/cleaning and any idea of what they used to clean them ?
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Re: 1963 LI125 Engine Rebuild - Rebuild Has Started 15/11/17

Postby Toddy » Thu Nov 16, 2017 1:20 pm

Just had a couple of Casings , Mags and Casing sides vapour blasted locally they came up great like yours , very happy with it
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Re: 1963 LI125 Engine Rebuild - Rebuild Has Started 15/11/17

Postby Cosmic Wizard » Wed Nov 22, 2017 11:16 am

Thanks for the comments guys :)

@MickYork - I can't remember what the company name is, but they are based on Canvey Island, Essex. My mate was in charge of the logistics lol.

I think it might've been a glass media as any dust that came out was reflective.

* Small Update *

I did a bit more at the weekend which was in the form of putting the gearbox back together.

I found the endfloat between the layshaft and the faceplate was out of tolerance (loose). The shim that was fitted was 2mm in thickness. I had one knocking about that was 2.2mm, so fitted that.

This brought the endfloat back into tolerance, but only just. This has stopped play tempoarily. I have ordered a few different sized shims which have now arrived, so I'll be back on the build at the weekend.

See you then
Jim :D
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