Lis 125 starting issues

[johnnyXS]

have you found the source of the leak yet Kris ?
I thought at first it might be a fuel leak from a stuck carb needle valve .
if fuel is leaking from the carb it could get sucked into the flywheel cowl and blown up into the engine cowling

[Kristof Lammy pie]

Hi.

I think the air leak is the u bend at the gasket possibly a stud has snapped. Not sure if the inlet is leaking but the carb definitely isn't.

I've been a bit side tracked with the purchase of a gp150

[johnnyXS]

Hi.


I've been a bit side tracked with the purchase of a gp150

you mad impetuous fool ..........here starts the madness

re the leak I meant the fuel bowl overflowing occasionally whilst you are riding . Its very common which is why Innocenti put a drain valve and pipe on the air filter hose . It could have happened prior to you cleaning the carb perhaps.

[Kristof Lammy pie]

That seems fine. I checked float bowl for damage and other isn't taking on any fuel and the needle seems new so all good there.

[bigbthesoulman]

check your choke cable, I bought my scooter had numerous starting issues,especially when hot,I took cable off found it was shorter than standard cable,so affectivley ,scooter started first or second kick from cold but everytime I sat on it put choke on flooded all the time,took me years to suss what was doing it lol, good luck

[johnnyXS]

soooo kris what was the cause of the leak ? we are all waiting here on tenterhooks

[Kristof Lammy pie]

Apologies, I've not touched it since the last update as I've been busy at work etc.

I've got the weekend as of tomorrow so I hope to drag it out of the garage and start stripping the exhaust off. Hopefully the u bend I've bought will fit the exhaust. Otherwise I might shelf the idea and buy a gt186 kit for it.

Kris

[Kristof Lammy pie]

So today I had a bit of time on my own so I removed the exhaust. Got the exhaust off and had a good look around and it clearly was a cheapo gasket failure and a very old rusty u bend.

I havent taken the cowl off yet but all appears good with the inlet manifold, head gasket and base gasket. So pretty pleased.

[Kristof Lammy pie]

So I've just checked old u bend with the new one I've bought and it's exactly the same. But a thought has occurred to me that maybe the old u bend was wrong in the first place and resulted in the exhaust not fitting correctly and causing the ths bad blow at the manifold.

Hmm! So I've decided to buy a new full exhaust. Can anyone suggest a good exhaust that will maximise the standard lis125 engine?

Cheers
Kris

[johnnyXS]

from what I've read it seems that it is very rare that any exhaust fits properly the first time without some fettling even matched pair U bend and exhaust.
if your exhaust is in good condition I would stick with what you've got and fit it with the new manifold.

Fit the new manifold with the new copper gasket and brass nuts but don't over-tighten or you run the risk of shearing the studs which would put you in a World of woe .
Then loose fit the exhaust with a new clamp and when its fitting well without needing any force to put it in the correct alignment ,then tighten all the nuts . That way the exhaust fixings will not be under stress and the vibration should'nt fracture the fixing tabs

If all that oil is coming out the cylinder exhaust port then there is something seriously wrong with your fuel mixture or you have a leaking crankcase seal which is the more likely.
Actually studying your photos it looks to me like either excess crankcase pressure is forcing the oil out of the crankcase breather ,( hole in your piston or rings are worn or broken), or ... your cover gasket is leaking

[Kristof Lammy pie]

Bloody hell ok.

Ok so I will clean up all the mess on the motor, check oil level. Then fit the old exhaust with the new u bend run it and see what happens,keeping an eye on any further leaks.

If the motor has to come out then it's a good excuse to get a kit on it.

[Storkfoot]

To me, looking on an iPhone, that looks entirely symptomatic of a leaking exhaust gasket. They do produce black gunge just like that when leaking.

A couple of points:

The exhaust. If it was me, I'd clean the inside with caustic soda if I was going to refit. It could well be all gunged up inside. I'd also make sure the mating surface was flat.

Fitting a kit. In what way do you believe this will resolve any issues? Again, if it was me I'd take the engine out and give it a thorough going over. Sticky's manual shows you how to do this very well

[Kristof Lammy pie]

I meant removing the motor, resolving the problem then fitting a kit for a little extra power, I should have explained myself better.

I will have a further investigation tomorrow and decide.

I'm not convinced that stripping the motor is essential just yet. The head and barrel gasket joints are very clean and dont appear to be leaking at all. The only visible leak is from the exhaust port as I've said.

Also we don't know how this was transported over here, I seem to remember it being stored on its side which would explain a lot of oil visible.

I will see what it's like tomorrow and update it on here.

[Kristof Lammy pie]

So I've gunked all the motor and cleaned the surface of the exhaust port. Wire brushed the threads on the studs and cleaned the exhaust.

I will put it back together tomorrow morning and take it for a spin.

I need to sort out the front end too as the front wheel is on the piss.

[johnnyXS]

I

Also we don't know how this was transported over here, I seem to remember it being stored on its side which would explain a lot of oil visible.

.

ahh I wasn't aware of that Kris . I don't know why but I assumed that you had been running it for a while.

I'll be keen to see how it goes over the weekend when you have the new manifold on

[Kristof Lammy pie]

No, apologies I've only just got it. It was imported from Italy and came over in a van.

It hasn't been used or started in over a year when I bought it but has only done 400km since a full a rebuild.

I will get it all back together check the oil level and see if I can start it.

[Kristof Lammy pie]

Right I've put the exhaust on and it's miles out as predicted. I then swapped the u bend with the old one and that's miles out too! So I think I've found my problem the exhaust and u bend aren't a match, causing it to blow badly

So the whole lot had come off again and I will get a new exhaust.

With it peeing down outside I thought I would remove the cowling and look at the head and barrel.

Taken the head off and the piston isn't holed but it's very oily with a small bit of carbon build up.

The head is marked 125 with an innocenti symbol, so its a totally standard motor.

Going to remove the inlet manifold now and prepare to remove the barrel I'm guessing the motor has to be lifted up a lot to remove it from the studs??

[dickie]

Take off the rear shock and the bumpstop so that the wheel can travel right up into the mudguard.

The barrel can be slid down the studs once you have done that.

[Kristof Lammy pie]

Cool, some lunch then I will have a go

[johnnyXS]

excellent progress Kris . Now at least you'll know the condition of the engine