first rebuild fire-up advice please!

[Andie]

Thank you for the replies.

I stripped the carb again today, float out, blew through it all and rebuilt, tightened up the U-bend clamp some more and checked the electrics,re- set the plug gap and bumped it a few times, flooded so stripped it again - not much luck, until it finally bumped well with the choke closed, and now starts on kick

Left it for an hour and it still starts on kick with a little throttle (but not with choke.., so i'll look at that asap.
The carb needs dialling in, tick over a little high maybe, Etc, but quite pleased. Opening the choke does make the engine splutter and stop.



Thanks for the advice. Andrew

[CHRIS in MARGATE]

Well done that man.
Get it warmed up for 5 minutes and then you have 2 adjustments.
Tick over screw and idle mixture screw.
Turn up the tick over a little and then adjust mixture screw for highest tick over setting. It will vary as you turn the mixture in and out. Once that's done lower the tick over to a nice easy beat. Then rev it and be confident that the tick over speed returns immediately to that nice easy beat.
Sometimes you may have to rev it between adjustments.
I think you're nearly there.

Then importantly check that the plug is a nice brown...mocha some call it.

[mainstand]

I'd use regular fuel. Super unleaded is full of detergents designed to clean up the engine. Possibly not a good idea if you're trying to get it to bed in.

Oh, and treat yourself to some Rock Oil Groundsman. Same stuff, but cheaper.

What he said.

[GP240]

You say you have the 'Casatronic' fitted at 19degs. Should be static at around 24 and checked with a strobe to see it move to around 17degs when revved high.

[Warkton Tornado No.1]

You say you have the 'Casatronic' fitted at 19degs. Should be static at around 24 and checked with a strobe to see it move to around 17degs when revved high.

I agree with this, yet another contributor advising that timing is an important fundamental, following, what is after all a request for advice!

However, all attention would appear to be on carburetion as if everything will then come right.....

[Andie]

You say you have the 'Casatronic' fitted at 19degs. Should be static at around 24 and checked with a strobe to see it move to around 17degs when revved high.

I agree with this, yet another contributor advising that timing is an important fundamental, following, what is after all a request for advice!

However, all attention would appear to be on carburetion as if everything will then come right.....

Thank you both. My block was rebuilt elsewhere by a specialist and I have continued the rebuild from there, I don't actually know the timing set on the Electronic Ignition, I shouldn't have said 19 degrees as I wasn't told that; but i was told it was set good... sorry! I will have it all set by the real mechanic after the Easter Holidays, and have it fully checked over to ensure I haven't made any obvious schoolboy errors. There's a lot I don't know but I am happy to learn.

Thank you for the advice on how to set the timing myself, however I am not confident in my abilities yet.

Sorting out the carburation has enabled the engine to work, and she kicks over well now, and I am gently letting it bed in.

I do appreciate all advice offered here and over the last year and have taken it all on board, trying not to always hear what I want to hear! I don't reply to every post as I don't want to fill the forum with too many of my own postings but thank you again. Andrew

[GP240]

Andie, I hope I haven't jumped in too soon (with Ignition) whilst you have been playing with the carb, but to be honest, you have done pretty well so far.

If you buy yourself a 'timing disc' and 'strobe lamp' (and Sticky's book) I'm sure you could be easily talked thru how to set/check Ignition. If you do take it to be strobed, try and see how they do it, be something useful for the future.

All the best with your build.

[Andie]

Andie, I hope I haven't jumped in too soon (with Ignition) whilst you have been playing with the carb, but to be honest, you have done pretty well so far.

If you buy yourself a 'timing disc' and 'strobe lamp' (and Sticky's book) I'm sure you could be easily talked thru how to set/check Ignition. If you do take it to be strobed, try and see how they do it, be something useful for the future.

All the best with your build.

