LCGB Forums

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 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:

I like threads like this... Keep the posts coming....

Agree keep the updates coming

Yes, very interesting, don't think we've had an engine rebuild thread.

Also agree, always nice to follow a journey. Good luck.

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.

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?

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

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

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.

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!

Morning all, as promised, an update

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 I will update you all when they come back. Until then, have a few more pics

BTW, thanks for the comments

Loads of Oil:



A bit too big:





WTF?! :



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



Front sprocket removed and clutch removal tool ready to go:



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





Clutch basket removed:



Crankshaft removed:







Endplate removal:



Out of my 'box:



Gear selector, output shaft and rear brake arm removed:



This is going to be fun:



There's always one:



And out:



It's getting hot in here:



Output shaft bearing removal:



My go-to socket for these jobs :



All stripped including studs:



Mag bearing and seals removed:



Chaincase cover stripped:





Hmm, caught that just in time I think:



These circlip removers are Pony :



Removing bearing track from crankshaft:





A quick clean up after track removal:



All ready for cleaning:



Hope you like the pics.
Cheers
Jim

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.

great thread, many thanks for sharing

Yep - keep them pics coming!

Brilliant thread, thank you.

Little Update:

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

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

The rebuild has started

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:



New mounts to be fitted:







Studs prior to fitting:



Studs and dowels fitted:

The casings look spot on.....who did the blasting/cleaning and any idea of what they used to clean them ?

Just had a couple of Casings , Mags and Casing sides vapour blasted locally they came up great like yours , very happy with it

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