Newbie desperate for help with LI 125

[harps2]

OK - just rebuilt my first 1962 LI 125 and come to the moment of truth - starting her up............... all wiring plugged in correctly, new points adjusted, and leads and plug all new - test for spark - great looks very strong, fit the new plug (which also has new 175 top end) coughs and splutters the starts for a few seconds then stops and nothing - checked spark again still fine but looks and smells like she is flooded now.
Left for an hour checked spark - OK fit plug and tried to kick over and this is where the PROBLEM starts -- - kick start going down but not returning (pulling back by hand) at first then getting harder and harder to kick over and FINALLY jams solid.
Took plug out and try to kick over - kick start goes down slowly at first and then after a few kicks returns to normal turning engine over fine (kickstart return no problem) and showing good spark with plug on side of engine!

QUESTION - what is going wrong when I fit plug and turn fuel on? - any help or suggestions would be greatly accepted.

Thanks again

Alan (frustrated Lammy newbie)

[Andie]

Hello Alan

I am not an expert but have you checked and topped up the oil in the crankcase?

I'm sure someone with more experience might advise - how intensive was your rebuild? is it a 125 with a new 175 top end fitted - are the rings properly seated? Have you replaced the gearbox and/or front sprocket ? Could it be the kickstart spring (doesn't sound like it...)?

carb floding is not unusual and you can generally empty the bowl by turning the tap off, removing the plug and kicking over a few times. When I fired mine the first time I flooded it constantly - a few carb strips and cleans and it was fine.


Good luck - Andrew

[harps2]

Hi Andrew - thanks for response - answers below

Yes Oil levels OK

Just 175 top end fitted - no sprockets changed and kickstart works and returns fine when kicking over with plug out!

OK to carb cleaning will give that a try.

It seems to be linked with the extra compression when the plug is screwed in so any more suggestions would be welcome.

[MickYork]

looks like you have 2 separate issues that are not related.

I'd take the crankcase side off and see what's fouling the kickstart. The kickstart coming up should not be a top end issue. There is a plunger which has a ratchet effect, catching on the way down but free on the way up......that sounds the area you want to be looking

The running/starting issue sounds like the carb. Have you tried with air filter off ? Is the choke working correctly ? basic things but they have to tested and eliminated.

Buy Sticky's Manual, loads of tips and invaluable when working on a Lambretta.

[harps2]

Hi Mick
You may be right about two issues and I was holding off taking side case until convinced this was the issue but what I can't get my head round is why the kickstart turns engine over ok and returns on Spring without problem when plug is out, this problem only occurs when I fit the plug !
This problem (1) then stops me from being able to try and start he engine so no real chance to check air filter/fuel flow etc - I have sticky's manual so will have a look through again to see if any similar problems mentioned - thanks for advice.

[MickYork]

With the plug in you are putting more strain in the kickstart area, this could cause something to twist/snag/etc.......just a thought

[harps2]

Sounds like logical thinking which I can not dispute, just hoped somebody had had similar problem and could direct me to the route cause ! - guess it's got to be side casing off and look for some evidence of the cause?

[Andie]

hope you get it sorted.

As a by-the-way I changed my front sprocket (125 gearing with 175 top end) to a 17T, on advice from the vendor, which raised it to a 4.99- 1 ratio.

edit/ I also fitted a new GP style crank to take the extra strain of the 175 (and facilitate a 12v Casatronic system). not that that sounds like an immediate problem.../edit

Andrew

[harps2]

OK - just rebuilt my first 1962 LI 125 and come to the moment of truth - starting her up............... all wiring plugged in correctly, new points adjusted, and leads and plug all new - test for spark - great looks very strong, fit the new plug (which also has new 175 top end) coughs and splutters the starts for a few seconds then stops and nothing - checked spark again still fine but looks and smells like she is flooded now.
Left for an hour checked spark - OK fit plug and tried to kick over and this is where the PROBLEM starts -- - kick start going down but not returning (pulling back by hand) at first then getting harder and harder to kick over and FINALLY jams solid.
Took plug out and try to kick over - kick start goes down slowly at first and then after a few kicks returns to normal turning engine over fine (kickstart return no problem) and showing good spark with plug on side of engine!

QUESTION - what is going wrong when I fit plug and turn fuel on? - any help or suggestions would be greatly accepted.

Thanks again

Alan (frustrated Lammy newbie)

STILL LOOKING FOR SOMEBODY WHO HAD SIMILAR PROBLEMS BEFORE I TAKE THE CASING OFF ?

[Digger]

It's a straightforward task to whip off the crankcase cover. It's time better spent than waiting for someone to second guess your problem.

Sorry if that sounds harsh but if you have a mechanical problem, and it seems likely that you have, you're going to need to get in there and sort it anyway.

If you provide your location there is quite likely to be a member local to you who offer assistance.

(Assuming that your in the UK).

[harps2]

Hi Digger - I hear what you are saying, my problem being everything works perfect when no plug in - kickstart goes down and returns great on spring thats why I am resisting as I dont know what to loook for when i get it off and I am not expecting it to be obvious?

[grandpa]

Hi harps2,
Agree with digger need chain case off.Probably kickstart plunger sticking. With no plug in engine is turning faster and plunger being thrown back, but with plug in speed of engine and gears is much less.You could of course try bump starting the machine if it runs Ok you will know it is just the kick start mechanism
Grandpa

[harps2]

Well you were right - casing off and problem found - kickstart shaft broken where it comes through the bronze bush (JUST LIKE THE PHOTO IN STICKY'S BOOK) - if you can give me some advice on best place to get a new one and anything I should be watching for on re-assembly again will all be appreciated !!

Thanks for pushing me to do disassy guys.

Alan

[HxPaul]

I find that SR are the best place to go.
http://www.scooterrestorations.com/lamb ... ft&x=3&y=5

[coaster]

Well you were right - casing off and problem found - kickstart shaft broken where it comes through the bronze bush (JUST LIKE THE PHOTO IN STICKY'S BOOK) - if you can give me some advice on best place to get a new one and anything I should be watching for on re-assembly again will all be appreciated !!

I've only just read through this thread and must say that I thought it would either be a broken shaft or a cracked boss on the casing brought on by the increased compression of the new top end and the additional kicking, sorry I didn't spot it sooner

Be sure you buy the right one, the shaft changed late in the production to make it stronger in the area where yours has broken. The later shafts can be fitted to earlier casings but about 2mm needs to be machined off the inside of the boss. That said, yours might have been modified already and if it hasn't then I think both types are available now anyway. You need to measure the length of the shaft to make sure.

Good shout about Scooter Restorations above btw, give them a call rather than trying to get the right online, they are very knowledgeable.

[Digger]

Well you were right - casing off and problem found - kickstart shaft broken where it comes through the bronze bush (JUST LIKE THE PHOTO IN STICKY'S BOOK) - if you can give me some advice on best place to get a new one and anything I should be watching for on re-assembly again will all be appreciated !!

Thanks for pushing me to do disassy guys.

Alan

Well done Alan.

[mickey c]

Whilst your are ordering the kick start shaft you might want to ask about jetting.
Have you done anything to the carb ? If not, you'll need to alter this. Lots of suggestions of carb sets for your engine on here.
Good luck with it but sounds like your are nearly on the road, thinking about jetting now might speed you up.