Thank you - no, not at all and all good. I need to learn how to set it myself - I've got Sticky's book, and I've watched the Rimini Video a few times. It looks quite a simple but lengthy procedure when they do it. Like many other jobs it seems a bit daunting at first. 12 months ago I was wary of changing a spark plug in case I threaded the cylinder head....

All the best! Andrew

[CHRIS in MARGATE]

Yep they're all correct. Setting the timing with a strobe is a wonderfully rewarding and satisfying job. It is not at all difficult.
If you do get round to checking it and you do adjust it you may have to then make some minute adjustments to the carburation, so don't go thinking something else has gone wrong.

[Warkton Tornado No.1]

I agree with this, yet another contributor advising that timing is an important fundamental, following, what is after all a request for advice!

However, all attention would appear to be on carburetion as if everything will then come right.....

I’ll offer up an apology as my last message was somewhat blunt.

Unfortunately, Grumpy Old Gits like me have learnt, often the hard way, that there are fairly mandatory functions of the Lambretta engine that must be set for the unit to work well.

One function that can be set, or checked, is the ignition.

Fortunately, instructions are there for the Casatronic ignition unit which makes it very concise. Many of the rest of us have to ‘guesstimate’ what to time our engines to because there is no precise setting as the engines were designed prior to the loss of higher octane fuels which incorporated lead as an anti-knocking agent.

Having said that, my own opinion is that fuel is fairly consistent dependent upon the supplier. Any fuel station that advertises its name & relies mainly on selling petrol & diesel fuel is much more likely to be a safer bet than to buy from than a Supermarket.

The best quality fuel for your Lambretta is likely to be a super unleaded from the likes of BP or Shell. It can’t be ‘too good’ & won’t be ‘bad’ whatever its constituent parts unless it has too greater a percentage of ingredients liable to harm the seals.

As for the two stroke oil to use there will be a variety of choice but a wild variation on what opinion the mix should be. Like modern fuels, the oils we use nowadays have changed dramatically since the engines were designed.

There appears to be a common practise of adding extra oil with a new engine build. That is a big mistake as it leans the carburetion.

Select oil & a mix ratio then try & stick with it for consistency.

There are many on this Forum that advocate a particular manufacture, type & mix of oil & you would do well to take on board their knowledge, particularly the rider/self tuners that cover fairly high mileages.

I really hope you enjoy gaining experience & knowledge of your Lambretta, but be warned. It becomes an addiction…..

[HxPaul]

"I really hope you enjoy gaining experience & knowledge of your Lambretta,but be warned.It becomes an addiction"

Amen to that.

My name is Paul and I'm a Lambretta,holic.

[Andie]

I really hope you enjoy gaining experience & knowledge of your Lambretta, but be warned. It becomes an addiction…..

Thank you Mr Warkton - no offense taken at all - your advice is always very concise, and welcome, and the reason I use this forum is that I can find first-hand advice from engineers like yourself who have the experience I lack. I could not have got so far on my build without it and, yes, I am finding the hours spent on understanding every aspect of my modest machine to be expanding somewhat!
I have been looking today at getting the neccesary tools to set the timing myself; maintaining and running a 50 + year old engine is so more than just riding it and I'm rewarded with each new task i can master.

Andrew

[Stevepshipley]

You are going to have so much fun with your new hobby, seriously. It really is rewarding learning and doing things for yourself and sometimes your cockups will be hysterical (for your mates).

[bluebob]

I had a cast iron 175 barrel with a jetex on when I bought it.45 pilot.erratic starting.ran poorly at low revs.upped it to 50 pilot.worked a treat.

[coaster]

I have just read through all this whole post and can see a lot of good advice and progress made, well done One thing I would add though is don't be afraid to rev it a bit on the stand, you won't do it any harm so long as you don't go mad and don't hold it wide open. Be gentle when you start rising it, a cast iron barrel requires careful running in

Also be aware that the correct starting procedure for any 2 stroke is with the throttle closed. A lot of people make the mistake of twisting the throttle as they kick but this had the effect of weakening the mixture and makes starting difficult.

Colin